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FINAL  REPORT 
BASELINE  METEOROLOGY  AND  AIR  QUALITY 
IN  THE  UKIAH  DISTRICT 


scieNce  ApplicanoNS,  inc. 


Jfc  6~  IrW 


BUREAU  OF  LAND  MANAGEMENT 


m 

V,  / 


FINAL  REPORT 
BASELINE  METEOROLOGY  AND  AIR  QUALITY 
IN  THE  UKIAH  DISTRICT 


Submitted  to: 


Bureau  of  Land  Management 
Sacramento,  California 


Prepared  by: 

W.  P.  Lynott 

D.  Rykaczewski 

J.  Rodell 

H.  Frentz 

D.  Cover 

February  22,  1980 


147 

Denver,  Colo;  < 


Center 


JD 


SCIENCE  APPLICATIONS,  LA  JOLLA,  CALIFORNIA 

ALBUQUERQUE  •  ANN  ARBOR  •  ARLINGTON  .  ATLANTA  .  BOSTON  •  CHICAGO  •  HUNTSVILLE 

LOS  ANGELES  •  McLEAN  .  PALO  ALTO  •  SANTA  BARBARA.  SUNNYVALE  •  TUCSON 


P.O.  Box  2351.  1200  Prospect  Street,  La  Jolla,  California  92037 


TABLE  OF  CONTENTS 

Section  Page 

1.  INTRODUCTION  1 

2.  PHYSICAL  FEATURES  7 

3.  CLIMATOLOGY 13 

3.1  PRINCIPLES  OF  CLIMATOLOGY  13 

3.2  CLIMATIC  ZONES 24 

3.3  SOURCES  OF  CLIMATOLOGICAL  DATA 27 

3.3.1  Observations  and  Records 27 

3.3.2  Climatological  Data 28 

3.4  TEMPERATURE 32 

3.4.1  Mean  Temperature  Distribution  37 

3.4.2  Temperature  Extremes  40 

3.4.3  Frost-Free  Period  41 

3.5  PRECIPITATION 44 

3.5.1  Annual  Distribution  44 

3.5.2  Seasonal  Precipitation  46 

3.5.3  Snowfall 48 

3.5.4  Precipitation  Frequency  53 

3.6  PREVAILING  WINDS  56 

3.6.1  Annual  Wind  Distribution 56 

3.6.2  Seasonal  Wind  Distribution 60 

3.7  EVAPORATION  AND  RELATED  PARAMETERS  64 

3.7.1  Evaporation  and  Evapotranspiration  64 

3.7.2  Sky  Conditions 67 

3.7.3  Solar  Radiation 75 

3.8  OTHER  CLIMATIC  PARAMETERS  79 

3.8.1  Relative  Humidity  and  Dew  Point 79 

3.8.2  Severe  Weather 80 

3.8.3  Atmospheric  Pressure  93 

3.8.4  Visibility  and  Fog 98 

3.8.5  Ocean  Temperatures  108 

3.9  URBAN  EFFECT  UPON  METEOROLOGIC  PARAMETERS  Ill 

3.10  GENERAL  ASSISTANCE  IN  CLIMATIC  PROBLEMS  115 

3.11  GLOSSARY  OF  TERMS 115 


TABLE  OF  CONTENTS 
(Cont.) 

Section  Page 

4.    DISPERSION  METEOROLOGY  131 

4.1  INTRODUCTION 131 

4.2  PRINCIPLES  OF  DISPERSION  METEOROLOGY  133 

4.2.1  Principles  of  Turbulence  and  Diffusion  133 

4.2.2  Prevailing  Winds  139 

4.2.3  Atmospheric  Stability  146 

4.2.4  Mixing  Heights  and  Inversions  155 

4.2.5  Influence  of  Topography  on  Transport  and  Diffusion  .  .  156 

4.3  DATA  SOURCES 168 

4.4  PREVAILING  WINDS  172 

4.4.1  Wind  Roses 172 

4.4.2  Diurnal  Wind  Distribution 182 

4.4.3  Wind  Speed  Distribution 184 

4.4.4  Persistence  Analyses  193 

4.4.5  Trajectory  Analyses  194 

4.4.6  Winds  Aloft 194 

4.5  ATMOSPHERIC  STABILITY  198 

4.5.1  Seasonal  and  Annual  Stability  Distributions  198 

4.5.2  Diurnal  Stability  Distributions  204 

4.5.3  Stability  Persistence  207 

4.5.4  Stability  Wind  Roses 207 

4.6  MIXING  HEIGHTS  AND  INVERSIONS  212 

4.6.1  Mixing  Height 212 

4.6.2  Inversion  Types  and  Frequencies  219 

4.7  TYPICAL  AND  WORST-CASE  CONDITIONS  223 

4.7.1  Typical  Dispersion  Conditions  223 

4.7.2  Worst-Case  Dispersion  Conditions  223 

4.8  AIR  BASIN  ANALYSIS 228 

4.9  FIRE  WEATHER 232 

4.10  GENERAL  DISPERSION  MODELING  239 

4.10.1  Classes  of  Models  239 

4.10.2  Model  Suitability  and  Application  240 

4.10.3  The  Gaussian  Model  242 

4.11  ASSISTANCE  IN  DISPERSION  METEOROLOGICAL  PROBLEMS  270 

4.12  GLOSSARY  OF  TERMS 272 


TABLE  OF  CONTENTS 
(Cont.) 

Section  Page 

5.  BASELINE  AIR  QUALITY  EMISSION  LEVELS  284 

5.1  FORMATION  OF  AIR  POLLUTANTS 284 

5.1.1  Introduction 284 

5.1.2  The  Gaseous  Compounds  of  Carbon 284 

5.1.2.1  The  Hydrocarbons  290 

5.1.2.2  The  Oxygenated  Hydrocarbons  290 

5.1.2.3  The  Oxides  of  Carbon 295 

5.1.3  The  Gaseous  Compounds  of  Sulfur 304 

5.1.3.1  The  Sulfur  Oxides  304 

5.1.3.2  Reduced  Sulfur  Compounds  307 

5.1.4  The  Gaseous  Compounds  of  Nitrogen 309 

5.1.4.1    The  Oxides  of  Nitrogen  309 

5.1.5  Ozone  and  Oxidants 316 

5.1.6  Particulate  Matter  318 

5.1.7  Atmospheric  Chemistry  of  Air  Pollution  321 

5.2  AIR  POLLUTION  EFFECTS  ON  AIR  QUALITY  RELATED  VALUES  327 

5.3  BASELINE  AMBIENT  AIR  QUALITY  353 

5.4  POINT  AND  AREA  SOURCES  OF  THE  UKIAH  DISTRICT 368 

5.5  ASSISTANCE  IN  AIR  POLLUTION  PROBLEMS  377 

5.6  GLOSSARY  OF  TERMS 384 

6.  AIR  QUALITY  REGULATIONS 400 

6.1    EXECUTIVE  SUMMARY  400 

6.1.1  Background 400 

6.1.2  Permit  Rules  for  New  or  Modified  Sources 401 

6.1.2.1  Nonattainment  Areas  401 

6.1.2.2  Attainment  Areas  and  Prevention  of 
Significant  Deterioration  Review  401 

6.1.2.3  Role  of  the  Federal  Land  Manager  in  the 

Permit  Review  Process  402 

6.1.2.4  Role  of  the  Federal  Land  Manager  in 

Class  Redesignation  Procedures  404 

6.1.3  Visibility  Protection  404 

6.1.4  Emission  Standards  404 

6.1.5  State  Regulations  405 

6.1.5.1    Permit  Rules  405 


TABLE  OF  CONTENTS 
(Cont.) 

Section  Page 

6.2  THE  ROLE  OF  THE  FEDERAL  LAND  MANAGER 406 

6.3  HISTORY  OF  AIR  QUALITY  LEGISLATION 407 

6.4  SUMMARY  OF  THE  CLEAN  AIR  ACT  AMENDMENTS  OF  1977,  AND 

RELATED  REGULATIONS   410 

6.4.1  National  Ambient  Air  Quality  Standards  (NAAQS)   ...  410 

6.4.2  Designation  of  Attainment  Status  410 

6.4.3  State  Implementation  Plans  411 

6.4.3.1  Nonattainment  Areas  411 

6.4.3.2  Attainment  Areas  412 

6.4.4  Visibility  Protection  424 

6.4.5  Ozone  Protection  426 

6.5  STATE  AND  COUNTY  REGULATIONS  427 

6.5.1  State  Ambient  Air  Quality  Standards  427 

6.5.2  County  Regulations  427 

6.5.3  Permit  Rules 430 

6.5.3.1  Description  of  Model  Rule/Districts' 

Rules 430 

6.5.3.2  California's  Air  Conservation 

Program  (ACP)   431 

6.5.3.3  Emission  Regulations  432 

6.5.3.4  Burning  Regulations  440 

6.6  GLOSSARY  OF  TERMS 448 

7.    MONITORING  RECOMMENDATIONS  454 

7.1  GENERAL  REQUIREMENTS  454 

7.2  INSTRUMENTATION 457 

7.2.1  General  Requirements  457 

7.2.2  Meteorological  Instruments  460 

7.2.3  Air  Quality  Instruments 473 

7.2.3.1  Particulates  473 

7.2.3.2  Continuous  Gas  Analyzers  477 

7.2.4  Monitoring  Program  Operation  482 

7.3  UKIAH  DISTRICT  MONITORING  REQUIREMENTS  492 

7.4  GLOSSARY  OF  TERMS 496 


TABLE  OF  CONTENTS 
(Cont.) 

APPENDIX  A  -  ISOPLUVIAL  OR  RAINFALL  INTENSITY  ANALYSES  OF  CALIFORNIA 
APPENDIX  B  -  MONTHLY  SEA  SURFACE  TEMPERATURES  OFF  COASTAL  CALIFORNIA 
APPENDIX  C  -  SEASONAL  AND  ANNUAL  MIXING  HEIGHTS  DURING  THE  MORNING  AND 

AFTERNOON  HOURS  IN  THE  CONTIGUOUS  UNITED  STATES 
APPENDIX  D  -  BASELINE  AIR  QUALITY  IN  THE  UKIAH  DISTRICT 
APPENDIX  E  -  LONG-TERM  BASELINE  AIR  QUALITY  IN  THE  UKIAH  DISTRICT 
APPENDIX  F  -  1976  -  EMISSIONS  DATA  FOR  THE  UKIAH  DISTRICT  POINT  SOURCES 
APPENDIX  G  -  1976  -  EMISSIONS  DATA  FOR  THE  UKIAH  DISTRICT  AREA  SOURCES 
APPENDIX  H  -  SUMMARY  ANALYSIS  -  UNITED  STATES  COURT  OF  APPEALS,  D.  C.  CIRCUIT 

JUNE  18,  1979  DECISION  -  ALABAMA  POWER  COMPANY,  ET  AL.  V.  USEPA  ET  AL. 


1.   INTRODUCTIOI 


This  document  provides  baseline  data  on  meteorology  and 
air  quality  impacting  BLM  lands  in  California,  and  specifically, 
in.  the  Ukiah  District.  Air  quality  considerations  have  become 
important  factors  in  the  establishment  and  execution  of  Federal 
land  management  policies.  As  with  any  resource,  an  assessment  of 
current  air  quality  and  meteorological  data  must  be  performed  to 
determine  the  present  environmental  baseline  conditions. 

BLM  manages  approximately  16.5  million  acres  in  Cali- 
fornia as  depicted  in  Figure  1-1.  Figure  1-2  depicts  BLM  admin- 
istered lands  in  the  Ukiah  District.  Figure  1-2  is  also  provided 
as  Overlay  A.  In  addition,  gridded  township  and  range  locations 
for  the  Ukiah  District  are  provided  on  Figure  1-3.  This  map  can 
be  used  directly  with  the  color  coded  overlays  provided  for  key 
parameters . 

The  purpose  of  this  document  is  to  provide  information 
which  can  be  used  with  other  resource  information  to  facilitate 
land  use  planning  decisions  for  the  Ukiah  District. 


f  ol  1  owi  ng 


The  specific  objectives  of  this  work  effort  include  the 


Describe  the  climatology,  dispersion  meteorology 
and  air  quality  in  the  Ukiah  District  utilizing 
available  historical  data. 


Assess  the 
1  and  area s 


emission  sources  which  influence  all 
in  the  Ukiah  District. 


BLM 


•  Assess  past  and  present  air  quality  and  meteor- 
ological monitoring  activities  and  provide  mon- 
itoring recommendations  for  the  Ukiah  District. 

•  Provide  a  complete  bibliography  of  available  infor- 
mation and  a  glossary  of  all  technical  terms. 

The  above  provides  a  brief  synopsis  of  the  objectives  of  this 
report.  The  document  is  intended  for  use  by  BLM  personnel  in  all 
activities  involved  in  the  management  of  BLM  administered  lands. 


This  document  uses  a  graphics  intensive  approach  in  the 
presentation  of  the  meteorological  and  air  quality  baseline  for 
BLM  lands  in  the  Ukiah  District.  The  data  base  which  has  been 
used  to  develop  this  document  comprises  that  available  in  pub- 
lished form  from  governmental,  academic,  and  private  institutions 
within  the  state.  These  sources  of  data  are  summarized  in  the 
appropriate  sections  for  dispersion  meteorology,  climatology,  air 
quality,  and  emissions. 


Figure  1-1 

BLM  Lands  in  the  Ukiah  District 

and  the  State  of  California 


CRESCENT /* 
CITY  \ 

DEL  NORTE 


60 

-I 


MILES 


BUREAU  OF  LAND 
MANAGEMENT  DOMAIN 


MENDOCINO 


LAKE 


COLUSA 

UKIAH*     UT^A^^nr^T 

LJ        YV/LAKE  P0RT' 


X               SONOMA     'v£/L_ 

A/A]  WOODLAND 
,\ NAPAVJ.                   • 

\      El        W 

ru\y/%,  yol° 

X^SANTA  ROSA  H? 

^napaTsolano 

11* 

J     J      FAIRFIELD 

)     MARIN 

SAN  RAFAEL   • 

Figure  1-2 

BLM  Lands   in  the  Ukiah  District 

60 


SAN  RAFAE 


Figure  1-3 
Gridded  Township  (N-S)  and  Range  (E-W) 
Locations  in  the  likiah  District 


The  report  presents  data  which  represent  meaningful 
(i.e.,  long-term)  and  representative  time  periods.  The  primary 
climatic  parameters  such  as  temperature  and  precipitation  are 
based  on  a  minimum  of  ten  years  of  record  and  have  been  updated 
through  1976.  For  the  secondary  climatic  parameters,  e.g.  evap- 
oration, shorter  periods  of  record  were  used  due  to  poor  data 
availability;  however,  the  most  recent  available  data  are  pre- 
sented . 


The  dispersion  meteorological  analyses  are  based  on  five 
or  more  years  of  data  for  the  primary  parameters,  i.e.,  wind 
speed,  wind  direction,  atmospheric  stability  and  mixing  height. 
The  actual  period  of  record  varies  for  many  stations  depending 
upon  the  period  for  which  summarized  data  are  available  from  the 
National  Climatic  Center  (NCC).  In  addition,  other  sources  of 
data  which  significantly  contributed  to  the  analysis  were  used 
although  these  consisted  of  shorter  periods  of  record. 

Baseline  air  quality  levels  in  the  Ukiah  District  are 
based  on  1975  data,  while  frequencies  of  violations  utilize  1977 
information.  Emissions  data  presented  in  the  report  are  based 
upon  1976  inventories.  And  finally,  pollutant  attainment  status 
analyses  have  incorporated  the  most  recent  1979  decisions. 

Data  are  presented  in  the  text  in  a  graphics  intensive 
manner  with  heavy  dependence  upon  charts,  tables,  figures  and 
overlays.  The  purpose  of  this  manner  of  presentation  is  to 
facilitate  the  use  of  the  data  by  BLM  personnel.  A  key  aspect  of 
the  graphical  approach  includes  the  use  of  color  coded  overlays 
for  key  parameters.  Figures  which  depict  conditions  throughout 
the  Ukiah  District  are  scaled  such  that  they  can  be  used  in 
conjunction  with  the  overlays  provided  in  the  report  jacket,  in 
order  to  better  grasp  the  interactive  nature  of  key  parameters. 


can 

The 

1  ang 

pers 

prov 

hand 

for 

cl  i  m 

i  n  t 

ronm 

grpu 

i  mpa 

tail 

i  mpa 

sis 


The  results  of  the  analyses  provided  in  this  docu 
be  used  by  BLM  personnel  for  a  multitude  of  applicati 
document  has  been  written  in  straightforward  and  simpli 
uage  such  that  it  can  be  used  by  all  levels  of  BLM  techn 
onnel.  A  sufficient  review  of  basic  principles  has 
ided  throughout  the  text  such 
book  for  training  purposes, 
making  a  first  cut  analysis 
atological  problems.  In  addition,  the  information  conta 
his  document  is  suitable  for  use  in  the  development  of  E 
ental  Statement  sections.  Some  of  the  data  provides  b 
nd  information  suitable  for  the  environmental  setting 
ct  sections.  However,  the  reader  is  cautioned  that  a 
ed  analysis  of  major  problem  areas,  such  as  the  poten 
ct  of  new  pollutant  sources,  would  require  additional  an 
and  analytical  review  beyond  that  contained  in  this  docum 


that  it  can  also  be  used 
It  provides  an  excellent 
for  specific  air  quality 


ment 
ons  . 
stic 
i  ca  1 
been 
as  a 
base 
and 
i  ned 
nv  i  - 
ac  k- 
and 
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ent . 


Finally,  in  addition  to  its  uses  as  a  training  handbook 
and  for  use  in  Environmental  Statements,  this  document  can  be 
used  for  overall  planning  purposes  by  BLM  land  managers.   This  is 


one  of  the  major  intents  for  publishing  the  document.  It  is  felt 
that  the  information  contained  herein  will  provide  suitable 
information  on  which  one  can  base  judgments  relative  to  the 
optimum  utilization  of  BLM  lands  in  terms  of  such  potential 
alternatives  as  agriculture,  forest  management  and  energy  devel- 
opment, as  these  relate  to  the  air  resource. 

This  report  is  intended  as  an  environmental  baseline 
document  suitable  for  use  in  the  administration  of  BLM  lands. 
Recommendations  have  been  provided  in  the  text  concerning  the 
need  for  additional  data  to  adequately  describe  the  environmental 
baseline,  i.e.,  air  quality  and  meteorology  in  certain  portions 
of  the  Ukiah  District.  Monitoring  would  be  required,  as  well  as 
additional  analyses,  prior  to  making  final  decisions  relative  to 
major  potential  sources  of  air  pollutants  on  BLM  lands.  Recom- 
mendations contained  in  this  document  for  additional  data  col- 
lection and  for  additional  analyses  must  be  seriously  considered 
by  BLM  planners  during  any  final  decision-making  process.  In 
addition,  the  information  contained  herein  is  current  as  of  the 
publication  date,  but  care  must  be  taken  while  using  the  docu- 
ment, to  ensure  that  all  information  and  materials  are  up  to 
date,  particularly  with  regard  to  air  quality  regulations.  For 
this  reason,  it  is  recommended  that  this  document  be  updated  on 
an  annual  basis  by  qualified  technical  personnel. 


Separate  reports  have  also  been  prepared  for  the 
Riverside,  Redding,  Susanville,  Bakersfield  and  Fol som  Districts. 
Reference  should  be  made  to  the  appropriate  reports  for  air 
quality  and  meteorological  baseline  conditions  for  BLM  lands 
outside  of  the  Ukiah  District  in  California. 


2.   PHYSICAL  FEATURES 


The  following  discussion  provides  a  review  of  the  major 
terrain  and  vegetation  features  in  the  Ukiah  District.  Ukiah  is 
comprised  of  numerous  terrain  and  vegetation  types  as  indicated 
inthe  accompanying  figures.  Elevations  range  from  sea  level  to 
over  7,000  feet  above  mean  sea  level  (MSL)  in  the  Siskiyou  Moun- 
tains.  Vegetation  types  range  from  marshlands  to  Douglas  Fir. 


The  major  vegetation  types  as  classified  by  Durrenberger 
(1967)  are  depicted  in  Figure  2-1.  This  figure,  illustrates  the 
variety  of  vegetation  types  found  in  the  coastal  and  interior 
mountainous  regions.  In  coastal  Northern  California,  vegetation 
types  primarily  include  Douglas  Fir,  fir  and  plains  grass.  The 
mountainous  portions  of  the  Ukiah  District  are  characterized  by 
fir  and  woodlands.  The  Central  Valley  area  is  primarily  charac- 
terized by  plains  grass  and  marshlands. 

As  indicated  earlier,  these  vegetation  types  are  dis- 
tinctly influenced  by  terrain  considerations.  Figure  2-2  pro- 
vides a  review  of  major  terrain  features  in  the  State  of  Cali- 
fornia. Figure  2-3  illustrates  the  Ukiah  District  terrain.  This 
figure  is  also  included  as  Overlay  B. 

The  Ukiah  District  includes  all  or  parts  of  eleven 
counties  which  comprise  the  northwestern  portion  of  the  State  of 
California.  The  terrain  of  the  District  exhibits  considerable 
variation  ranging  from  the  coastline  of  Marin,  Sonoma,  Mendocino, 
Humboldt  and  Del  Norte  Counties  to  the  rugged  terrain  of  the 
Coast  Ranges.  Elevations  rapidly  increases  with  inland  distance 
from  the  Coast  in  all  portions  of  the  District  with  the  exception 
of  the  extreme  south.  In  the  extreme  northwest,  elevations 
rapidly  increase  with  rugged  terrain  in  Del  Norte  and  Siskiyou 
Counties,  particularly  in  the  Siskiyou,  and  further  inland,  and 
the  Klamath  Mountains.  Some  of  the  highest  elevations  in  the 
District  are  located  in  Del  Norte  and  Siskiyou  Counties  in  the 
rugged  terrain  of  the  Six  Rivers  National  Forest  and  further 
inland  in  the  Siskiyou  National  Forest.  Further  south  in 
Humboldt  County  the  trend  towards  rugged  terrain  with  inland 
progression  increases,  however,  elevations  do  not 
idly.  Elevations  in  most  of  the  Humboldt  County 
between  two  and  four  thousand  feet. 


rise  as  ra  p- 
are  generally 


The  northwest  is  drained  by  several 
including  the  Klamath  and  the  Eel  Rivers, 
inland  extent  of  the  District  increases  and 
Lake,  Colusa,  Yolo,  Solano,  Napa,  Sonoma  and 
District  coastal  areas  traverses  the  Coast 
portions  of  the  Sacramento  Valley  in  Colusa,  Yolo  and  Solano 
Counties.  In  Mendocino  County,  the  trend  exhibited  further  north 
continues  with  the  terrain  becoming  fairly  rugged  with  inland 
progression.  However,  elevations  continue  to  decrease  with  most 
elevations  between  one  and  three  thousand  feet.   A  major  valley 


maj  or  ri  ver  systems 

Further  south  the 

includes  Mendocino, 

Marin  Counties.   The 

Ranges  and  i  ncl udes 


I  Redwood 
I  Douglas  Fir 

mm  Fir 

[:'£•:';:]  Pine-Douglas  Fir-Fir 

Pine 

Lodgepole-l/Vhitebark  Pine 
|///n  Pinon  Pine— Juniper 


Figure  2-1 
Major  Vegetation  Types 
in  California 

Source:  "Patterns  on  the  Land"  Robert  W.  Durrenberger 

8 


ELEVATIONS 
14495 


Figure  2-2 
California  Topography 


ELEVATIONS 


ARCATA 


6000 

3000 
1500 

® 

500 
0 

W.  SACRAMENTO 


Figure  2-3 
Ukiah  District  Topography 


10 


system  exists  in  the  middle  of  Mendocino  County  along  the  drain- 
age flow  of  the  Russian  River.  This  valley  includes  the  city  of 
Ukiah,  the  district  office  for  the  Ukiah  District.  Lake  County 
includes  much  of  the  Coast  Range  and  is  the  center  of  much  geo- 
thermal  activity.  Clear  Lake  is  located  in  this  county  and  is 
the  largest  standing  body  of  fresh  water  in  the  Uk i ah"  Di str i ct . 
La-ke  County  is  characterized  by  rugged  forested  terrain  in  the 
north  with  elevations  approaching  7,000  feet  in  the  Mendocino 
National  Forest.  Southward  progression  in  the  County  exhibits  a 
generally  decreasing  elevation.  Sonoma  and  Marin  Counties  are 
generally  characterized  by  the  valley  floor  of  the  Santa  Rosa  and 
Petal  urn a  Rivers  as  well  as  the  Pacific  terminus  of  the  Russian 
River.  Major  cities  located  in  the  valley  include  Santa  Rosa, 
Novato  and  San  Rafael.  The  mountains  of  Sonoma  and  Marin 
Counties  are  generally  characterized  as  low  rolling  hills  with 
elevations  generally  less  than  2,000  feet.  Napa  county  contains 
the  southern  portion  of  the  Coast  Ranges.  Further  progression  to 
the  south  leads  to  the  major  break  in  the  Coast  Ranges  in  the 
State  of  California  through  the  San  Francisco-Oakland  area.  Napa 
Valley  is  the  center  of  much  wine  activity  and  contains  the 
second  largest  standing  body  of  water  in  the  district,  Lake 
Berryessa.  Finally,  the  eastern  three  counties  of  the  Ukiah 
District  include  Colusa,  Yolo  and  Solano  which  are  in  the 
Sacramento  Valley  with  the  exception  of  the  extreme  western 
areas.  These  counties  are  characterized  by  relatively  flat 
terrain  with  slowly  decreasing  elevations  reaching  a  minimum 
along  the  Sacramento  River. 

Local  terrain  plays  a  major  role  in  determining  regional 
climatology.  Therefore,  a  properly  scaled  overlay  (Overlay  B) 
displaying  the  Ukiah  District  topographic  features  is  provided 
with  this  report  in  order  that  terrain  features  can  be  compared 
with  averages  (isopleths)  of  the  important  climatic  parameters. 


11 


1.    Du r r e n b er g er  ,  Robert  W._ 

Press  Books,   Palo  Alto, 
1967. 


BIBLIOGRAPHY 

Patterns 


on  the  Land 


California,   Second 


National 
Printing, 


12 


3.   CLIMATOLOGY 

This  section  is  designed  to  characterize  the  prevailing 
climate  of  the  Ukiah  District  as  well  as  to  describe  the  physical 
processes  that  determine  regional  climate.  Long-term  manifes- 
tations of  weather  are  best  described  by  regional  -and  local 
an-alyses  of  the  numerous  climatic  parameters,  i.e.,  temperature, 
precipitation,  winds,  evaporation  and  ev apotranspi rat i on  ,  sky 
conditions,  dew  point  and  humidity,  pressure  distributions, 
severe  weather  and  many  others.  The  following  sections  shall 
describe  the  various  climatic  statistics  pertinent  to  the  area  . 

Color  coded  overlays  for  selected  key  climatic  summaries 
are  provided  to  facilitate  the  correlation  of  the  primary  cli- 
matic variables  in  particular  geographic  areas.  Much  of  the 
enclosed  graphical  material  is  properly  scaled  to  the  overlay 
dimensions. 


3.1 


PRINCIPLES  OF  CLIMATOLOGY 


E  nergy 

The  energy  expended  in  atmospheric  processes  is  orig- 
inally derived  from  the  sun.  This  transfer  of  energy  from  the 
sun  to  the  earth  and  its  atmosphere  is  the  result  of  radiational 
heat  by  electromagnetic  waves.  The  radiation  from  the  sun  has 
its  peak  of  energy  transmission  in  the  visible  range  (0.4  to  0.7 
microns)  of  the  electromagnetic  spectrum  but  renergy  in  the 
ultraviolet  and  infrared  regions  as  well.  The  greatest  part  of 
the  sun's  energy  is  emitted  at  wave  lengths  between  0.1  and  30 
microns.  Some  of  this  radiation  is  reflected  from  the  tops  of 
clouds  and  from  the  land  and  water  surfaces  of  the  earth.  The 
general  term  for  this  reflectivity  is  the  albedo.  For  the  earth 
and  atmosphere  as  a  whole,  the  albedo  is  36  per  cent  for  mean 
conditions  of  cloudiness  over  the  earth.  This  reflectivity  is 
greatest  in  the  visible  range  of  wavelengths.  When  light  (or 
radiation)  passes  through  a  volume  containing  particles  whose 
diameter  is  smaller  than  the  wavelength  of  the  light,  scattering 
of  a  portion  of  this  light  takes  place.  Shorter  wavelengths 
scatter  most  easily,  which  is  the  reason  the  scattered  light  from 
the  sky  appears  blue.  Sunlight,  near  sunrise  and  sunset,  passes 
through  a  greater  path-length  of  the  atmosphere  and  appears  more 
red  because  of  the  increased  scattering  of  shorter  wave  lengths. 
Absorption  of  solar  radiation  by  some  of  the  gases  in  the  atmos- 
phere (notably  water  vapor)  also  takes  place.  Water  vapor, 
although  comprising  only  3  per  cent  of  the  atmosphere,  on  the 
average  absorbs  about  six  times  as  much  solar  radiation  as  all 
other  gases  combined.  Consequently,  the  amount  of  radiation 
received  at  the  earth's  surface  is  considerably  less  than  that 
received  above  the  atmosphere. 

The  earth  also  radiates  energy  in  proportion  to  its 
temperature  according  to  Planck's  law.  Because  of  the  earth's 
temperature,  the  maximum  emission  is  about  10  microns,  which  is 


13 


in  the  infrared  region  of  the  spectrum.  The  gases  of  the  atmos- 
phere absorb  some  wave  length  regions  of  this  radiation.  Water 
vapor  absorbs  strongly  between  5.5  and  7  microns  and  at  greater 
than  27  microns  but  is  essentially  transparent  from  8  to  13 
microns.  Carbon  dioxide  absorbs  strongly  between  13  and  17.5 
microns.  Because  the  atmosphere  absorbs  much  more  of  the  terres- 
trial radiation  than  solar  radiation,  some  of  the  heat  energy  of 
the  earth  is  conserved.   This  is  the  "greenhouse"  effect. 

Figure  3.1-1  shows  the  amount  of  solar  radiation  absorb- 
ed by  the  earth  and  atmosphere  compared  to  the  long  wave  radia- 
tion leaving  the  atmosphere  as  a  function  of  latitude.  The  sine 
of  the  latitude  is  used  as  the  abscissa  to  represent  area.  It 
can  be  seen  that  if  there  were  no  transfer  of  heat  poleward,  the 
equatorial  regions  would  continue  to  gain  heat  and  the  polar 
regions  would  continue  to  cool.  However,  temperatures  do  remain 
nearly  constant  because  of  this  poleward  transfer  of  heat.  The 
required  transfer  of  heat  across  various  latitudes  is  given  in 
Table  3.1-1. 

Table  3. 1-1 
Required  Flux  of  Heat  Toward  the 
Poles  Across  Latitudes  (10    calories  per  day)  *  ' 


Lc 

1 1  i  t  u  d  e  ( 

0 
10 
20 
30 
40 
50 
60 
70 
80 
90 

°) 

Fl  ux 
0 

4.05 
7.68 
10.46 
11.12 
9.61 
6.68 
3.41 
0.94 
0 


1.   Source:  H.  G.  Houghton,  "On  the  Annual  Heat  Balance  of  the 
Northern  Hemisphere." 

The  General  Circulation 

The  previous  section  has  indicated  the  necessity  of 
transfer  of  heat  from  the  warm  equatorial  regions  to  the  cold 
polar  regions  in  order  to  maintain  the  heat  balance  of  the  atmos- 
phere. This  thermal  driving  force  is  the  main  cause  of  atmos- 
pheric motion  on  the  earth.  The  portion  of  the  earth  near  the 
equator  acts  as  a  heat  source  and  the  polar  regions  as  a  heat 
sink.  The  atmosphere  functions  as  a  heat  engine  transforming  the 
potential  energy  of  heat  difference  between  tropics  and  poles  to 
kinetic  energy  of  motion  which  transports  heat  poleward  from 
source  to  sink. 


14 


tec 


*X> 


•OMTO*       SO 

/lANGim  \ 

\ BTV } 


>oc 


A 

• 

\ 

\ 

m  X  40  X       »C      K   «C 

tINl       O'       IATITU0I 


A  Solar  Radiation  Absorbed  by  Earth  and  Atmosphere 
B  Long  Wave  Radiation  Leaving  the  Atmosphere 


Figure  3.1-1 
Global  Radiation  Balance 


15 


tor 

unt  i 

surf 

defl 

fore 

and 

erly 

(  zon 

equa 

and 

Figu 

i  mpo 

wi  nd 

lies 

t  i  on 

caus 

t  i  on 

and 

the 

heat 

t  ran 


If  the 
would  move 
1  the  time 
ace  current 
ect s  winds 
flow  from 
flow  from  the 
The  resul t 


earth  did  not  rotate,  rising  air  above  the  equa- 
poleward  continually  giving  up  some  of  its  heat 
it  would  sink  and  return  toward  the  equator  as  a 
Since  the  earth  does  rotate,  the  Coriolis  force 
in  the  northern  hemisphere  to  the  right.   There- 
the  tropics  toward  the  poles  become  more  westerly 
poles  toward  the  equator  tends  to  become  east- 
is  that  more  of  the  motion  is  around  the  earth 


al  )  with  less  than  one-tenth  of  the  motion  between  poles  and 
tor.    The  meridional   (along  meridians,  i.e.,  between  poles 
equator)  circulation  is  broken  into  three  cells  shown  in 
re  3.1-2  according  to  Palmen's  (1951)  model.   Of  considerable 
rtance  is  the  fact  that  the  jet  stream  (i.e.,  a  core  of  high 
s  usually  50  miles  per  hour  or  more  embedded  in  the  wester- 
in  the  high  troposphere)  does  not  remain  long  in  one  posi- 
but  meanders  and  is  constantly  changing  position.    This 
es  changes  in  the  location  of  the  polar  front  and  perturba- 
s  along  the  front.   The  migrating  cyclones  (counterclockwise) 
anticyclones  (clockwise)  resulting,  play  an  important  part  in 
heat  exchange,  transferring  heat  northward  both  as  a  sensible 
and  also  latent  heat.    Also,  a  small  amount  of  heat  is 
sferred  poleward  by  the  ocean  currents. 


Temperature 


Variation  with  Height 

In  the  lower  region  of  the  atmosphere  extending  from  the 
surface  to  about  2  km.  (6600  ft.),  the  temperature 
distribution  varies  considerably  depending  upon  the 
character  of  the  underlying  surface  and  upon  the  amount 
of  radiation  at  the  surface.  Within  this  region,  the 
temperature  may  decrease  with  height  or  it  may  actually 
increase  with  height  (inversion).  This  region,  commonly 
called  the  lower  troposphere,  is  the  region  of  greatest 
interest  in  air  pollution  meteorology.  The  remainder  of 
the  troposphere  is  typified  by  a  decrease  of  temperature 
with  height  on  the  order  of  4  to  8  C  per  km.  The  strat- 
osphere is  a  region  with  isothermal  or  slight  inversion 
lapse  rates.  The  layer  of  transition  between  the  tro- 
posphere and  stratosphere  is  called  the  tropopause.  The 
tropopause  varies  in  height  from  about  8  to  20  km 
(26,000  to  66,000  ft.),  and  is  highest  near  the  equator, 
lowest  near  the  poles.  Figure  3.1-3  and  3.1-4  indicate 
typical  temperature  variations  with  height  for  two 
latitudes  for  summer  and  winter  in  the  troposphere  and 
1 ower  stratosphere . 

Above  the  stratosphere,  the  high  atmosphere  has  several 
layers  of  differing  characteristics.  A  rough  indication 
of  the  variation  of  temperature  with  height  including 
the  high  atmostphere  is  shown  in  Figure  3.1-5. 


16 


JOlAI      TIOPOPAUSt 


fOLAl      FIONT      JET 


TtOPICAL 
THOPOPAUSE 


Figure  3.1-2 
General  Circulation  Model  (after  Palmen) 


17 


23 


IS    — 


HEIGHT 
(KM.)         10    t— 


•  •0 


.40  -20  0 

TtMHtATUlf    {*C) 


VAtkMON  Of  TlMKfcATUK    WITH  HltCHT  AT  3D*  NOtTM  CATfTVOC 

Figure  3.1-3 


MCICHT 

<KM.) 


20 


IS 


10 


UMMfl         — 


••0  -60  .40  -20  0 

TlMfflATUlC    (*C» 


20 


VAIUTOH    Of    TlMKtATUM  WITH  HIICMT  AT  «0»  NOMH  UTITVW 

Figure  3.1-4 


18 


Horizontal  Variation 

Temperature  also  varies  horizontally  particularly  with 
latitude,  being  colder  near  the  poles  and  warmer  near 
the  equator.  However,  the  influence  of  continents  and 
oceans  have  considerable  effects  on  modifying  tempera- 
tures. The  continents  have  more  extreme  temperatures 
(continental  climate)  becoming  warmer  in  summer  and 
colder  in  winter,  whereas  the  oceans  maintain  a  more 
moderate  temperature  (marine  or  maritime  climate)  year- 
round  . 


Winds 


Wind  is  nothing  more  than  air  in  motion  and  although  it 
is  a  motion  in  three  dimensions,  usually  only  the  horiztontal 
component  is  considered  in  terms  of  direction  and  speed.  In  the 
free  atmosphere  (above  the  effects  of  the  earth's  friction),  two 
forces  are  important.  The  first,  the  Coriolis  force,  is  due  to 
the  tendency  for  the  air  to  move  in  a  straight  path  while  the 
earth  rotates  underneath  thereby  deflecting  the  wind  to  the  right 
in  the  northern  hemisphere  and  to  the  left  in  the  southern  hemis- 
phere. The  deflection  is  proportional  to  the  wind  velocity,  and 
decreases  with  latitude.  The  other  force  affecting  the  horizon- 
tal wind  component  is  the  pressure  gradient  force,  which  directs 
flow  from  high  to  low  pressure.  Above  the  friction  layer,  in  re- 
gions where  the  lines  of  constant  pressure  (isobars)  are  straight 
and  the  latitude  is  greater  than  20°,  the  two  forces  are  in 
balance  (See  Figure  3.1-6)  and  the  wind  blows  parallel  to  the 
isobars.  Where  isobars  are  curved,  the  forces  are  not  in  bal- 
ance, their  resultant  producing  a  centripetal  acceleration.  In 
:he  lowest  portion  of  the  atmosphere  frictional  drag  (not  due  to 

but  to  eddy  viscosity)  slows  down  the  wind 
the  Coriolis  force  is  proportional  to  the  wind 
Coriolis  force.  The  balance  of  forces  under 
shown  in  Figure  3.1-7.  It  will  be  noted  that 
under  frictional  flow  the  wind  has  a  component  across  the  isobars 
toward  lower  pressure. 


molecular  friction 
speed  ,  and  beca  use 
s  peed  ,  red  uces  the 
frictional  flow  is 


Anticyclones  and  Cyclones 

Migrating  areas  of  high  pressure  (anticyclones)  and  low 
pressure  (cyclones)  and  the  fronts  associated  with  the  latter  are 
responsible  for  the  day  to  day  changes  in  weather  that  occur  over 
most  of  the  mid-latitude  regions  of  the  earth.  The  low  pressure 
systems  in  the  atmospheric  circulation  are  related  to  perturba- 
tions along  the  jet  stream  (the  region  of  strongest  horizontal 
temperature  gradient  in  the  upper  troposphere  and  consequently 
the  region  of  strongest  winds)  and  form  along  frontal  surfaces 
separating  masses  of  air  having  different  temperature  and  mois- 
ture characteristics.  The  evolution  of  a  low  pressure  system  is 
accompanied  by  the  formation  of  a  wave  in  the  circulation  pat- 
tern. This  develops  further  into  a  warm  front  and  a  cold  front 
both  moving   around  the   low  in   a   counterclockwise   (cyclonic) 


19 


»« 


IB 


MO 


•  I 1 » T T" 1  t 


Ainruof 


»       . 


ONOt*«( 


TtMMIATUM      (*K) 


SO 


Figure  3.1-5 
General  Variation  of  Temperature  with  Height  Throughout 

the  Atmosphere 


LOW 


C«A.OKNT   K»Cf 


1 

> 

GfOSTtO^HC 

WIN& 

< 

■ 

COtOltS 
K)tCE 


MICH 


r  -  2 


»  •  i 


UJ 


low 


FE&slwi 

OAAOKNT   KStCf 


♦  WIMC 

WICTlON     L^^""*"^ 

ETON  ♦     i^    FOtCt 


«KTON  ♦     ♦•    *OtCI 

COtOLB    POtCE 


MICH 


r  -  J 


r  -  i 


r  ♦ 


Figure  3.1-6 
Balance  of  Forces  in 
the  Upper  Atmosphere 


Figure  3.1-7 
Balance  of  Forces  in  the 
Lower  (Friction  Layer)  Atmosphere 


20 


sense.  The  life  cycle  of  a  typical  cyclone  is  shown  in  Figure 
3.1-8.  The  cold  front  is  a  transition  zone  between  warm  and  cold 
air.   The  cold  air  typically  is  moving  toward  and  over  the  area 


previously  occupied 
si  opes  from  1/50  to 
air  from  retreating 
1/-100  to  1/300  due 
edge  of  the  front  . 
sect  ion  through  both 

Air  Masses 


by  warm  air.  Cold  fronts  generally  have 
1/150.  Warm  fronts  separate  advancing  warm 
cold  air  and  have  slopes  on  the  order  of 
to  the  effects  of  friction  on  the  trailing 
Figure  3.1-9  illustrates  a  vertical  cross 
a  warm  and  a  cold  front. 


Air  masses  are  frequently  divided  by  frontal  systems  and 
are  usually  classified  according  to  the  source  region  of  their 
recent  history.  Air  masses  are  classified  as  maritime  or  conti- 
nental to  indicate  origin  over  the  ocean  or  land,  and  arctic, 
polar,  or  tropical  depending  principally  on  the  latitude  of 
origin.  Air  masses  are  modified  by  vertical  motions  and  radia- 
tion upon  the  surfaces  over  which  they  move. 

Condensation,  Clouds,  and  Precipitation 

Condensation  of  water  vapor  upon  suitable  condensation 
nuclei  in  the  atmosphere  causes  clouds.  (Table  3.1-2  indicates 
the  relative  sizes  of  different  particles.)  Large  hygroscopic 
nuclei  wil  condense  water  vapor  upon  them  even  before  saturation 
as  opposed  to  crystallization  nuclei  which  promote 
of  ice  crystals,  at  the  expense  of  small  water  drop- 
a  supercooled  cloud.  Of  course,  only  a  small  propor- 
clouds  produce  rain.  It  is  necessary  that  droplets 
size  so  that  they  will  have  appreciable  fall  velocity 
prevent  complete  evaporation  of  the  drops  before  they 
reach  the  ground.  Table  3.1-3  indicates  the  distance  of  fall  for 
different  size  drops  before  evaporation  occurs.  Growth  of  water 
droplets  into  rain  drops  large  enough  to  fall  is  thought  to 
originate  predominately  with  the  large  condensation  nuclei  which 
grow  larger  as  they  fall  through  the  cloud.  The  presence  of  an 
electric  field  in  clouds  generally  promotes  the  growth  of  rain- 
drops. 


i  s  reached  , 
the  growth 
lets  within 
t  i  o n  of  all 
increase  in 
and  al so  to 


Particles 


Table  3. 1-2 
Sizes  of  Particles 

Size  (microns)* 


Smal 1  ions 
Medium  ions 
Large  ions 
Aitken  nuclei 
Smo  ke  ,  ha  ze  ,  d  ust 


less  than  10 


-3 


10"3  to  5  X  10~2 

5  X  10"2  to  2  X  10"1 


5  X  10 
10"1  to  2 


to  2  X  10 


-1 


21 


Figure  3.1-8 
Idealized  Development  of  a  Low-Pressure  (cyclone)  System 


22 


F»Om  sm 


"   U    F10M  S 


2, 


Cross  Section  Through  a  Cold  Front 
and  a  Warm  Front 

Figure  3.1-9 


Key: 


Ci 

-  Cirrus 

Cb  - 

■  Cumulonimbus 

Cs 

-  Cirrostratus 

Ns  ■ 

-  Mimbostratus 

Cu 

-  Cumulus 

Sc  - 

-  Stratocumulus 

Ac 

-  Altocumulus 

As  ■ 

-  Altostratus 

23 


Particles 


Table  3.  1-2  (cont'd) 
Si  zes  of  Particles 

Size  (microns)* 


Large  condensation  nuclei 
Giant  condensation  nuclei 
Cloud  or  fog  dropl et  s 
Drizzle  drops 
Rai  ndrops 


2  X  10"1  to  10 
10  to  30 
1  to  100 
100  to  500 
500  to  4000 


*1  Micron  =  3.94  X  10 


-5 


inches 


Tabl e  3. 1-3 
Distance  of  Fall  Before  Evaporation  (Findeison  1939) 
Radius  (microns)*      Distance  of  Fall 


1 

10 

100 

1000 

2500 


1.3  x  10"   inches 
1.3  i  nc  hes 
492  feet 
2  6.1  miles 
174  miles 


*1  Micron  =  3.94  X  10 


-5 


inches 


3.2 


CLIMATIC  ZONES 


California  encompasses  a  vast  amount  of  territory  and 
offers  a  wide  variety  of  climate  types,  ranging  from  hot,  arid 
desert  climates  to  cold,  moist  mountain  climates.  It  is  there- 
fore advantageous  to  present  the  climatic  analysis  in  terms  of 
climatic  zones.  Figure  3.2-1  depicts  the  general  climatic  zones 
for  California  in  each  of  the  six  BLM  districts.  Overlay  C 
presents  the  climatic  zones  for  the  Ukiah  District, 
topography  as  well  as  latitude  plays  a  major  role  in 
mi  nation  of  the  characteristic  climate  of  the  various 
regions . 


Reg  ion  a  1 
the  deter- 
C  a  1  i  f  o  r  n  i  a 


The  Ukiah  District  is  comprised  of  a  complete  cross- 
section  of  the  various  types  of  topographic  features  present  in 
California  as  described  in  Section  2  and  includes  three  of  the 


24 


LEGEND: 


S5&S    COASTAL 


^Mm   COASTAL  MOUNTAIN 


CENTRAL  PLAIN 


#&>]    INTERIOR  MOUNTAIN 


N.E.  MOUNTAIN 


DESERT 


-.r=z^rZ  RIVERSIDE-  ..  needles 
—   DISTRICT  - 


SAN  BERNARDINO— - 


..=■■  PARKER  DAM 


LOS  ANGE 


li^j&;v:~-;V-RIVERSIDE  •:%?»: r:.jz. r     —     I 


Figure  3.2-1 
California  Climatic  Zones 


BLYTHE 


OCEANSIDE 


..-•   '  '_:'-  EL  CENTRO 


SAN  DIEGOi#; 


25 


major  climatic  subdivisions  or  zones  existing  in  the  State. 
These  include  the  Coastal,  Coastal  Mountain  and  Central  Climatic 
Zones  ( CZ)  . 

The  Coastal  CZ  includes  most  of  the  area  between  the 
coastline  and  the  various  coastal  ranges  below  elevations  of 
approximately  1500  feet  MSL.  The  Coastal  CZ  experiences  a  dis- 
tinctly maritime  climatic  regime  which  is  characterized  by 
substantial  annual  precipitation,  a  modest  range  in  the  average 
and  diurnal  temperatures  and  fairly  strong  onshore  winds.  In 
California,  the  Coastal  CZ  also  experiences  a  Mediterranean  style 
climate  with  a  distinct  winter  rainy  season. 

The  Coastal  Mountain  CZ  experiences  similar  climatic 
conditions  to  those  at  lower  coastal  elevations.  However, 
throughout  the  Coastal  and  Coastal  Mountain  CZ's,  local  terrain 
features  play  a  distinct  role  in  determining  winds  speeds  as  well 
as  wind  direction.  Rainfall  tends  to  be  more  variable  depending 
upon  the  exposure  of  the  higher  terrain  and  the  associated  oro- 
graphic enhancement  or  suppression  of  precipitation  amounts. 
Westward  facing  slopes  experience  increased  rainfall  while  east- 
ward or  leeward  facing  terrain  experiences  a  distinct  "rain- 
shadow"  effect  with  lower  rainfall  amounts.  Temperatures  at 
higher  elevations  tend  to  be  more  variable  than  those  along  the 
immediate  coastline.  Finally,  wind  speeds  tend  to  be  higher  in 
mountainous  regions  and  become  less  influenced  by  local  effects 
at  the  highest  levels. 

The  southeastern  portion  of  the  Ukiah  District  comprises 
a  part  of  the  Central  Plain  CZ.  While  some  variability  exists  in 
terms  of  climatic  conditions  across  this  area,  the  region  is 
generally  characterized  by  modest  rainfall  and  larger  seasonal 
and  diurnal  temperature  ranges.  The  observed  differences  in  the 
annual  climate  in  the  Central  Plain  CZ  are  largely  a  function  of 
latitude  although  this  portion  of  the  district  is  fairly  small 
with  only  modest  climatic  differences.  The  climatic  variability 
observed  within  this  small  portion  of  Ukiah  District  is  due 
largely  to  proximity  to  the  major  break  in  the  Coastal  Ranges  in 
the  San  Francisco  -  Oakland  area  commonly  known  as  the  Carquince 
Straits.  Temperatures  tend  to  be  more  moderate,  precipitation 
amounts  greater  and  winds  stronger  in  the  southern  portion  of  the 
Central  Plain  CZ  within  the  Ukiah  District  due  to  the  maritime 
influence  exhibited  in  this  region.  On  a  typical  summer  day, 
Vallejo  and  Benicia  will  be  considerably  cooler  than  Williams 
located  some  eighty  miles  to  the  north. 

Latitude  also  plays  an  very  important  role  in 
determining  the  local  climate  throughout  the  State  of  California. 
Areas  located  to  the  north  experience  a  higher  frequency  of 
migratory  storm  systems  during  the  winter  season  and  hence, 
heavier  rainfall.  This  is  also  the  case  within  the  Ukiah 
District  with  Eureka  and  Crescent  City  receiving  considerably 
more  rainfall  than  Santa  Rosa  and  San  Rafael  located  further  to 
the  south  . 


26 


3.3 


SOURCES  OF  CLIMATOLOGICAL  DATA 


It  is  necessary  in  the  consideration  of  most  climato- 
logical  problems  to  obtain  meteorological  information.  Frequent- 
ly, a  special  observational  program  must  be  initiated  as  will  be 
discussed  in  more  detail  in  Section  7.  However,  there  are  also 
many  situations  where  current  or  past  meteorological  records  from 
a  Weather  Service  station  will  suffice.  The  following  outline 
provides  a  brief  insight  into  the  types  of  observations  taken  at 
Weather  Service  stations  and  some  of  the  summaries  compiled  from 
this  data.  The  discussion  also  serves  to  describe  the  bulk  of 
the  published  data  sources  used  in  the  Ukiah  District  analysis. 
Many  other  data  sources  used  in  this  report  are  noted  in  the 
bibliography  as  appropriate. 


3.3.1 


Observations  and  Records 


Surface 


First  Order  Stations 

There  are  100  Weather  Bureau  stations  where  24  hourly 
observations  are  taken  daily.  The  measurements  taken 
are:  dry  bulb  temperature  and  wet  bulb  temperature  (from 
which  dew  point  temperature  and  relative  humdity  are 
calculated),  pressure,  wind  direction  and  speed,  cloud 
cover  and  visibility.  These  observations  are  trans- 
mitted each  hour  on  weather  teletype  circuits  and  are 
entered  on  a  form  with  one  day  to  each  page.  The  orig- 
inal is  sent  to  the  National  Climatic  Center  (NCC)  in 
Asheville,  North  Carolina,  and  a  duplicate  is  maintained 
in  the  station  files.  Each  station  also  maintains  a 
cl imatol og i cal  record  book  where  certain  tabulations  of 
monthly,  daily,  and  hourly  observations  are    recorded. 

Second  Order  Stations 

These  stations  usually  take  hourly  observations  similar 
to  the  first  order  stations  above  but  not  throughout  the 
entire  24  hours  of  the  day. 

Military  Installations 

Many  military  installations,  especially  Air  Force  Bases, 
take  hourly  observations.  These  are  transmitted  on 
military  teletype  circuits  and  therefore  not  available 
for  general  use.  No  routine  publications  of  these  data 
is  done.  Records  of  observations  are  sent  to  NCC  where 
special  summaries  can  be  made  by  use  of  punched  cards. 

Supplementary  Airways  Reporting  Stations 
These  stations  are  located  at  smaller  airports.  Obser- 
vations are  not  taken  at  regular  intervals,  usually 
being  taken  according  to  airline  schedules.  These 
observations  are  not  published  and  are  not  available  on 
punched  cards.  Original  records,  however,  are  sent  to 
the  NCC. 


27 


Cooperative  Stations 


Ther 

most 

take 

mini 

are 

orig 

cl  i  m 

CI  im 

stat 

data 

v  at  i 

are 

meas 


e  are  about  10,000  of  these  stations  manned,  for  the 
part,  by  volunteer  observers.  The  observations  are 
n  once  each  day  and  consist  generally  of  maximum  and 
mum  temperatures  and  24  hour  rainfall.  Otrservat  i  on  s 
recorded  on  a  form  with  one  month  to  a  page.   The 

carbon  sent  to  the  state 


i  nal   is  sent  to  NCC ,  a 
atologist  (prior  to  the 
atologist  Positions),  and 
ion.    A  few  cooperative 
on  evaporation  and  wind, 
ons  are    taken  only  a  few 


termination  of  the  State 

a  carbon  maintained  at  the 

stations  have  additional 

However,  the  wind  obser- 

inches  off  the  ground  and 


of  use  mainly 
urement s . 


in  connection  with  the  evaporation 


Fire  Weather  Service  Stations 

There  are  a  number  of  special  stations  maintained  during 
certain  times  of  the  year  in  forested  regions  where 
measurements  of  wind,  relative  humidity,  and  cloud  cover 
are  taken.  These  are  generally  not  on  punched  cards  nor 
are  they  summarized. 


Upper  Air 


There  are  between  60  and  70  stations  in  the  contiguous 
United  States  where  upper  air  observations  are  taken  twice  daily 
(at  0000  GMT  and  1200  GMT)  by  radiosonde  balloon  and  radio  direc- 
tion-finding equipment.  The  measurements  taken  include  tempera- 
ture, pressure,  relative  humidity  and  wind  speed  and  direction  at 
several  levels.  These  observations  are  transmitted  to  teletype 
and  original  records  are  sent  to  NCC  where  these  data  are  pub- 
lished. Since  these  data  are  collected  primarily  to  determine 
large  scale  meteorological  patterns  and  have  relatively  little 
refinement  in  the  lower  2  to  3  thousand  feet  of  the  atmosphere, 
they  are    of  limited  use  in  air  pollution  meteorology. 


3.3.2 


Cl imatol og  i  cal  Data 


There  are  a  number  of  routine  and  special  publications 
available  from  the  Superintendent  of  Documents,  U.S.  Government 
Printing  Office,  Washington,  D.C.,  20402,  that  are  useful  in  air 
pollution  evaluation.  A  number  of  these  are  listed  in  Price  List 
48,  available  from  the  Superintendent  of  Documents. 

Routinely  Prepared  Data 

•     Daily  Weather  Maps  -  Weekly  Series 

The  charts  in  this  4-page,  weekly  publication  are  a 
continuation  of  the  principal  charts  of  the  former 
Weather  Bureau  publication,  "Daily  Weather  Map."  All  of 
the  charts  for  1  day  are  arranged  on  a  single  page  after 
being  copied.  They  are  copies  from  operational  weather 
maps  prepared  by  the  National   Meteorological   Center, 


28 


National 
presents 
EST. 


Weather   Service.    The   Surface   Weather  Map 
station  data  and  the  analysis  for  7:00  a.m. 


The  500-Millibar  Height  Contour  chart  presents  the 
height  contours  and  isotherms  of  the  500-millibar  sur- 
face at  7 : 00  a.m.  EST . 

The  Highest  and  Lowest  Temperatures  chart  presents  the 
maximum  and  minimum  values  for  the  24-hour  period  ending 
at  1:00  a.m.  ,  EST. 

The  Precipitation  Areas  and  Amounts  chart  indicates  by 
means  of  shading,  areas  that  had  precipitation  during 
the  24  hour  period  ending  at  1:00  a.m.,  EST. 

Local  Climatological  Data  (LCD) 

These  data  are  published  individually  for  each  station 

and  include  3  issues  discussed  below. 

Monthly  Issue  LCD 

This  issue  gives  daily  information  on  a  number  of  mete- 
orological variables  and  monthly  means  of  temperature, 
heating  degree  days,  pressure  and  precipitation.  Also 
tabulated  are  observations  at  3-Hourly  Intervals  (obser- 
vations for  each  hour  of  the  day  were  discontinued  after 
December  31,  1964).  This  publication  is  usually  avail- 
able between  the  10th  and  15th  of  the  following  month. 

LCD  Supplement  (monthly) 

This  issue  is  available  for  stations  having  24  hourly 
observations  daily  until  December  31,  1964  when  pub- 
lication was  discontinued.  For  air  pollution  investi- 
gations, Tables  B,  E,  F,  and  G  would  be  of  greatest 
interest  (Frederick,  1964).  The  Supplement  is  usually 
available  from  20  to  40  days  after  the  end  of  the  month. 

LCD  with  Comparative  Data  (annual) 

This  issue,  published  annually,  has  a  table  of  clima- 
tological data  for  the  current  year  and  a  table  of 
normals,  means,  and  extremes  for  a  longer  period  of 
record.  This  issue  is  usually  available  between  45  and 
60  days  after  the  end  of  the  year. 

Northern  Hemisphere  Data  Tabulations 

This  publication,  issued  daily,  contains  approximately 
30  pages  of  surface  synoptic  observations  and  upper  air 
observations.  The  surface  data  are  for  one  hour  only 
(1200  GCT).  In  this  publication,  the  radisonde  infor- 
mation is  of  principal  interest  in  air  pollution  mete- 
orol ogy. 

Climatological  Data  -  National  Summary 

This  publication  of  approximately  50  pages,  issued 

monthly,   contains   a   narrative   summary  of   weather 


29 


conditions,  climatological  data  (similar  to  those  given 
in  each  station's  LCD)  in  both  English  and  metric  units, 
mean  monthly  radiosonde  data,  and  solar  radiation  data. 
Also  included  are  a  number  of  maps  of  the  United  States 
showing  spatial  distribution  of  temperature,  precipita- 
tion, solar  radiation  and  winds.  The  mean  "radiosonde 
and  solar  radiation  data  are  of  main  interest  in  this 
publication  for  air  pollution  meteorology. 

Climatological  Data  (by  State) 

This  summary ,  issued  monthly  and  annually,  contains  data 

primarily  on  temperature  and  precipitation.   This  will 

provide  only  limited  information  to  the  air  pollution 

meteorologist. 

Selected  Climatic  Maps 

This  publication  consists  of  30  U.S.  maps  of  various 
meteorological  parameters  such  as:  maximum  and  minimum 
temperature,  heating  and  cooling  degree  days,  precipita- 
tion, relative  humidity,  solar  radiation,  and  surface 
wind  roses  for  January  and  July  together  with  the  annual 
wind  rose.  Wind  data  are  presented  for  74  locations 
within  the  contiguous  U.S.  A  list  of  the  basic  Climatic 
Maps  from  which  the  generalized  maps  of  this  publication 
are  taken  is  included. 


Summar i  es 


Summary  of  Hourly  Observation 

This  series  of  publications,  Climatography  of  the  United 
States,  No.  82-,  Decennial  Census  of  United  States 
Climate,  has  been  prepared  for  over  100  Weather  Bureau 
stations  where  24  hourly  observations  are  recorded.  One 
issue  is  prepared  for  each  station,  and  where  the  period 
of  record  is  sufficient,  the  ten  year  period  1951  -  1960 
has  been  considered.  For  other  stations,  the  5  year 
period  1956  -  1960  has  been  summarized.  This  series 
supersedes  the  series,  "Climatography  of  the  United 
States"  No  30-,  a  5  year  summary  published  in  1956. 

Climatic  Guide 

This  series  of  climatological  publications  contains  a 
wealth  of  climatological  information  useful  to  the  air 
pollution  meteorologist  fortunate  enough  to  have  had  one 
prepared  for  his  city.  Of  major  interest  to  air  pollu- 
tion meteorologists,  are  tables  of  wind  frequencies, 
solar  radiation  and  degree  days. 

Climatic  Summary  of  the  United  S t a t e s - S u p p 1  erne nt  for 
1931  -  1952. 

This  summary,  issued  by  state,  contains  tables  of  month- 
ly and  annual  precipitation,  snowfall,  and  temperature 
for  stations  within  the  state. 


30 


Terminal  Forecasting  Reference  Manual 

This  manual  ,  publ  i  shed  by  stat  i  on  ,  cTe  scribes  the  weather 
conditions  at  the  station,  and  contains  information  on 
local  topography,  visibility  effects  due  to  fog  and 
smoke,  ceiling,  precipitation,  special  weather  occur- 
rences, and  mean  wind  and  visibility  conditions.  Num- 
erous charts  are  included  summarizing  the  above  ele- 
ments. Of  special  interest  are  surface  wind  roses  by 
month  and  a  wind  rose  chart  related  to  restricted  visi- 
bility conditions.  A  topographic  and  smoke  source  map 
for  the  station  is  included. 

Key  to  Meteorological  Records  Documentation 
Thi  s  series  of  publications  was  establ i  shed  to  provide 
guidance  to  those  making  use  of  observed  data.  A  recent 
addition  to  this  series  No.  4.11,  "Selective  Guide  to 
Published  Climatic  Data  Sources  prepared  by  U.S.  Weather 
Bureau"  (1969)  is  extremely  useful  to  anyone  contemplat- 
ing use  of  climatic  data. 

The  series  No.  1.1  title  "Substation  History"  and  issued 
by  state  contains  information  regarding  history  of 
station  locations,  type  and  exposure  of  measuring  in- 
struments, location  of  original  meteorological  records, 
where  published,  and  dates  of  first  and  last  observa- 
tions . 


31 


3.4 


TEMPERATURE 


Temperature  is  a  critical  climatological  parameter  for 
land  management  activities.  Temperature  and  related  parameters, 
such  as  the  length  of  the  growing  season,  greatly  influence  the 
suitability  of  land  areas  for  utilization  in  agriculture,  forest- 
ry and  grazing. 


Ambient  temperatures  are 
factors,  including  the  following: 


determined  by  a  multitude  of 


as 


and 


The  intensity  and  duration  of  solar  radiant  energy 

The  degree  of  depletion  of  this  energy  by  reflection, 

scattering  and  absorption  in  the  atmosphere 

The  surface  a  1 bedo 

The  physical  characteristics  of  the  surface  such 

terrain  types 

The  local   heat  budget  in  terms  of  terrestrial 

atmospheric  radiation 

Heat  exchanges  involved  in  water  phase  changes 

Importation  or  advection  of  warm  or  cold  air  masses 

by  horizontal  air  movement 

Transport  of  heat  upward  or 

currents  caused  by  natural 

ani  cal  t urbul ence 


downward  by  vertical  air 
convection  and/or  mech- 


In  the  United  States,  temperature  is  most  commonly 
measured  in  degrees  Fahrenheit  (  F),  however,  there  is  an  in- 
creasing trend  towards  the  use  of  degrees  Centigrade  (  C).  For 
this  reason,  temperature  data  and  analyses  presented  in  this 
report  are  in  degrees  Fahrenheit,  with  Table  3.4-1  providing  a 
summary  of  temperature  conversion  information  for  aid  in  the 
usage  of  both  systems. 

Temperature  data  are  available  for  numerous  stations  in 
California.  For  this  reason,  key  stations  have  been  used  to 
represent  the  various  climatic  zones  in  the  district  in  an  effort 
to  limit  the  amount  of  data  analysis  necessary  to  present  the 
required  information.  Once  again,  the  Ukiah  District  has  been 
divided  into  three  key  climatic  zones  in  which  temperature  is 
fairly  homogeneous.  For  each  of  these  regions,  data  from  the 
selected  key  stations  has  been  used  to  describe  temperature 
characteristics.  Data  provided  for  each  of  the  key  stations 
includes  monthly  and  annual  means,  mean  maximum,  mean  minimum  as 
well  as  the  record  high  and  low  temperatures. 

Figure  3.4-1  presents  the  three  climatic  zones  super- 
imposed on  the  district  map  with  selected  station  locations  for 
which  temperature  data  are  available.  Tables  3.4-2  through  3.4-4 
summarize  the  temperature  statistics  for  these  stations  in  each 
climatic  zone.  Section  3.2  briefly  summarizes  temperature  and 
other  climatic  characteristics  of  each  climatic  zone. 


32 


Table  3.4-1 


TEMPERATURE  CONVERSIONS 

Temperature?  in  this  publication  are  given  in  degrees  Fahrenheit  (°F) .   The  Celsius 
(C)  temperature  scale,  also  called  Centigrade,  is  used  in  most  countries  of  the 
world.   A  temperature  conversion  scale  is  shown  on  the  left,  note  that  the  values 
coincide  only  at  the  -40  degree  mark. 


°F 

°C 

i. 

212   - 

100 

(Water 
\  Boils 

194 

90 

176 

80 

158 

70 

140 

60 

2. 

134 

rG7J  U.S.  Record 
56-7>High 

122 

50 

104 

40 

86   - 

30 

68   - 

20 

50 

10 

32 

0 

1. 
(  Water 
\  Freezes 

14 

-10 

-4 

-20 

-2? 

-.   -30 

-40 

-40 

1  Scales 
^Coincide 

-58 

-50 

-76 

-60 

3. 
(  U.S.  Record 

-94 

-70 

\  Low 

-112 

-80 

-130 

-90 

-148 

-   -100 

The 
°C 

;  standard  formulas  to  convert 
to  °F  are  shown  below: 

°F  to 

°C  and 

op 

=  9/5  °C  h 

•  32 

°C 

=  5/9  (°F 

-32) 

• 

Atlernate,  easy  to  remember  conversion 
fol low : 

methods 

°F 

=  9/5  (°C 

+  40)  -40 

°C 

=  5/9  (°F 

+  40)  -40 

To  use  the  alternate  conversion 
converting  from  one  scale  to  the 

formulas  for 
other : 

(a) 

add  40  to  the  value  to  b 

e  converted 

(bj 

multiply 
(5/9  for 
(9/5  for 

that  sum  by  the 
°F  to  °C) 
°C  to  °F) 

fract  ion : 

(c0 

subtract 

40  from  the  pro 

duct 

For  exa 

mple,  to  convert  68°F  to 

°C: 

(a) 

add  40: 

68+40  =  108 

(b) 

multiply 
5/9x108'  = 

the  sum  by  5/9 
=  60 

(°F  to 

°C)  : 

(c) 

subtract 

40:    60-40  =  20 

(d) 

answer : 

68°F  =  20°C 

1.  Under  Standard  Sea  Level  Pressure 

2.  Greenland  Ranch,  CA  -  July  10,  1913 

3.  Rogers  Pass,  Montana  -  January  20,  1954 


33 


JCRESCEN 
fcn 


COASTAL  MOUNTAIN 


CENTRAL  PLAIN 


SACRAMENTO 


SANRA 


Figure  3.4-1 
Temperature  Stations  for  the  Ukiah  District 


34 


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3.4.1 


Mean  Temperature  Distribution 


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The  data  presented  in  'the  figures  and  tables  in  this 

ion  provide  generalized  information  for  BLM  lands  located 

in  each  of  the  study  regions.    However,  temperature  is  a 

able  which  is  subject  to  microclimatological  effects  and  the 

al  temperature  at  a  given  location  will  depend  upon  several 

ables  as  previously  indicated.   The  data  show  that  var iabili- 

mong  stations  within  a  particular  region  is  fairly  modest  and 

the  average  values  provided  in  the  summary  figures  can  be 

with  a  good  degree  of  confidence.   Caution  when  using  these 

es  is  warranted  when  the  location  of  interest  varies  signifi- 

ly  from  the  elevation  of  the  key  stations  or  if  a  particular 

tion  experiences  important  micro-scale  effects  (e.g.,  anoma- 

ground  cover  conditions). 


Annual  Average 

Figure  3.4-2  provides  the  mean  annual  temperature  dis- 
tribution for  the  Ukiah  District  and  also  appears  as  Overlay  D. 
The  figure  shows  a  modest  6°F  range  in  mean  annual  temperature 
across  the  region  from  a  low  of  54°F  along  most  of  the  northern 
coastal  areas  to  a  maximum  of  just  over  60°F  in  the  northeast 
portion  of  the  Central  Plains  CZ.  Temperatures  are  uniform  along 
coastal  locations  showing  the  strong  maritime  influence  of  the 
Pacific  Ocean  on  ambient  temperatures  in  this  area.  Temperatures 
show  very  little  variation  with  a  gradual  increase  with  inland 
progression  in  the  southern  portion  of  the  District.  The  de- 
creased influence  of  the  Pacific  Ocean  in  the  Central  Plain 
portion  of  the  Ukiah  District  in  the  lee  of  the  Coast  Ranges  is 
evident  from  the  somewhat  increased  mean  annual  temperatures. 

Mean  maximum  and  mean  minimum  temperature  data  are 
summarized  in  Figures  3.4-3  through  3.4-5  for  the  three  major 
climatic  zones  in  the  Ukiah  District  on  a  monthly  basis.  The 
influence  of  the  Pacific  Ocean  on  coastal  and  coastal  mountain 
temperature  characteristics  can  be  noted  with  the  figures  which 
provide  a  comparison  between  the  climatic  zones.  Coastal  regions 
experience  a  modest  15°F  temperature  increase  from  winter  to 
summer  while  Central  Plain  locations  experience  a  25°F  differ- 
ence . 

Mean  Maximum 

During  the  months  of  December  and  January,  maximum 
temperatures  range  from  the  low  50's°F  at  Eureka  to  the  upper 
50.'s°F  at  Ukiah  and  Santa  Rosa  (See  Figure  3.4-4.)  During  the 
summer,  temperatures  show  considerable  variation  ranging  from  the 
low  60's°F  at  Eureka  to  the  low  90's°F  at  Ukiah,  Davis  and 
Sacramento.  Maximum  temperatures  generally  reach  a  peak  in  July 
and  August  in  all  areas  except  along  the  north  coast  where  the 
maximum  is  generally  shifted  10  August  and  September.  -. 


37 


54 


60 


Figure  3.4-2 
Mean  Annual  Temperature  Contours  (°F)  in  the  Ukiah  District 


38 


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Ukiah  District 
Mean  Temperature 


Coastal _ 

Coastal  Mountain 
Coastal  Plain 


Figure  3.4-4 

Ukiah  District 

Mean  Maximum  Temperature 


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Figure  3.4-5 

Ukiah  District 

Mean  Minimum  Temperature 


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Mean  Minimum 

Figure  3.4-5  indicates  that  during  the  winter  months, 
minima  in  the  mountainous  and  valley  areas  tend  to  be  in  the  mid- 
30's°F.  Along  the  immediate  coastline,  temperatures  are  gen- 
erally in  the  low  to  mid-40's°F.  By  summertime,  overnight  lows 
in-  the  mountains  and  the  Central  Valley  are  in  the  mid  to  upper 
50's°F.  Along  the  coastline,  temperatures  generally  remain  in 
the  low  60's°F. 


3.4.2 


Temperature  Extremes 


Temperature  extremes  for  key  stations  in  each  of  the 
three  climatic  zones  identified  for  the  Ukiah  District  are  pro- 
vided in  Tables  3.4-2  through  3.4-4.  Temperature  extremes  are 
strongly  influenced  by  mi crocl i mat ol ogi cal  effects  and  consider- 
able caution  must  be  used  when  identifying  extreme  temperatures 
for  use  at  locations  within  the  Ukiah  District.  Some  locations 
may  not  be  adequately  described  by  the  key  stations  provided  in 
the  tabl es . 

The  data  indicate  that  in  the  Coastal  CZ,  record  maximum 
temperatures  range  from  83°F  at  Eureka  to  116°F  at  Healdsburg. 
Temperatures  of  this  magnitude  at  coastal  locations  generally 
occur  in  conjunction  with  "Santa  Ana"  conditions  which  occur  most 
frequently  during  late  summer  and  fall,  but  which  can  occur 
during  any  time  of  the  year.  During  a  Santa  Ana,  air  is  com- 
pressed and  heated  as  it  rapidly  descends  from  higher  elevations 
in  the  interior  resulting  in  hot,  dry  conditions  at  coastal 
California  locations. 

Record  low  temperatures  along  the  Coastal  CZ  range  from 
a  minimum  of  16°F  at  Santa  Rosa  to  23°F  at  San  Rafael.  Record 
low  temperatures  are  generally  associated  with  particularly  large 
outbreaks  of  Artie  air  which  occasionally  reach  this  area  during 
the  winter. 

In  the  nearby  Coastal  Mountain  CZ ,  data  are  only  pro- 
vided for  Ukiah.  The  record  maximum  temperature  at  Ukiah  of 
115°F  occurred  during  September.  This  temperature  probably 
occurred  during  Santa  Ana  conditions.  The  wide  temperature  range 
experienced  in  this  zone  as  opposed  to  the  Coastal  CZ  reflects 
the  increase  in  distance  from  the  moderating  influence  of  the 
Pacific  Ocean.  The  record  minimum  temperature  at  Ukiah  was  13°F. 
This  is  colder  than  the  record  minima  observed  at  coastal  sta- 
tions, once  again  reflecting  the  more  continental  nature  of  the 
area  . 

Record  temperatures  are  available  for  two  stations  in 
the  Central  Plain  CZ  as  indicated  in  Table  3.2-4.  Record  maxima 
range  from  113°F  at  Davis  to  115°F  at  Sacramento.  Temperatures 
of  this  magnitude  can  occur  either  with  "Santa  Ana"  conditions  or 
during  late  summer  when  surface  heating  reaches  a  maximum  at 


40 


low-lying  inland  locations.  Record  low  temperatures  in  the 
Central  Plain  CZ  are  19°F  at  Davis  and  20°F  at  Sacramento. 
Minimum  temperatures  reflect  local  terrain  and  mi c rometeor o- 
logical  effects  as  well  as  such  factors  as  the  degree  of  urban 
development  and  the  length  of  record  available  for  the  data  base. 
However,  the  table  would  indicate  that  temperatures  -lower  than 
20-°F  represent  a  typical  extreme  minimum  value  at  Sacramento 
Val 1 ey  stations. 


3.4.3 


Frost-Free  Period 


The  growing  season  varies  considerably  as  a  function  of 
specific  crop  types.  Some  types  of  vegetation  continue  to  grow 
when  air  temperatures  are  near  freezing  (32  F),  whereas  other 
forms  of  plant  life  die  at  temperatures  above  freezing.  In 
general,  it  is  convenient  to  define  the  growing  season  for  a 
particular  region  by  noting  the  mean  number  of  days  between  the 
first  and  last  occurrence  of  freezing  temperatures,  i.e.,  the 
frost-free  period. 

The  mean  length  of  the  growing  season  is  depicted  by 
isolines  of  50  day  intervals  for  the  entire  Ukiah  District  in 
Figure  3.4-6.  As  indicated  in  the  figure,  the  growing  season 
length  differs  considerably  at  coastal  locations  as  compared  to 
regions  located  further  inland.  The  coastal  areas  are  largely 
influenced  by  nearby  Pacific  waters.  The  marine  environment 
tends  to  warm  ambient  air  masses  in  winter  and  reduce  air  temper- 
atures during  the  summer  months.  Coastal  areas  in  the  Ukiah 
District  experience  growing  seasons  on  the  order  of  300  days 
south  of  Eureka  decreasing  to  around  200  days  near  the  Oregon 
border.  This  maritime  influence  is  limited,  however,  to  a  very 
narrow  strip  of  land  along  the  coast  that  extends  roughly  10 
miles  inland.  In  areas  of  elevated  terrain,  within  the  Coast 
Ranges,  the  mean  growing  season  is  reduced  to  less  than  150  days 
in  portions  of  Lake  and  Mendocino  Counties.  In  most  areas  of  the 
district,  the  growing  season  is  between  200  and  300  days  in 
length.  The  mean  frost-free  period  for  the  Central  Plain  CZ 
ranges  between  250-300  days,  offering  a  rather  lengthy  growing 
season  for  this  key  agricultural  area.  This  area  constitutes  one 
of  the  most  important  agricultural  zones  in  the  United  States. 

Table  3.4-5  presents  15  years  of  historical  freeze  data 
for  selected  stations.  For  each  year  since  1960,  the  occurrence 
of  the  last  spring  freeze  and  first  fall  occurrence  of  32°F  are 
provided.  The  number  of  Julian  days  between  the  freezing  events 
are  also  listed  to  provide  the  growing  season  length. 

In  summary,  little  difference  in  frost-free  period 
lengths  is  experienced  along  the  coast  south  of  Eureka.  Inland 
stations  observe  a  considerable  change  in  the  length  of  the 
frost-free  period.  Sacramento  Valley  locations  experience  frost- 
free  periods  ranging  from  250  days  in  the  west  to  300  days  along 
the  Sacramento  River.  The  mountainous  areas  reveal  a  wide  range 
of  growing  season  lengths  with  growing  seasons  often  less  than 
150  days  at  the  higher  elevations. 


41 


15  0 
2  0  0  .     ELK  VALLEY 


AHCATA 


7?  W.SACRAMENTO 


Figure  3.4-6 
Ukiah  District 
Frost-Free  Period  or  Length  of  Growing  Season  by  50-Day  Intervals 


42 


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43 


3.5 


PRECIPITATION 


Precipitation  plays  a  very  important  role  in  the  effec- 
tive management  of  large  land  areas  for  agriculture,  forest 
management,  energy  development  or  other  pertinent  interests. 
Precipitation  is  one  of  the  most  basic  of  climatolog-ical  para- 
meters and  is  best  described  in  terms  of  seasonal  and  annual 
means  and  extremes  coupled  with  a  discussion  of  the  type  of 
precipitation  experienced  in  a  given  area .  A  region  can  be  prone 
to  either  general  prolonged  rainfall  or  precipitation  occurrences 
in  short,  violent  bursts,  such  as  heavy  showers  or  thunderstorms. 
The  nature  of  the  precipitation  is  almost  equal  in  importance  to 
the  amount  of  precipitation  in  terms  of  the  effectiveness  of  the 
moisture  for  interests  such  as  agriculture.  In  addition,  the 
type  of  precipitation  (i.e.,  liquid  vs.  frozen)  and  the  amount  of 
each  also  plays  an  important  role. 

Precipitation  results  from  the  expansion  and  cooling  of 
ascending  air.  Therefore,  it  is  important  to  investigate  and 
understand  the  atmospheric  conditions  that  cause  large  masses  of 
air  to  spontaneously  rise.  Three  characteristic  causes  that  can 
result  in  precipitation  are : 


•   Convective  lifting  due 
d  i  t  i  o  n  s 


to  unstable  atmospheric  con- 


•  Orographic  or  terra  in- induced  lifting  of  air  masses 

•  Large  scale  atmospheric  disturbances 


The  three  are  not  mutually  exclusive,  and  precipitation 
is  generally  not  the  result  of  just  one  type,  but  more  often  the 
joint  action  of  several  types  of  atmospheric  lifting  processes. 

The  following  sections  provide  a  detailed  breakdown  of 
precipitation  amounts,  types  and  frequencies.  Seasonal  and 
annual  means  and  extremes  are  provided  as  well  as  rainfall  inten- 
sity, and  a  detailed  discussion  on  snowfall.  More  unusual  types 
of  precipitation  such  as  hail  are  discussed  in  the  section  pro- 
vided on  severe  weather. 


3.5.1 


Annua  1  Distribution 


Figure  3.5-1  presents  a  base  map  which  includes  the 
selected  stations  for  which  precipitation  data  are  available.  A 
climatic  zone  overlay  (Overlay  C)  for  the  Ukiah  District  is 
suitable  for  use  with  the  precipitation  maps. 

Precipitation  in  California  and  within  the  Ukiah  Dis- 
trict is  primarily  the  result  of  the  influence  of  maritime 
Pacific  air  and  orographic  influences  imposed  by  the  substantial 
terrain  within  the  region.  The  neighboring  Pacific  Ocean  serves 
as  the  major  moisture  source  for  precipitation  in  the  district. 


44 


JCRESCENTM 
IS 


COASTAL  MOUNTAIN 


SACRAMENTO 


SAN  RAFAEL*  A 


Figure  3.5-1 
Selected  Precipitation  Stations  for  the  Ukiah  District 


45 


Therefore,  locations  closest  to  the  westward  facing  slopes  of 
higher  terrain  experience  the  heaviest  precipitation  totals  in 
the  district. 

The  mean  annual  precipitation  for  the  Ukiah  District  is 
depicted  on  Figure  3.5-2  in  the  form  of  contours  ( i  s  o  try  e  t  s  ) .  An 
id-entical  map  is  provided  with  this  district  report  as  a  color 
coded  overlay  (Overlay  E)  to  facilitate  inter-parameter  compari- 
sons and  correlations  by  the  reader.  The  figure  indicates  con- 
siderable variation  in  annual  rainfall  totals  through  the  Ukiah 
District.  Totals  range  in  excess  of  120  inches  in  the  higher 
elevations  of  Humboldt  and  Del  Norte  Counties  to  less  than  15 
inches  in  Colusa  County.  In  Del  Norte  and  Humboldt  Counties, 
rainfall  amounts  are  generally  in  excess  of  70  inches  along  the 
coast  and  the  extreme  north  and  in  excess  of  50  inches  in  the 
remainder  of  Humboldt  County.  Rainfall  amounts  generally 
increase  with  inland  progression,  reaching  a  maximum  on  west  and 
southward  facing  slopes  of  elevated  terrain.  Maximums  occur  in 
Del  Norte  County  and  also  in  the  Humboldt  Redwoods  State  Park 
area  of  southwestern  Humboldt  County.  In  this  latter  location, 
rainfall  amounts  reach  in  excess  of  110  inches.  Further  to  the 
south  in  Mendocino,  Sonoma  and  Lake  County  rainfall  amounts  are 
generally  between  40  to  70  inches  per  year  in  the  higher  eleva- 
tions of  the  Coast  Ranges  reaching  totals  in  excess  of  80  inches 
south  of  Lakeport  and  in  portions  of  northwestern  Mendocino 
County.  Rainfall  amounts  along  the  coastline  of  Marin,  Sonoma 
and  Mendocino  Counties  range  from  around  40  inches  in  the  south 
to  70  inches  in  the  north.  Rainfall  amounts  are  generally  lower 
in  valley  locations  along  the  Russian  and  Santa  Rosa  Rivers.  The 
city  of  Santa  Rosa,  for  example,  experiences  an  annual  precipita- 
tion total  of  just  30  inches  per  year  while  Ukiah,  further  to  the 
north,  experiences  a  total  of  about  40  inches.  A  marked  decrease 
in  annual  precipitation  amounts  is  exhibited  in  the  Central  Plain 
CZ  which  includes  most  of  Colusa,  Yolo  and  Solano  Counties.  In 
these  regions,  rainfall  amounts  are  generally  around  15  to  20 
inches  per  year  with  amounts  of  less  than  15  inches  in  some 
locations. 


3.5.2 


Seasonal  Precipitation 


A  major  portion  of  the  precipitation  that  occurs  in 
California  is  associated  with  cyclonic  storms,  both  surface  and 
upper  air.  Cyclonic  storms  originating  in  the  western  Pacific 
are  intensified  as  they  move  through  the  Gulf  of  Alaska.  These 
storms  are  a  winter  season  phenomenon  which  result  in  a  distinct 
rainy  season  in  California  during  the  winter  months.  The  amount 
of  precipitation  associated  with  these  storm  systems  depends  upon 
the  "storm  track"  or  path  with  the  greatest  amounts  of  precipi- 
tation occurring  near  the  storm  center. 

Rainy  season  storms  from  the  west  can  result  in  rain  for 
prolonged  periods  when  the  storm-track  becomes  established  across 
northern  California.  Rains  may  last  for  a  week  or  more  with  only 
partial  clearing  between  episodes.   The  actual  amount  of  precipi- 


46 


Figure  3.5-2 
Mean  Annual  Precipitation  (Inches)  in  the  Ukiah  District 


47 


tat  ion  at  a  given  station  in  the  District,  therefore,  will  be 
dependent  upon  such  factors  as  (1)  storm  path,  (2)  station  eleva- 
tion and  (3)  nearby  terrain  features.  Storms  from  the  northwest 
dre  the  most  common  type  of  rainy  season  system  and  often  bring 
heavily  saturated  air  masses  which  can  result  in  considerable 
flooding  during  the  winter  season. 

Table  3.5-1  provides  monthly  precipitation  means  and 
extremes  for  selected  station  locations  throughout  the  Ukiah 
District.  A  review  of  these  statistics  indicates  that  in  each  of 
the  climatic  zones,  a  definite  rainy  season  exists  between  late 
fall  and  early  spring.  Coastal  areas  and  the  windward  -slopes  of 
the  coastal  ranges  experience  the  greatest  precipitation  totals. 
Precipitation  amounts  generally  increase  with  northward  progres- 
sion due  to  the  closer  proximity  of  the  northern  portion  of  the 
region  to  the  mean  rainy  season  storm  track.  However,  in 
California,  elevation  is  usually  the  critical  variable  in  the 
determination  of  precipitation  amounts. 

Rainy  season,  cyclonic  storm  and  frontal  activity 
throughout  the  district  constitutes  the  primary  form  of  precipi- 
tation observed  in  the  Ukiah  District. 


3.5.3 


Snowf a  1 1 


Snowfall  has  been  observed  at  many  locations  within  the 
Ukiah  District.  However,  snow  only  accumulates  in  the  higher 
elevations  of  the  Coast  Ranges.  Table  3.5-2  provides  the  his- 
torical record  of  maximum  monthly  snowfall  amounts  for  various 
stations  throughout  the  Ukiah  District.  Average  amounts  are  not 
provided  as  snow  is  extremely  rare  at  sea  level  and  low-lying 
stations.  Snow  is  not  an  important  climatic  parameter  at  such 
locations  and  is  more  of  a  novelty  topic. 

Table  3.5-3  provides  the  mean  monthly  and  mean  annual 
maximum  snowpack  depth  and  associated  water  content  for  stations 
within  the  mountainous  areas  of  the  Ukiah  District.  Figure  3.5-3 
illustrates  the  North  Coastal  Snow  Basin  (#2)  located  in  the 
Ukiah  District  as  organized  by  the  California  Department  of  Water 
Resources,  Division  of  Flood  Management.  Snow  basins  are  deter- 
mined according  to  particular  river  systems  in  which  snow  melt 
can  contribute  a  significant  water  supply. 

The  greatest  snowfall  on  record  for  the  entire  snow 
season  in  California  fell  in  1906  and  1907  at  Pomerac  in  Alpine 
County  where  884  inches  of  snow  was  recorded  at  8000  feet  MSL. 
The  average  seasonal  snowfall  at  that  station  is  450  inches.  The 
greatest  24-hour  snowfall  occurred  at  Giant  Forest  in  Sequoia 
National  Park  at  6360  feet  MSL  on  January  19,  1933  when  60  inches 
fell.  It  should  be  noted  that  there  are  relatively  few  snow 
observation  stations  in  the  Sierra,  therefore,  snowfall  amounts 
in  excess  of  these  record  amounts  may  have  occurred. 


48 


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•  TATt    OF    CALIFORNIA 

THE  RESOURCES  AGENCY  OF  CALIFORNIA 
DEPARTMENT  OF  WATER  RESOURCES 

DIVISION   OF   FLOOD  MANAGEMENT _ 
CALIFORNIA     COOPERATIVE     SNOW     SURVEYS 

INDEX  TO  BASIN   MAPS 
1978 


COLORADO 
DESERT 


Figure  3.5-3 
Snow  Basin  Map 


52 


In  the  Ukiah  District,  at  non-mountain  stations,  the 
maximum  monthly  snowfall  occurred  at  Santa  Rosa  with  an  accumu- 
lation of  6.5  inches.  At  Ukiah,  in  Mendocino  County,  5  inches  of 
snow  have  occurred  in  January.  Other  monthly  maximum  snowfall 
data  are    presented  in  Table  3.5-2. 


3.5.4 


Precipitation  Frequency 


An  analysis  of  rainfall  intensity  for  selected  areas 
offers  added  insight  into  regional  precipitation  characteristics. 
Rainfall  frequency  and  intensity  studies,  sometimes  referred  to 
as  pluvial  indices,  provide  an  understanding  of  the  nature  of 
precipitation  and  rainfall  in  a  given  region.  Isopluvial  maps 
facilitate  an  evaluation  of  rainfall  intensity  for  particular 
areas  over  selected  short-term  time  periods  or  intervals.  Isoh- 
yet  analyses  coupled  with  isopluvial  studies  provide  an  indica- 
tion of  the  nature  of  the  precipitation  means  for  the  area  ,  i.e., 
frequent  light  rains  versus  sporadic  heavy  rainstorms. 

Appendix  A  provides  isopluvial  analyses  for  the  Ukiah 
District  as  well  as  for  the  entire  state  of  California.  These 
figures  provide  information  for  the  following  return  periods  and 
rainfall  duration  times: 

2  year-6  hour  precipitation 
5  year-6  hour  precipitation 
10  year-6  hour  precipitation 
25  year-6  hour  precipitation 
50  year-6  hour  precipitation 
100  year-6  hour  precipitation 
2  year-24  hour  precipitation 
5  year-24  hour  precipitation 
10  year-24  hour  precipitation 
25  year-24  hour  precipitation 
50  year-24  hour  precipitation 
100  year-24  hour  precipitation 

These  maps  present  precipitation  amounts  received  within 
designated  time  periods  based  on  recurrence  intervals  of  2,  5, 
10,  25,  50  or  100  years.  For  example,  Figure  A - 1  provides  iso- 
pluvials  of  precipitation  amounts  for  a  6  hour  period,  experi- 
enced at  least  once  in  a  2  year  time  frame.  The  isoline  inter- 
vals provided  on  these  maps  were  designed  to  provide  a  reasonably 
complete  description  of  isopluvial  patterns  in  various  regions  of 
the  state.  Dashed  intermediate  lines  are  placed  between  the 
normal  isopluvial  intervals  where  a  linear  interpolation  would 
lead  to  erroneous  results. 

Rainfall  frequency  values  for  selected  key  stations 
within  the  Ukiah  District  were  obtained  from  the  Appendix  and 
summarized  in  Table  3.5-4.  This  table  provides  easy  reference  to 
pluvial  indices  for  the  climatic  zones  throughout  the  district. 
The  tables  and  figures  indicate  that  coastal  and  coastal  mountain 
areas  could  expect  the  most  intense  rainfall  amounts  over  a  6  or 


53 


Table  3.5-4 

Pluvial  Indices  (in  tenths  of  inches) 

at  Selected  Stations  in  the  Ukiah  District 


Time  Frame 

6  HOUR 

24 

HOUR 

Return  Period 

2  YR 

10 

YR    25  YR    50  YR 

2  YR 

10  YR 

25  YR 

50  YR 

Station 

Coastal 

Crescent  City 

22 

30 

34      36 

45 

65 

80 

80 

Orick 

20 

27 

30      33 

45 

68 

75 

85 

Eureka 

16.5 

23 

28      31 

30 

45 

52 

56 

Bridgeville 

20 

26 

30      32.5 

47 

65 

75 

80 

Garbervil le 

22 

26 

32      35 

50 

70 

80 

88 

Ft.  Bragg 

17 

21 

25      29 

34 

45 

50 

55 

Annapolis 

27 

36 

40      43 

60 

80 

95 

95 

Santa  Rosa 

18 

23 

26      27.5 

34 

45 

50 

60 

Vallejo 

14 

19 

21      22.5 

X 

25 

33 

45 

45 

Coastal  Mountain 

Ukiah 

18 

23 

26      27.5 

35 

50 

62 

68 

Cloverdale 

24 

30 

38      38 

50 

72 

79 

90 

Lakeport 

14 

18 

20      22.5 

30 

44 

52.5 

60 

Coastal  Plain 

Williams 

12 

16 

17      19 

20 

27.5 

32.5 

36 

Woodland 

12 

16 

18.5     20 

20 

28 

33 

38 

Dixon 

14 

20 

24      27 

24 

35 

42 

45 

Vacaville 

16.5 

22 

27      29 

32 

47 

55 

62 

54 


24  hour  period.  At  Annapolis,  for  example,  rainfall  could  total 
as  high  as  6  to  10  inches  in  a  single  2  4  hour  period.  At  coastal 
and  coastal  mountain  locations,  24-hour  maxima  are  quite  variable 
ranging  between  4  and  8  inches  slong  the  north  coast  and  between 
3  and  5  inches  along  the  south  coast.  In  the  Sacramento  Valley, 
maximum  24-hour  values  are  generally  betweed  2  and  4  inches.  The 
isopluvial  maps,  as  previously  mentioned,  strongly  reflect  the 
influence  of  topography  on  the  nature  of  precipitation  as  evi- 
denced by  the  values  indicated  in  Table  3.5-4  for  the  District's 
mount  a  i  nous  areas . 


55 


3 .  5 


PREVAILING  WINDS 


Wind  is  considered  a  primary  climatic  parameter  since 
air  flow  characteristics  directly  affect  ambient  air  moisture 
content  and  regional  temperature  levels.  Seasonal  and  diurnal 
air  flow  patterns  can  promote  periods  of  wet  or  dry  weather  as 
we-11  as  determine  hot  or  cold  climates.  The  prevailing  winds  are 
responsible  for  much  of  the  climatic  characteristics  of  an  area 
and  are  deeply  interrelated  with  other  climatic  parameters.  The 
distribution  of  wind  direction  and  wind  speed  are  used  to  cate- 
gorize this  parameter. 


Observations  of  wind  direction 
into  the  16  cardinal  compass  directions 
tional   abbreviation  or  the  heading   in 
associated  with  each  compass  heading  are 
Meteorological 
associated  with 

which  the  air  is  flowing.    In  other  words,  north  or 
winds  mean  that  air  is  moving  from  north  to  south. 


are  usually  classified 

using  either  a  direc- 

degrees.    The  degrees 

listed  in  Table  3.6-1. 

convention  requires  that  the  compass  heading 

a  given  wind  observation  is  the  direction  from 

norther! y 


The  following  sections  will  describe  wind  on  both  an 
annual  and  seasonal  basis.  A  primary  tool  used  to  graphically 
describe  the  prevailing  wind  conditions  at  a  given  station  is 
known  as  a  wind  rose.  As  described  in  detail  in  Section  4.2.1,  a 
wind  rose  is  a  plot  of  the  frequency  of  winds  from  each  of  the 
sixteen  cardinal  directions.  The  diagram  resembles  a  compass 
face  with  the  length  of  the  line  drawn  for  each  direction  indi- 
cating the  frequency  of  occurrence  of  flow  from  that  direction 
for  the  indicated  period  of  record. 


3.6.1 


Annual  Wind  Distribution 


California  lies  within  the  zone  of  prevailing  westerly 
winds  and  is  situated  on  the  east  side  of  the  Eastern  Pacific 
semi-permanent  high  pressure  center.  Since  general  air  flow 
patterns  in  the  Northern  Hemisphere  are  clockwise  (  a nt i cy c 1 oni c ) 
about  high  pressure  centers,  basic  air  flow  over  California  is 
from  the  west  and  northwest.  Figure  3.6-1  illustrates  a  typical 
pressure  situation  off  the  California  coast  and  depicts  the 
associated  wind  flow  patterns.  As  the  seasons  progress,  there 
exists  considerable  variation  in  this  generalized  scheme  due  to 
mesoscale  (several  hundred  miles)  and  synoptic  (thousands  of 
miles)  scale  pressure  distribution  changes.  Most  importantly, 
several  mountain  chains  within  the  state  are  responsible  for 
deflecting  the  large  scale  flow.  Except  along  the  immediate 
coast,  wind  direction  and  speed  is  likely  to  be  largely  a  func- 
tion of  local  terrain  and  orographic  effects  rather  than  the 
prevailing  circulation  patterns  observed  in  a  hemispheric  sense. 

Figure  3.6-2  depicts  various  selected  station  locations 
in  the  Ukiah  District  for  which  reduced  historical  wind  speed  and 
direction  data  have  been  summarized.  Annual  wind  roses  are 
superimposed  on  this  study  map  for  selected  key  stations  within 


56 


Table  3.6-1 
Wind  Direction  Classification 


Direction 
(Abbreviation) 

Di  recti  on 
( Degrees  ) 

Di  recti  on 
(Winds  From) 

N 

NNE 

NE 

ENE 

E 

ESE 

SE 

SSE 

S 

SSW 

sw 

wsw 

w 

WNW 

NW 

NNW 

348.75  -   11.25 

11.25  -   33.75 

33.75  -   56.25 

56.25  -   78.75 

78.75  -  101.25 

101.25  -  123.75 

123.75  -  146.25 

146.25  -  168.75 

168.75  -  191.25 

191.25  -  213.75 

213.75  -  236.25 

236.25  -  258.75 

258.75  -  281.25 

281.25  -  303.75 

303.75  -  326.25 

326.25  -  348.75 

North 

North  -  Northeast 

Northeast 

East  -  Northeast 

East 

East  -  Southeast 

Southeast 

South  -  Southeast 

South 

South  -  Southwest 

Southwest 

West  -  Southwest 

West 

West  -  Northwest 

Northwest 

North  -  Northwest 

< 


57 


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t       WOODLAND 

W.SACRAMENTO 


FAIRFIELD 


Note 


RIO  VISTA 


SAN  RAFAEL 

KENTFIELD 

Figure  3.6-2 

Annual  Wind  Roses  at  Selected  Key  Stations 

in  the  Ukiah  District 

Each  Division  on  the  Roses  is  Equal  to  an  Annual  Frequency  of  5%. 

59 


each  climatic  zone  in  the  district  coupled  with  trajectory  analy- 
ses based  upon  the  use  of  the  most  frequently  occurring  wind 
direction  at  each  station.  The  climatic  zone  overlay  (Overlay  C) 
map  may  be  used  to  isolate  these  particular  areas.  A  detailed 
analysis  and  breakdown  of  wind  speed  versus  wind  direction  char- 
acteristics is  provided  in  the  dispersion  meteorology  section. 

The  annual  wind  roses  provided  in  Figure  3.6-2  indicate 
that  the  flow  along  the  coast  is  from  the  northwest  and  north  at 
all  stations  with  the  exception  of  Crescent  City  where  south- 
easterly flow  represents  the  prevailing  wind.  However,  even  at 
this  station,  a  strong  secondary  maximum  for  winds  from  the 
nort h- northwest  exists.  At  coastal  mountain  stations,  flow  tends 
to  be  up  the  major  river  valleys  including  the  Santa  Rosa, 
Russian  and  Napa  River  Valleys.  This  results  in  a  prevailing 
south  to  southeasterly  flow  at  stations  such  as  Ukiah,  Santa 
Rosa  and  Napa.  Further  inland,  in  the  Sacramento  Valley,  flow  is 
once  again  upvalley  as  evidenced  by  southerly  flow  at  Sacramento, 
southeasterly  flow  at  Williams.  The  flow  in  the  Sacramento 
Valley  and  in  the  Coastal  Mountains  is  still  maritime  in  nature 
coming  into  the  region  through  the  gap  in  the  Coast  Ranges  in  the 
San  Francisco  -  Oakland  area. 

Figure  3.6-3  provides  an  annual  trajectory  analysis 
based  upon  the  most  frequently  occuring  wind  direction  at  each  of 
the  stations  for  which  wind  data  were  available  in  the  Ukiah 
District.  The  prevailing  downcoast  flow  at  coastal  stations  from 
the  northwest  to  north  is  evident  as  is  upvalley  flow  in  most  of 
parts  of  Sonoma,  Mendocino,  Lake,  Napa,  Solano,  Yolo  and  Colusa 
Counties.  The  area  contains  considerable  rugged  terrain  and  the 
wind  flow  as  presented  in  Figure  3.6-3  may  not  be  indicative  of 
sites  which  are  dominated  by  local  terrain  affects. 


3.6.2 


Seasonal  Wind  Distribution 


Seasonal  wind  data  are  available  in  the  Ukiah  District 
for  Eureka,  Areata,  San  Rafael,  Ukiah,  Fairfield  (Travis  AFB)  and 
Sacramento  and  are  presented  in  Table  3.6-2.  The  first  three 
stations  are  indicative  of  conditions  along  the  Pacific  Coast. 
Ukiah  is  indicative  of  conditions  in  the  Coast  Ranges  while  Fair- 
field and  Sacramento  are  indicative  of  sites  in  the  Sacramento 
Valley.  At  Eureka  and  Areata  in  Humboldt  County,  downcoast  north 
to  northwesterly  flow  prevails  during  the  period  spring  through 
fall.  During  this  time  of  the  year,  California  is  under  the 
influence  of  the  semi-permanent  Pacific  high  pressure  zone  which 
results  in  an  onshore  maritime  flow  at  most  California  coastal 
locations.  The  sea  breeze  regime  which  results  from  this  pres- 
sure pattern  generally  brings  an  ample  supply  of  moist  maritime 
air  to  coastal  locations  resulting  in  a  distinctly  maritime 
climate  with  modest  temperature  ranges.  Both  Eureka  and  Areata 
show  deviations  from  this  trend  towards  onshore  flow  during  the 
winter  months  with  southeasterly  flow  at  Eureka  and  easterly  flow 
at  Areata.   During  the  winter  months,  drainage  flow  from  inland 


60 


ELEVATIONS 


6000 

3000 

1500 

500 

0 

» 

CRAMENTO 


Figure  3.6-3 
Trajectory  Analyses  for  the  Ukiah  District 

61 


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62 


areas  of  substantial  terrain  tends  to  dominate  the  annual  distri- 
bution. This  offshore  component  is  further  supplemented  by 
southeasterly  and  easterly  flow  in  advance  of  migratory  pressure 
systems  during  the  rainy  season  months. 

Further  down  the  coast  at  San  Rafael,  the  prevailing 
distribution  is  somewhat  more  erratic.  Northwesterly  flow  dom- 
inates during  most  months  but  is  absent  during  midwinter  as  well 
as  during  late  summer  and  early  fall.  Once  again,  the  north- 
westerly flow  is  indicative  of  the  maritime  sea  breeze  regime 
while  southeasterly  and  easterly  flow  at  San  Rafael  represents  a 
combination  of  upvalley  flow  as  well  as  outflow  from  the  Central 
Valley  of  California. 

Ukiah  is  representative  of  conditions  at  an  inland 
valley  location.  Here,  the  trend  is  similar  to  that  observed  at 
San  Rafael.  South-southeasterly  flow  prevails  during  the  winter 
months  and  during  late  summer  while  north  and  northwesterly  flow 
dominates  during  other  periods  of  the  year .  The  northwesterly 
flow  is  indicative  of  the  general  down  coastal  flow  observed  in 
Northern  California  particularly  during  the  summer  months.  The 
switch  to  south-southeasterly  flow  again  occurs  in  late  summer  as 
surface  heating  becomes  most  intense  and  topographical  influences 
dominate.  This  results  in  upvalley  flow  as  warm  air  masses  tend 
to  move  upslope.  During  the  winter  months,  the  south-southeast- 
erly flow  reflects  the  heavy  influence  of  migratory  storm  systems 
which  result  in  southerly  and  southeasterly  flow  on  many  occa- 
sions, particularly  in  Northern  California. 

Finally,  Fairfield  and  Sacramento  provide  data  indica- 
tive of  conditions  in  the  Sacramento  Valley  portion  of  the  Ukiah 
District.  Southwesterly  flow  dominates  at  Fairfield  as  maritime 
air  moves  inland  through  the  Carquinez  Straits.  At  Sacramento, 
southwesterly  flow  dominates  during  the  summer  as  maritime  air 
comes  in  through  the  Carquinez  Straits  and  upvalley  into  the 
Sacramento  Valley.  During  winter,  southeasterly  and  south-south- 
easterly flow  is  evident  as  noted  at  most  stations  within  the 
District. 

At  coastal  and  coastal  mountain  stations,  wind  speeds 
tend  to  be  strongest  during  the  period  April  through  June.  Down 
coastal  flow  is  well  established  during  this  period  resulting  in 
brisk  winds  ranging  from  5  knots  at  Ukiah  to  over  8  knots  at 
Eureka  and  Areata  during  April.  Wind  speeds  tend  to  be  lowest  at 
these  locations  during  the  fall  months.  At  Fairfield  and  Sacra- 
mento in  the  Sacramento  Valley,  wind  speeds  are  clearly  strongest 
during  summer  when  the  maritime  influence  of  the  sea  breeze  is 
strongest  as  air  rushes  through  the  San  Francisco-Oakland  area 
moving  southward  into  the  San  Joachin  Valley  and  northward  into 
the  Sacramento  Valley.  Wind  speeds  tend  to  be  lowest  in  this 
area,    once  again,  during  the  fall  months. 


63 


3.7 


EVAPORATION  AND  RELATED  PARAMETERS 


Evaporation  is  the  physical  process  by  which  water  is 
transformed  from  the  liquid  to  the  gaseous  state.  The  rate  of 
evaporation  in  a  particular  region  is  dependent  upon  many  cli- 
matic parameters,  but  is  primarily  influenced  by  wind,  temper- 
at-ure,  relative  humidity,  sky  conditions,  precipitation  and  solar 
radi  at  i  on  . 

E vapot ransp i rat i on  is  the  process  whereby  water  vapor  is 
returned  to  the  atmosphere  both  by  living  plants  (transpiration) 
and  from  the  earth's  surface  (evaporation)-.  An  assessment  of 
regional  evapotranspiration  is  important  to  the  water  and  agri- 
cultural industries  as  it  provides  a  complete  picture  of  natural 
water  demand  for  a  given  geographical  area. 

Solar  radiation  is  the  earth's  principle  source  of  en- 
ergy. This  energy  is  naturally  dispersed  in  numerous  forms  such 
that  much  of  the  received  solar  energy  is  used  to  generate  winds, 
heat  air  masses,  as  well  as  supply  latent  heat  energy  to  the 
atmosphere  by  contributing  to  the  rate  of  evaporation  of  large 
quantities  of  water  into  the  atmosphere.  Consequently,  mean 
monthly  and  annual  solar  radiation  levels  for  particular  loca- 
tions are  often  expressed  in  terms  of  equivalent  evaporation 
units.  The  standard  conversion  of  solar  radiation  units,  as 
expressed  in  Langleys,  to  inches  of  evaporation,  requires  that  1 
inch  of  evaporation  be  equivalent  to  1486  Langleys. 


3.7.1 


Evaporation  and  Evapotranspiration 


The  California  State  Department  of  Water  Resources  has 
determined  regional  evaporative  demand  areas  on  the  basis  of 
similar  monthly  levels  of  evaporation  and  evapotranspiration 
rates.  These  areas  are  provided  in  Figure  3.7-1  for  the  entire 
state  of  California. 

The  Ukiah  District  includes  three  of  the  eleven  state- 
wide zones  of  similar  evaporative  demand.  A  contour  map  depict- 
ing areas  of  equal  annual  evaporative  demand  levels  for  the  Ukiah 
District  is  provided  as  Figure  3.7-2.  Note  that  a  considerable 
gradient  of  evaporative  demand  exists.  These  rapid  changes  in 
regional  evaporation  rate  are  a  result  of  the  considerable  dif- 
ference between  the  nearby  Pacific  Ocean  and  the  Sacramento 
Valley.  Air  masses  along  the  coast  experience  modest  temperature 
variations  coupled  with  high  relative  humidity.  These  factors 
significantly  limit  the  potential  rate  of  evaporation  since  the 
ambient  air  has  a  diminished  ability  to  hold  additional  water 
vapor.  This  is  diammetrically  opposed  to  the  evaporative  poten- 
tial of  the  dry  valley  areas  further  east. 

A  comparison  of  annually  averaged  evaporative  demand  and 

evapotranspiration  rates   for  different   geographical   areas  can 

lead  to  ambiguous  results.    Annual  evaporative  totals  for  two 

areas  may  be  similar,  but  monthly  patterns  of  evaporation  and 


64 


c      r      i      c 


ZONES  OF  SIMILAR  EVAPORATIVE 
DEMAND  IN  CALIFORNIA 


1.  North  Coast,  Coastal  Valleys  and  Plains 

2.  North  Coast  Interior  Valleys 

3.  Northeastern  Mountain  Valleys 

4.  Sacramento  Valley  Floor 

5.  San  Joaquin  Valley  Floor 

6.  Central  Coast  Interior  Valleys 

7.  Sierra 

8.  Central  Coast,  Coastal  Volleys  and  Plains 

9.  South  Coast,  Coastal  Valleys  and  Plains 

10.  South  Coast  Interior  Valleys 

11.  Southern  California  Desert  * 


\ 


t  *■     -■     •      <■ 


\ 


V 


L-  ) 


"~\ 


Figure  3.7-1 


Source:   "Vegetative  Water  Use  in  California,  1974",  State  of 
California  Department  of  Water  Resources 


65 


35 


ELK  VALLEY 


W  SACRAMENTO 


Figure  3.7-2 
Annual   Evaporative  Demand 
in  the  Ukiah  District 


Estimated  from  evaporation  observed  in  non-irrigated  environments  adjusted  to 
appropriate  evaporation  from  Class   "A"  pans  in  irrigated  pasture  environments. 

66 


evapotransiration  may  differ  significantly.  Monthly  tabulations 
of  average  pan  evaporation  rates  and  estimated  potential  evapo- 
transpiration  rates  for  the  various  California  climatic  regions 
are    presented  in  Table  3.7-1. 

Maximum  evaporation  rates  generally  occur  during  July. 
During  this  month,  in  all  climatic  regions,  the  incidence  of 
solar  radiation  is  at  a  maximum.  The  North  Coast  Coastal  Valleys 
and  Plains  experience  about  4.5  inches  of  evaporation  during  July 
while  the  North  Coast  Interior  Valleys  experience  just  over  9 
inches  of  evaporation  during  this  month.  In  the  Sacramento 
Valley,  average  pan  evaporation  rates  reach  just  over  10  inches 
during  the  month  of  July.  In  winter,  evaporation  rates  drop  to 
less  than  an  inch  in  the  North  Coast  Coastal  Valleys  and  Plains 
and  between  one  and  two  inches  in  the  North  Coast  Interior  Val- 
leys and  Sacramento  Valley.  Figure  3.7-2  indicates  that  annual 
average  pan  evaporation  rates  are  greater  than  65  inches  in  Yolo 
County  and  less  than  35  inches  in  the  extreme  northwest. 

The  ratio  of  ev a  pot ra ns p i rat i on  to  evaporation  (ET/Ep) 
is  obtained  empirically  by  simply  observing  and  comparing  simul- 
taneous pan  evaporation  and  net  water  loss  from  vegetation  soil 
tanks  (the  tank  is  designed  such  that  all  water  added  to  the 
apparatus  and  all  water  left  after  a  testing  period  can  be  mea- 
sured). This  ratio  thus  allows  a  more  definitive  evaluation  of 
water  demand  in  a  particular  region. 

Since  evapot ransp i rat i on  values  are  so  dependent  upon 
crop  and  vegetation  type,  it  is  useful  to  observe  ET/Ep  ratios  on 
a  monthly  basis  for  the  entire  growing  season  of  particular 
crops.  In  general,  potential  evapotranspiration  values  as  pre- 
sented in  Table  3.7-1  are  determined  by  using  grass  as  the  stan- 
dard vegetation  type.  Table  3.7-2  provides  a  summary  of  observed 
monthly  ET/Ep  ratios  for  the  principle  irragated  crops  in  Cali- 
fornia as  provided  by  the  California  State  Water  Resources  Con- 
trol Board  in  Sacramento. 


3.7.2 


Sky  Conditions 


Sky  cover  is  a  measure  of  the  degree  of  cloudiness 
characteristic  of  a  given  area  for  a  certain  time  period.  Sky 
cover  conditions  experienced  in  a  particular  region  are  inter- 
related with  the  mean  incoming  solar  radiation,  mean  temperature, 
and  precipitation  levels,  as  well  as  having  numerous  secondary 
effects  on  many  other  climatic  parameters,  all  of  which  effect 
the  local  evaporative  demand.  In  addition,  as  discussed  in 
Section  4.2-2,  sky  cover  has  an  application  to  dispersion  meteor- 
ology through  its  impact  on  insolation,  and  thus  is  an  important 
parameter  in  the  determination  of  atmospheric  stability. 

Clouds  substantially  insulate  the  surface  from  receiving 
large  quantities  of  solar  energy.  Reflection  and  scattering  of 
light  energy  from  cloud  tops  and  cloud  interiors  contribute 
significantly  to  the   overall   reduction   of   light   received  at 


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ground  level.  Generally,  cloud  cover  is  classified  according  to 
various  categories.  These  categories  include  clear  or  cloudless 
sky  conditions,  mostly  clear  skies,  partly  cloudy  conditions, 
mostly  cloudy  and  cloudy  conditions,  or  completely  overcast 
skies.  In  order  to  make  sky  cover  observations  more  definitive, 
these  observations  are  defined  in  terms  of  categories  using 
fractional  units  expressed  in  tenths  of  the  sky  covered  by  clouds 
(See  Table  3.7-3). 

Table  3.7-3 
Sky  Cover  Categories 


Generalized  Category 
clear 

mostly  clear 
parti y  cl oudy 
most! y  cl oudy 
cloudy  or  complete  overcast 


Sky  Cover  in  Tenths 

0 
0-3 
4-7 
8-10 

10 


Mean  monthly  and  annual  sky  conditions  at  coastal  and 
valley  stations  are  provided  in  Figures  3.7-3  and  3.7-4.  At 
Eureka,  very  little  variation  is  evident  as  a  function  of  the 
season  of  the  year.  The  mean  sky  cover  ranges  from  6/10ths  to 
8/10ths  with  a  maximum  occurring  during  December  and  a  minimum 
occurring  during  September.  During  all  other  months  of  the  year  , 
sky  cover  totals  7/10ths  at  Eureka.  This  station  is  heavily 
influenced  by  the  maritime  influx  of  air  from  the  Pacific  Ocean. 
Onshore  flow  dominates  during  all  months  of  the  year  and  fog  and 
low  stratus  are  quite  common.  The  maximum  for  cloud  cover  during 
the  winter  represents  the  increased  frequency  of  migratory  low 
pressure  systems  during  this  month  while  the  minimum  in  September 
reflects  the  generally  good  weather  experienced  throughout  Cali- 
fornia during  fall  due  to  the  presence  of  the  sem  i  -  perma  nent 
eastern  Pacific  high  pressure  system. 

Further  down  the  coast  at  San  Rafael,  considerable 
variability  is  evident  in  the  sky  cover  data  ranging  from  l/10th 
during  August  and  September  to  a  maximum  of  6/10ths  during  Decem- 
ber and  January.  The  low  frequency  of  cloudiness  during  the 
summer  months  is  once  again  indicative  of  the  improved  sky  cover 
conditions  experienced  at  most  California  coastal  stations  during 
late  summer.  The  high  frequency  of  cloudiness  during  winter 
reflects  the  increased  frequency  of  storm  systems  passing  through 
the  area.  In  addition,  cloud  cover  remains  fairly  high  through 
May,  representing  the  influence  of  maritime  air  in  this  region 
during  the  spring  months  and  the  fairly  high  frequency  of  occur- 
rence of  low  cloudiness  and  fog. 

At  Sacramento  in  the  central  plain  climatic  zone,  condi- 
tions are  similar  to  those  experienced  at  San  Rafael.  Cloudiness 
reaches  a  peak  in  mid-winter  with  a  minimum  during  late  summer 
and  early  fall.  The  winter  maximum  reflects  both  the  increased 
frequency  of  the  passage  of  migratory  storm  systems  as  well  as 


72 


u 

MEAN  SKY  COVER  -  EUREKA 

9 
8 

8 

(33  YEARS  OF  DATA) 
(IN  TENTHS) 

7 

m 

7     7     7     7     7     7     7     7         7     7 

6 

- 

6 

5 

4 

3 

2 

1 

Annual 

Mean 

6.9 


M 
MONTH 


10 

9 

8 

7 
6 

5 

4 


MEAN  SKY  COVER  -  SAN  RAFAEL  (TRAVIS  AFB) 
(4  YEARS  OF  DATA) 
(IN  TENTHS) 


2              2 

1 

1 

Annual 

Mean 

3.7 


M 


A 


M 
MONTH 


J 


A 


Figure  3.7-3 
Coastal  Climatic  Zone 
Monthly  and  Annual  Sky  Cover  Distribution 

73 


10 

MEAN  SKY  COVER  -  SACRAMENTO  AIRPORT 

9 

(27  YEARS  OF  DATA) 
(IN  TENTHS) 

8 

en 

LU 

> 

o 
o 

7 
6 
5 

7 

7 

6     6                                     6 

>- 
o 

5 

oo 

4 
3 

4 

1— 

3 

2 

2 

2 

1 

1 

1 

ANNUAL 

MEAN 

4.1 


FMAMJJAS 

MONTH 


Figure  3.7-4 
Central  Plain  Climatic  Zone 
Monthly  &  Annual  Sky  Cover  Distribution 


74 


heavy  stratus  and  fog  which  tends  to  occur  over  this  region 
during  the  winter.  The  frequency  of  low  stratus  and  fog  remains 
fairly  high  through  the  spring  months.  During  late  summer, 
surface  heating  reaches  a  maximum  and  the  skies  tend  to  be  fairly 
cloudless  throughout  the  San  Joaquin  and  Sacramento  Valleys.  Sky 
cover  generally  averages  between  1/1  Oth  and  2/10ths  at  -Sacramento 
in-  the  summer  and  early  fall  months. 

Table  3.7-4  provides  the  diurnal,  monthly  and  seasonal 
frequency  of  mostly  clear,  partly  cloudy  and  mostly  cloudy  condi- 
tions at  Areata  and  Ukiah.  These  data  are  only  available  for 
stations  for  which  summarized  digital  data  in  the  form  of  STAR 
summaries  are  available.  At  Areata,  located  on  the  north  coast 
in  Humboldt  County,  cloudy  conditions  clearly  dominate  reaching  a 
maximum  in  the  early  morning  hours.  The  frequency  of  clear 
conditions  reaches  a  maximum  during  the  late  afternoon  and  early 
evening  hours.  At  Ukiah,  mostly  clear  conditions  dominate  at 
this  inland  valley  location.  Clear  conditions  reach  a  maximum 
during  the  middle  of  the  night  while  cloudy  conditions  are  most 
frequently  observed  during  the  early  morning  hours.  Partly 
cloudy  conditions  are  most  frequent  during  the  afternoon  and 
early  evening  hours  as  fair  weather  cumulus  develop  during  the 
period  of  most  intense  surface  heating. 

The  importance  of  sky  cover  as  a  parameter  affecting 
atmospheric  stability  will  be  discussed  further  in  Section  4.2.3 
and  is  especially  detailed  in  Table  4.2-4 


3.7.3 


Solar  Radiation 


Monthly-annual  averages  of  total  incoming  solar  radia- 
tion for  the  various  evaporative  demand  zones  in  California 
(equivalent  in  inches  of  evaporation  of  water)  are  presented  in 
Table  3.7-5.  The  Ukiah  District  includes  areas  in  the  North 
Coast,  Coastal  Valleys  and  Plains,  North  Coast  Interior  Valleys 
and  Sacramento  Valley. 

The  Ukiah  District,  on  an  annual  basis,  receives  an 
abundant  amount  of  sunshine,  particularly  in  the  Sacramento 
Valley.  The  north  coastal  portion  of  the  Ukiah  District  receives 
approximately  50%  of  the  total  possible  sunshine  on  an  annual 
basis.  In  the  Sacramento  Valley,  over  70%  of  the  total  possible 
hours  of  sunshine  are    received  annually. 

A  further  distinction  can  be  made  between  the  various 
climatic  zones  in  the  Ukiah  District  when  comparing  solar  radia- 
tion data  on  a  monthly  basis.  Table  3.7-6  provides  a  monthly- 
annual  breakdown  of  mean  daily  solar  radiation  in  Langleys  as 
observed  at  selected  stations  within  the  Ukiah  District.  As 
indicated  by  this  table,  the  Coastal  Mountains  receive  abundant 
amounts  of  sunshine  during  the  year.  Daily  solar  radiation 
totals  reach  over  700  langleys  at  Upperlake  in  June  and  July. 
Along  the  coast  and  in  the  Sacramento  Valley,  values  exceed  600 
langleys  during  the  period  May  through  August.  During  winter, 
daily  totals  drop  off  to  less  than  200  langleys  along  the  coast 
at  some  stations. 

75 


Table  3.7-4 
Seasonal   and  Diurnal   Frequencies    (%) 
of  Sky  Coverage  Conditions   in  the  Ukiah  District 


Time 

Areata 

Ukiah 

0-3 

4-7 

8-10 

0-3 

4-7 

8-10 

01 

29.0 

7.3 

63.6 

66.5 

7.7 

25.8 

02 

* 

* 

• 

64.0 

8.2 

27.8 

03 

* 

• 

* 

62.9 

8.7 

28.4 

04 

26.7 

7.6 

65.7 

61.8 

8.3 

29.9 

05 

* 

• 

* 

60.8 

7.9 

31.3 

06 

• 

• 

• 

57.6 

8.6 

33.8 

07 

21.7 

8.4 

69.9 

54.1 

9.1 

36.8 

08 

* 

• 

• 

51.5 

10.4 

38.1 

09 

* 

* 

• 

51.0 

9.4 

39.6 

10 

23.4 

11.0 

65.6 

51.7 

9.5 

38.7 

11 

* 

• 

• 

54.2 

10.2 

35.6 

12 

• 

• 

* 

55.7 

10.7 

33.6 

13 

30.7 

12.1 

57.2 

55.9 

11.4 

32.7 

14 

* 

* 

• 

56.5 

11.4 

32.1 

15 

• 

• 

• 

56.2 

12.1 

31.7 

16 

31.8 

13.8 

54.4 

56.4 

11.2 

32.4 

17 

* 

* 

• 

56.2 

11.3 

32.4 

18 

* 

• 

• 

55.3 

13.3 

31.4 

19 

32.2 

11.4 

56.4 

58.0 

12.1 

30.0 

20 

• 

* 

* 

60.4 

12.8 

26.8 

21 

• 

* 

* 

63.2 

11.3 

25.5 

22 

32.7 

9.3 

58.1 

64.9 

10.1 

25.0 

23 

• 

• 

• 

65.7 

9.5 

24.8 

24 

• 

* 

* 

66.3 

8.4 

25.3 

Month(s) 

DEC 

22.3 

10.8 

66.9 

38.0 

13.0 

49.0 

JAN 

26.4 

9.6 

64.0 

35.9 

11.5 

52.6 

FEB 

16.0 

10.3 

73.8 

39.6 

9.9 

50.5 

WINTER 

21.8 

10.2 

68.0 

37.8 

11.5 

50.7 

MAR 

29.7 

11.0 

59.3 

42.0 

13.2 

44.8 

APR 

33.6 

12.3 

54.1 

49.8 

14.3 

36.0 

MAY 

24.0 

12.1 

63.9 

55.7 

11.6 

32.7 

SPRING 

29.0 

11.8 

59.1 

49.2 

13.0 

37.8 

JUN 

24.4 

8.5 

67.1 

73.7 

9.9 

16.5 

JUL 

26.3 

6.4 

67.3 

89.3 

4.8 

5.8 

AUG 

32.4 

8.4 

59.2 

87.0 

5.7 

7.3 

SUMMER 

27.7 

7.7 

64.5 

83.4 

6.8 

9.8 

SEP 

44.3 

8.1 

47.6 

81.4 

7.0 

11.6 

OCT 

36.0 

11.4 

52.6 

62.7 

10.1 

27.2 

NOV 

26.2 

12.6 

61.3 

47.4 

10.8 

41.8 

FALL 

35.5 

10.7 

53.8 

63.8 

9.3 

26.9 

76 


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3.8 


OTHER  CLIMATIC  PARAMETERS 


This  section  presents  analyses  of  various  secondary 
climatic  parameters.  These  parameters  have  considerable  poten- 
tial for  short-term  influence  on  BLM  land  use  alternatives,  but 
when  considered  on  a  long-term  cl i mat ol og i ca  1  basis,-  they  are 
le-ss  significant  in  characterizing  the  climate  than  the  para- 
meters previously  discussed.  The  particular  climatic  parameters 
reviewed  in  this  section  include: 


Dew  Point  and  Relative  Humidity 

Severe  Weather 

Barometric  Pressure 

Fog  and  Visibility 

Ocean  Surface  Temperatures 

Variations  of  these  particular  climatic  parameters  are 
briefly  discussed  and  variations  within  specific  climatic  zones 
of  the  Ukiah  District  are  presented  in  the  form  of  figures  and 
tables.  A  complete  bibliography  is  provided  in  the  back  as  for 
previous  sect  ions. 


3.8.1 


Relative  Humidity  and  Dew  Point 


Relative  humidity  and  dew  point  temperature  are  dis- 
cussed together  in  this  section  as  they  both  represent  measures 
of  the  available  moisture  in  the  atmosphere  as  a  function  of 
ambient  air  temperatures.  Relative  humidity  describes  the  satur- 
ation moisture  percentage  of  the  atmosphere.  More  accurately, 
this  parameter  is  defined  by  the  ratio  of  the  actual  vapor  pres- 
sure of  air  to  the  saturation  vapor  pressure  of  ambient  air 
parcels.  Dew  point  temperature  represents  the  temperature  to 
which  a  given  parcel  of  air  must  be  cooled,  at  constant  pressure 
and  water  vapor  content,  in  order  for  saturation  to  occur.  For 
example,  the  dew  point  temperature  is  the  temperature  at  which 
moisture  condenses  on  grass  and  other  exposed  surfaces  during  the 
cool  early  morning  hours.  When  this  temperature  is  below  freez- 
ing, it  becomes  the  frost  point  temperature,  i.e.,  the  point  at 
which  frost  will  develop  on  exposed  surfaces. 

Dew  point  and  relative  humidity  both  provide  a  measure 
of  the  amount  of  moisture  available  in  the  atmosphere  for  con- 
densation. However,  care  must  be  used  in  interpreting  these 
parameters.  For  example,  the  higher  the  relative  humidity,  the 
higher  the  amount  of  moisture  available  for  condensation.  How- 
ever, a  low  dew  point  does  not  necessarily  mean  low  availability 
of.  moisture.  The  key  criterion  in  interpreting  dew  point  data  is 
the  difference  between  the  dew  point  temperature  and  the  ambient 
air  temperature  which  is  commonly  known  as  the  dew  point  depres- 
sion. When  this  temperature  difference  is  small,  the  amount  of 
available  moisture  is  high.  When  there  is  no  difference,  the 
atmosphere  is  saturated.  Finally,  when  the  dew  poi  nt  ■.  depress  i  on 
is  large,  the  amount  of  available  moisture  in  the  atmosphere  is 


79 


quite  small.  In  a  great  majority  of  normal  atmospheric  condi- 
tions, supersaturat i on  does  not  occur;  therefore,  the  dew  point 
temperature  should  never  be  higher  than  the  ambient  air  temper- 
ature. 

Atmospheric  moisture  content  also  plays  an  important 
roje  in  air  quality.  High  moisture  levels  not  only  reduce 
visibility  but  can  also  enhance  the  formation  of  secondary  air 
pollutants  such  as  sulfates  and  nitrates,  which  can  further 
reduce  visibility. 

Summary  tables  and  figures  have  been  provided  for  the 
Ukiah  District  which  present  relative  humidity  and  dew  point 
temperature  data  on  a  diurnal,  monthly,  seasonal  and  annual 
basis.  Relative  humidity  and  dew  point  temperature  data  are 
generally  available  only  for  major  first  order  stations;  however, 
the  data  base  for  the  Ukiah  District  is  sufficient  to  provide 
regional  long-term  averages. 

Figure  3.8-1  summarizes  seasonal  mean  dew  point  tempera- 
ture and  relative  humidity  for  the  state  of  California.  The  data 
indicate  that  atmospheric  moisture  content  is  highest  along  the 
coastline,  particularly  in  the  extreme  northwestern  portion  of 
the  state.  There  is  a  tendency  for  moisture  to  flow  in  through 
the  Bay  Area  and  during  the  late  fall,  winter  and  early  spring 
seasons,  this  moisture  reaches  the  Central  Valley.  During  other 
seasons  of  the  year,  most  of  the  valley  is  significantly  dryer 
than  coastal  locations  as  indicated  by  the  figure.  The  southeast 
desert  is  the  dryest  portion  of  the  state  during  all  seasons. 

In  the  Ukiah  District,  relative  humidities  tend  to  be 
highest  in  winter  and  lowest  in  summer.  Detailed  information  on 
relative  humidity  is  presented  in  Figures  3.8-2  -  3.8.4.  Figure 
3.8-5  provides  a  review  of  average  dew  point  temperatures  on  a 
monthly  basis  at  key  first  order  stations.  Finally,  diurnal 
distributions  of  relative  humidity  and  dew  point  at  key  stations 
are  provided  on  a  seasonal  basis  in  Tables  3.8-1  and  3.8-2. 

To  summarize  the  data  in  the  tables  and  figures,  rela- 
tive humidities  remain  fairly  constant  at  a  rather  high  level  at 
the  coastal  locations  throughout  the  year  and  are  consistently 
lower  in  the  Sacramento  Valley.  There  is  a  strong  moisture 
gradient  between  coastal  and  inland  stations  particularly  during 
the  warmer  months. 


3.8.2 


Severe  Weather 


This  section  presents  a  basic  summary  of  severe  weather 
in  the  Ukiah  District.  The  regional  formation  and  statistical 
incidence  of  thunderstorms,  tornadoes,  hail  and  ice  are  discussed 
in  this  section.  The  damaging  effects  of  these  abnormal  weather 
features  are  also  reviewed.  In  comparison  with  other  areas  of 
the  country,  thunderstorms,  tornadoes,  hail  and  ice  occur  rela- 
tively infrequently  in  most  portions  of  the  state. 


80 


MEAN  DEW  POINT  TEMPERATURE 


Winter 


Spring     Summer      Fall 


_3  0* 


60 


MEAN   RELATIVE   HUMIDITY 


Figure  3.8-1 
Mean  Seasonal    Dew  Point  (°F) 
and  Relative  Humidity   {%)   in  California 


81 


90    - 


80   - 


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Areata 


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Figure  3.8-2 
Coastal   Climatic  Zone  Monthly-Annual   Humidity 
Distribution  in  the  Ukiah  District 


82 


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Coastal  Mountain  Climatic  Zone  Monthly-Annual   Humidity 

Distribution   in   the  Ukiah  District 


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Central  Plain  Climatic  Zone  Monthly-Annual  Humidity 
Distribution  in  the  Ukiah  District 


84 


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Ukiah  District 

Monthly-Annual   Dew  Point  Temperature 


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Thunderstorms 

Thunderstorms  are  rare  along  the  coast  and  have  no  well 
defined  season.  On  the  other  hand,  thunderstorms  developing  over 
the  interior  mountains  are  severe  on  occasion  and  occur  primarily 
during  summer.  Most  of  the  thunderstorms  that  occur  in  the  Ukiah 
Di  "strict  cause  little,  if  any,  damage.  The  storms  usually  are 
accompanied  by  brief  gusts  of  wind,  heavy  rain  and  lightning  as 
well  as  some  small  hail.  Large  hail,  strong  winds  and  a  funnel 
cloud  or  tornado  are  quite  rare.  Flash  flooding  comprises  the 
primary  source  of  damage  associated  with  summer  thunderstorms. 

Winter  thunderstorms  generally  occur  in  conjunction  with 
rapidly  moving  cold  fronts  that  pass  over  the  district.  Advanc- 
ing frontal  systems  can  promote  considerable  instability  aloft 
which  contributes  to  thunderstorm  development.  Summer  thunder- 
storms develop  over  mountainous  and  desert  areas  as  strong  sur- 
face heating  effects  couple  with  moist  maritime  air  and,  in  the 
mountians,  forced  orographic  lifting. 

Isolines  of  the  annual  mean  number  of  thunderstorm  days 
are  depicted  on  a  national  scale  in  Figure  3.8-6.  Generally,  the 
Ukiah  District  experiences  5-10  thunderstorm  days  per  year. 
Considerable  data  resolution  is  lacking  on  Figure  3.8-6  and  the 
distribution  does  not  reflect  the  higher  incidence  of  thunder- 
storm days  that  can  be  experienced  in  the  mountainous  areas. 
Isolated  thunderstorm  activity,  as  observed  on  radar  over  moun- 
tain areas,  averages  as  high  as  50  to  60  days  per  year  at  some 
locations.  Lightning  strikes  resulting  from  these  thunderstorms 
can  cause  dry  brush  to  ignite  and  promote  forest  fires.  Detailed 
data  for  selected  stations  in  the  Ukiah  District  are  presented  in 
Table  3.8-3. 


Table  3.8-3 
Mean  Number  of  Thunderstorm  Days 


Station 

Areata 

Eureka 

San  Francisco 

Ukiah 

Sacramento 


w 

int 

er 

2. 

0 

3. 

0 

0. 

8 

2. 

0 

0. 

5 

Spring 

4.0 
0.8 
0.8 
5.0 
2.3 


Summer 

2.0 
0.8 
0.8 
17.0 
0.8 


Fal  1 


1.0 
1.  5 
0.8 
6.0 
1.5 


Annual 

4.0 
6.  1 
3.2 
30.0 
5.1 


Tornadoes 

Tornadoes  and  funnel  clouds  are  associated  with  severe 
thunderstorms.  They  develop  when  just  the  right  conditions  of 
moisture,  atmospheric  stability,  and  winds  are  present.  Torna- 
does frequently  form  within  thunderstorms  that  have  organized 
into  lines.   Frequently,  but  not  always,  these  "squall  lines"  are 


88 


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associated  with  vigorous  and  rapidly  advancing  cold  fronts  that 
promote  rapid  lifting  of  ambient  air  to  heights  in  excess  of 
60,000  feet. 

The  environmental  setting  in  California  limits  the 
potential  for  the  development  of  tornadic  conditions.  The  near 
proximity  of  the  cool  waters  of  the  Pacific  Ocean  and  the  Eastern 
Pacific  semi -permanent  high  pressure  center  tends  to  inhibit  the 
necessary  rapid  lifting  of  surface  air.  The  downward  air  motion 
associated  with  this  high  pressure  area  tends  to  warm  and  stabi- 
lize the  atmosphere,  thus  creating  conditions  adverse  to  tornado 
or  severe  thunderstorm  activity.  On  rare  occasions,  surges  of 
cold  air  at  upper  levels  move  into  California  and  can  combine 
with  warm  moist  onshore  surface  winds  to  produce  the  unstable 
atmospheric  conditions  necessary  for  tornado  formation. 


average 


Tornadoes  have  been  reported 
frequency  of  only  1  or  2  per 


in  California,  but  with  an 
year.   They  are  generally 


not  severe,  in  many  cases  causing  little  more  than  damage  to 
trees  or  light  buildings.  Pilots  occasionally  report  sightings 
of  funnel  clouds  aloft,  particularly  off  the  southern  California 
coast.  The  map  on  Figure  3.8-7  depicts  areas  of  tornado  activity 
in  California  for  the  period  from  1930-1974.  Table  3.8-4  pro- 
vides a  complete  listing  of  historical  tornado  and  funnel  cloud 
observations  for  the  Ukiah  District  and  nearby  regions. 

Fujita  has  presented  a  classification  scheme  for  tor- 
nadoes, presented  in  Table  3.8-5,  which  has  been  used  to  cate- 
gorize California  tornadoes  as  shown  in  Table  3.8-5.  A  scale  is 
presented  below  as  devised  by  Fujita  and  as  outlined  in  a  report 
submitted  to  the  University  of  California  by  Meteorology  Re- 
search, Inc  ( MR  I ) .  Specifications  of  damage  are  presented  as 
visual  guidelines,  and  not  as  absolute  criteria. 


Table  3.8-4 
Review  of  Tornado  Sightings  in  the  Ukiah  District 


Date 

April  19,  1967 
April  27,  1970 

January  12,  1971 
August  25,  1973 


Time 

1108 
1720 


1655 


Location 

Fairfield 
Williams,  Colusa 

Santa  Rosa 
Point  Arena 


Type 

FC* 
FC 

FC 
FC 


Remark  s 


Ver i  f i  ed  by 
Sacramento  Radar 


Funnel  Cloud 


90 


SAN  FRANCISCO 


Figure  3.8-7 
Tornado  Activity  in  California 
During  the  Period  1930-1974 


91 


(FO) 


(Fl) 


(F2) 


(F3) 


(F4) 


(F5) 


Table  3.8-5 
Fujita  Tornado  Classification  Scheme 

GALE  TORNADO,  Light  Damage 

40-72  mph 

Some  damage  to  chimneys  and  TV  antennae; 

twigs  off  trees;  pushes  trees  over. 


break  s 


(F6) 

(F7) 

(F8) 

(F9) 

(F10) 

(Fll) 

(F12) 


WEAK  TORNADO,  Moderate  Damage 

73-112  mph 

Peels  surface  off  roofs;  windows  broken;   light 

trailer  houses  overturned;  some  trees  uprooted  or 

snapped;  automobiles  pushed  off  the  road. 

STRONG  TORNADO,  Considerable  Damage 

113-157  mph 

Roofs  torn  off  frame  houses  leaving  only  strong 

walls   upright;   trailer  houses  destroyed;   large 

trees  snapped  or  uprooted;  railroad  box  cars 

derailed;   light  object  missiles  generated;  cars 

bl own  off  hi  ghway . 

SEVERE  TORNADO,  Severe  Damage 
158-206  mph 

Roofs  and  some  walls  torn  off  frame  houses;  trains 
derailed  or  overturned;  steel  framed  hangar-ware- 
house type  structures  torn;  cars  lifted  off  the 
ground . 

DEVASTATING  TORNADO,  Devastating  Damage 

207-260  mph 

Whole  frame  houses  leveled,  leaving  piles  of 

debris;  steel  structures  badly  damaged;  small 

flying  objects  debark  trees;  cars  and  trains 

thrown  or   rolled  considerable  distances,   large 

missiles  generated. 

INCREDIBLE  TORNADO,  Incredible  Damage 
261-318  mph 

whole  frame  houses  tossed  off  foundations;  auto- 
mobile-sized missiles  generated;  incredible  phe- 
nomena can  occur. 

319-379  mph 

380-445  mph 

446-513  mph 

514-585  mph 

586-659  mph 

660-737  mph 

738-818  mph 


92 


Photographs  and  eyewitness  accounts  of  the  larger  tor- 
nadoes have  been  used  to  compile  the  various  classifications. 
Table  3.8-6  presents  a  summary  of  the  historical  intensities  of 
California  tornadoes. 

Table  3.8-6 


Historical  Intensity  Of  California  Tornadoes 
Based  Upon  the  Fujita  Classification  Scheme 


Class 

FO 

Fl 

F2 

F3  or  worse 


No.  of 
Storms 

8 
32 

8 

0 


Percentage  (%) 

of  Observations 
16.7 

66.  7 

16.7 

0.0 


Hail 

Hail  results  from  the  formation  of  spheres  of  irregular 
chips  of  ice  which  are  produced  by  convective  activity  in  storm 
clouds,  such  as  in  cumulonimbus  types.  Thunderstorms  which  are 
characterized  by  strong  updrafts,  high  water  content,  large  cloud 
drop  sizes,  and  great  vertical  height  extent  offer  great  poten- 
tial for  hail  and  ice  formation.  Hail  sizes  can  range  from  that 
of  a  few  millimeters  in  diameter  to  sizes  on  the  order  of  several 
centimeters.  Table  3.8-7  presents  the  incidence  of  hail  and 
sleet  seasonally  and  annually  at  several  selected  stations  in  the 
Ukiah  District. 

Table  3.8-7 


Stat  i  on 

Areata 

Ukiah 


Mean  Number  of  Days  With  Hail/Sleet  or  Ice 


Winter 

Spring 

Summer 

Fall 

Annua 

1.0 

0.0 

0.0 

0.0 

1.0 

1.0 

0.0 

0.0 

0.0 

1.0 

3.8.3 


Atmospheric  Pressure 


Atmospheric  pressure,  as  a  climatic  parameter,  has 
little  direct  effect  on  the  ambient  environment  but  acts  as  a 
climatic  control  parameter,  such  that  slight  variations  in  atmos- 
pheric pressure  can  induce  remarkable  variations  in  general 
weather  conditions.  Pressure  gradients  regulate  wind,  and  wind 
is  a  major  determinant  of  regional  air  temperature  and  moisture 
conditions.  This  also  provides  a  connection  between  pressure  and 
dispersion  meteorology  and  ambient  air  quality.  In  addition, 
pressure  systems  are  often  positively  correlated  with  pollutant 


93 


levels.  For  example,  the  semi-permanent  eastern  Pacific  High 
Pressure  system  permits  the  buildup  of  high  pollutant  levels  in 
Southern  California  during  summer. 

Atmospheric  pressure  is  defined  as  the  force  exerted  by 
the  atmosphere  upon  a  unit  surface  area  as  a  consequence  of 
gravitational  attraction  on  all  air  molecules.  Hence,  atmos- 
pheric pressure  is  a  measure  of  the  total  weight  of  air  situated 
above  an  area    in  question. 


Pressure 


is  defined  in  dimensions  of  fo>rce  per  unit 
area,  such  as  dynes  p,er  square  centimeter  (dynes/cm  ),  pounds  per 
square   inch   (lbs/in  ),   or  newtons   per   square 


inch 
Meteorologists  often 
(mb ) ,  such  that ,  1  mb 


or 
refer 


newtons 
to  the 


dynes/cm' 
equals  1,000  dynes/cm 


meter   (N /m  ) . 
ratio  as  millibars 


Pressure  measurements  are  at  times  expressed  in  terms  of 
standards.  The  average  global  mean  sea  1  e  v  e,l  pressure  has  been 
determined  to  be  1,013.25  mb  (14.7  lbs/ in  ).  This  value  of 
pressure  is  often  referred  to  as  1  Standard  Atmosphere  (Atm). 
Similarly,  the  pressure  level  of  approximately  506  mb  (7.35 
lbs/in  )is  referred  to  as  0.5  Atm. 

Atmospheric  pressure  values  are  often  expressed  in  terms 
of  equivalents.  Since  the  atmosphere  exerts  a  force  or  weight 
per  unit  area  ,  it  therefore  counter-balances  an  equivalent 
weight.  A  column  of  air  one  square  inch  in  cros s- sect i onal  area 
extending  from  sea  level  to  the  top  of  the  atmosphere  weighs 
approximately  14.7  pounds.  This  weight  can  be  balanced  by  a 
column  of  mercury  having  the  same  cross-sectional  area  extending 
vertically  29.92  inches  or  760  millimeters.  Therefore,  pressure 
values  can  be  referred  to  in  units  of  inches  (in)  or  millimeters 
of  mercury  (mmHg)  with  the  understanding  that  these  values  repre- 
sent the  atmospheric  mass  that  supports  a  vertical  column  of 
mercury  so  many  inches  or  millimeters  long.  As  atmospheric 
pressure  changes  in  an  area,  the  air  mass  above  that  region 
changes,  and  likewise,  its  ability  to  counter- bal ance  the  weight 
of  the  previously  described  column  of  mercury. 

Table  3.8-8  provides  the  conversion  factors  necessary  to 
transform  pressure  values  into  various  conventional  pressure 
units  and  equivalents.  An  example  demonstrating  how  to  use  these 
factors  is  provided  below  the  table. 

Figures  3.8-8  through  3.8-11  provide  a  representive 
cross- sect i on  of  the  mean  seasonal  pressure  contours  on  a  na- 
tional scale.  General  atmospheric  flow  can  be  estimated  by 
assuming  that  winds  move  nearly  parallel  to  isobars  (lines  of 
equal  pressure  values).  In  the  northern  hemisphere,  winds  blow 
clockwise  ( anticycl oni c)  around  the  high  pressure  centers  and 
counterclockwise  (cyclonic)  about  low  pressure  centers. 

During  the  winter  months,  a  high  pressure  center  is 
generally  situated  to  the  northeast  of  California  and  the  semi- 
permanent Eastern  Pacific  high  pressure  system  is  depressed  well 


94 


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Figure  3.8-8 
Mean  Winter  (January)  Pressure  Distribution 
in  the  United  States 


br  --!■■  zzkz  kiMkii* 


Based  on    1931-60 


r7*r  fia  m  "■"■  ma 


Figure  3.8-9 
Mean  Spring  (April)  Pressure  Distribution 
in  the  United  States 


96 


Figure  3.8-10 

Mean  Summer  (July)  Pressure  Distribution 
in  the  United  States 


rl5!i-_* 


r NORHAL~SEA  ilvEL  ^RESSURI,   OCTOBErV— -^     ~~ SyTZzE^F 

- ] — —   (Millibars   and   Inches)-^ \  \         *  i/_3TM. 


t?F^^fe^;^ii  N«?  t>":'  -----  ---- 

>'  .  i=j^^EfrA    l-i^^---.^  -   Based  on  1931-6 


Fi  gure  3.8-11 

Mean  Fall  (October)  Pressure  Distribution 
in  the  United  States 


97 


to  the  south.  This  permits  moist  air  to  be  channeled  into  the 
state  from  the  northwest,  west  and  southwest.  The  strong  poten- 
tial for  moisture  advection  during  the  winter  months  in  Cali- 
fornia promotes  the  "rainy"  season.  Air  quality  also  tends  to  be 
better  during  this  season. 

In  the  hot  summer  months,  a  low  pressure  center  domi- 
nates the  southwestern  portion  of  the  nation.  Winds  generally 
flow  inland  as  the  sea  breeze  regime  becomes  established.  The 
Eastern  Pacific  High  Pressure  area  becomes  well  entrenched  over 
California  and  inhibits  the  flow  of  moist,  maritime  air  into  the 
area,  thus  permitting  the  development  of  high  pollutant  levels. 

Definite  pressure  cycles  occur  on  numerous  time  scales. 
Mean  pressure  values  experienced  in  particular  regions  vary 
seasonally  and  diurnally.  Latitude,  elevation,  topography  and 
surface  albedo  collectively  influence  the  mean  pressure  tenden- 
cies registered  at  a  particular  location.  Variations  in  atmos- 
pheric pressure,  at  Areata  and  Ukiah,  are  depicted  on  a  monthly- 
annual  basis  in  Figure  3.8-12  and  on  a  diurnal-seasonal  basis  in 
Figure  3.8-13.  The  monthly  seasonal  distribution  indicates  that 
barometric  pressure  reaches  a  seasonal  maximum  in  spring  at 
Areata  and  in  winter  in  Ukiah.  At  many  stations  throughout  the 
United  States  winter  is  the  traditional  season  of  maximum  high 
pressure,  however,  at  Areata  the  frequent  passage  of  migratory 
storm  systems  prohibits  this.  Highest  surface  pressure  occurs 
during  December  at  Ukiah  and  in  April  at  Areata.  On  a  diurnal 
basis  maximum  surface  pressure  is  generally  observed  during  the 
mid-morning  hours  at  each  station  with  a  minimum  occurring  during 
late  afternoon.  Surface  pressure  is  generally  higher  at  Areata 
than  at  Ukiah  during  all  months  except  winter,  the  rainy  season. 
Ukiah  is  strongly  influenced  by  surface  heating  effects  and 
during  other  seasons  of  the  year  this  tends  to  result  in  lower 
pressure  at  this  station  as  opposed  to  the  coastal  site  of 
Areata . 


3.8.4 


Visibility  and  Fog 


Visibility  provides  an  indication  of  atmospheric  clar- 
ity. Visibility  measurements  or  estimates  are  generally  ex- 
pressed in  miles  or  kilometers  denoting  the  maximum  distance  at 
which  one  can  distinguish  objects  such  as  buildings,  mountains 


and  other  large  landmarks, 
numerous  physical  factors 
as  well  as  thermodynamic 
more  common  factors  that 
visibility  and  contrast 


Visibility  reduction  is  the  result  of 
that  include  both  general  air  quality 
and  optical  properties.  Some  of  the 
play  an  important  role  in  atmospheric 
reduction  are  air  moisture  content, 
relative  humidity,  falling  rain,  snow,  hail,  blowing  dust,  sea 
spray,  high  concentrations  of  suspended  particulate  matter, 
sulfates,  oxides  of  nitrogen,  and  smoke. 

Tables  3.8-9  and  3.8-10  present  monthly,  seasonal  and 
annual  percentage  frequency  distributions  of  visibility  for  Ukiah 
and   Areata   in   the   Ukiah   District.    The   data   represent 


98 


"  1016  I— 

1015 


L. 

Q. 


i. 

.c 
o. 
</) 

o 

E 


1014 
1013 
1012 
1011 
1010 
1009 
1008 
1007 
1006 
1005 


Ukiah 


I        I L__J I L 


M        A        M       J       J         AS 
Month    of    the    Year 


0        N 


Figure  3.8-12 
Monthly-Annual   Distribution  of  Atmospheric  Pressure  in 

the  Ukiah  District 


99 


1     2     3     4     5     6     7     •     9     10   11    12   13   14  15    16  17  18   19  20  21   22   23  24 

HOUR  OF  THE  DAY 


Figure  3.8-13 
Diurnal-Seasonal  Pressure  Variations  in  the  Ukiah  District 


Analyses  based  on  8  obs/day 


100 


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observations  of  visual  range  by  trained  NWS  observers  at  major 
airport  locations.  The  data  indicate  that  the  frequency  of 
significantly  reduced  visibilities  is  greatest  at  Areata  due 
largely  to  higher  moisture  levels.  Visibility  is  generally 
between  5  and  10  miles  during  all  seasons.  The  frequency  of 
significantly  reduced  visibility  is  greatest  between-  June  and 
October  at  Areata  when  fog  and  stratus  frequently  occur.  At 
Ukiah,  visibilities  are  generally  between  10  and  2  5  miles. 
Poorest  visibility  occurs  in  winter  when  fog  occurs  most  fre- 
quent 1  y . 

In  the  mountains,  visibility  is  extremely  variable. 
Data  is  very  scarce  and  the  BLM  is  participating  in  programs 
geared  to  determine  visibility  on  federally-administered  lands. 
The  data  presented  in  Tables  3.8-9  through  3.8-10  is  not  felt  to 
be  indicative  of  conditions  in  rural,  mountainous  locations. 

Air  quality  can  be  determined  from  visibility  observa- 
tions at  particular  locations  within  the  district.  By  elimina- 
ting moisture  influences  on  atmospheric  clarity,  the  remaining 
reduction  in  visibility  is  largely  due  to  suspended  to  air  con- 
taminants. Table  3.8-11  presents  the  number  of  hours  during  a 
representative  five  year  period  that  substantial  visibility 
reduction  occurred  due  to  non-moisture  effects  at  Areata  and 
Ukiah.  The  criteria  denoting  a  visibility  violation  in  Cali- 
fornia was  used  to  develop  this  table.  A  violation  occurs  when 
visibility  is  less  than  10  miles  and  the  relative  humidity  is 
less  than  70  percent.  Once  again,  data  are  not  available  for 
much  of  the  mountainous  areas  in  the  district. 

Table  3.8-11  indicates  that  at  Areata  violations  of  the 
California  visibility  standard  occur  primarily  during  the  fall 
and  winter  months  when  stagnation  episodes  occur.  At  Ukiah, 
summer  and  fall  provide  the  maximum  frequency  of  violations  of 
the  standard.  Photochemical  processes  occur  most  actively  during 
this  season  resulting  in  visibility  impairment  at  Ukiah.  The 
frequency  of  violations  is  generally  greater  at  Ukiah  then  at 
Areata  which  is  greatly  impacted  by  the  onshore  flow  of  clean, 
maritime  Pacific  air. 

Fog 

Considerable  visibility  reduction  is  directly  related  to 
ambient  moisture  levels.  Table  3.8-12  presents  the  mean  number 
of  days  that  visibility  is  less  than  one-quarter  mile  due  to  the 
presence  of  heavy  fog. 

Table  3.8-12  indicates  that  the  frequency  of  fog  is 
greatest  during  the  winter  months  at  all  stations  with  the  excep- 
tion of  Areata.  At  Eureka,  San  Francisco,  Ukiah,  and  Sacramento 
the  frequency  of  fog  reaches  a  maximum  during  the  December  - 
January  time  frame  when  the  passage  of  migratory  storm  systems 
reaches  a  maximum.  The  frequency  of  fog  during  the  winter  months 
increases  with  northward  progression  along  the  coast.    Areata 


103 


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shows  a  maximum  frequency  of  heavy  fog  during  the  summer  and  fall 
months,  with  heavy  fog  being  not  uncommon  during  any  month  of  the 
year . 

Fog,  is  associated  with  moist,  cool,  surface  air  masses 
at  the  point  of  saturation.  Fog  can  be  classified  i  n  tro  numerous 
types  according  to  the  physical  processes  responsible  for  its 
development.  Fog  types  that  are  common  in  the  Ukiah  District 
i  ncl ude : 

0   Radiational 

•  Advection 

•  Fronta 1 

A  very  common  type  of  land  fog  often  experienced  in  the 
mountian  valleys  known  as  radiational  or  surface  inversion  fog, 
is  produced  by  the  radiational  cooling  of  relatively  shallow 
layers  of  calm,  humid  air,  overlying  a  chilled  land  surface. 
This  type  of  fog  development  requires  certain  nighttime  condi- 
t i  ons  whi  ch  i  ncl ude  : 

•  Stabl e  surface  ai  r 

•  Light  or  calm  winds 

•  Clear  skies 

Stable  surface  conditions  inhibit  vertical  diffusion  of  fog 
formed  at  the  surface.  Light  winds  promote  radiational  fog 
development  by  limiting  mixing.  Cloudless  skies  promote  fog 
since  they  allow  rapid  heat  loss  from  the  surface  thus  permitting 
the  ground  to  cool  rapidly,  even  below  surface  air  temperatures. 

Radiational  fog  occurs  in  low-lying  areas  as  cool,  dense 
air  drains  into  valleys  and  low-lying  regions.  Often,  hilly 
areas  will  remain  clear  while  adjacent  lowlands  are  foggy. 
Radiational  or  ground  fog  deepens  from  the  ground  upward  at  night 
and  is  dissipated  during  the  day  by  the  warming  sunlight  from  the 
top  downward. 

Advection  fog,  unlike  radiational  fog,  requires  consid- 
erable air  movement  to  promote  formation.  It  simply  requires 
that  warm  moist  air  masses  be  moved  over  cold  surfaces  and  this 
most  commonly  occurs  over  ocean  and  coastal  locations  during 
summer.  During  this  period,  pressure  gradients  between  oceanic 
and  inland  air  masses  are  at  a  maximum,  thus  promoting  inland 
movement  (sea  breeze).  At  coastal  locations,  warm  moist  air  is 
channelled  over  and  mixed  with  cold,  moist,  surface  maritime  air. 
Condensation  of  water  vapor  in  the  ambient  air  is  promoted,  thus 
forming  fog.  This  type  of  coastal  sea  fog  is  most  commonly 
observed   during  the  summer  months. 

The  frequency  of  occurrence  of  fog  by  month  in  the 
Ukiah  District  is  presented  in  Figure  3.8-14.  The  figure  pro- 
vides fog  frequency  at  selected  key  stations  in  of  the  Ukiah 
District. 


106 


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Figure  3.8-14 
Frequency  of  Fog  Development  in  the 
Ukiah  District 


107 


3.8.5 


Ocean  Temperatures 


Seasonal  variations  of  ocean  temperatures  have  a  de- 
finite effect  on  the  climatology  of  coastal  areas.  During  the 
winter  months,  ocean  temperatures  are  near  and  often- above  am- 
bient air  temperatures.  In  the  summer,  however,  ocean  tempera- 
tures are  generally  below  ambient  air  temperatures.  The  physical 
effect  of  ocean  temperatures  on  mean  seasonal  air  temperatures  at 
coastal  locations  in  comparison  to  inland  areas  is  outlined  in 
the  temperature  section  of  this  report.  Mean  monthly  ocean  tem- 
perature contours  are  presented  in  Appendix  B.  The  mean  monthly 
temperature  change  from  the  maximum  to  the  minimum  is  4.4°C 
(7.9°F)  at  San  Francisco  and  only  2.2°C  (4.0°F)  at  Cape  Mendo- 
cino. Table  3.8-13  presents  the  mean  monthly  ocean  temperatures 
for  San  Francisco  and  Cape  Mendocino.  Generally,  ocean  tempera- 
tures are  warmer  at  San  Francisco  than  at  Cape  Mendocino  during 
all  seasons.  Mean  annual  temperatures  for  much  of  the  California 
coastline  are  presented  in  Figure  3.8-15.  Generally,  the  coastal 
waters  along  the  Ukiah  District  average  about  52  F. 


108 


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3.9 


URBAN  EFFECT  UPON  METEOROLOGIC  PARAMETERS 


There  is  hardly  a  meteorologic  element  that  can  be  named 
that  is  not  influenced  to  some  extent  by  cities.  It  is,  however, 
difficult  to  separate  urban  effects  from  microclimatologic  ef- 
fects since  yery  few  measurements  have  been  made  with  the  specif- 
ic aim  of  comparing  urban  and  non-urban  measurements.  There  are 
several  causes  for  the  differences  between  urban  and  open  country 
climates.  One  of  these  is  the  alteration  of  the  surface,  e.g., 
the  change  from  meadow,  forest  or  swamp  to  buildings  and  streets 
of  concrete,  brick,  steel,  and  asphalt.  Not  only  does  this  cause 
changes  in  reception  and  reflection  of  solar  radiation  and  evap- 
oration, but  also  in  the  roughness  of  the  surface  over  which  the 
wind  moves.  Another  change  involves  the  production  of  a  sizable 
quantity  of  heat  due  to  combustion  processes  carried  out  in  the 
city  and  the  addition  of  material  to  the  atmosphere  in  the  form 
of  dusts,  gases,  and  vapors  which  change  the  atmosphere's  compo- 
sition in  the  vicinity  of  cities. 

Temperature 

The  comparison  of  temperatures  within  cities  with  those 
outside  reveal  that  city  temperatures,  especially  at  time  of 
minimum,  are  higher  (Mitchell,  1961).  Also  during  the  period 
right  after  sunset,  the  city  temperature  does  not  cool  as  rapidly 
as  does  the  country  air  due  to  heat  content  of  buildings  and 
radiation  between  buildings,  rather  than  toward  the  sky.  Between 
sunrise  and  noon,  urban  and  non-urban  temperatures  are  nearly  the 
same  (Landsberg,  1956).  The  influence  of  the  city  extends  in 
the  vertical  on  the  order  of  three  times  the  height  of  the  build- 
ings (Duckworth  and  Sandberg,  1954).  The  average  heat  island 
effect  over  New  York  City  extends  to  300  meters  (-1000  feet)  and 
has  been  observed  as  high  as  500  meters  (-1650  feet)  (Bernstein, 
1968).  Also,  the  change  of  temperature  with  height  is  quite 
different  over  the  city,  especially  at  night.  In  the  open  coun- 
try, radiation  inversions  form  frequently,  whereas  in  the  city, 
isothermal  or  neutral  conditions  frequently  exist  through  the 
night  with  a  radiation  inversion  layer  above  the  city  (DeMarrais, 
1961)  . 

Since  temperatures  in  the  city  are  warmer  than  those  of 
the  surrounding  countryside,  the  city's  heating  requirements  are 
less  by  as  much  as  10%.  Variations  between  city  and  country 
temperatures  are  extremely  noticeable  at  northern  latitudes  when 
the  countryside  is  covered  with  snow  which  has  melted  in  the 
city. 


Preci  pi  tat  i  on 

Precipitation  is  one  of  the  most  variable  meteorological 
elements  and,  because  of  this,  it  is  difficult  to  establish 
significant  differences  between  urban  and  non-urb-an  areas. 
However,  numerous  studies  have  been  made  which  show  either  great- 
er precipitation  amounts  and/or  greater  frequency  of  precipita- 
tion within  cities.  Schmauss  in  1927  showed  11  percent  increase 
of  days  with  small  amounts  of  precipitation  occurring  in  Munich 
compared  to  stations  outside  the  city.  Bolgolepow  in  1928  re- 
ported an  increase  in  precipitation  of  10  percent  in  Moscow 
compared  to  a  country  station  for  17  years  of  record.  Ashworth 
in  1929  noted  the  increase  of  average  annual  precipitation  over  3 
decades  amounting  to  13  percent.  He  also  noted  less  increase  for 
Sundays  than  for  weekdays.  Wiegel  in  1938  using  a  35  year  re- 
cord, noted  a  5  percent  increase  in  precipitation,  as  well  as  a 
12  to  18  percent  increase  in  the  number  of  days  with  precipita- 
tion for  the  Ruhr  area  of  Germany.  These  references  are  all 
reported  in  Landsberg  (1956).  Landsberg  also  reports  a  study  for 
Tulsa  where  topographical  effects  are  at  a  minimum  and  the  urban 
area  is  confined  to  a  rather  definite  area.  In  addition  to  a 
precipitation  increase  within  the  city  over  a  70  year  period, 
there  was  an  increase  of  7  percent  in  the  city  compared  to  sur- 
roundings for  a  14  year  period. 

Two  more  recent  studies  by  Changnon  (1961a,  1961b) 
indicate  there  may  be  some  urban  effect  upon  preci pi tai ton  over 
Chicago  and  the  moderate- si  zed  communities  of  Champaign,  and 
Urbana,  Illinois. 

The  principal  suspected  causes  of  the  increase  of  pre- 
cipitation over  cities  is  the  increase  of  condensation  nuclei 
over  cities  due  to  air  pollutants  and  the  increased  turbulence 
caused  by  increased  surface  roughness.  Although  water  vapor  is 
added  to  the  air  from  combustion  sources,  this  is  not  expected  to 
add  significantly  to  the  amount  of  precipitable  water  or  to  evoke 
a  major  effect. 

Snow 


Precipitation  in  the  form  of  snow  indicates  to  some 
extent  the  influence  of  temperature  in  the  urban  area.  Kossner 
in  1917  and  Maurain  in  1947  indicated  greater  frequencies  of 
snowfall  outside  as  compared  to  within  Berlin  and  Paris,  respec- 
tively. On  the  other  hand,  Kratzer  in  1937  in  Munich  reported 
occurrances  of  snow  within  the  city 
surroundings,  and  Keinle  in  Mannheim, 
reported  that  snow  fell  from  a  fog 
successive  days  in  January  1949  while 
area.  It  is  probable  that  this  was 
nishing  condensation  nuclei  for  supercooled  water  vapor.  These 
references  appear  in  Landsberg  (1956)  who  also  estimates  a  5% 
average  decrease  in  snowfall  for  urban  areas  (Landsberg,  1968). 


when  none  occured  in  the 

a  heavy  industry  location, 

and  stratus  layer  on  two 

none  fell  outside  the  urban 

due  to  air  pollutants  fur- 


112 


Cloudiness 

From  cl i matol og i cal  records  there  seems  to  have  been  a 
slight  increase  in  cloudiness  over  the  years  but  this  has  been  so 
slight  (less  than  1/10  of  mean  sky  cover)  that  for  so  subjective 
a  measure  as  sky  cover  this  may  not  be  significant.  Any  increase 
may  be  primarily  due  to  city  fogs,  as  increases  in  early  morning 
cloud  cover  seems  to  be  greatest.  Nearly  all  large  cities  show  a 
decrease  in  the  number  of  clear  days  over  that  obseved  in  adja- 
cent rural  areas.  The  primary  effects  may  be  expected  to  be  due 
to  addition  of  condensation  nuclei  by  air  pollution  and  the 
release  of  additional  water  vapor.  Kratzer  in  1937  in  Munich 
indicated  an  8  percent  increase  in  summer  cloudiness  compared  to 
a  3  percent  increase  in  winter  cloudiness  over  the  city  (Lands- 
berg,  1956).  This  may  indicate  that  surface  roughness  and  there- 
fore, increasing  turbulence,  may  play  a  part  in  the  formation  of 
cumulus  type  summer  clouds. 

Wind 

Because  of  the  general  increase  of  the  size  of  the 
roughness  elements  in  the  city  over  that  in  the  rural  areas,  wind 
speeds  are  decreased  within  the  city.  Also  the  frequency  of 
calms  is  increased  on  the  order  of  5  to  20  percent  (Landsberg, 
1956).  Recently,  Pooler  (1961)  has  shown  that  under  conditions 
of  light  stable  flow,  an  inflow  of  air  toward  the  center  of  the 
city  of  Louisville  occurs  (heat  island  effect).  In  addition  to 
the  decrease  of  wind  speed  in  cities,  there  is  of  course  channel- 
ing of  the  wind  in  the  canyons  formed  by  alternating  streets  and 
groups  of  buildings. 

Radiation 

The  decrease  of  solar  radiation  within  cities  as  com- 
pared to  rural  areas  is  on  the  order  of  15  to  20  percent.  This 
is  due  to  the  absorption,  reflection,  and  scattering  of  particles 
in  the  atmosphere,  and  the  absorption  of  gases.  These  particles 
and  gases  are  primarily  the  result  of  air  pollution.  The  radia- 
tion most  affected  is  the  ultraviolet  with  the  infrared  being 
least  affected.  This  is  important  because  of  the  bactericidal 
effect  of  ultraviolet  radiation. 

Recently,  McCormick  (1960)  has  begun  measuring  of  the 
attenuation  of  the  solar  beam  at  0.5  micron  wave  length  in  order 
to  have  an  objective  measure  of  the  entire  pollution  layer.  In 
terms  of  duration  of  sunshine,  Landsberg  (1968),  shows  a  decrease 
in  the  range  of  5-15%  in  urban  areas.  Randerson  (1970)  has 
showed  an  average  of  23%  loss  in  intensity  of  light  attributed  to 
pollution  in  Houston,  Texas. 


113 


Visual  Range 

The  decrease  of  visibility  in  urban  areas  is  probably 
the  most  noticeable  of  meteorological  differences  between  urban 
and  rural  areas.  Comparisons  between  hourly  observations  of 
visibility  at  city  locations  and  at  rural  locations  (-Landsberg, 
1956)  have  shown  higher  frequencies  of  fog,  smoke,  and  low  visi- 
bilities than  in  neighboring  rural  areas. 

Holzworth  and  Maga  (1960)  analyzed  visibility  measure- 
ments from  California  locations  to  determine  if  trends  which 
might  be  caused  by  increases  in  air  pollution  were  noticeable. 
Results  indicated  that  several  cities  showed  trends  toward  lower- 
ing visibilities.  Other  showed  lowering  visibilities  until 
efforts  at  controlling  certain  pollutants  were  made,  after  which 
no  trend  was  discernible. 


114 


3.10      GENERAL  ASSISTANCE  IN  CLIMATIC  PROBLEMS 

REFERENCES 

t     Abstracts 

Meteorological  and  Geoast rophys i cal 
Abstracts 

American  Meteorological  Society 

45  Beacon  Street 

Boston  ,  Mass . 

•    Periodicals 

Bulletin  of  the  American  Meteorological 
Soc  i  ety 

American  Meteorological  Society  (See  above) 

Journal  of  Applied  Meteorology 

American  Meteorological  Society  (See  above) 

Journal  of  the  Atmospheric  Sciences 
(formerly  Journal  of  Meteorology) 

American  Meteorological  Society  (See  above) 

Monthly  Weather  Review 

U.S.  Dept.  of  Commerce 

Weather  Bureau,  Washington,  D.C. 

Quarterly  Journal   of  the  Royal  Meteorological 
Society 

Royal  Meteorological  Society 

49  Cromwel 1  Road 

London  ,  S. W  .  7 

Weather 

Royal  Meteorological  Society  (See  above) 

Weatherwise 

American  Meteorological  Society  (See  above) 


Books 

American  Meteorological  Society,  On  Atmospheric 
Pollution, 

Meteorol ogical  Monographs,  1_,  4,  Nov.  1951. 

Byers,  H.R.   General  Meteorology, 

McGraw-Hill,  New  York,  3rd  ed.  1959. 

Geiger,  R.  (Translated  by  Scripta  Technica  Inc.) 
The  Climate  Near  the  Ground. 

Rev.  ed.,  Harvard  University  Press,  Cambridge, 

Mass.  1965. 


115 


Haltiner,  G.J.;  and  Martin, 
Physical  Meteorology. 

McGraw-Hill,  New  York. 


F. L.  Dynami  cal  and 
1957 


Hess,  S.L.  Introduction  to  Theoretical  Me-teorology. 
Henry  Holt,  New  York,  1959. 

Hewson,  E.W.:  and  Longley,  R.W.  Meteorol ogy , 
Theoretical  and  Applied 

Wiley,  New  York.   1944. 

Professional  Meteorological  Consultants 

Professional  meteorologists  advertise  their  services  in 
the  Professional  Directory  section  of  the  Bulletin  of  the  Ameri- 
can Meteorological  Society.  In  the  May  1979  Bulletin,  83  such 
firms  and  individuals  were  listed.  The  American  Meteorological 
Society  has  in  the  last  several  years  instituted  a  program  of 
certifying  consulting  meteorologists.  Of  the  83  professional 
services  listings  in  the  Bulletin,  40  list  Certified  Consulting 
Meteorologists. 

Local  U.S.  National  Weather  Service  Office 

A  wealth  of  meteorological  informaiton  and  experience  is 
available  at  the  local  city  or  airport  Weather  Service  Office 
pertaining  to  local  climatology,  pecularities  in  local  micro- 
meteorological  conditions  including  topographic  effects,  and 
exposure  and  operating  characteristics  of  meteorological  instru- 
ments . 

Contract  Work 

Many  universities  do  contract  work  for  private  organi- 
zations and  for  government  agencies  on  meteorological  problems. 


116 


BIBLIOGRAPHY 

Bernstein,  R .  D  .  ,  Observations  of  the  Urban  Heat  Island  Effect  in 
New  York  City.   J.  Appl.  Meteor.  7_,    4:575-592,  Aug.,  1968. 

California  Energy  Commission,  California  Solar  Data  Manual , 
Sacramento,  California,  1978. 

California  Snow  Survey  Service,  Historical  Data  of  Cooperative 
Snow  Survey  Measurements  ,  available  through  the  State  of 
California  Resources  Building,  Sacramento. 

Changnon,  Stanley  A.  Jr.,  "Precipitation  Contrasts  Between  the 
Chicago  Urban  Area  and  An  Offshore  Station  in  Southern  Lake 
Michigan",  Bull,  of  the  American  Meteorol.  Soc.,  4_2,  1,  1-10, 
Jan.  1961. 

Climatic  Atlas  of  the  United  States 

Climatological  Study;  Southern  California  Operating  Area,  Fleet 
Weather  Facility,  San  Diego,  California. 

DeMarrais,  Gerard  A.  "Vertical  Temperature  Difference  Observed 
Over  an  Urban  Area",  Bull,  of  the  Amer.  Meteorol.  Soc.,  42 , 
8,  548  -  554,  Aug.  1961. 

Duckworth,  F.S.  and  Sandberg,  J.S.  "The  Effect  of  Cities  Upon 
Horizontal  and  Vertical  Temperature  Gradients",  Bull,  of  the 
Amer.  Meteorol.  Soc,  35.,  5,  198-207,  May  1954. 

Elford,  C.  Robert,  Climate  of  the  States:  Climate  of  California, 
U.S.  Department  of  Commerce,  ESSA,  1970. 

Felton,  Ernest  L.,  C  a  1 i f  o  r  n  i  a ' s  Many  Climates ,  Pacific  Books 
Publishers,  Palo  Alto,  California,  1968. 

Findeison,  W.,  Meteorol.  Z.  5_6,  453  1937. 

Frederick,  R.H.  Weather  Data  for  Air  Pollution-Available,  Analy- 
zed and  Inexpensive.  J.  of  Air  Pollution  Control  Assoc. 
14:2,  60-65.  1964. 

Fujita,  T.T.,  1970a:  Estimate  of  a  Real  Probability  of  Tornadoes 
from  Inflationary  Reporting  of  Their  Frequencies.  Dept.  of 
Geophys.  Sci.,  Univ.  of  Chicago,  SMRP  Research  Paper  No.  89. 

Go.odridge,  Dr.  James,  personal  notes,  Dept  of  Water  Resources, 
State  of  California,  Sacramento,  California. 

Hoecker,  W.H.,  1961:  Three-Dimensional  Pressure  Pattern  of  the 
Dallas  Tornado  and  Some  Resultant  Implications.  Mon .  Wea . 
Rev.  ,  89,  12,  533-542. 


117 


Holzworth,  G.C.  and  Maga,  J. A.,  "A  Method  for  Analyzing  the  Trend 
in  Visibility",  J. Air  Poll.  Control  Assoc,  1_0,  6,  430-435, 
Dec.  1960. 

Houghton,  H.G.,  "On  the  Annual  Heat  Balance  of  the  Northern 
Hemisphere"  J.  Meteorol,  l±t    1,  1-9.  Feb.  1954. 

Landsberg,  H.E.  "The  Climate  of  Towns"  in  Man's  Role  in  Changing 
the  Face  of  the  Earth,  Thomas,  W.L.  Jr."  ecL  Univ.  of  Chi  cago 
Press,  1956. 

Landsberg,  H.E.  Climate  and  Urban  Planning  Pres.  WMO  Symposium  of 
Urban  Climates  and  Building  Climatology.  Brussels,  October 
19,  1968. 

Lynn,  Ronald  J.,  Seasonal  Variation  of  Temperature  and  Salinity 
at  10  meters  in  the  California  Current,  Bureau  of  Commerc  i a  1 
Fisheries,  Tuna  Resources  Laboratory,  La  Jolla,  California. 

McCormick,  R.A.  and  Tabor,  E.C.  "U.S.  Weather  Bureau-Public 
Health  Service  Precipitation  Chemistry  and  Aerometric 
Studies"  presented  at  the  12th  General  Assembly,  Int.  Union 
of  Geodesy  and  Geophysics,  Helsinki,  Finland,  July  26  -  Aug. 
6,  1960. 

Mitchell,  J.  Murray,  Jr.  "The  Temperature  of  Cities",  Weather- 
wise,  14,  6,  224-229,  December  1961. 

National  Data  Buoy  Center,  National  Ocean  Survey,  National  Ocean- 
ic and  Atmospheric  Association,  Environmental  Conditions 

within  Specified  Geographical  Regions: Offshore  East  and 

West  Coasts  of  the  United  States  and  in  the  Gulf  of  Mexico. 

Palmen,  E.  ,  Quart,  J.  Roy.  Meteorol  Soc,  7_7_337.  1951. 

Pooler,  Francis,  Jr.  "Stable  Airflow  Patterns  at  Louisville, 
Ky .  "  ,  Presented  at  Joint  Meeting  of  Amer.  Geophy.  Union-Amer. 
Meteorol.  Soc,  Wash.,  D.C.,  April  18-21,  1961. 

Randerson,  D. ,  A  Comparison  of  the  Spectral  Distribution  of  Solar 
Radiation  in  a  Polluted  and  a  Clear  Air  Mass.  JAPCA,  20 , 
8:546-548,  Aug.,  1970. 

Reynolds,  G.W.  1970a:   A  Practical  Look  at  Tornado  Forces.   Tech. 
Paper  No.  3,  Utah  State  Univ.    Presented  Conf.  on  Tornado 
Phenomenology  and  Related  Protective  Design  Measures,  Univ. 
-  of  Wisconsin,  April  26-28. 

Smith,  T.B.,  Mirabella,  V.A.  1972:  Characteristics  of  California 
Tornadoes .,  For  University  of  California,  Ernest  Q.  Lawrence 
Livermore  Laboratory,  7  January  1972. 

State  of  California  Air  Resources  Board,  "Climate  of  the  Sacra- 
mento Valley  Air  Basin." 


118 


State  of  California,  Department  of  Water  Resources,  19  7  8  Cali- 
fornia Snow  Survey  Measurement  Schedule,  California  Coopera- 
tive Snow  Surveys,   1978. 

State  of  California,  The  Resources  Agency,  Department  of  Water 
Resources,  California  Sunshine  -  Solar  Radiation  Data;  May 
1978. 


State  of  California,  The  Resources  Agency,  Department  of  Water 
Resources,  Vegetative  Water  Use  in  California,  1974,  Bulletin 
No.  113-3,   April  1975. 

Thorn,  H.C.S.,  1970b:  Estimate  of  Maximum  Wind  Speeds  of  Tor- 
nadoes in  Three  Northwestern  States.  Dept.  of  Geophys.  Sci., 
Univ.  of  Chicago,  SMRP  Research  Paper  No.  92. 

Thorn,  H.C.S.,  1970b:  Tornado  Force  Considerations  for  Construc- 
tion Decisions.   Utah  State  Univ.,  Logan,  Utah,  3pp. 


Thorn,  H.C.S.,  1963 
730-736. 


Tornado  Probabilities.  Mon .  Wea ♦  Rev . ,  9  1, 


U.S.  Department  of  Commerce,  ESSA,  Climates  of  the  States: 
Climate  of  California,  CI imatography  of  the  United  States 
60- Y .  ,  Silver  Springs,  Maryland. 

U.S.  Department  of  Commerce,  ESSA,  CI  i  m  a  t  e  s of  the  States  - 

C 1 i  mate  of  California  ,  Silver  Springs,  MD,  1970. 

U.S.  Department  of  Commerce,  NCC,  Supplement  1  to  Climate  of 
California,  CI i matography  of  the  United  States  No.  60.  Ashe- 
ville,  N.C. ,  1977. 

U.S.  Department  of  Commerce,  N0AA,  CI j  ma  t  o 1 o  g  i  c  a  1  D  a  t  a  -  C  a  1  i  - 
f orni  a  ,   National  Climatic  Center  ~  Ashv  i 1 1 e  ,  N.C. 

U.S.  Department  of  Commerce,  N0AA,  Comparative  Climatic  Data 
Through  1976 ,  National  Climatic  Center,  Asheville,  N.C. 

U.S.  Department  of  Commerce,  N0AA,  Local  C 1  i matol ogi cal  Data, 
1976,  Blue  Canyon,  San  Franc i sco/ Federal  Office  Buildings, 
San  Francisco  International  Airport,  Oakland  International 
Airport,  Bishop,  Fresno,  Stockton,  Sacramento,  National 
Climatic  Center,  Asheville,  N.C. 

U.S.  Dept.  of  Commerce,  National  Oceanic  and  Atmospheric  Adminis- 
tration, National  Weather  Service,  NOAA  Atlas  II:  Precipita- 
tion Atlas  of  the  Western  United  States,  Vol.  XI  -  Califor- 
n  i  a ,   Si  1 ver  Springs,  Maryland. 

U.S.  Department  of  Commerce,  National  Oceanic  and  Atmospheric 
Association,  TDF-14  Hourly  Observations,  Monterey,  Stockton, 
Fresno,  Bishop  California,  National  Climatic  Center,  Ashe- 
ville, N.C. 


119 


U.S.  Dept.of  Commerce,  Technical  Paper  No.  19:  Mean  Number  of 
Thunderstorm  Days  in  the  United  States,  Washington,  D.C. 
1952. 

U.S.  Department  of  Commerce,  Weather  Bureau,  Summary  of  Hourly 
Observat  i  ons ,  Sacramento,  Fresno,  San  Francisco,  Oakland, 
C  a  1  i  f  o  r  n  i  a  . 

U.S.  Environmental  Protection  Agency,  "Air  Pollution  Meteorolo- 
gy", Control  Programs  Development  Division,  Research  Triangle 
Park,  North  Carolina,  1973. 

World  Wide  Airfield  Climatic  Data,  Vol  VIII,  West  Coast,  Western 
Mountains,  and  Great  Basin  States. 


120 


3.  11 


GLOSSARY  OF  TERMS 


Abscissa 
Absorpt  i  on 
Advect i  on 


Air  Pollution 
Meteorology 


The  Horizontal  coordinate  or  axis  of  any 
graph;  usually  denoted  by  X.. 

The  process  in  which  incident  radiant  energy 
is  retained  by  a  substance. 

The  process  of  transport  of  an  atmospheric 
property  solely  by  the  mass  motion  (i.e., 
wind)  of  the  atmosphere. 

That  aspect  of  meteorology  concerned  with 
atmospheric  dispersion  characteristics. 


Aitken  Nuclei 


Al bedo 


Annual  Moi  st ure 
Deficit 


Ant i  cycl one 


Attentuation 
Ceiling 


Centri  petal 
Accel erat i  on 


CI i  mate 


The  microscopic  particles  in  the  atmosphere 
which  serve  as  condensation  nuclei  for  droplet 
growth.  These  nuclei  are  both  liquid  and 
solid  with  diameters  of  tens  of  microns  or 
sma 1 1 er . 

A  measure  of  the  part  of  the  incoming  solar 
radiation  which  is  reflected  from  the  earth 
and  the  atmosphere. 

The  moisture  deficit  of  a  month  is  the  poten- 
tial evapotranspiration  less  the  rainfall  and 
stored  soil  water.  The  sum  of  the  appropriate 
months  is  the  annual  moisture  deficit. 

Movements  of  air  traveling  in  a  clockwise 
direction  (in  the  northern  Hemisphere).  Since 
anticyclone  circulation  and  relative  high 
atmospheric  pressure  usually  coexist,  the 
terms  anticyclone  and  high  pressure  are  often 
used  interchangeably. 

The  process  by  which  energy  decreases  with 
increasing  distance  from  the  energy  source 

The  height  of  the  lowest  layer  of  clouds  or 
other  obscuring  phenomena  (e.g.,  dust). 
During  clear  weather,  the  ceiling  in  unlimit- 
ed.  With  fog,  the  ceiling  is  obscured. 

Acceleration  on  a  particle  moving  in  a  curved 
path,  directed  toward  the  center  of  curvature 
of  the  path. 

The  average  condition  of  the  weather  at  a 
place  over  a  period  of  years  as  exhibited  by 
temperature,  wind  velocity,  and  precipitation. 


121 


Compress  i  onal 
Heating 


Condensat  i  on 


Condensation 
Nuclei 


Continental 
CI  i m a t e 


Convect  i  on 


Cooling  Degree 


The  disturbance  of  a  fluid  (e.g.,  air)  such 
that  the  pressure  and  density  and,  therefore 
temperature,  increase  in  the  direction  of 
mot  ion. 

The  physical  process  by  which  a  vapor  becomes 
a  liquid  or  a  sol i  d . 

A  particle,  either  liquid  or  solid,  upon  which 
condensation  of  water  vapor  begins  in  the 
atmosphere . 

The  climate  that   is   characteristic  of  the 

interior  of  a  land  mass.   It  is  marked  bylarge 

annual,  daily  and  day  to  day  ranges  of  temper- 
ature, humidity  and  precipitation. 

In  general,  mass  motions  within  a  fluid  (e.g., 
air)  resulting  in  transport  and  mixing  of  the 
properties  of  that  fluid. 

A  form  of  degree  day  used  to  estimate  the  Days 
energy  requirements  for  air  conditioning 
or  refrigeration.  One  cooling  degree-day  is 
given  for  each  degree  that  the  daily  mean 
temperature  deports  above  a  base  of  75°F. 


Coriolis  Force 


A  deflective  force  resulting  from 
rotation;  it  acts  to  the  right  of 
tion  in  the  Northern  Hemisphere 
left  in  the  Southern  Hemisphere. 


the  earth  '  s 
wind  direc- 
and  to  the 


Crystal  1 i  zat i  on 
Cumul oni  mbus 


Cumul us 


Cycl ones 


Cyclonic  Storms 


A  particle  which  serves  as  a  nucleus  in  the 
formation  of  ice  crystals  in  the  atmosphere. 

A  principal  cloud  type,  exceptionally  dense 
and  vertically  developed,  occurring  either  as 
isolated  clouds  or  as  a  line  or  wall  of  clouds 
with  separated  upper  portions. 

A  principal  cloud  type  in  the  form  of  indi- 
vidual, detached  elements  which  are  generally 
dense  and  possess  sharp  non-fibrous  outlines. 

Movements  of  air  traveling  in  a  counterclock- 
wise direction  (in  the  northern  Hemisphere). 
Since  cyclonic  circulation  and  relative  low 
atmospheric  pressure  usually  coexist,  the 
terms  clclone  and  low  pressure  system  often 
are    used  interchangeably. 

Large  storm  systems  (50  to  900  miles  in  diam- 
eter or  more)  characterized  by  air  rotating 
around  a  center  of  low  pressure.   More  common 


122 


Dew  Point 


in  winter  than  summer.  Rainfall  and  snowfall 
associated  with  such  storms  may  be  light,  but 
may  persist  for  two  to  three  days  or  longer. 

The  temperature  to  which  air  must  be  cooled  in 
order  for  saturation  to  occur. 


Dew  Point 
Depressi  on 

Di  vergence 


Dry  Bulb 
Temperature 

Eddy  Vi  scosi ty 


The  difference  between  the  air  temperature  and 
the  dew  poi  nt . 

The  expansion  or  spreading  out  of  a  vector 
field  (e.g.,  velocity  field). 

The  ambient  temperature  of  the  air  as  measured 
by  a  dry-bulb  thermometer. 

The  turbulent  transfer  of  momentum  by  eddies 
(a  glob  of  fluid  with  a  fluid  mass  that  has  a 
life  history  of  its  own)  giving  rise  to  fluid 
friction. 


El ectromagnet  i  c 


El ectromagnet  i  c 
Waves 


E vaporat  i  on 


Evapo- 

t ranspi  rati  on 


Ex  posure 


The  ordered  array  of  all  known  electromagnetic 
Spectrum  radiations,  extending  from  the 
shortest  cosmic  rays,  through  gamma  rays, 
x-rays,  ultraviolet  light,  visible/light, 
infrared  radiation,  and  including  microwave 
and  all  xother  lengths  of  radio  energy. 

Energy  propagated  through  space  or  through 
material  media  in  the  form  of  an  advancing 
disturbance  in  electric  and  magnetic  fields 
exi  st  i  ng  in  space . 

The  physical  process  by  which  a  liquid  or 
solid  is  transformed  to  the  gaseous  state. 

The  combined  processes  by  which  water  is 
transferred  from  the  surface  of  the  earth  to 
the  atmosphere;  e  vaporat  i  on  of  liquid  or  solid 
water  plus  t ranspi  rat  i  on  from  plants. 

The  general  surroundings  of  a  site,  with 
special  reference  to  its  openness  to  winds  and 
sunshine. 


Fall  Velocity 


First  Order 
Stations 


That  limited  velocity  attained  by  a  body 
freely  falling  in  air  when  the  resisting  force 
is  equal  to  the  gravitational  force. 

A  meteorological  station  at  which  automatic 
records  and  hourly  readings  of  weather  ele- 
ments are  made. 


123 


Free  Atmosphere 


Friction  Layer 


Frictional  Drag 
Front 


Frost-Free 
Period 


Fuj  i  ta  Seal e 
Gradient 
Greenhouse  Effect 


Growing  Season 


Heat  Isl and 


Heating  Degree 


Hygroscopic 
Nuclei 


That  portion  of  the  earth's  atmosphere,  above 
the  planetary  boundary  layer,  in  which  the 
effects  of  the  earths  surface  friction  on  the 
air  motion  are  negligible. 

The  term  is  interchangeable  with  planetary 
boundary  layer  and  surface  boundary  layer  and 
refers  to  the  layer  between  the  surface  and 
the  free  atmosphere. 

The  frictional  impedence  offered  by  air  to  the 
motion  of  bodies  passing  through  it. 

In  meteorology,  generally,  the  interface  or 
transition  zone  between  two  air  masses  of 
different  density. 

The  frost-free  period  refers  to  the  length  of 
the  growing  season  as  determined  by  the  number 
of  days  between  the  last  frost  (i.e.,  32°F)  in 
spring  and  the  first  frost  in  fall. 

A  scale  baed  upon  maximum  wind  speed  to  define 
the  intensity  of  a  tornado. 

The  rate  of  change  of  a  parameter  as  a  func- 
tion of  di  stance  . 

The  heating  effect  exerted  by  the  atmosphere 
upon  the  earth  by  virtue  of  the  fact  that  the 
atmosphere  absorbs  and  reemits  infrared  radia- 
tion. 

Generally,  the  period  of  the  year  during  which 
the  temperature  of  cultivated  vegetation 
remains  sufficiently  high  to  allow  plant 
growth  (Usually  synonymous  with  Frost-Free 
Period) . 

The  accumulation  of  heat  by  large,  man-made 
structures  such  as  cities,  resulting  in  con- 
siderable differences  in  temperature  in  com- 
parison with  surrounding  areas,  particularly 
at  night. 

A  form  of  degree-day  used  as  an  indication  Day 
of  fuel  consumption;  in  the  United  States,  one 
heating  degree  day  is  given  for  each  degree 
that  the  daily  mean  temperature  departs  below 
a  base  of  65°F. 

Nuclei  with  a  marked  ability  to  accelerate  the 
condensation  of  water  vapor. 


124 


I nf rared 
(Radiation) 


Inversion 


Ions 

I sobars 
I  sohyet 

I  sot hermal 

Jet  Stream 
Jul i  an  Days 

Killing  Frost 

Kinetic  Energy 
Lake  Evaporation 

Langl ey 


Lapse  Rate 


Electromagnetic  radiation  lying  in  the  wave- 
length interval  between  visible  radiation 
(light)  and  microwave  radiation. 

An  increase  in  temperature  with  height--a 
reversal  of  the  normal  decrease  with  height  in 
the  troposhpere;  may  also  be  applied  to  other 
meteorological  properties. 

In  atmospheric  electricity,  any  of  several 
types  of  electrically  charged  submi croscopi c 
particles  normally  found  in  the  atmosphere. 

Lines  of  equal  or  constant  pressure. 

A  line  drawn  through  geographical  points 
recording  equal  amounts  of  precipitation 
during  a  given  time  period  or  for  a  particular 
storm. 

Of  equal  or  constant  temperature,  with  respect 
to  either  space  or  time;  more  commonly,  tem- 
perature with  height;  a  zero  lapse  rate. 

Relatively  strong  winds  concentrated  in  a 
narrow  stream  in  the  atmosphere. 

A  calendar  system  based  upon  the  sequantial 
numbering  of  each  day  of  the  year  up  to  365 
with  no  monthly  delineation. 

The  frost  sufficiently  severe  to  damage  the 
vegetation  of  an  area.  For  the  purpose  of 
this  report,  when  temperatures  are  28°F  or 
1  ess  . 

The  energy  which  a  body  possesses  as  a  conse- 
quence of  its  motion. 

Evaporation  from  a  lake  large  enough  and  deep 
enough  so  that  evaporation  from  most  of  its 
surface  is  unaffected  by  the  temperature  of 
the  surrounding  and  underlying  land. 

Unit  of  energy  per  unit  area  commonly  employed 
in  radiation.  One  Langl  ey  is  equal  to  one 
gram  -  calorie  per  square  centimeter.  The 
unit  was  named  in  honor  of  the  American  scien- 
tist, Samuel  P.  Langley  (1834-1906)  who  made 
many  contributions  to  the  knowledge  of  solar 
radiation. 

The  decrease  of  an  atmospheric  variable  (com- 
monly, temperature)  with  height. 


125 


Latent  Heat 


Leeward 


The  amount  of  heat  absorbed  (converted  to 
Kinetic  Energy)  during  the  processes  of  change 
of  liquid  water  to  water  vapor,  ice  to  water 
vapor,  or  ice  to  liquid  water;  or  the  amount 
released  during  the  reverse  process-es.  Four 
such  processes  are  condensation,  fusion, 
sublimation  and  vaporization. 

The  downwind  side  of  an  obstacle. 


Marine 

( al so  Maritime) 


Mechani  cal 


Mediterranean 
Climate 

Meridional 


A  regional  climate  which  is  under  the  predomi- 
nant influence  of  the  sea.  A  marine  climate 
is  characterized  by  small  diurnal  and  annual 
ranges  in  temperature. 

Turbulence  due  to  the  roughness  of  the  surface 
over  which  the  air  is  passing. 

A  type  of  climate  characterized  by  hot,  dry, 
sunny  summers  and  a  winter  rainy  season. 

Longitudinal;  northerly  or  southerly;  opposed 
to  zonal . 


Meso  Scale 


Mi  crometeorol ogy 
(also,  Micro- 
cl imatol ogy) 


That  portion  of  meteorology  which  deals  with 
atmospheric  phenomena  on  a  scale  larger  than 
that  of  micrometeorol  ogy  but  smaller  than  the 
cyclonic  scale  ( - 5  to  50  miles). 

That  portion  of  the  science  that  deals  with 
the  observation  and  exploration  of  the  small- 
est  scale  physical   and   dynamic  occurrences 
within  the  atmosphere. 


Moisture  Deficit 


The  moisture  deficit  of 
tial  evapotranspiration 
stored  soil  water. 


a  month  is  the  poten- 
1  ess  the  ra  i  nf al 1  and 


Mol ecul ar 
Friction 


Whenever  the  surface  of  one  molecule  slides 
over  that  of  another,  each  molecule  exerts  a 
frictional  force  on  the  other,  parallel  to  the 
surfaces  . 


Norther 


A  strong,  very  dry,  dusty,  northerly  wind 
which  blows  in  late  spring,  summer  and  early 
fall  in  the  Valley  of  California  or  in  the 
West  Coast  when  pressure  is  high  over  the 
mountains  to  the  north. 


Orographi  c 
Li  f t i  ng 

Palmen ' s  Model 


The  lifting  of  an  air  current  caused  by  its 
passage  up  and  over  mountains. 

A  model  describing  the  general  meridional 
circulation  of  the  earth's  atmosphere  broken 
into  three  cells. 


126 


Pan  Evaporat  i  on 


The  standard  way  to  measure  evaporation  of 
water  by  using  small  pans  exposed  to  the 
atmosphere.  The  standard  Class  A  land  pan  is 
four  feet  in  diameter  and  ten  inches  deep, 
raised  six  inches  from  the  ground  so  that  air 
can  circulate  around  it. 


Parameter 


Pert urbat  i  on 
PI anc  k ' s  Law 


In  general,  any  quantity  that  is  not  an  inde- 
pendent variable.  The  term  is  often  used  in 
meteorology  to  describe  almost  any  meteorolo- 
gical or  climatological  quantity  or  element. 


Any  departure  introduced 
steady  state  of  a  system. 


into   an   assumed 


An  expression  for  the  variation  of  monochro- 
matic emittance  as  a  function  of  wavelength  of 
black-body  radiation  at  a  given  temperature. 
It  is  the  most  fundamental  of  the  radiation 
1  aws  . 


Pluvial  Indices 


Pol ar    Front 


Potential  Energy 


Potent  i  al 
Evapo- 

transpiration 

Pressure 
Gradient  Force 

Radiational  Fog 


Rad  i  osonde 


Rainfall 
Frequency 


An  index  showing  the  amount  of  precipitation 
falling  in  one  day,  or  other  specified  period, 
that  is  likely  to  be  equalled  or  exceeded  at  a 
given  place  only  once  in  a  given  return  period 
(often  ,  100  years  )  . 

The  s em i - pe rm a nent  ,  s em i - c ont i n uou s  front 
separating  air  masses  of  tropical  and  polar 
origins. 

The  energy  which  a  body  possesses  as  a  conse- 
quence of  its  position  in  the  field  of  gravi- 
ty. 

Combined  evaporation  from  the  soil  surface  and 
transpiration  from  plants  when  the  water 
supply  in  the  ground  is  unlimited. 


The  force  due  to 
within  a  fluid  mass 


differences 
(e.g. ,  air) . 


in  pressure 


A  major  type  of  fog,  produced  over  a  land  area 
where  radiational  cooling  reduces  the  air 
temperature  to  or  below  its  dew-point. 

A  balloon-borne  instrument  for  the  simultane- 
ous measurement  and  transmission  of  meteor- 
ological data  . 

The  number  of  times  during  a  specific  period 
of  years  that  precipitation  of  a  certain 
magnitude  or  greater,  occurs  or  will  occur  at 
stat i  ons  . 


127 


Snow  Pack 


Sol  ar 

I  n  s  o  1  a  t  i  o  n 


The  amount  of  annual  accumulation  of  snow  at 

higher   elevations   in   the   Western  United 

States,  usually  expressed  in  terms  of  average 
water  equivalent. 

The  total  radiant  energy  from  the  sun  incident 
on  a  unit  area  of  a  horizontal  plane  located 
at  the  surface  of  the  earth. 


Solar  Radiation 


The  total  electromagnetic  radiation  emitted  by 
the  sun . 


Squall  Line 


Any  non-frontal  line  or  narrow  band  of  active 
thunderstorms  . 


Stagnation 
Epi  sodes 


Standard 
Atmosphere 


Storm  Track 


Stratosphere 


Periods  of  poor  atmospheric  ventilation  re- 
sulting in  the  potential  for  substantial 
pol 1 utant  levels. 

A  hypothetical  vertical  distribution  of  atmos- 
pheric temeprature,  pressure  and  density, 
which  by  international  agreement  is  taken  to 
be  representative  of  the  global  atmosphere 
(59°F  and  29.92  in.  of  mercury  at  sea  level). 


The  path  followed 
pheric  pressure. 


by  a  center  of  low  atmos- 


The  atmospheric  layer  above  the  tropopause, 
average  altitude  of  base  and  top,  7  and  22 
miles  respectively;  a  \/ery  stable  layer  char- 
acterized by  low  moisture  content  and  absence 
of  clouds. 


Stratus 


Supercool ed 


Supersaturation 


A  principal  cloud  type  in  the  form 
layer  with  a  rather  uniform  base. 


of  a  gray 


The  reduction  of  temperature  of 
below  the  melting  point  of  that 
solid  phase;  that  is,  cooling 
nominal  freezing  point. 


any  liquid 
substance' s 
beyond  i  t  s 


In  meteorology,  the  condition  existing  in  a 
given  portion  of  the  atmosphere,  when  the 
relative  humidity  is  greater  than  100  percent. 


Synoptic 


In  general,  pertaining  to  or  affording  an 
overall  view.  In  meteorology,  it  refers  to 
the  use  of  meterol og i cal  data  obtained  simul- 
taneously over  a  wide  area  for  the  purpose  of 
presenting  a  comprehensive  and  nearly  instan- 
taneous picture  of  the  state  of  the  atmos- 
phere . 


128 


Synopt  i  c  Scale 


Terrestrial 
Radiation 


Weather  patterns  associated  with  high  and  low 
pressure  systems  in  the  lower  troposphere, 
i.e.,  1  arge  seal e . 

(also  called  earth  radiation,  eradiation)  The 
total  infrared  radiation  emitted  from  the 
eart h ' s  surface . 


Thermal 
Buoyancy 

Transpi  rat  i  on 


Tropopause 


Tropos  phere 


Buoyancy  attributable  to  a  local 
temperature . 


l  ncrease  l  n 


Tul e  Fog 


Turbul ence 


Ultraviolet 
(radiation) 


Water 
Equivalent 

Wa vel ength 


Weather 


The  process  by  which  water  in  plants  is  trans- 
ferred as  water  vapor  to  the  atmosphere. 

The  transition  zone  between  the  troposphere 
and  stratosphere,  usually  characterized  by  an 
abrupt  change  of  lapse  rate. 

That  portion  of  the  atmosphere  from  the 
earth's  surface  to  the  tropopause;  that  is, 
the  lowest  6  to  12  miles  of  the  atmosphere. 
The  troposphere  is  characterized  by  decreasing 
temperature  with  height  and  by  appreciable 
water  vapor . 


A  persistent,  dense  fog 
Valley  of  California. 


common  in  the  Central 


A  state  of  fluid  flow  in  which  the  instanta- 
neous velocities  exhibit  irregular  and  appar- 
ently random  fluctuations  so  that  in  practice 
only  statistical  properties  can  be  recognized 
and  subjected  to  analysis. 

Electromagnetic  radiation  of  shorter  wave- 
length than  visible  light  but  longer  than 
x- rays  . 

The  liquid  water  present  within  a  sample  of 
snow . 

In  general,  the  mean  distance  between  maxima 
of  a  roughly  periodic  pattern  (e.g.,  light). 

The  state  of  the  atmosphere  mainly  with  re- 
spect to  its  effects  upon  life  and  human 
activities.  As  distinguished  from  climate, 
weather  consists  of  the  short  term  (minutes  to 
months)  variations  of  the  atmosphere.  Popu- 
larly, weather  is  thought  of  in  terms  of 
temperature,  humidity,  precipitation,  cloudi- 
ness, brightness,  visibility  and  wind. 


129 


Wet  Bulb 
Temperature 


The  temperature  measured  by  a  wet,  muslim- 
covered  bulb  thermometer.  The  temperature  an 
air  parcel  would  have  if  cooled  adiabatically 
to  saturation  at  constant  pressure  by  evapora- 
tion of  water  into  it. 


Wind  Roses 


Diagrams  designed  to  show  the  distribution  of 
wind   speed   and  direction   experienced   at   a 

over  a  considerable  period. 

form  consists  of  a  circle  from 

lines  emanate, 

The  length  of 

the  frequency 

the   frequency 


given   1 ocat  i  on 
The  most  common 
which  8  or  16 
compass  poi  nt . 
proportional   to 
that   direction; 


one  for  each 
the  line  is 

of  wind  from 
of  calms   is 


entered  in  the  center. 


Zonal 


Latitudinal;  easterly  or  westerly;  opposed  to 
meridional . 


130 


4.   DISPERSION  METEOROLOGY 


4.1 


INTRODUCTION 


An  understanding  of  the  dispersion  potential  of  a  region 
is  essential  in  determining  the  impact  of  both  existing  and 
proposed  sources  of  ground  level  and  elevated  emissions  of  pollu- 
tants. Areas  that  are  plagued  with  poor  dispersion  conditions 
for  extended  periods  of  time  are  apt  to  suffer  stringent  limita- 
tions on  land  use  and  industrial  development.  Under  such  poor 
dispersion  conditions,  seemingly  insignificant  sources  of  pollu- 
tion can  result  in  excessive  concentrations  over  large  areas.  As 
discussed  in  Section  6,  The  Clean  Air  Act  Amendments  of  1977 
impose  strict  regulatory  requirements  on  new  sources  of  air 
pollution  in  areas  with  high  ambient  pollutant  concentrations. 

The  dispersion  potential  within  the  Ukiah  District  has 
been  developed  through  the  maximum  utilization  of  available  data. 
The  following  sections  describe  the  dispersion  meteorology  of  the 
Ukiah  District  in  terms  of  the  following  analyses: 

Data  Sources 

Prevailing  Winds 

Atmospheric  Stability 

Mixing  Heights  and  Inversions 

Typical  and  Worst-Case  Conditions 

Air  Basins 

Fi  re  Weather 

General  Dispersion  Modeling 

Surface  data  suitable  for  use  in  the  analysis  of  the 
Ukiah  District  dispersion  meteorology  are  derived  primarily  from 
the  National  Weather  Service  (NWS)  first-order  meteorological 
stations.  The  availability  of  mixing  height,  inversion  and  winds 
aloft  data  is  limited  to  those  stations  that  take  routine  meas- 
urements of  upper  air  winds  and  temperatures.  There  are  no  NWS 
station  of  this  type  in  the  District.  However,  upper  air  winds 
and  temperature  data  are  also  available  at  other  sites  as  part  of 
a  program  being  conducted  by  the  California  Air  Resources  Board 
(CARB).  Additional  data  from  lower-order  NWS  or  other  govern- 
mental and  special  interest  stations  have  been  reviewed  and 
included  where  they  provide  additional  significant  information 
regarding  the  characterization  of  the  dispersion  meteorology  of 
the  Ukiah  Di  st ri  ct . 

Section  4.2  provides  a  review  of  the  general  principles 
of  dispersion  meteorology.  Sources  of  data  which  have  been  used 
to  describe  the  dispersion  potential  of  the  Ukiah  District  are 
discussed  in  Section  4.3.  The  discussion  then  turns  to  a  review 
of  specific  dispersion  parameters  including  prevailing  winds, 
atmospheric  stability,  mixing  heights,  and  inversions  in  Sections 
4.4  through  4.6,  respectively.  More  detailed  analyses  are  then 
provided,  including  a  review  of  typical  and  worst-case  conditions 


131 


for  a  variety  of  potential  sources  in  Section  4.7.  The  air  basin 
analysis  approach  to  dispersion  meteorology  is  outlined  in  Sec- 
tion 4.8.  Section  4.9  provides  a  discussion  of  the  impact  of 
dispersion  meteorology  on  burn  conditions  while  section  4.10 
describes  concepts  of  air  quality  modeling  including  suggestions 
as  to  the  manner  in  which  the  data  presented  in  thi*s  document 
should  be  interfaced  with  appropriate  models.   Finally,  Section 

4.11  provides  a  review  of  sources  of  assistance  to  BLM  personnel 
encountering  problems  in  dispersion  meteorology  while  Section 

4.12  provides  a  glossary  of  terms. 


132 


4.2 


PRINCIPLES  OF  DISPERSION  METEOROLOGY 


Dispersion  meteorology  provides  an  evaluation  of  the 
capability  of  the  atmosphere  to  disperse  airborne  effluents  in  a 
given  geographical  region.  That  capability  depends  largely  on 
the  critical  meteorological  parameters  wind  speed  and  direction, 
atmospheric  stability  and  mixing  height.  The  topography  of  the 
region  also  plays  an  important  role. 

The  air  pollution  cycle  can  be  considered  to  consist  of 
three  phases:  the  release  of  air  pollutants  at  the  source,  the 
transport  and  diffusion  in  the  atmosphere,  and  the  reception  of 
air  pollutants  in  reduced  concentrations  by  humans,  plants, 
animals,  or  inanimate  objects.  The  major  influence  of  meteorolo- 
gy occurs  during  the  diffusion  and  transport  phase.  The  motions 
of  the  atmoshphere  which  may  be  highly  variable  in  four  dimen- 
sions, are  responsible  for  the  transport  and  diffusion  of  air 
pol 1 utants  . 

Although  the  distribution  of  a  cloud  of  pollutant  mate- 
rial with  time  will  depend  on  the  summation  of  all  motions  of  all 
sizes  and  periods  acting  upon  the  cloud,  it  is  convenient  to 
first  consider  some  mean  atmospheric  motions  over  periods  on  the 
order  of  an  hour. 

The  following  sections  discuss  (1)  the  principles  of 
turbulence  and  diffusion,  (2)  the  key  dispersion  parameters,  (3) 
the  role  of  topography  in  diffusion  and  (4)  atmospheric  chemis- 
try. Modeling  is  discussed  in  detail  in  Section  4.9  while  in- 
strumentation is  reviewed  in  Section  7. 


4.2.1 


Principles  of  Turbulence  and  Diffusion 


When  a  small  concentrated  puff  of  gaseous  pollutant  is 
released  into  the  atmosphere,  it  tends  to  expand  in  size  due  to 
the  dynamic  action  of  the  atmosphere.  In  so  doing,  the  concen- 
tration of  the  gaseous  pollutant  is  decreased  because  the  same 
amount  of  pollutant  is  now  contained  within  a  larger  volume. 
This  natural  process  of  high  concentrations  spreading  out  to 
lower  concentrations  is  the  process  of  diffusion. 

Atmospheric  diffusion  is  ultimately  accomplished  by  the 
wind  induced  movement  of  pollutants,  but  the  character  of  the 
source  of  pollution  requires  that  this  action  of  the  wind  be 
taken  into  account  in  different  ways.  These  sources  can  be 
conveniently  grouped  into  three  classes:  point  sources,  line 
sources,  and  area  sources.  In  practice,  the  first  two  classes 
must  be  further  divided  into  instantaneous  and  continuous 
sources . 

The  instantaneous  point  source  is  essentially  a  "puff" 
of  material  created  or  ejected  in  a  relatively  short  time,  as  by 
a  nuclear  explosion,  the  sudden  rupture  of  a  chlorine  tank,  or 


133 


the  bursting  of  a  tear-gas  shell.  The  wind  of  immediate  impor- 
tance is,  of  course,  that  occurring  at  the  place  and  time  at 
which  the  pollutant  is  created.  Since  the  wind  is  highly  vari- 
able, the  initial  direction  of  movement  of  the  puff  is  also 
variable  and  difficult  to  predict;  a  soap-bubble  pipe  and  five 
minutes'  close  observation  of  the  initial  travel  of  "successive 
bubbles  will  convincingly  demonstrate  the  difficulty  of  predict- 
exact  trajectory  of  the  next  bubble.  In  addition,  dilu- 
a  puff  source  is  a  very  strong  function  of  time  after  its 
At  first,  the  small-scale  fluctuations  of  the  wind 
to  grow  rather  slowly  and  the  larger-scale  wind  varia- 

paths.   But  as  the  puff 
"hold" 


i  n  g  the 
t  i  o n  of 
rel ease 


cause  i  t 

tions  simply  carry  it  along  on  erratic 

grows,  larger-scale  motions  can  get  a 


on  it  to  tear  it 


apart  and  dilute  it  more  rapidly.  Thus,  the  unique  feature  of 
the  instantaneous  point  source  is  its  increasing  dispersion  rate 
with  time,  hence,  the  necessity  to  consider  successively  larger 
scales  of  meterorological  phenomena  in  calculating  its  spread. 


Continuous  point  sources  (the  smoke  plume  from  a  fa 
chimney,  the  pall  from  a  burning  dump)  are  the  most  familiar 
most  conspicuous,  and  the  most  studied  of  all  pollution  sou 
The  meteorology  of  the  continuous  source  must  take  into  ac 


the  time  changes  of  the  wind  at 
behavior  of  a  plume  from  a  factory 
of  water  from  a  hose  being  played 
It  is  evident  that  if  the  hose  is 
continually  exposed  to  the  water, 
back  and  forth  in  an  arc 
uted  over  a  wider  area. 


the  point  of  emission, 
chimney  is  very  much  like 
back  and  forth  across  a 
steady,  the  same  area  wi 
But  if  the  hose  ( wi  nd ) 
the  water  (pollution)  will  be  dis 
hence  the  concentration  will  be 


For  a  truly  continuous  source,  there  are  other  changes  of 
importance  -  primarily  the  diurnal  and  seasonal  cycles. 


ctory 
,  the 
rces  . 
count 
The 
that 

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II  be 
moves 
t  r  i  b  - 
less, 
great 


The  isolated  line  source  is  less  common,  and  therefore, 
of  less  general  interest,  with  two  important  exceptions  -  heavily 
traveled  highways,  and  the  swath  of  chemicals  emitted  by  crop- 
dusting  apparatus.  In  both  these  examples,  if  the  line  of  pollu- 
tant is  uniform  and  is  long  enough,  the  dispersion  of  the  pollu- 
tion must  be  attained  in  only  two  dimensions,  along  the  wind  and 
in  the  vertical.  If  the  line  source  is  a  continuous  one,  as 
might  be  the  case  of  a  freeway  in  rush  hours,  spreading  in  the 
downwind  direction  becomes  ineffective  (at  a  particular  downwind 
location),  so  that  only  the  vertical  dimension  is  left  to  provide 
dilution.  This  behavior  of  the  continuous  line  source  has  been 
exploited  by  meteorologists  in  field  experiments  with  controlled 
tracers  to  permit  the  detailed  study  of  vertical  diffusion, 
uncomplicated  by  effects  in  the  other  two  coordinates. 

The  area  source  can  \iary  enormously  in  size.  It  may  be 
distributed  over  several  square  miles,  as  in  an  industrial  park, 
over  tens  or  hundreds  of  square  miles,  as  in  a  city,  or  over 
thousands  of  square  miles,  exemplified  by  the  almost  continuous 
strip  city  (the  "megalopolis"  or  "megapolitan  area")  along  the 
eastern  seaboard  of  the  United  States.  These  area  sources  usual- 
ly include  combinations  of  all  the  s i ngl e- source  configurations. 


134 


A  large  city  will  include  many  thousands  of  home  chimneys,  thou- 
sands of  factories  and  shops,  hundreds  of  miles  of  streets,  open 
dumps,  burning  leaves,  evaporating  fumes  from  gasoline  storage  or 
from  cleaning  plants  and  paint  factories,  and  everywhere  the 
automobile.  The  weather  problem  of  the  city  area  source  becomes, 
in  the  aggregate,  quite  different  from  that  of  a  single  source. 
Here  we  are  concerned  not  with  the  increasing  rate  of  wind  dis- 
persion with  increasing  scale,  or  with  the  behavior  of  wind  with 
time  at  a  single  point,  but  rather  with  the  replenishment  rate  of 
the  air  over  the  city.  We  must  consider  the  total  movement  of  a 
large  volume  of  air  as  it  "ventilates"  the  city.  Anything  that 
reduces  this  ventilation  rate,  whether  it  be  the  confining  effect 
of  surrounding  mountains  or  the  reduced  velocities  of  a  slow- 
moving  anticyclone,  is  of  concern. 

In  the  construction  of  cities  man  has  modified  the 
weather  as  will  be  discussed  in  more  detail  in  Section  4.2.6. 
The  volume  of  effluent  injected  into  the  air  has  reduced  the 
solar  radiation.  The  absorption  characteristics  of  cement  and 
asphalt  instead  of  grass  and  trees  create  urban  "heat  islands." 
These  effects  must  be  considered  in  the  meteorology  of  urban  air 
pollution.  The  urban  heat  island  effect  is  discussed  in  more 
deta  i 1  in  Sect  ion  3.9 

The  atmosphere  disperses  pollutants  because  it  is  in 
constant  mostion,  and  this  motion  is  always  turbulent  to  some 
degree.  There  is,  as  yet,  no  fully  accepted  definition  of  turbu- 
lence, but  empirically  it  can  be  described  as  random  (three- 
dimensional)  flow.  The  understanding  of  turbulent  diffusion  in 
the  atmosphere  has  progressed  largely  through  empirical  treat- 
ments of  controlled  tracer  experiments.  The  current  tendency  is 
to  deal  with  turbulence  through  statistical  concepts  derived  from 
aerodynamics  and  fluid  dynamics,  in  contrast  to  earlier  theories 
which  centered  around  a  v i rt ua 1 -d i f f us i v i ty  concept.  In  the 
practical  application  of  computing  pollution  concentrations,  the 
common  practice  is  to  employ  the  statistical  method  for  distances 
to  perhaps  150  kilometers  (93  miles)  from  the  source,  and  equa- 
tions based  on  v i rt ua 1 -di f f us i v i ty  ("K")  theory  for  longer  dis- 
tances, particularly  for  calculations  on  a  hemispheric  or  global 
scale. 

Vertical  Turbulent  Diffusion 

To  all  intents  and  purposes  rapid  atmospheric  diffusion 
in  the  vertical  is  always  bounded:  on  the  bottom  by  the  surface 
of  the  earth  and  at  the  top  by  the  tropopause.  The  tropopause  - 
the  demarcation  between  the  troposphere,  where  temperature  de- 
creases with  altitude,  and  the  stratosphere,  where  the  tempera- 
ture is  relatively  constant  or  increases  with  altitude  -  is 
lowest  over  the  poles,  at  about  5  miles,  and  highest  in  the 
tropics,  at  about  12  miles.  The  full  depth  of  the  troposphere  is 
available  for  vertical  dispersion.  However,  utilization  of  this 
total  vertical  dimension  can  take  place  at  very  different  rates, 
depending  on  the  thermally  driven  vertical  wind.   These  rates  are 


135 


intimately  related  to  the  vertical  temperature  profile.  On  the 
average  (and  if  we  neglect  the  effects  of  the  phase  change  of 
water  in  the  air),  enhanced  turbulence  is  as soc i ated  wi th  a  dro 
in  temperature  with  height  of  10  C  per  kilometer  (29  F  per  mile 
or  greater  (this  is  the  dry  adiabatic  rate  as  discussed  in  Sec- 
tion 4.2.3).  If  the  temperature  change  with  height  is  at  a 
lesser  rate,  turbulence  tends  to  be  decreased,  and  if  the  temper- 
ature increases  with  height  (an  "inversion"),  turbulence  is  very 
much  reduced. 


The  temperature  profiles  particularly  over  land,  show  a 
large  diurnal  variation  as  seen  in  Figure  4.2-1.  Shortly  after 
sunrise,  the  heating  of  the  land  surface  by  the  sun  results  in 
rapid  warming  of  the  air  near  the  surface;  the  reduced  density  of 
this  air  causes  it  to  rise  rapidly.  Cooler  air  from  aloft  re- 
places the  rising  air  "bubble,"  to  be  warmed  and  rise  in  turn. 
This  vigorous  vertical  interchange  creates  a  "  super- adi ab at i c" 
lapse  rate  -  a  temperature  decrease  of  more  than  29  F  per  verti- 
cal mile  -  and  vertical  displacements  are  accelerated.  The  depth 
of  this  well-mixed  layer  depends  on  the  intensity  of  solar  radia- 
tion and  the  radiation  characteristics  of  the  underlying  surface. 
Over  the  deserts,  this  vigorous  mixing  may  extend  well  above  2 
miles,  while  over  forested  lake  country,  the  layer  may  be  only 
from  three  to  seven  hundred  feet  thick.  Obviously,  this  effect 
is  highly  dependent  on  season;  in  winter,  the  lesser  insolation 
and  unfavorable  radiation  characteristics  of  snow  cover  greatly 
inhibit  vertical  turbulence. 


I  n  contrast  , 
temperature  profile  at 
radiational  cooling  of 
the  layers  of  air  near  the  surface, 
of  the  daytime  temperature  profile, 


with  clear  or  partly  cloudy  skies  the 

night  is  drastically  changed  by  the  rapid 

the  ground  and  the  subsequent  cooling  of 

This  creates  an  "inversion" 

since  there  is  now  an  in- 


crease in  temperature  with  height.  In  such  a  situation  the 
density  differences  rapidly  dampen  out  vertical  motions,  which 
tends  to  reduce  vertical  turbulence,  and  stabilize  the  atmos- 
phere . 


Two  other  temperature  configurations,  on  very  different 
scales,  have  important  effects  on  vertical  turbulence  and  the 
dilution  of  air  pollution.  At  the  smaller  end  of  the  scale,  the 
heat  capacity  of  urban  areas  and,  to  a  lesser  extent,  the  heat 
generated  by  fuel  consumption  act  to  modify  the  temperature 
profile.  The  effect  is  most  evident  at  night,  when  the  heat 
stored  by  day  in  the  buildings  and  streets  warms  the  air  and 
prevents  the  formation  of  the  surf  ace- based  temperature  inver- 
sions typical  of  rural  areas.  Over  cities,  it  is  rare  to  find 
inversions  in  the  lowest  300  feet;  the  city  influence  is  usually 
evident  700  to  1000  feet  above  the  surface.  The  effect  is  a 
function  of  city  size  and  building  density,  but  not  enough  obser- 
vations are  yet  available  to  provide  any  precise  quantitative 
relations.  Although  the  effect  even  for  the  largest  cities  is 
probably  insignificant  above  three  thousand  feet,  this  locally 
produced  vertical  mixing  is  quite  important.   Pollution,  instead 


136 


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137 


of  being  confined  to  a  narrow  layer  near  the  height  of  emission, 
perhaps  only  300  feet  in  thickness,  can  be  freely  diluted  in  more 
than  double  the  volume  of  air,  the  concentrations  being  reduced 
by  a  similar  factor . 

On  a  much  larger  scale  the  temperature  profile  can  be 
changed  over  thousands  of  square  miles  by  the  action  of  large- 
scale  weather  systems.  In  traveling  storm  systems  (cyclones), 
the  increased  pressure  gradients  and  resulting  high  winds,  to- 
gether with  the  inflow  of  air  into  the  storm,  create  relatively 
good  vertical  mixing  conditions.  On  the  other  hand,  the  flat 
pressure  patterns,  slower  movement,  and  slow  outflow  of  surface 
air  in  hig h- press ure  cells  (anticyclones)  result  in  much  less 
favorable  vertical  mixing.  This  is  primarily  due  to  the  gradual 
subsidence  of  the  air  aloft  as  it  descends  to  replace  the  outflow 
at  the  surface.  During  this  descent,  the  air  warms  adiabatical- 
ly,  and  eventually  there  is  created  a  temperature  inversion 
aloft,  inhibiting  the  upward  mixing  of  pollution  above  the  inver- 
sion level.  As  the  anticyclone  matures  and  persists,  this  subsi- 
dence inversion  may  lower  to  very  near  the  ground  and  persist  for 
the  duration  of  the  particular  weather  pattern. 

Horizontal  Turbulent  Diffusion 

The  most  important  difference  between  the  vertical  and 
horizontal  dimensions  of  diffusion  is  that  of  scale.  In  the 
vertical,  rapid  diffusion  is  limited  to  about  10  kilometers  (  6 
miles).  But  in  the  horizontal,  the  entire  surface  of  the  globe 
is  eventually  available.  Even  when  the  total  depth  of  the  tropo- 
sphere is  considered,  the  horizontal  scale  is  larger  by  at  least 
three  orders  of  magnitude,  and  the  difference,  say  during  a 
nocturnal  inversion  which  might  restrict  the  vertical  diffusion 
to  within  a  hundred  feet,  is  even  greater  since  the  lateral 
turbulence  is  reduced  less  than  the  vertical  component.  Mechan- 
ically produced  horizontal  turbulence  is,  on  a  percentage  basis, 
much  less  important  than  the  thermal  effects;  its  effects  are  of 
about  the  same  order  of  magnitude  as  the  vertical  mechanical 
effects  . 

The  thermally  produced  horizontal  turbulence  is  not  so 
neatly  related  to  horizontal  temperature  gradients  as  vertical 
turbulence  is  to  the  vertical  temperature  profile.  The  hori- 
zontal temperature  differences  create  horizontal  pressure  fields, 
which  in  turn  drive  the  horizontal  winds.  These  are  acted  upon 
by  the  earth's  rotation  (the  Coriolis  effect)  and  by  surface 
friction,  so  that  there  is  not  such  a  thing  as  a  truly  steady- 
state  wind  near  the  surface  of  the  earth.  Wind  speeds  may  vary 
from  nearly  zero  near  the  surface  at  night  in  an  anticyclone,  to 
200  miles  per  hour  under  the  driving  force  of  the  intense  pres- 
sure gradient  of  a  hurricane.  The  importance  of  thi s *var i at i on , 
even  though  in  air  pollution  we  are  concerned  with  much  more 
modest  ranges,  is  that  for  continuous  sources  the  concentration 
is  inversely  proportional  to  the  wind  speed. 


138 


The  variation  of  turbulence  in  the 
perhaps  the  most  important  factor  of  all  and 
most  interesting.  In  practice,  this  can  be 
the  changes  in  horizontal  wind  direction  i 
4.2-2.  Within  a  few  minutes,  the  wind  m 
through  90  degrees  or  more.  Over  a  few  hour 
with  much  short-period  variability,  through 
the  course  of  a  month  it  will  have  changed 
numerous  times.  Over  the  seasons,  preferred 
will  be  established  depending  upon  latit 
pressure  patterns.  These  patterns  may  be  v 
years,  and  thus  establish  the  wind  climato 
location. 


lateral  direction  is 

certainly  one  of  the 
st  be  represented  by 
llustrated  in  Figure 
dy  fluctuate  rapidly 
s  it  may  shift  ,  still 

180  degrees ,  and  i  n 
through  360  degrees 

directional  patterns 
ude  and  1 arge- seal e 
ery  stable  over  many 
logy  of  a  particular 


The  emitted  pollution  travels  with  this  ever-varying 
wind.  The  high-frequency  fluctuations  spread  out  the  pollutant, 
and  the  relatively  steady  "average"  direction  carries  it  off  - 
for  example,  toward  a  suburb  or  a  business  district.  A  gradual 
turning  of  direction  transports  material  toward  new  targets  and 
gives  a  respite  to  the  previous  ones.  Every  few  days  the  cycle 
is  repeated,  and  over  the  years  the  prevailing  winds  can  create 
semipermanent  patterns  of  pollutions  downwind  from  factories  or 
cities. 


4.2.2 


Prevailing  Winds 


Wind  speed  and  direction  play  a  fundamental  role  in  the 
dispersion  of  airborne  contaminants.  The  following  paragraphs 
discuss  wind  speed  and  direction  and  other  wind  characteristics 
and  their  associated  impact  on  local  and  regional  dispersion 
potential  . 

Mean  wind  direction  has  a  basic  impact  on  air  pollutant 
levels.  If  the  wind  direction  is  representative  of  the  height  at 
which  the  pollutant  is  released,  the  mean  direction  will  be 
indicative  of  the  direciton  of  travel  of  the  pollutants.  In 
meteorology,  it  is  conventional  to  consider  the  wind  direction  as 
the  direction  from  which  the  wind  blows,  therefore,  a  northwest 
wind  will  move  pollutants  to  the  southeast  of  the  source. 

The  effect  of  wind  speed  is  two- fold.  The  wind  speed 
will  determine  the  travel  time  from  a  source  to  a  given  receptor, 
e.g.,  if  a  receptor  is  located  1000  meters  (3281  ft)  downwind 
from  a  source  and  the  wind  speed  is  5  met ers/ second  (16.4 
ft/sec),  it  will  take  260  seconds  for  the  pollutants  to  travel 
from  the  source  to  the  receptor.  The  other  effect  of  wind  speed 
is-  a  dilution  in  the  downwind  direction.  If  a  continuous  source 
is  emitting  a  certain  pollutant  at  the  rate  of  10  grams/second 
(  1.3  lbs/min)  and  the  wind  speed  is  1  meter/second  (  2.2  mph) 
then  in  a  downwind  length  of  the  plume  of  1  meter  (3.3  feet)  will 
be  contained  10  grams  (  0.02  lbs)  of  pollutant  since  1  meter  (3.3 
feet)  of  air  moves  past  the  source  each  second.  Next,  consider 
that  the  conditions  of  emission  are  the  same  but  the  wind  speed 
is  5  met ers/ second  (  11  mph).   In  this  case,  since  5  meters  (16.4 


139 


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feet)  of  air  moves  past  the  source  each  second,  each  meter  of 
plume  length  contains  2  grams  (  0.04  lbs)  of  pollutant.  There- 
fore, it  can  be  seen  that  the  dilution  of  air  pollutants  released 
form  a  source  is  proportional  to  the  wind  speed.  This  may  be 
restated  in  another  form:  The  concentration  of  air  pollutants  is 
inversely  proportional  to  wind  speed. 

Wind  speed  is  generally  found  to  increase  with  height 
above  the  ground  and  wind  direction  to  veer  (turn  clockwise)  with 
height  (in  the  northern  hemisphere  at  extratropical  latitudes) 
due  to  the  effects  of  friction  with  the  earth's  surface.  The 
amount  of  these  increases  in  speed  and  veering  in  direction  are 
quite  variable,  and  to  a  great  degree,  related  to  the  roughness 
of  the  surface  and  the  stability  of  the  atmosphere. 


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In  the  preceding  paragraphs,  consideration  of  only  the 
speed  and  direction  of  wind  has  been  made.   Of  course,  there 
deviations  from  these  means.   There  are  velocity  components 
11  directions  creating  vertical  motions  as  well  as  horizontal 
These  random  motions  of  widely  different  scales  and  peri- 
are  essentially  responsible  for  the  movement  and  diffusion  of 
utants  about  the  mean  downwind  path.   These  motions,  commonly 
ed  eddys,  are    considered  as  atmospheric  turbulence.   If  the 
e  of  a  turbulent  motion,  i.e.,  the  size  of  an  eddy,  is  larger 
the  size  of  the  pollutant  plume  in  its  vicinity,  the  eddy 
portion  of  the  plume.   If  an  eddy  is  smaller   than 
effect  will  be  to  diffuse  or  spread  out  the  plume, 
caused  by  the  eddy  motion  is  widely  variable,  but 
duffusion  is  at  the  minimum,  it  is  roughly  three 
rs  ot  magnitude   greater  than  the  diffusion  by  molecular 
on 


move  that 

pi ume  ,  its 

diffusion 

when  this 

of  magni  t  ude 
alone. 


During  the  daytime,  solar  heating  causes  turbulence  to 
be  at  a  maximum  and  vertical  motions  to  be  strongest.  This 
causes  the  maximum  amount  of  momentum  exchange  between  various 
levels  in  the  atmosphere.  Because  of  this,  the  variation  of  wind 
speed  with  height  is  least  during  the  daytime.  Also,  the  amount 
of  veering  with  height  is  least  (on  the  order  of  15  to  20  over 
average  terrain).  The  thickness  of  the  friction  layer  will  also 
be  greatest  during  the  day  due  to  the  vertical  exchange. 

At  night,  the  vertical  motions  are  least  and  the  effect 
of  friction  is  not  felt  through  as  deep  a  layer  as  during  the 
day.  The  surface  speed  over  average  terrain  is  much  less  than 
the  free  atmosphere  wind  (on  the  order  of  1/4  to  1/3  that  of  the 
1000  meter  (3281  feet)  wind)  and  the  amount  of  veering  with 
he-ight  may  be  on  the  order  of  40  to  45  .  Figure  4.2-3  shows  the 
diurnal  variation  of  wind  speed  at  two  different  levels  on  a 
meteorological  tower  (Singer  and  Raynor,  1957). 

Wind  data  are  generally  only  available  in  terms  of  speed 
and  direction.  Turbulence  data  are  considerably  more  sophisti- 
cated and  are  generally  only  available  as  a  result  of  special- 
ized, si te- speci f i c  data  gathering  programs.   Such  data  are  only 


141 


WIND 
SPIED 
(M/SEC, 


10 
9 

e 

7 

6 

5 

4 

3 

? 

1 

0 


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37  FEET 


-L 


1 


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SUNPISE 


MIDDAY        SUNSET       MIDNIGHT      SUNRISE 


Figure  4.2-3 
Diurnal   Variations  in  Wind  Speed 
As  a  Function  of  Height 


{*■'  Data  from  Meteorological  Tower 
Brookhaven  National  Laboratory 
April    1950-March   1952 


142 


wind  direction. 

wh  i  c  h  eight  or 

The  1 ength  of 

wind  from  that 


used  in  very  detailed  modeling  analyses.  The  bulk  of  the  model- 
ing analyses  conducted  for  the  air  pollution  industry  require 
only  basic  wind  data  for  speed  and  direction.  This  latter  type 
of  data  are  generally  summarized  in  the  form  of  wind  roses. 
These  may  be  viewed  in  Figure  4.4-1. 

A  wind  rose  is  defined  in  the  Glossary  of  Meteorology 
as,  "Any  one  of  a  class  of  diagrams  designed  to  show  the  distri- 
bution of  wind  direction  experienced  at  a  given  location  over  a 
considerable  period;  it  thus  shows  the  prevailing 
The  most  common  form  consists  of  a  circle  from 
sixteen  lines  emanate,  one  for  each  compass  point 
each  line  is  proportional  to  the  frequency  of 
direction;  and  the  frequency  of  calm  conditions  is  entered  in  the 
center.  Many  variations  exist.  Some  indicate  the  range  of  wind 
speeds  from  each  direction;  some  relate  wind  direction  with  other 
weather  occurrences."  Wind  roses  may  be  constructed  for  data 
from  a  given  time  period  such  as  a  particular  month  or  may  be  for 
a  particular  time  of  day  or  season  from  a  number  of  years  of 
data.  In  constructing  or  interpreting  wind  roses,  it  is  neces- 
sary to  keep  in  mind  the  meteorological  convention  that  wind 
direction  refers  to  the  direction  from  which  the  wind  is  blowing. 
A  line  or  bar  extending  to  the  north  on  a  wind  rose  indicates  the 
frequency  of  winds  blowing  from  the  north,  not  the  frequency  of 
winds  blowing  towa  rd  the  north.  Some  of  the  specialized  wind 
roses  that  may  be  constructed  are  precipitation  wind  roses, 
stability  wind  roses,  and  pollution  wind  roses.  The  latter  two 
require  additional  data  than  are  generally  available  at  standard 
Weather  Bureau  stations.  An  informative  article  on  the  history 
and  variants  of  wind  roses  has  been  published  by  Court  (1963). 

Prior  to  January  1964,  the  surface  wind  direction  was 
reported  by  U.S.  Weather  Bureau  stations  as  one  of  the  16  direc- 
tional points  corresponding  to  the  mariner's  compass  card  or 
compass  rose,  qn  which  each  direciton  is  equivalent  to  a  22  1/2 
sector  of  a  360  circle.  Table  4.2-1  illustrates,  in  the  form  of 
a  frequency  table  of  wind  direction  versus  wind  speed  groups,  the 
data  essential  to  the  development  of  a  16-point  wind  rose.  It  is 
an  example  of  summaries  of  hourly  observations  published  monthly 
until  January  1964  in  the  Local  Climatological  Data  (LCD)  Supple- 
ment. Frequencies  are  totaled  by  direction  and  wind  speed  group. 
A  quick  look  at  this  wind  rose  indicates  the  highest  directional 
frequency  is  from  the  ENE  and  the  highest  speed  frequency  is  the 
8  to  12  mph  column.  Average  speeds  have  been  computed  for  each 
direction. 

When  wind  roses  are  employed  to  summarize  climatological 
data  involving  long  periods  of  record,  percentage  frequencies  are 
favored  over  numerical  totals  for  tabular  presentation  since  the 
number  of  observations  in  any  one  cell  can  become  quite  large. 
Moreover,  wind  rose  diagrams  can  be  drafted  directly  from  tabular 
data  if  percentages  are  available.  Table  4.2-2  presents  10  years 
of  hourly  wind  data  observed  at  New  Orleans  Moisant  International 


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Airport  during  January  for  the  years  1951  through  1960,  as  pub- 
lished in  the  "Decennial  Census  of  United  States  Climate."  This 
10-year  summary  of  meteorological  data  is  compiled  for  most  U.S. 
Weather  Bureau  first  order  stations. 


On  January  1,  1964,  the  U.S.  Weather  Bureau  Changed  the 
wind  direction  reporting  procedure  from  16  points  to  36  -  10° 
intervals.  Table  4.2-3  is  the  result;  a  3  6-point  wind  rose. 
Since  36  cannot  be  divided  by  16  there  is  no  way  of  grouping  36 
points  into  16  points  and  there  is  no  easy  way  of  combining  wind 
data  if  the  wind  rose  summaries  include  both  16-point  and  36- 
point  wind  direction  observations.  For  this  and  other  reasons, 
the  36-point  wind  rose  was  dropped  after  1964.  A  few  air  quality 
models  such  as  CRSTER  require  36  point  wind  rose  data,  and  for 
such  an  application,  1964  data  must  be  used. 

This  report  will  present  wind  roses  using  a  very  sim- 
plistic format.  The  frequency  of  the  wind  direction  for  each  of 
the  16  cardinal  directions  is  plotted  and  lines  are  drawn  connec- 
ting each  directional  frequency  (See  Section  4.4.1) 


4.2.3 


Atmospheric  Stability 


Whether  the  atmosphere  has  a  tendency  to  enhance  or  to 
dampen  out  vertical  motions  is  important  to  atmospheric  processes 
which  produce  weather  as  well  as  to  the  effects  upon  air  pollut- 
ant dispersion.  The  stability  of  the  atmosphere  is  highly  de- 
pendent upon  the  vertical  distribution  of  temperature  with 
height . 

Adiabatic  Lapse  Rate 

Due  to  the  decrease  of  pressure  with  height,  a  parcel  of 
air  lifted  to  higher  altitude  will  encounter  decreased  pressure 
and  expand  and,  in  undergoing  this  expansion,  will  cool.  If  this 
expansion  takes  place  without  loss  or  gain  of  heat  to  the  parcel, 
the  change  is  adiabatic.  Similarly,  a  parcel  of  air  forced 
downward  in  the  atmosphere,  will  encounter  higher  pressures, 
contract,  and  become  warmer.  This  rate  of  cooling  with  lifting, 
or  heatina  with  descent  is  the  dry  adiabatic  lapse  rate  and 
equals  5.4  F  per  1000  feet  or  approximately  1°C  per  100  meters. 
This  process  lapse  rate  is  the  rate  of  heating  or  cooling  of  any 
descending  or  rising  parcel  of  air  in  the  atmosphere  and  should 
not  be  confused  with  the  existing  temperature  variation  with 
height  at  any  one  time,  i.e.,  the  environmental  lapse  rate. 

Environmental  or  Prevailing  Lapse  Rate 

The  manner  in  which  temperature  changes  with  height  at 
any  one  time  is  the  environmental  or  prevailing  lapse  pate.  This 
is  principally  a  function  of  the  temperature  of  the  air  and  of 
the  surface  over  which  it  is  moving  and  the  rate  of  exchange  of 

For  example,  during  clear  days  in  mid- 


heat  between  the  two. 


summer  the  ground  is  rapidly  heated  by  solar  radiation.  This  in 
turn,  provides  for  rapid  heating  of  the  layers  of  the  atmoshpere 


146 


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147 


nearest  the  surface.  Further  aloft,  however,  the  atmospheric 
temperature  will  remain  relatively  unchanged.  Conversely,  at 
night,  radiation  from  the  earth's  surface  cools  the  ground  and 
the  air  adjacent  to  it,  resulting  in  only  slight  decrease  of 
temperature  with  height,  and  in  cases  when  the  surface  cooling  is 
great  enough,  temperature  may  increase  with  height.  "Hi  i  s  atmos- 
phere is  considered  stable. 


If 


If  the  temperature  decreases 
than  the  dry  adiabatic  lapse  rate,  the 
or  strong  lapse  rate  and  the  air  is  unstable . 
is  forced  upwards  it  will  cool  at  the  adiabatic 
will  still  be  warmer  than  the  environmental  air 
continue  to  rise.   Similarly,  a  parcel  which  is 
will   heat  dry  ad i abat i cal  1  y  but  will   remain 
environment  and  will  continue  to  sink. 


more  rapidly  with  height 

air  has  a  su pe r- ad i abat i c 

a  parcel  of  air 

1  apse  rate  ,  but 

Thus  it  will 

forced  downward 

cool er  than  the 


For  environmental  lapse  rates  that  decrease  with  height 
at  a  rate  less  than  the  dry  adiabatic  lapse  ( sub- adi abat i c  or 
weak  lapse)  a  lifted  parcel  will  be  cooler  than  the  environment 
and  will  sink;  likewise,  a  descending  parcel  will  be  warmer  than 
the  environment  and  will  rise.  Figure  4.2-4  shows  the  relative 
relation  between  the  environmental  lapse  rates  of  super- adi abat i c 
(strong  lapse),  sub-ad iabatic  (weak  lapse),  isothermal,  and 
inversion  with  the  dry  adiabatic  process  lapse  rate  presented  as 
dashed  lines. 

Lifting  motions  which  promote  cooling  at  dry  adiabatic 
lapse  rates  may  be  caused  by  upslope  motion  over  mountains  or 
warmer  air  rising  over  a  colder  air  masses.  Descending  motion 
(subsidence)  may  occur  to  compensate  for  the  lateral  spreading  of 
air  in  high  pressure  areas. 

Classification  Schemes 

The  dispersive  power  of  the  atmosphere  can  be  cate- 
gorized into  seven  classes,  labeled  stability  categories,  in 
accordance  with  a  method  proposed  by  Pasquill  (1962)  and  modified 
by  Gifford  (1961)  and  Markee  (1966).  Pasqu  ill's  first  three 
classes,  A,  B,  and  C,  range  from  extreme  to  slight  instability. 
Class  D  represents  neutral  or  well-mixed  conditions,  while  E  and 
F  represent  slight  and  moderate  stability,  respectively.  Disper- 
sive power  decreases  with  progression  through  these  classes. 
Markee  (1966)  has  further  divided  the  original  class  F  into 
classes  F  and  G,  with  G  representing  extreme  stability.  For  the 
purpose  of  simplifying  the  presentation,  classes  A,  B,  and  C  have 
be-en  combined,  in  some  instances,  to  form  one  category  called 
unstable.  Similarly,  class  D  will  be  referred  to  as  the  neutral 
category,  and  classes  E,  F,  and  G  together  form  the  stable  cate- 
gory. 

The  stability  of  the  atmosphere  is  determined  by  various 
methods  using  numerous  forms  of  meteorological  data.  A  frequent- 
ly used  means  of  assessing   ambient  atmospheric   stability  is 


148 


V 

\ 

\ 

SUPER- 

■ADIABAT1C 

\ 

v\ 

\ 

\ 

\x 

\ 

\ 

\ 

\ 

\ 

\ 

^  \  SUB-ADIABATIC 


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INVERSION 
\ 

TEMPERATURE 


Figure  4.2-4 

Types  of  Temperature  Structure  with  Height  Related  to 
the  Dry  Adiabatic  Process  Lapse  Rate 


149 


through  the  measurement  of  changes  in  atmospheric  temperature 
with  altitude  (  T/  Z)  above  an  area  in  question.  This  is  accom- 
plished by  probing  the  atmosphere  with  specialized  temperature 
sensors  mounted  on  aircraft,  balloons,  or  on  tall  meteorological 
towers . 

Figure  4.2-5  graphically  illustrates  the  T/  Z  criteria 
for  stable,  neutral  and  unstable  conditions.  Temperature  profile 
"A"  is  classified  as  unstable  because  its  profile  slope  is  less 
than  the  dry  adiabatic  lapse  rate  (  T/  Z  =  -9.8°C/km)  (-28.4° 
F/mi).  A  neutral  atmosphere  is  one  that  exhibits  a  temperature 
profile  approximately  equivalent  to  the  dry  adiabatic  lapse  rate. 
Stable  atmospheres  have  T/  Z  values  greater  than  -9.8  C/km 
(-28.4  F/mi).  An  atmospheric  inversion,  a  special  case  of  a 
stable  atmosphere,  occurs  when  the  ambient  T/  Z  value  increases 
with  altitude  rather  than  decreases. 

Unstable  conditions  generally  occur  during  periods  of 
high  positive  net  radiation  (toward  the  earth's  surface)  and  low 
wind  speeds.  Stable  conditions  require  high  negative  net  radia- 
tion (away  from  the  earth's  surface)  and  low  wind  speeds,  while 
neutral  conditions  generally  develop  because  of  cloudy  skies 
and/or  high  winds  speeds.  This  more  general  method  of  defining 
atmospheric  stability  is  the  one  most  frequently  used  in  the  air 
pollution  industry  today. 

The  NCC  in  Asheville,  North  Carolina,  has  devised  a 
somewhat  subjective  technique  based  upon  available  measurements 
of  surface  wind  speed  coupled  with  the  strength  of  incoming  solar 
insolation  as  defined  by  such  parameters  as  sky  cover,  time  of 
day  and  latitude.  This  technique  is  summarized  in  Table  4.2-4 
and  is  used  by  the  NCC  to  develop  the  STAR  (Stability  A_R_ay)  data 
that  is  used  extensively  in  this  document.  One  interesting 
aspect  of  this  technique  results  from  the  heavy  dependance  upon 
solar  insolation.  By  this  definition,  stable  conditions  can 
occur  only  at  night,  unstable  conditions  only  during  the  day, 
while  neutral  conditions  can  occur  during  either  night  or  day. 

The  Influence  Of  Vertical  Temperature  Structure  Upon  Plume 
Behavior 

The  manner  in  which  stack  effluents  diffuse  is  primarily 
a  function  of  the  stability  of  the  atmosphere.  Church  (1949)  has 
typified  the  behavior  of  smoke  plumes  into  five  classes.  Hewson 
(1960)  has  added  a  sixth  class,  taking  into  account  inversions 
aloft  (Inversions  will  be  discussed  in  more  detail  in  section 
4 .  -2 . 4 ) .  Figure  4.2-6  depicts  each  class  and  the  appropriate 
dispersion  characteristics  for  an  idealized  chimney.  The  Pas- 
quill  stability  classes  are    also  noted. 

Looping 

Looping  occurs  with  a  super- ad i abat i c  lapse  rate.  Large 
thermal  eddies  are  developed  in  the  unstable  air  and  high  concen- 
trations may  be  brought  to  the  ground  for  short  time  intervals. 


150 


1.0 


E 


LU 

a    0.5 


10 


15 


20 


25 


T(°C) 


Figure  4.2-5 
Temperature  Profiles  which  are  Examples  of 
(A)  Unstable,  (B)  Stable,  and  (C)  Very  Stable  Inversion 
Lapse  Rates  in  a  Dry  Atmosphere 


151 


Table  4.2-4 
Key  to  Stability  Categories 


Surface  Wind 
Speed  (at  10  m) 
m/sec 

Isolation 

Slight 

Night 

<  3/8 
Cloud 

Thinly  Overcast 

or 
>  4/8  Low  Cloud 

Strong 

Moderate 

<     2 

A 

A-B 

B 

- 

- 

2-3 

A-B 

B 

C 

E 

F 

3-5 

B 

B-C 

c 

D 

E 

5-6 

C 

C-D 

D 

D 

D 

>     6 

C 

D 

D 

D 

D 

The  neutral  category,  D,  should  be  assumed  for  overcast  conditions  during 
day  or  night. 


152 


Stability  Category  A-C;  Looping 


Stability  Category  D;  Coning 


Stability  Category  E-G;  Fanning 

T 


BK  i.  —>  ■  '  .  ■  .1  ■  <-tf 


Stability  Categories  As  Noted, 
Lofting 


J L 


E-G 


Stability  Categories  As  Noted; 
Fumigation 


E-G 


Figure  4.2-6 

i 

Typical  Plume  Behavior 


Stability  Categories  As  Noted; 
Trapping  Inversion 


E-G 


A-D 


Plume  behavior  influenced  by  the  temperature  lapse  rate  above  and  below  the 
release  height.  The  dashed  lines  in  the  profiles  are  the  adiabatic  lapse 
rates,  included  for  reference,  while  the  solid  lines  indicate  the  actual 
lapse  rate.  The  Pasquill  stability  categories  are  also  provided. 


153 


Diffusion  is  good,  however,  when  considering  longer  time  periods. 
The  super-ad iabatic  conditions  which  cause  looping  occur  only 
with  light  winds  and  strong  solar  heating.  Cloudiness  or  high 
winds  will  prevent  such  unstable  conditions  from  forming. 

Coning 

With  vertical  temperature  gradients  between  dry  adia- 
batic  and  isothermal,  slight  instability  occurs  with  both  hori- 
zontal and  vertical  mixing  but  not  as  intense  as  in  the  looping 
situation.  The  plume  tends  to  be  cone  shaped  hence  the  name 
coning.  The  plume  reaches  the  ground  at  greater  distances  from 
the  source  than  with  the  looping  plume.  Coning  is  prevalent  on 
cloudy  or  windy  days  or  nights.  Diffusion  equations  are  more 
successful  in  calculating  concentrations  for  this  type  of  plume 
than  for  any  other. 

Fanning 

If  the  temperature  increases  upward  as  in  an  inversion, 
the  air  is  stable  and  vertical  turbulence  is  suppressed.  Hori- 
zontal mixing  is  not  as  great  as  in  coning  but  still  occurs.  The 
plume  will,  therefore,  spread  horizontally  but  little  if  any 
vertically.  Since  the  winds  are  usually  light,  the  plume  will 
also  meander  in  the  horizontal.  Plume  concentrations  are  high 
but,  little  effluent  from  elevated  sources  reaches  the  ground, 
except  when  the  inversion  is  broken  due  to  surface  heating,  or 
terrain  effects  at  the  elevation  of  the  plume.  Clear  skies  with 
light  winds  during  the  night  are  favorable  conditions  for 
f anni  ng  . 

Lof t i  ng 

Lofting  occurs  when  there  is  a  super- adi abati c  layer 
above  a  surface  inversion.  With  this  condition,  diffusion  upward 
is  rapid,  but  downward,  diffusion  does  not  penetrate  the  inver- 
sion and  so  is  dampened  out.  Under  these  conditions,  gases  will 
not  reach  the  surface  but  particles  with  appreciable  settling 
velocities  will  drop  through  the  inversion.  Near  sunset  on  a 
clear  evening  in  open  country  is  most  favorable  time  for  lofting. 
Lofting  is  generally  a  transition  situation  and,  as  the  inversion 
deepens,  is  replaced  by  fanning. 

F  umi  gat i on 

As  solar  heating  increases,  the  lower  layers  are  heated 
and  a  super-ad iabatic  lapse  rate  occurs  through  a  continuously 
deeper  layer.  When  the  layer  is  deep  enough  to  reach  the  fanning 
plume,  thermal  turbulence  will  bring  high  concentrations  to  the 
ground  along  the  full  length  of  the  plume.  This  is  -favored  by 
clear  skies  and  light  winds  and  is  apt  to  occur  more  frequently 
in  summer  due  to  increased  heating. 


154 


Another  type  of  fumigation  may  occur  in  the  early  even- 
ing over  cities.  Heat  sources  and  mechanical  turbulence  due  to 
surface  roughness  causes  an  adiabatic  condition  to  develop  in  the 
lower  layers  of  the  stable  air  moving  into  the  city  from  non- 
urban  areas  where  radiation  inversions  are  already  forming.  This 
causes  a  fumigation  until  the  city  loses  enough  heat  so  that  the 
adiabatic  condition  is  dim i shed. 

Trapp  i  ng 

When  an  inversion  occurs  aloft,  such  as  a  frontal  or 
subsidence  inversion,  a  plume  released  beneath  the  inversion  will 
be  trapped  beneath  it.  Even  if  the  diffusion  is  good  beneath  the 
inversion,  such  as  with  a  coning  plume,  the  limit  to  upward 
diffusion  will  increase  concentrations  in  the  plume  and  at  ground 
1 evel  . 


4.2.4 


Mixing  Heights  and  Inversions 


An  adiabatic  diagram  can  be  used  to  plot  the  distribu- 
tion of  temperature  and  moisture,  with  height  in  the  atmosphere. 
This  is  of  considerable  use  to  the  meteorologist  in  determining 
freezing  levels,  condensation  levels  of  moisture  in  lifted  air 
parcels,  forecasting  cloud  bases  and  tops,  determining  stability 
for  cloud  formation  and  thunderstorm  forecasting.  Moisture 
levels  are  especially  important  to  the  air  pollution  meteorolo- 
gist as  moisture  works  as  a  catalyst  for  the  formation  of  secon- 
dary pollutants  such  as  sulfates  and  nitrates  and  high  moisture 
content  will  serve  to  reduce  visibility. 

To  the  air  pollution  meteorologist  a  sounding  plotted  on 
an  adiabatic  chart  is  principally  used  to  determine  the  large 
scale  stability  of  the  atmosphere  over  a  given  location.  The 
principal  source  of  atmospheric  measurements  that  may  be  plotted 
on  the  adiabatic  chart  are  the  radiosonde  measurements  taken 
twice  daily:  0000  GMT  (1900  EST)  and  1200  GMT  (0700  EST)  at  about 
66  stations  in  the  contiguous  United  States.  The  method  of 
obtaining  these  soundings  is  to  release  into  the  atmosphere  a 
balloon  borne  instrument  package  having  sensors  for  temperature, 
pressure,  and  humidity  and  a  radio  transmitter  for  relaying  this 
information  to  the  ground  station.  This  information  on  the  upper 
air  is  collected  primarily  to  serve  the  purpose  of  forecasting 
and  aviation  briefing.  Consequently,  the  information  is  not  as 
detailed  in  the  lowest  5000  feet  as  an  air  pollution  meteorolo- 
gist desires.  Also,  in  air  pollution  meteorology,  it  is  desira- 
ble to  have  information  more  frequently  than  12  hours  apart.  In 
spite  of  these  deficiencies  for  air  pollution  purposes,  the 
soundings  from  the  radiosonde  network  will  give  indications  of 
the  stability  of  the  atmosphere.  On  an  adiabatic  chart,  tempera- 
ture is  plotted  on  a  linear  scale  against  pressure  on  a  logarith- 
mic scale.  A  temperature  sounding  may  be  plotted  by  locating 
each  significant  level  reported  by  the  temperature  and  pressure 
given  for  that  level.  The  plotted  points  may  then  be  connected 
by  straight  lines  to  give  the  temperature  sounding. 


155 


As  indicated  in  Section  4.2.3,  the  stability  of  a  por- 
tion of  the  sounding  may  be  compared  with  the  dry  adiabatic  lapse 
rate.  If  the  temperature  decreases  more  rapidly  than  the  dry 
adiabats  through  a  layer,  this  layer  is  super-adiabatic  and  quite 
unstable.  If  the  temperature  decreases,  but  at  a  rate*  less  than 
the  dry  adiabatic  lapse  rate,  the  layer  is  sub- ad i abat i c  and  is 
more  stable  than  super-adiabatic.  If  the  temperature  increases 
with  height,  it  is  an  inversion. 

Inversions  with  bases  at  ground  level  are  generally 
radiation  inversions  caused  by  the  cooling  of  the  earth's  surface 
and  the  adjacent  air.  However,  there  may  also  be  advection 
inversions  formed  by  the  air's  passage  over  a  relatively  cold 
surface.  These  two  types  of  surface  based  inversions  generally 
cannot  be  distinguished  by  inspection  of  the  sounding  plotted  on 
an  adiabatic  diagram.  A  surface  based  inversion  on  an  afternoon 
sounding  is  more  apt  to  be  an  advection  inversion. 

There  are  two  general  classifications  of  inversions  with 
bases  above  the  ground:  frontal  inversions  and  subsidence  inver- 
sions.  Both  of  these,  however,  can  also  be  ground  based. 

Frontal  inversions  are  discontinuities  in  the  tempera- 
ture profile  due  to  the  transition  between  cold  air  below  and 
warm  air  aloft.  Frontal  inversions  usually  are  accompanied  by 
increases  in  moisture  through  the  inversion.  Subsidence  inver- 
sions are  caused  by  the  sinking  motion  above  high  pressure  areas 
and  generally  have  rapidly  decreasing  humidities  above  the  base 
of  the  inversion. 

Surveys  of  the  meteorological  aspects  of  air  pollution 
are  often  concerned  with  the  extent  of  horizontal  and  vertical 
mixing.  A  quantity  referred  to  as  the  mixing  depth  is  quite 
useful  when  considering  dilution  of  pollutants  in  the  vertical. 
The  usual  method  of  estimating  mixing  depths  is  to  consider  the 
stability  as  portrayed  on  a  temperature  sounding  remembering  that 
unstable  lapse  rates  favor  vertical  mixing  and  stable  lapse  rates 
restrict  vertical  motion.  The  mixing  depth  is  generally  the 
height  above  the  ground  to  which  a  super  or  dry-adi abat i c  lapse 
rate  is  maintained  as  depicted  in  Figure  4.2-7. 


4.2.5 


Influence  of  Topography  on  Transport  and  Diffusion 


In  many  cases,  the  transport  and  diffusion  of  air  pollu- 
tants is  complicated  by  terrain  features.  Most  large  urban  areas 
are  located  either  in  river  valleys  or  on  the  shores  of  lakes  or 
oceans.   Both  of  these  features  alter  meteorological  conditions. 

Val ley  Effects 

t     Channeling 

Although  the  more  extreme  effects  of  a  valley  location 
occur  when  the  general  flow  is  light,  valleys  tend  to 


156 


en 


a; 

DC 


en 


i 


O) 

S_ 

CD 


X 


4-> 


U 


157 


channel  the  general  flow  along  the  valley  axis  resulting 
in    a    bi-directional    wind    frequency    distribution. 

Slope  and  Valley  Winds 

When  the  general  wind  flow  is  light  and  skies  are  clear, 
the  differences  in  rates  of  heating  and  cooling  of 
various  portions  of  the  valley  floor  and  sides  cause 
slight  density  and  pressure  differences  resulting  in 
small  circulations.  During  the  evening  hours  radia- 
tional  heat  from  the  earth's  surface  and  the  resultant 
cooling  of  the  ground  and  air  adjacent  to  the  ground 
causes  density  changes.  The  air  at  point  A  (Figure 
4.2-8)  is  more  dense  than  at  point  B  since  point  A  is 
nearer  the  radiating  surface.  Therefore,  the  more  dense 
air  at  point  A  tends  to  flow  in  the  general  direction  of 
B  and  similarly  at  other  points  along  the  slope.  This 
i  s  the  si  ope  wi  nd . 

If  the  slope  in  Figure  4.2-8  is  a  side  of  a  valley  as  in 
Figure  4.2-9,  the  cold  air  moving  down  the  slopes  will 
tend  to  drain  into  the  valley  floor  and  deepen  with 
time,  intensifying  the  radiation  inversion  that  would 
form  even  without  the  addition  of  cold  air.  Any  pollu- 
tants that  are  emitted  into  this  air,  because  of  the 
inversion  structure,  will  have  very  limited  vertical 
mot  i  on  . 

If,  in  addition,  the  valley  floor  has  some  slope,  the 
cold  air  will  have  a  tendency  to  move  downhill  along  the 
valley  axis.  This  is  usually  referred  to  as  the  valley 
wind  (See  Figure  4.2-10).  Because  of  the  necessity  of 
some  accumulation  of  cold  air  from  slope  winds,  the 
onset  of  the  valley  wind  usually  lags  several  hours 
behind  the  onset  of  the  slope  wind. 

The  steeper  the  slopes  of  the  valley,  the  stronger  the 
slope  wind  can  become.  Vegetation  will  tend  to  reduce 
the  effect  by  impeding  the  flow  and  also  restricting  the 
amount  of  radiation  that  can  take  place. 

On  a  clear  day  with  the  light  winds,  the  heating  of  the 
valley  may  cause  upslope  and  upvalley  winds.  However, 
the  occurance  of  upslope  and  upvalley  winds  is  not  as 
frequent  nor  as  strong  as  the  downslope  and  downvalley 
winds,  principally  due  to  the  fact  that  downslope  and 
downvalley  winds,  because  of  their  density,  hug  the 
surfaces  over  which  they  travel.  Flow  in  complex  valley 
systems  where  several  valleys  merge  at  angles  or  slopes 
varies,  usually  require  special  observations  to  deter- 
mine flow  under  various  meteorologic  conditions. 

Inversions  A  1  oft 

The  trapping  of  air  pollutants  beneath  inversions  aloft 

is  also  a  problem  encountered  in  valleys.   Two  types  of 


158 


Figure  4.2-8 


COLO      All 


Figure  4.2-9 


Figure  4.2-10 


Valley  Wind  Circulations 


159 


inversions:  warm  frontal  and  subsidence  inversions  are 
of  particular  concern  since  they  are  usually  slow  mov- 
ing. High  concentrations  may  occur  particularly  if  the 
layer  of  air  beneath  the  inversion  becomes  unstable 
enough  to  mix  pollutants  from  elevated  sources  to  ground 
level  (Hewson  et  al  ,  1961). 

Shoreline  Winds 

The  differences  in  heating  and  cooling  of  land  and  water 
surfaces  and  the  air  above  them,  result  in  the  setting  up  of 
circulations  if  the  general  flow  is  light,  and  in  the  modifi- 
cation of  thermal  characteristics,  and  consequently,  the  diffu- 
sive abilities  of  the  lower  layers  of  the  atmosphere  when  a 
general  flow  occurs. 

•  Sea  or  Lake  B  reeze 

On  summer  days  with  clear  skies  and  light  winds,  the 
heating  of  the  land  surface  adjacent  to  a  large  lake  or 
the  ocean  is  much  more  rapid  than  the  heating  of  the 
body  of  water.  This  results  in  a  temperature  differ- 
ence, and  consequently,  a  density  and  pressure  differ- 
ence between  the  air  just  above  the  land  surface  and  the 
air  over  the  water.  Because  of  the  pressure  gradient 
forces,  a  local  circulation  is  set  up  with  wind  from  the 
water  toward  the  land,  There  is  usually  some  upward 
motion  over  the  land  and  subsidence  over  the  water 
accompanying  the  sea  breeze  (Estoque,  1961).  There  may 
result  a  weak  transport  from  land  to  water  aloft  com- 
pleting a  cellular  structure  (See  Figure  4.2-11). 

In  cases  where  a  strong  lake  breeze  occurs,  air  from 
quite  some  distance  out  over  the  water  may  be  brought 
toward  the  land  and,  due  to  Coriolis  forces  acting  over 
the  long  trajectory,  the  resulting  flow  will  become 
nearly  parallel  to  the  shoreline  (Sutton,  1953).  This 
occurs  just  after  the  sea  breeze  is  strongest  and  re- 
sults in  decreasing  the  flow  normal  to  the  coastline  and 
the  subsequent  breakdown  of  the  sea  breeze. 

•  Land  Breeze 

At  night,  the  rapid  radiational  cooling  of  the  land 
causes  lower  temperatures  above  the  land  surface  than 
over  the  water.  Thus  a  reverse  flow,  the  land  breeze, 
may  result.  The  land  breeze  does  not  usually  achieve  as 
high  a  velocity  as  the  lake  breeze,  and  is  usually 
shallower  than  the  sea  or  lake  breeze. 

Of  course,  any  wind  flow,  because  of  the  large  scale 
pressure  pattern,  will  alter  the  local  circulation  and 
the  flow  will  be  the  resultant  of  the  two  effects. 
Usually,  a  light  general  flow  is  enough  to  overshadow 
the  effects  of  land  and  sea  breezes. 


160 


\\\\\\\\\ 


LAND 


WATER 


Figure  4.2-11 
Idealized  Sea  Breeze  Regime 


161 


Modi  f i  cat i on  of  Thermal  Structure  by  Bodies  of  Water 


At  different  seasons  of  the  year  and  also  different 
times  of  the  day,  the  temperature  of  bodies  of  water  and  adjacent 
land  surfaces  may  be  quite  different.  For  example,  during  the 
late  spring,  large  bodies  of  water  are  still  quite  cofd  relative 
to  adjacent  land  surfaces,  and  during  mid- afternoon  this  differ- 
ence is  greatest  due  to  the  more  rapid  heating  of  the  land  sur- 
face. If  the  general  flow  in  the  area  is  such  that  the  wind  has 
a  lengthly  trajectory  over  the  water  and  is  blowing  toward  the 
shore,  an  interesting  modification  of  the  temperature  structure 
takes  place.  Because  of  the  passage  over  the  cold  water  surface, 
the  air  will  have  an  inversion  in  the  lower  layer  as  it  reaches 
the  shoreline.  Any  air  pollutants  released 
will  essentially  have  the  characteristics  of 
the  air  passes  over  the  warm  land,  a  strong 
the  inversion  near  the  surface.  The  depth 
deepen  as  the  air  moves  over  more  heated  land  surface.  If  the 
layer  becomes  deep  enough  to  reach  the  fanning  effluent  from  an 
elevated  source,  fumigation  will  occur  and  continue  as  long  as 
the  temperature  difference  between  land  and  water  is  maintained 
and  flow  from  water  to  land  occurs.  At  greater  distances  from 
the  shoreline,  the  inversion  will  be  eliminated  and  plume  looping 
will  occur.  On  the  other  hand,  if  the  source  is  high  enough  to 
be  above  the  lake  induced  inversion,  lofting  of  the  plume  would 
occur  until  enough  distance,  and  consequently,  enough  heating 
takes  place  to  eliminate  the  inversion. 


into  this  inversion 

a  f anni  ng  pi ume  .   As 

lapse  rate  repl aces 

of  this  1  ayer  wi  1 1 


Figure  4.2-12  indicates  the  difference  in  vertical 
temperature  structure  that  occurs  in  the  above  example,  and 
Figure  4.2-13  indicates  the  effect  this  will  have  on  the  plume 
characteristics  of  an  elevated  shoreline  source. 

At  other  times  when  the  water  is  warmer  than  the  land 
surface  (late  fall),  offshore  flow  will  result  in  fumigation  over 
the  water. 

Influence  of  Hills 

The  influence  of  hills  upon  transport  and  diffusion 
depends  upon  a  number  of  factors.  Whether  the  source  is  on  the 
windward  or  lee  side  of  the  hill  or  ridge  is  important.  A  smooth 
hill  will  only  slightly  alter  the  flow,  while  one  with  sharp 
ridges  will  cause  turbulent  eddies  to  form.  The  stability  of  the 
atmosphere  will  affect  the  overall  influence  of  hills.  During 
stable  conditions,  the  air  will  tend  to  flow  around  obstructions. 
Under  unstable  conditions,  the  tendency  is  for  air  to  move  over 
obstructions. 

When  a  source  is  located  upwind  of  a  hill  orcridge,  the 
pollutants  may  come  in  contact  with  the  facing  slope,  particu- 
larly under  stable  conditions.  If  the  ridge  is  quite  rough, 
induced  turbulence  may  cause  mixing  down  to  the  slope  even  when 
the  general  flow  is  over  the  ridge.   Wind  tunnel  studies  or  field 


162 


GENERAL 
WINDFLOW 


^'2» 


WARM  LAND 


Figure  4.2-12 
Modification  of  Vertical  Temperature  Structure  Due  to  Flow 
Over  Differently  Heated  Surfaces 


GENERAL 
WINDFLOW 


Pc?£v& 


WARM    LAND 


Figure  4.2-13 
Effect  Upon  Plume  Characteristics  of  Flow  Over  Differently 

Heated  Surfaces 


163 


trials  with  constant  level  balloons  may  be  desirable  to  determine 
the  flow  under  given  circumstances. 

For  a  source  downwind  form  a  hill  or  ridge,  lee  eddies 
will  generally  cause  considerable  down  wash  of  the  effleunt  near 
the  source.  If  turbulent  flow  is  induced  by  the  hillsrde,  diffu- 
sion will  be  increased  but  high  concentrations  very  near  the 
stack  will  result  periodically,  due  to  the  downwash.  Examples 
may  be  viewed  in  Figure  4.2-14 

Persistence  of  Fog 

The  occurence  of  fog,  together  with  very  stable  atmos- 
pheric conditions  above  the  earth's  surface,  has  been  noted  in 
several  air  pollution  episodes,  particularly  in  Donora,  Pennsyl- 
vania, in  1948.  Under  clear  skies  at  night,  the  ground  loses 
much  heat  because  of  outgoing  radiation  and  the  air  in  contact 
with  the  ground  will  cool.  If,  in  such  cases  the  air  is  suffi- 
ciently humid,  cooling  will  bring  the  air  to  the  saturation  point 
and  a  fog  will  form.  This  is  the  mechanism  which  produces  radia- 
tion fog  and  is  quite  common  in  valley  locations.  The  top  of  a 
layer  of  fog  will  radiate  essentially  as  a  black  body  and  cool 
further,  thus  forming  an  inversion  layer  directly  above  the  fog. 
As  the  earth  continues  to  radiate  in  the  infrared,  the  fog  drop- 

this  heat  since  the  droplet  size  distribu- 
wavelengths  of  the  radiation.  Theory  and 
that  when  the  top  of  a  fog  layer  radiates 
interior  of  the  layer  will  become  more 
Increased  vertical  mixing  will  occur  from 
below  but  will  be  capped  by  the  inversion.  Since  the  air  is 
saturated,  an  unstable  lapse  rate  will  exist  if  the  temperature 
decrease  with  height  is  greater  than  the  moist  or  pseudo-adia- 
batic  lapse  rate  (3  F  per  1000  ft.),  rather  than  the  dry  adia- 
batic  lapse  rate  of  (5.4°F  per  1000  ft.) 


lets  absorb  nearly  all 
tion  is  similar  to  the 
observation  have  shown 
during  the  night,  the 
unstable  with  time. 


Thus,  pollutants  that  are  emitted  aloft  into  an  orig- 
inally stable  layer  at  night,  and  would  not  normally  reach  the 
ground  until  morning,  may  be  contained  within  a  fog  layer  as  the 
night  progresses  and  be  brought  to  the  ground  in  relatively  high 
concentrations. 


After  daybreak,  fog  will  often  persist  for  several  hours 
or  even  the  entire  day  under  full  sunlight  due  to  the  high  re- 
flectivity of  the  top  layer.  The  reflectivity  or  albedo  of  thick 
fogs  averages  50%  and  can  be  as  high  as  85%.  This  delays  and 
lessens  the  heating  of  the  ground  and  subsequent  evaporation  of 
the  fog  droplets.  An  unstable  lapse  rate  may  occur  above  the  fog 
layer,  but  due  to  a  lack  of  surface  heating,  an  inversion  will 
often  occur  within  the  layer.  If  high  concentrations  of  particu- 
late pollutants  are  present,  it 
just  when  the  fog  has  dissipated 
absorb  visible  light  very  well 
quite  restricted. 


may  be  difficult  to*  determine 

since  particulates  scatter  and 

and  the  visibility  may  remain 


164 


Figure  4.2-14 
Influence  of  Hills  Upon  Transport  and  Diffusion 


165 


Figure  4.2-15  illustrates  how  fog  can  persist  in  valley 
situations  and  maintain  a  lid  on  vertical  dispersion.  This 
situation  often  occurs  over  the  Central  Valley  of  California 
during  winter.  The  conditions,  known  locally  as  "Tule  Fog"  can 
persist  for  days  resulting  in  reduced  visibilities  and  poor 
ambient  air  quality. 


166 


IT) 


I 


CD 


CD 


CD 


C 

>> 

Q 

a; 

■4-J 
CD 


S- 

Q 

in 
QJ 


O 

S- 

o. 

a> 

s_ 

=5 
4-> 
fO 

S- 

a> 
a. 

E 
a) 


CD 

c 
•r— 

C 

o 

CL 

in 

S- 

s_ 
o 
o 

-a 
c 
ra 

cr 

o 


u 

c 
<u 
+-> 

to 

1/1 

s_ 

OJ 

a. 


167 


4.3 


DATA  SOURCES 


A  limited  number  of  sources  of  dispersion  meteorological 
data  are  available  in  the  Ukiah  District.  Some  of  these  data  are 
available  in  unreduced  or  partially  reduced  form  and  have  not 
been  utilized  in  the  present  analysis.  However,  a  knowledge  of 
their  availability  is  desirable  in  instances  where  they  may  be  of 
value  for  future  more  detailed  site-specific  analyses. 

For  the  present,  the  data  base  has  been  limited  to 
sources  of  data  readily  available,  reduced,  and  in  summarized 
form  which  cover  a  period  of  5  years  or  more.  As  discussed 
earlier,  key  parameters  of  interest  include  wind  speed  and  wind 
direction,  atmospheric  stability,  mixing  heights,  temperature 
inversions,  and  winds  aloft.  Primary  sources  of  such  complete 
data  include  first  order  National  Weather  Service  (NWS)  stations 
and  special  interest  (usually  private  industry)  stations.  Figure 
4.3-1  provides  an  illustration  of  the  locations  of  key  meteorolo- 
gical stations  located  in  the  Ukiah  District  which  have  been  used 
to  establish  a  regional  assessment  of  dispersion  meteorology. 
Other  reference  materials  and  data  sources  are  also  discussed  in 
the  text  in  instances  where  they  add  additional  insight  into  the 
dispersion  meteorology  for  specific  areas. 

The  following  sections  are  based  upon  three  key  sets  of 
data.  These  include  (1)  STability  ARray  (STAR)  data  as  available 
from  the  National  Climatic  Center  (NCC)  in  Asheville,  North 
Carolina  and  (2)  NWS  and  California  Air  Resources  Board  (CARB) 
upper  air  temperature  and  wind  data.  STAR  data  provide  the  joint 
frequency  distribution  of  wind  speed,  wind  direction  and  atmos- 
pheric stability  class  on  a  monthly,  seasonal  and  annual  basis. 
Within  the  Ukiah  District,  STAR  data  for  Areata  and  Ukiah  have 
been  used  in  the  more  exhaustive  analyses.  STAR  data  are 
available  for  other  stations  in  the  district  as  indicated  on  the 
study  map.  The  data  used  in  this  report  were  chosen  to  provide  a 
representative  and  cost-effective  cros s- sect i on  of  the  dispersion 
meteorology  of  the  District.  Table  4.3-1  provides  a  summary  of 
the  available  dispersion  meteorological  data  from  NWS  and  CARB 
sources  in  the  Ukiah  District.  All  of  these  data  have  been 
utilized  in  the  present  analysis  as  appropriate. 


168 


ELK  VALLEY 


SMITH  RIVER 
CRESCENT  CITY 

DEL  NORTE 

KLAMATH 

1 

I 

ORICK 

HUMBOLDT 

HOOPA      . 


ARCATA 


BLUE  LAKE 

KORBEL 
A 
•    KNEELAND 


^^Eudfx 


.      FORTUNA 
TIA      •  .     BRIDGEVILLE 


ALDERPOINT 

•    GARBERVILLE, 


,  CUMMINGS 

•    COVELO 

BRANSCOMB 


TYPES  OF  DATA 


*    STAR  DATA 

▲    UPPER  AIR  DATA 


20 

L_ 


20 


MILES 


DELEVAN 


•     POTTER  VALLEY 

MENDOCINO  1  ^N 

•  CALPELLA  "  "•» 


^1 


MAXWELL 


UKIAH 


**[A    LAKE 


WILLIAMS* 


I  m.    LAKE  I 

y   •  LAKEPORT         ^ 
•  HOPLAND  .  CLEARLAKE HIGHLANDS 

•  CLOVERDALE  f       \ 

ANNAPOLIS  *  /  \ 

HEALDSBURG     »-""  *"" 


40 

_L_ 


60 

-J 


W.SACRAMENTO 


SONOMA 

.     SANTA  ROSA 
OCCIDENTAL     \ 
BODEGA  \ 

N 
\ 

MARIN 

SAN  RAFAEL 


Figure  4.3-1 
Sources  of  Dispersion  Meteorological  Data 
Used  in  the  Ukiah  District  Analysis 


169 


Table  4.3-1 

Available  Dispersion  Meteorological  Data 

in  the  Ukiah  District 


Period  of 

Station  Name 

County  Location 

Data  Description 

Data  Base 

Areata 

Humboldt 

Wind  speed,  wind  direction 
and  atmospheric  stability 
(24  obs./day) 

1/68-12/72 

Ukiah 

Mendocino 

Wind  speed,  wind  direction 
and  atmospheric  stability 
(24  obs./day) 

1/55-12/64 

Fairfield 

Travis  AFB 

Wind  speed,  wind  direction 

1/60-12/64 

Solano 

and  atmospheric  stability 
(24  obs./day) 

San  Rafael 

Hamilton  AFB 

Wind  speed,  wind  direction 

1/60-12/64 

Marin 

and  atmospheric  stability 
(24  obs./day) 

1/66-12/70 

Ukiah 

Mendocino 

Vertical    temperature 
sounding  and  mixing 
height  summaries 

ongoing 

Areata 

Humboldt 

Vertical   temperature 
soundings 

4/45-9/45 

Eureka 

Humboldt 

Vertical    temperature 
soundings 

10/71-11/71 

170 


Upper  air  wind  and  temperature  data  are  also  available 
for  certain  portions  of  the  Ukiah  District.  There  are  no  first 
order  stations  routinely  taking  temperature  and  winds  aloft  data 
in  the  district.  Nearby  data  from  Oakland  have  been  utilized  by 
Holzworth  (1972)  to  provide  data  on  inversion  types  and 
frequencies,  as  well  as  mixing  heights  and  mean  w4nd  speeds 
through  the  mixing  layer.  The  CARB  has  also  conducted  various 
programs  for  the  collection  and  summarization  of  temperature 
sounding  and/or  pilot  balloon  (winds  aloft)  release  data  at 
selected  stations  throughout  the  state.  In  the  Ukiah  District, 
this  includes  Ukiah.  The  availability  of  these  data  permits 
finer  resolution  of  mixing  heights  and  inversions  in  the 
district.  The  available  NWS  data  would  be  insufficient  to 
clearly  describe  these  parameters  in  the  Ukiah  District. 


171 


4.4 


PREVAILING  WINDS 


The  characterization  of  prevailing  surface  winds  and 
winds  aloft  is  essential  in  the  development  of  an  understanding 
of  the  dispersion  meteorology  of  the  Ukiah  District.  This  sec- 
tion provides  analyses  that  are  designed  to  identify  specific 
characteristics  of  the  prevailing  winds.   These  analyses  include: 

Wind  Roses 

Diurnal  Wind  Distributions 
Wind  Speed  Distributions 
Wind  Persistence  Analyses 
Trajectory  Analyses 
Winds  Aloft 


The  prevailing  winds  define  the  net  regional  transport  character- 
istics for  pollutants  in  a  given  geographical  area.  An  under- 
standing of  the  physical  behavior  of  air  flow  in  and  out  of  a 
particular  area  of  interest  provides  insight  as  to  the  fate  of 
air  pollutants. 


4.4.1 


Wind  Roses 


Wind  roses  provide  a  graphical  representation  of  the 
frequency  of  occurrence  of  winds  from  each  of  the  16  cardinal 
directions  for  specified  averaging  periods.  This  subsection 
discusses  the  prevailing  winds  using  wind  rose  analyses  on  a 
seasonal  and  annual  basis. 

Regional  wind  characteristics  throughout  the  Ukiah 
District  are  discussed  in  considerable  detail  in  Section  3.4. 
This  includes  a  summary  of  monthly  and  annual  average  wind  speeds 
and  prevailing  wind  directions  throughout  the  study  area.  Also, 
a  Ukiah  District  study  map  with  numerous  superimposed  annual  wind 
roses  was  provided  in  order  to  depict  the  air  flow  on  a  regional 
scale.  The  discussion  provided  in  this  section  is  designed  to 
summarize  prevailing  air  flow  characteristics  in  terms  of  a 
dispersion  analyses  for  subsequent  use  in  pollutant  impact 
st udi  es  . 

Annual 

Annual  wind  rose  diagrams  for  selected  key  stations  in 
the  district  are  provided  in  Figures  4.4-1  through  4.4-4.  Areata 
and  San  Francisco  wind  roses  describe  wind  conditions  character- 
istic of  coastal  areas.  Ukiah  represents  a  typical  inland  valley 
station  while  Sacramento  represents  a  Central  Valley  station. 
Figure  4.4-5  provides  a  study  map  of  the  district,  superimposed 
with  several  annual  wind  rose  diagrams.  This  figure  appeared  in 
Section  3.4  but  is  presented  here,  as  well,  due  to  its  importance 
in  describing  regional  flow  characteristics. 


172 


FREQUENCY  OF  OCCURRENCE   (%) 
ANNUAL  WIND  ROSE 

SITE: 
ARCATA 
bl 

wni/     /     /CI    \1^ 

\NNE 

\^0      / 

ssw   ^""" 

5 '       "     SSE 

PERIOD 
YEARS   1968-1972 

Figure  4.4-1 
Annual  Wind  Rose  for  Areata 


173 


FREQUENCY  OF  OCCURRENCE    {%) 
ANNUAL  WIND  ROSE 

SITE: 
SAN   FRANCISCO  WBAS 

NNk-^-^"~ 

^^\NNE 

HNl/            /'            JK^          \ 

— -To     /\       \     3fNE 

WSw\           \       /\\2 

\  ^s\  /     Ase 

~~^\       yS£ 

\^0      / 

SSW                   "  "Tj                       sit 

PERIOD 
YEARS   1948-1965 

Figure  4.4-2 
Annual  Wind  Rose  for  San  Francisco 


174 


FREQUENCY  OF  OCCURRENCE    {%) 
ANNUAL  WIND  ROSE 

SITE: 
UKIAH 
N 

wni/       /       p         \JW 

\-U/\     /       /ese 

SSW              '           S                       bbb 

PERIOD 
YEARS   1955-1964 

Figure  4.4-3 
Annual  Wind  Rose  for  Ukiah 


175 


FREQUENCY  OF  OCCURRENCE    (%) 
ANNUAL  WIND  ROSE 

SITE: 
SACRAMENTO 

~^\NNE 

x\    \  3fNE 

NlX             s^C~ 

WNl/           /          /\ 

Xri/ 

"^^^g 

wsw\        \      /^^wB 

\    ^/\     /            /ESE 

*""     SSE 

PERIOD 
YEARS   1966-1970 

SwV               /^. 

\^0      / 

ssw 

^5 

Figure  4.4-4 
Annual  Wind  Rose  for  Sacramento 


176 


'CRESCENT  CITY 


KLAMATH 


BLUE  LAKE 


.EUREKA 


N^PT  BRAGG 


UKIAH 


PT  ARENA 


.  CALPELLA  ^"*^\         <_^twiLLI> 

W       '  •  UPPERLAKE  "*^*K     V 

"*        V     •  LAKEPORT      )  \   ) 


WILLIAMS 


LAKEPORT 
\       wKELSEYVILLE 

. — -X 

•     CLOVERDALE 

v  J 

HEALDSBURG 


K 


•      DUNNIGAN 


^ 


HftSAN 

*7\ 


SANTA  ROSA 


\  \       DAVIS  •, 

x#  VACAVILLE 
NAPA 

I  *  F 

PETALUMA'  /   I       • 

\ 


WOODLAND 

W  SACRAMENTO 


SAN  RAFAEL 

KENTFIELD 


»  RIO  VISTA 


Figure  4.4-5 

Annual   Wind  Roses  at  Selected  Key  Stations 

in  the  tlkiah  District 


177 


The  annual  wind  roses  for  Areata  and  San  Francisco 
presented  in  Figures  4.4-1  and  4.4-2  indicate  the  preponderance 
of  onshore  flow  at  coastal  locations.  The  wind  rose  for  Areata 
shows  a  primary  maximum  for  flow  from  the  north- northwest  which 
is  indicative  of  coastal  flow  conditions  along  much  of  the  north 
coast  of  California.  Secondary  maxima  are  evident  for  flow  from 
the  east  and  south-southeast.  Easterly  flow  is  indicative  of 
drainage  conditions  from  higher  terrain  lying  east  of  the  station 
while  south-southeasterly  flow  is  indicative  of  prefrontal  condi- 
tions. At  San  Francisco,  Figure  4.4-2  indicates  a  clear  prefer- 
ence for  onshore  flow  from  the  west  through  northwest.  The 
dominance  of  onshore  flow  is  clearly  evident  in  San  Francisco 
with  winds  from  all  other  directions  occurring  very  infrequently. 

At  Ukiah,  Figure  4.4-3  indicates  a  bimodal  distribution. 
Winds  from  the  sout h- southeast  occur  most  frequently  while  winds 
from  the  west- north  west  clockwise  through  north  constitute  the 
bulk  of  the  remainder  of  the  annual  flow  at  this  station.  South- 
southeasterly  flow  at  Ukiah  is  generally  indicative  of  upslope 
flow  as  well  as  prefrontal  winds.  Many  of  the  inland  valley 
stations  in  the  southern  portion  of  Ukiah  District  experience 
prevailing  flow  from  the  southeast.  Winds  from  the  northwest 
quadrant  also  comprise  an  important  portion  of  the  wind  rose  at 
Ukiah  and  are  indicative  of  the  general  down  coastal  flow  experi- 
enced in  northwestern  California. 

Finally,  at  Sacramento,  the  annual  wind  rose  shows  a 
clear  preference  for  winds  from  the  south  clockwise  through 
southwest.  This  wind  rose  is  indicative  of  flow  in  the  Sacra- 
mento Valley  portion  of  the  Ukiah  District.  Maritime  air  moves 
into  the  Central  Valley  of  California  through  the  Carquinez 
Straits  and  diverges  both  to  the  south  towards  Stockton  and 
Fresno  and  to  the  north  to  Sacramento  and  Redding.  This  flow 
results  in  a  preference  for  south-southwesterly  flow  at  many 
Sacramento  Valley  stations.  In  the  Ukiah  District,  in  Colusa  and 
Yolo  Counties  this  flow  turns  more  to  the  south-southeast  as  the 
maritime  air  begins  to  move  upslope  into  the  valleys  and  the 
Coast  Ranges  . 

Seasona 1 


Seasonal  wind  roses  for  Areata,  Ukiah  and  Sacramento  are 
provided  in  Figures  4.4-6  through  4.4-8.  The  seasonal  wind  roses 
for  Areata  are  generally  trimodal.  During  the  winter  months,  the 
primary  maximum  occurs  for  winds  from  the  east  which  are  repre- 
sentative of  nocturnal  drainage  conditions  from  elevated  terrain 
ly-ing  east  of  the  station.  A  secondary  maxima  is  evident  for 
winds  from  the  so ut h- sout hea st  which  are  indicative  of  prefrontal 
flow  conditions  which  occur  frequently  during  the  rainy  season 
months.  Finally,  a  tertiary  maximum  is  evident  for  flow  from  the 
nort h- northwest  which  is  indicative  of  the  more  general  down 
coastal  wind  flow  conditions  commonly  observed  throughout  north- 
western California.  During  spring  and  summer,  the  down  coastal 
north-northwesterly  flow  represents  the  primary  maximum  at 


178 


FREQUENCY  OF  OCCURRENCE  {'  ) 
SEASONAL  WIND  ROSE 


SITE:  2Ml~, 


SSW 

ALL  WIND  SPEEDS 
ALL  STABILITY  CLASSES 


WINTER 


FREQUENCY    OF   OCCURRENCE    (i  ) 
SEASONAL  WIND  ROSE 

SITE:    2i2e3 

NNW^-"-"* 

-\NNE 

nw/            J*r 

/^l4 

\Mr 

/      /^    yv&7 

\js    y^ 

wnii/         /        /C       Hr^>r 

■     s\ 

\           jf ''- 

/       "~s~sCr53l 

\Jky 

\  ^-"a'/^j 

^\k.yyZ. 

\^\        \    /^/ 

\     \y^l 

/             /ESE 

\y    ^s?^  / 

SwV               /^-~_ 

/   BE 

^vJO     / 

ssw 

SSE 

ALL  WIND  SPEEDS 

ALL   STABILITY   CLASSES 

SPRIN3 

FREQUENCY  OF  OCCURRENCE 
SEASONAL  WIND  ROSE 

N __ 

SITE: 

24282 

NNl^ 

nuS         Jk 

"/"^i  7\ 

\NE 

wnu^    /     yc     \ 

7C12  y\ 

VnE 

—Je  y    \^^\ 

\   ^-A^/HS 

/ 

\^\    \  y^ii/ 

^/ 

wShi\    \  /\jp/ 

/ESE 

\/  \^  / 

SwV                7^-^__ 

'SE 

>jp    / 

SSW 

5 SSE 

ALL  WIND  SPEEDS 

ALL   STABILITY   CLASSES 

FALL 

FREQUENCY  OF   OCCURRENCE    ('. ) 
SEASONAL   WIND  ROSE 

SITE:    24283 

NNW^- — " 

~~-^JNNE 

\w[ 

NU/ 

"a^?4 

/^  7\ 

WNl/            /                *   '           ^  * 

\             ^Nr 

1   ^Cj2    y\ 
—hy  \^~\ 

\  ^A/*s^i 

\^^\           \      T^Zl 

WSA.       \   /\je/ 

/       /ese 

Nv/              ^N?£    / 

swV            y^^_ 

/SE 

\,2o   / 

SSW 

5 SSE 

ALL  WIND  SPEEDS 

ALL   STABILITY   CLASSES 

SUMMER 

Figure  4.4-6 
Seasonal  Wind  Roses  for  Areata 


179 


FREQUENCE  OF  OCCURRENCE 
SEASONAL  WIND  ROSE 


SITE:  23275 


US- 


ssu 

ALL  WIND  SPEEDS 

ALL  STABILITY  CLASSES 


WI'.TEf 


FREQUENCY  OF  OCCURRENCE 
SEASONAL  WIND  ROSE 


SITE:  23275 


WSUP 


SSU 
ALL  WIND  SPEEDS 
ALL  STABILITY  CLASSES 


SPRING 


FREQUENCY   OF   OCCURRENCE 
SEASONAL  WIND  ROSE 

N 

7^30 

SITE:    23275 

NIX                   S^K 

\lvjC 

wni/     /     yc 

±2    /\ 

\        3^NE 

3fo 

^H§ 

^ll 

WSr.                      \          /\, 

s  / 

/         /ESE 

\s       ^^  1 

Su\                       y^ 

/SE 

\^0      / 

SSU 

SSE 

ALL  WIND  SPEEDS 

ALL   STABILITY   CLASSES 

SUMMER 

FREQUENCY  OF  OCCURRENCE 
SEASONAL  WIND  ROSE 

NNW-^ 

WNl/             /            /C             V— — 

SITE:   23275 

"~\NNE 
/^30 

— --In  /\    \  3fNE 

%&/  \^\    \    \ 

WSu\             \           /N.           / 

.   w;>   \        \y   Xie/ 

\/           ^v£"    / 

SuV                           y^^__ 

^s30     / 

\ *s\  /    /ESE 

SSU                   H>                    s>s>t 
ALL  WIND  SPEEDS 
ALL   STABILITY   CLASSES                                                                                 FALL 

Figure  4.4-7 
Seasonal  Wind  Roses  for  Ukiah 


180 


FREQUENCY  OF  OCCURRENCE   (I) 
SEASONAL  WIND  ROSE 

wni/     /     yc     \ 

^JNNE 
/S20 

SITE: 

sacramento 
Vne 

wsw\        \     /Xjg/ 

\56   / 

ssw      " 

5 SSE 

/ese 

WINTER 

FREQUENCY  OF  OCCURRENCE  (%) 
SEASONAL  WIND  ROSE 


FREQUENCY  OF  OCCURRENCE    {%) 
SEASONAL  WIND  ROSE 

WNl/           /          /C           V 

SITE: 
SACRAMENTO 

~~-\NNE 

— /r  JX    \   3fNE 

WSw\           \         /^NA^g/^^ 
\§0    / 

.    ssw^ ' 

r      \  -/\  /        /ESE 
— — -~^\          /**■ 

5 "           SSE 

SUMMER 

FREQUENCY  OF  OCCURRENCE  (S) 
SEASONAL  WIND  ROSE 


SITE: 
SACRAMENTO 


N9c 

WNl/            / 

KINt^-" 

Xne 

\  3fNE 

wsw\         \ 

/    /ESE 

\^e   / 

ssw                 ' 

5 "          SSE 

FALL 


Figure  4.4-8 
Seasonal  Wind  Roses  for  Sacramento 


181 


Areata.  The  secondary  maximum  for  winds  from  the  east  and  south- 
southeast  occurs  much  less  frequently  during  these  months.  By 
fall,  however,  the  nocturnal  drainage  flow  conditions  from  the 
east  once  again  dominate  with  secondary  maxima  for  flow  from  the 
nort h- northwest  and  sout h- southeast . 

At  Ukiah,  Figure  4.4-7  indicates  a  bi modal  distribution 
aligned  along  a  sout h- sout heast/ nort h- northwesterl  y  axis,  which 
is  well  aligned  with  the  Russian  River  Valley.  During  winter, 
upslope  flow  from  the  south-southeast  clearly  dominates  as  this 
also  represents  winds  associated  with  prefrontal  conditions. 
During  spring  and  summer,  winds  from  the  northwest  quadrant 
dominate,  however,  upslope  flow  from  the  south- southeast  still 
occurs  with  a  fairly  substantial  frequency  of  occurrence.  The 
downslope  northwesterly  flow  observed  at  Ukiah  during  the  warm 
season  months  is  indicative  of  conditions  throughout  this  portion 
of  California  resulting  from  the  influence  of  the  semi -permanent 
Pacific  high  pressure  system.  By  fall,  the  distribution  is 
nearly  split  between  flow  from  the  so uth- southeast  and  northwest. 
This  season  represents  a  transition  period  between  the  influence 
of  the  Pacific  high  pressure  system  and  the  onset  of  migratory 
storm  systems  which  move  through  the  Pacific  northwest  during  the 
rai  ny  season  . 

Finally,  at  Sacramento,  the  seasonal  distribution  is 
indicative  of  conditions  observed  in  the  Sacramento  Valley  por- 
tion of  Ukiah  District.  During  spring,  summer  and  fall,  south- 
west and  sout h- southwes terl y  flow  dominate  at  Sacramento  while 
southeasterly  winds  are  prevalent  during  the  winter  months.  A 
secondary  maximum  occurs  for  nort h- northwesterl y  flow  during  all 
seasons.  Once  again,  these  latter  winds  are  indicative  of  pre- 
vailing flow  throughout  northwestern  California  while  southeast- 
erly winds  represent  a  combination  of  upslope  flow  and  prefrontal 
wi  nds  . 


4.4.2 


Diurnal  Wind  Distribution 


The  diurnal  distribution  of  both  wind  speed  and  direc- 
tion provides  average  values  of  these  parameters  as  a  function  of 
the  hour  of  the  day.  Such  data  provides  useful  additional  infor- 
mation on  the  dispersion  characteristics  of  a  given  geographical 
area.  For  example,  the  diurnal  distribution  of  wind  direction 
provides  a  good  indication  of  when  certain  downwind  areas  could 
be  impacted  by  sources  of  air  pollutants.  In  addition,  the 
diurnal  distribution  of  wind  speed  provides  an  indication  of  the 
time  of  day  when  best  dispersion  conditions  can  be  expected  based 
upon  average  wind  speeds  and  the  associated  degree  of  pollutant 
transport.  This  is  important  to  know  in  activities  such  as 
prescri  bed  f i  res . 

Wind  Direction 

Figures  4.4-9  and  4.4-10  present  the  diurnal  wind  direc- 
tion distribution  for  Areata  and  Ukiah.  These  data  provide 
insight  into  the  direction  of  the  prevailing  winds  as  a  function 


182 


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of  time  of  day.  This  information  can  be  valuable  to  community 
and  industrial  planners  concerned  with  the  control  of  existing 
emission  sources  and  the  placement  of  new  sources  since  they  can 
be  used  to  determine  which  specific  areas  in  a  region  are  most 
likely  to  be  adversely  impacted  by  pollutants  throughout  the  day. 

The  diurnal  distribution  of  wind  direction  at  Areata  as 
depicted  in  Figure  4.4-9  indicates  the  prevalence  of  easterly 
drainage  flow  from  higher  terrain  lying  east  of  the  station 
during  the  evening  and  early  morning  hours.  From  mid-morning 
till  sunset,  the  flow  becomes  generally  northwesterly  to  west- 
northwesterly  as  the  onshore  flow  of  maritime  air  prevails. 
Further  inland  at  Ukiah,  flow  from  the  so uth- southeast  prevails 
during  the  nighttime  and  early  morning  hours.  This  is  indicative 
of  valley  flow  conditions.  During  the  afternoon,  flow  from  the 
northwest  quadrant  dominates  as  northwesterly  flow  indicative  of 
conditions  throughout  this  portion  of  the  state  begins  to  domi- 
nate . 

Wind  S  peed 

The  wind  speed  distributions  at  Areata  and  Ukiah  are 
very  similar  as  indicated  in  Figures  4.4-11  and  4.4-12.  Wind 
speeds  are  generally  lighter  at  Ukiah  than  at  the  more  exposed 
coastal  station  of  Areata.  At  both  stations,  minimum  wind  speeds 
occurr  during  the  early  morning  hours  between  midnight  and 
approximately  sunrise.  Maximum  wind  speeds  occur  at  Areata 
between  one  and  three  in  the  afternoon  and  around  four  to  five  in 
the  afternoon  at  Ukiah.  Maximum  wind  speeds  at  Areata  average  4 
meters  per  second  (9  mph)  with  minimum  wind  speeds  of  roughly  1.7 
meters  per  second  (3.8  mph).  At  Ukiah,  maximum  wind  speeds  reach 
approximately  3  meters  per  second  (6.6  mph)  during  the  afternoon 
with  overnight  values  reaching  as  low  as  0.5  mps  (1.1  mph). 

In  summary,  available  diurnal  wind  speed  data  for  Areata 
and  Ukiah  show  similar  distributions  with  wind  speeds  being 
lighter  at  the  inland  station,  Ukiah.  Wind  speeds  will  tend  to 
be  higher  along  coastal  regions  of  the  Ukiah  District  and  at 
exposed  sites  in  rugged  mountainous  terrain.  Wind  speeds  would 
be  lowest  in  sheltered  valley  locations  within  the  Coast  Ranges. 


4.4.3 


Wind  Speed  Distribution 


The  distribution  of  wind  speed  as  a  function  of  the 
frequency  of  occurrence  of  designated  wind  speed  categories  is 
routinely  available  for  first  order  stations  within  the  Ukiah 
Di-strict.  Figures  4.4-13  t  hrou  g  h  4. 4  -1  5  provide  seasonal  and 
annual  distributions  of  wind  speed  as  a  function  of  six  distinct 
categories  including;  (1)  0-3  knots  (0-3.5  mph),  (2)  4-6  knots 
(4.6-6.9  mph),  (3)  7-10  knots  (8.1-11.5  mph),  (4)  11-16  knots 
(12.7-18.4  mph),  (5)  17-21  knots  (19.6-24.2  mph),  and  (6)  greater 
than  21  knots  (24.2  mph).  The  frequency  of  calms  is  also  pro- 
vided in  each  figure  as  well  as  conversion  factors  to  facilitate 
the  use  of  both  English  and  metric  units. 


184 


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Hour  of  the  Day  (PST) 

Figure  4.4-11 
Diurnal   Wind  Speed  Distribution  at 
Areata,  CA*  (1968-1972) 


6  - 


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00   02   04    06 


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Hour  of  the  Day  (PST) 


18        20       22        24 


Figure  4.4-12 
Diurnal   Wind  Speed  Distribution  at 
Ukiah,   CA     (1955  -   1964) 


Note:    Diurnal  Wind  Speed  as  Defined  by  Magnitude  Average  SDeed 

1  MPS  =  2.237  MPH  =   1.944  Knots     10c 

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Annual-Seasonal   Frequency  of  Occurrence  of  Key  Wind  Speed  Classes 

at  Areata,  California   (1968-1972) 


Note:     IMPS  =  2.237  MPH  =   1.944  Knots 


186 


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Figure  4.4-14 
Annual-Seasonal    Frequency  of  Occurrence  of  Key  Wind  Speed  Classes 
at  Ukiah,  California   (1955-1964) 


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Figure  4.4-15 
Annual-Seasonal   Frequency  of  Occurrence  of  Key  Wind  Speed  Classes 
at  Sacramento,  California   (1966-1970) 


Note:      IMPS  =  2.237  MPH  =   1.944  Knots 


188 


The  figures  indicate  that  light  wind  speed  conditions 
tend  to  reach  a  maximum  frequency  during  winter  and  fall  at  each 
station.  The  0-3  knot  class  reaches  a  maximum  frequency  of  30.9% 
of  all  occurrences  at  Areata  during  this  season  and  accounts  for 
29.6%  of  the  fall  distribution  at  Sacramento.  At  tiki  ah,  the 
frequency  of  calm  and  light  wind  speed  conditions  is  exceptional- 
ly high.  The  frequency  of  calms  reaches  68.2%  of  the  distribu- 
tion during  winter  and  65.2%  of  the  distribution  during  fall  at 
this  station.  The  0-3  knots  wind  speed  category  clearly  domi- 
nates the  distribution  during  all  seasons  reaching  a  minimum 
frequency  in  summer  when  surface  heating  induced  upslope  flow 
creates  stronger  afternoon  winds.  The  very  high  frequency  of 
light  wind  speed  conditions  at  Ukiah  is  conducive  to  air  pollut- 
ant buildups,  particularly  during  the  fall  and  winter  seasons  at 
Ukiah. 

The  4-6  knot  wind  speed  category  is  the  most  common 
category  at  Areata  reaching  a  maximum  frequency  of  41%  of  all 
occurrences  during  fall.  On  an  annual  basis,  this  wind  speed 
category  occurs  35.2%  of  the  time.  At  Ukiah,  on  an  annual  basis, 
the  0-3  knot  wind  speed  category  occurs  61.7%  of  the  time  with 
the  second  most  frequently  occurring  category  being  the  7-10 
class  which  occurrs  17.7%  of  the  time.  Fully  57.6%  of  all  wind 
speed  occurrences  at  Ukiah  are    calm  conditions. 

Finally,  at  Sacramento,  the  4-6  knot  wind  speed  class  is 
the  most  common  during  all  seasons  with  the  exception  of  summer 
when  the  7-10  knot  wind  speed  class  dominates.  During  the  summer 
months,  the  influx  of  maritime  air  through  the  Carquinez  Straits 
into  the  Sacramento  Valley  results  in  brisk  afternoon  winds  at 
Sacramento  and  at  all  portions  of  the  Ukiah  District  in  the 
Sacramento  Valley.  On  an  annual  basis,  the  4-6  knot  wind  speed 
class  occurrs  most  frequently  at  Sacramento  accounting  for  33.7% 
of  the  distribution  with  calms  accounting  for  10.7%  of  all  occur- 
rences . 

Wind  Speed  as  a  Function  of  Wind  Direction 

The  distribution  of  wind  speed  as  a  function  of  wind 
direction  provides  important  information  for  dispersion  meteor- 
ological studies.  For  example,  when  sensitive  areas  are  situated 
near  possible  sources  of  pollutants,  it  is  often  beneficial  to 
examine  the  mean  wind  speed  of  the  flow  from  the  direction  of  the 
source.  Very  low  wind  speeds  are  generally  associated  with 
stable  or  limited  dispersion  conditions  and  could  serve  to  maxi- 
mize pollutant  impact  in  the  sensitive  area.  High  average  wind 
speeds  generally  imply  well-mixed  conditions  and  would  reduce 
downwind  pollutant  concentrations.  Plots  of  annual  average  wind 
speed  as  a  function  of  wind  direction  have  been  generated  for 
Areata,  Ukiah  and  Sacramento  and  are  presented  in  Figures  4.4-16 
through  4.4-18.  In  addition,  the  average  annual  wind  speed 
independent  of  wind  direction  for  each  station  is  presented  with 
each  pi ot . 


189 


Q- 


Annual   Averaqe 
6.8 


N  NNE  NE  ENE  E  ESE  SE  SSE  S  SSW  SW  WSW  W  WNW  NW  NNW  N 
Wind   Direction 
(Wind   From) 


Figure  4.4-16 
Annual  Wind  Speed  as  a  Function  of  Wind  Direction 
at  Areata,  California  (1968-1972)* 


8  Observations  per  day 


190 


UJ 
Q- 


Annual  Average 
3.6 


N  NNE  NE  ENE  E   ESE  SE  SSE  S  SSW  SW  WSW  W  WNW  NW  NNW  N 
Wind   Direction 
(Hind   From) 

Figure  4.4-17 
Annual   Wind  Speed  as  a  Function  of  Wind  Direction 
at  Ukiah,  California   (1955-1964) 


191 


CO 


Average 
Annual 
7.5 


N  NNE  NE  ENE  E  ESE  SE  SSE  S  SSW  SW  WSW  W  WNW  NW  NNW  N 
Wind  Direction 
(Wind  From) 


Figure  4.4-18 
Annual  Wind  Speed  as  a  Function  of  Wind  Direction 
at  Sacramento,  California  (1966-1970)* 


8  Observations  per  day 


192 


The  data  for  Areata  indicate  that  the  strongest  wind 
speeds  are  associated  with  winds  from  the  prevailing  directions. 
Winds  from  the  northwest  quadrant  account  for  the  strongest  wind 
speeds  at  this  station  as  maritime  air  flows  into  the  area  unin- 
hibited by  terrain  influences.  Wind  speeds  in  excess  Of  10  miles 
per  hour  are  common  for  onshore  flow.  Winds  from  the  southeast 
quadrant  commonly  associated  with  prefrontal  conditions  are  also 
accompanied  by  fairly  brisk  wind  speeds,  generally  on  the  order 
of  10  miles  per  hour.  Lightest  wind  speeds  are  associated  with 
uncommon  directions  and  for  drainage  flow  from  the  east.  Drain- 
age flow  conditions  are  generally  typified  by  winds  of  6-7  miles 
per  hour. 

Figure  4.4-17  indicates  that  at  Ukiah,  strongest  wind 
speeds  are  associated  with  flow  from  the  southeast  indicative  of 
upvalley  flow.  Winds  from  this  direction  represent  prevailing 
winds  during  most  seasons  of  the  year  at  this  station.  Wind 
speeds  approaching  10  miles  per  hour  are  not  uncommon  for  flow 
from  these  directions.  The  second  highest  wind  speeds  are  gen- 
erally associated  with  flow  from  the  northwest  quadrant  which  is 
indicative  of  regional  flow  conditions  associated  with  down 
coastal  winds  common  in  northwestern  California.  Northwesterly 
flow  is  generally  characterized  by  winds  of  between  8  and  10 
miles  per  hour  at  Ukiah.  The  annual  average  wind  speed  is  con- 
siderably lower  than  wind  speeds  shown  for  most  wind  directions. 
This  can  be  attributed  to  the  very  high  frequency  of  calms  at  the 
Ukiah  Station. 


Finally, 
the  highest  wind 
from  the  south  and 
westerly  flow  are 
10  miles  per  hour 


at  Sacramento,  the  same  trend  continues  with 
speeds  being  associated  with  prevailing  flow 
from  the  northwest.  Southerly  flow  and  north- 
both  characterized  by  wind  speeds  in  excess  of 
The  southerly  flow  is  generally  associated 
with  summer  sea  breeze  situations.  Northwesterly  flow  is  again 
indicative  of  regional  flow  conditions  commonly  observed  in  this 
part  of  the  state.  The  annual  average  wind  speed  at  Sacramento 
is  7.5  miles  per  hour . 


4.4.4 


Persistence  Analyses 


The  persistence  of  both  wind  speed  and  wind  direction 
also  plays  a  very  functional  role  in  a  complete  analysis  of 
dispersion  meteorology.  For  example,  the  persistence  of  a  par- 
ticular wind  direction  provides  information  relative  to  the 
likelihood  of  continued  impact  at  a  given  receptor  location  for 
either  existing  or  proposed  sources.  In  terms  of  wind  speed,  low 
wind  speeds  can  often  provide  a  maximum  impact  in  a  given  region 
particularly  if  they  persist  for  any  length  of  time.  Therefore, 
the  persistence  of  calms  or  lower  wind  speed  classes  can  also 
provide  very  useful  information  relative  to  the  overall  disper- 
sion potential. 


193 


Tables  4.4-1  and  4.4-2 
speed  persistence  tables  for 
three  hourly  basis  at  Areata 
tence  analyses.  These  data 
tence  of  these  parameters  in 
are  provided  in  terms  of  key 
24  or  more  hours . 


provide  wind  direction  and  wind 
Ukiah.   Data  are  only  available  on  a 
eliminating  its  utility  for  per  sis- 
provide  information  on  the  persi s- 
the  primary  BLM  land  area.   The  data 
persistence  intervals  of  2,  4,  10  or 


4.4.5 


Trajectory  Analyses 


Trajectory  analyses  are 
to  describe  regional  transport, 
oped  through  the  identification 
tions  to  establish  the  mean  flow 
These  data  are  then  useful   in 
scale  transport  of  pollutants. 


used  in  dispersion  meteorology 

Trajectory  analyses  are  devel- 

of  prevailing  flow  at  key  sta- 

over  a  large  geographical  area. 

determining  the  probable  large 


In  the  Ukiah  District,  diurnal  wind  direction  data  are 
only  availabe  for  Areata  and  Ukiah.  It  is  not  felt  that  the 
available  data  on  prevailing  flow  at  these  stations  is  sufficient 
to  definitively  determine  the  actual  trajectory  of  air  parcels 
throughout  this  large  area.  A  general  trajectory  analyses  is 
presented  in  Figure  3.6-3.  The  reader  is  cautioned  in  the  inter- 
polative  use  of  these  data  for  other  areas  as  local  terrain 
effects  may  dominate.  However,  some  useful  conclusions  can  be 
drawn  from  the  analysis. 


4.4.6 


Winds  Aloft 


Upper  level  winds  provide  a  measure  of  the  mean  trans- 
port above  the  surface  boundary  layer.  However,  upper  air  data 
are  only  available  for  a  very  few  NWS  station  locations  and,  for 
this  reason,  most  major  pollutant  studies  require  the  collection 
of  onsite  data  to  provide  a  measure  of  winds  aloft.  In  Cali- 
fornia, upper  air  data  are  only  routinely  collected  by  the  NWS  at 
Oakland,  Santa  Monica  and  San  Diego. 

Upper  level  wind  data  at  such  NWS  stations  are  generally 
taken  by  radiosonde.  This  is  a  balloon,  tracked  by  radar  which 
transmits  data  on  temperatures  aloft  as  well  as  wind  speed  and 
wind  direction  through  the  tracking  of  the  balloon's  downwind 
position.  Upper  level  winds  over  most  of  California  show  a 
characteristic  flow  from  the  northwest  quadrant  at  most  levels. 
The  impact  of  the  dominating  terrain  characteristics  of  much  of 
California  and  the  Ukiah  District  is  felt  most  critically  in  the 
first  few  thousand  feet,  the  area  of  interest  in  pollution 
st-ud  i  es  . 

As  stated  previously,  Oakland  is  the  only  regular  upper 
air  meteorological  station  operated  by  the  NWS  near  the  Ukiah 
District.  Other  winds  aloft  data  have  been  collected  by  the 
(California  Air  Resources  Board)  CARB  as  part  of  its  ongoing 
analysis  of  pollutant  transport  conditions  as  well  as  for  use  in 
the  development  of  burn/no-burn  forecasts.   This  data  collection 


194 


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program  by  the  CARB  is  primarily  geared  to  the  identification  of 
local  inversion  meteorology  and  the  establishment  of  the  mean 
height  of  the  mixing  layer.  Data  available  from  pilot  balloon 
releases  by  the  CARB  as  well  as  through  programs  operated  by 
private  industry  indicate  a  continuation  of  the  flow  observed  at 
the  surface  gradually  turning  towards  the  west  through  northwest 
as  commonly  observed  over  California  at  upper  levels. 

Holzworth  (1972)  has  provided  seasonal  and  annual  values 
of  the  mean  wind  speed  averaged  through  the  mixing  layer  for  both 
the  morning  and  afternoon  hours.  These  data  are  particularly 
useful  in  dispersion  studies  as  they  provide  a  realistic  measure 
of  mean  transport  in  the  layer  of  the  atmosphere  in  which  most 
pollutants  are  mixed. 

Table  4.4-3  provides  a  summary  of  these  data  for  the 
Ukiah  District.  The  data  provide  a  range  of  values  across  the 
district  which  indicate  that  lower  wind  speeds  occur  during  the 
morning  hours  as  opposed  to  the  afternoon.  In  addition,  winter 
and  fall  tend  to  be  the  most  restrictive  seasons  in  terms  of 
lower  wind  speeds.  A  review  of  the  geographical  distribution  of 
these  data  as  provided  by  Holzworth  (1972)  indicates  that  the 
lower  values  occur  in  the  interior  with  higher  wind  speeds  gen- 
erally along  the  Pacific  Coast.  It  is  pointed  out,  however,  that 
the  Holzworth  (1972)  data  are  based  upon  an  analysis  of  data 
available  from  Oakland,  Santa  Monica  and  San  Diego  and  as  such 
are  based  upon  very  few  data  points.  For  this  reason,  the  reader 
is  cautioned  in  the  utilization  of  these  data,  particularly  in 
areas  with  important  terrain  effects. 

The  CARB  data  indicates  that  weak  mixing  layer  winds  are 
known  to  occur  during  summer  at  Ukiah.  Mixing  layer  wind  speeds 
are  strong  at  Ukiah  during  winter.  Other  seasonal  mixing  layer 
wind  speeds  are  not  notable  at  Ukiah,  the  station  that  has  been 
studied  by  the  CARB  (1974). 


196 


Table  4.4-3 

Seasonal  and  Annual  Average  Wind  Speeds  (MPH) 

in  the  Mean  Mixing  Layer  Over  the  Ukiah  District 


Morning 

Afternoon 

Winter 

4.5  -  8.9 

8.9  -  11.2 

Spring 

6.7  -  8.9 

13.4 

Summer 

4.5  -  6.7 

11.2  -  13.4 

Fall 

4.5  -  6.7 

8.9  -  11.2 

Annual 

6.7 

11.2 

197 


4.5 


ATMOSPHERIC  STABILITY 


The  definition  of  atmospheric  stability  throughout  the 
Ukiah  District  is  a  critical  component  of  the  dispersion  meteor- 
ological analysis.  Section  4.2.2  provides  a  detailed  discussion 
of  atmospheric  stability  and  its  role  in  defining  the  dispersion 
of  airborne  effluents.  Figure  4.5-1,  which  also  appears  in 
Section  4.2.2,  summarizes  the  dispersion  characteristics  associ- 
ated with  the  various  stability  categories  for  the  traditional 
dispersion  scenarios.  This  section  provides  analyses  that  are 
designed  to  identify  specific  characteristics  of  atmospheric 
stability.   These  analyses  include: 

t  Seasonal  and  Annual  Distributions 

•  Diurnal  Distributions 

•  Persistence  Analyses 

•  Stabi 1 i  ty  Wind  Roses 

These  analyses  describe  a  key  component  of  the  disper- 
sion characteristics  of  the  Ukiah  District.  Data  are  unfortu- 
nately available  for  only  a  few  key  stations  in  the  region  and 
the  reader  is  cautioned  in  the  use  of  these  analyses,  particular- 
ly in  areas  of  rugged  terrain  or  other  locations  not  well  repre- 
sented by  the  available  data. 


4.5.1 


Seasonal  and  Annual  Stability  Distributions 


Annual  stability  distributions  provide  a  means  of  quan- 
tifying the  atmospheric  dispersive  power  of  an  area  in  an  easily 
comparative  form.  The  seasonal  variations  in  stability  reflect 
the  extent  to  which  the  dispersive  power  of  the  atmosphere 
changes  with  the  seasons. 

The  ability  of  the  local  atmosphere  to  disperse  airborne 
effluents  from  specific  source  types  can  be  discussed  in  terms  of 
atmospheric  stability.  When  the  atmosphere  is  stably  stratified, 
the  impact  of  ground  level,  non-buoyant  emissions,  will  be  great- 
est as  both  vertical  and  lateral  diffusion  are  restricted. 
Examples  of  such  emissions  include  automobile  exhaust  and  fugi- 
tive dust.  Typical  similar  sources  which  might  impact  BLM  lands 
include  range  management  activities  and  the  use  of  unpaved  sur- 
face roads.  The  lower  atmosphere  is  most  likely  to  be  stable  on 
calm  clear  nights  when  cold  air  tends  to  collect  at  lower  eleva- 
tions. Emissions  from  tall  stacks  under  such  conditions  will 
have  little  or  no  impact  at  ground  level  as  the  plume  remains 
relatively  intact  aloft.  Fall  and  winter  are  the  seasons  when 
su-ch  conditions  occur  most  frequently  in  California  and  in  most 
areas  of  the  United  States.  The  impact  of  ground  level  sources 
is  therefore  at  a  maximum  during  these  seasons. 

Intense  surface  heating  results  in  considerable  convec- 
tive  activity  and  unstable  conditions.  Under  such  conditions, 
vertical  diffusion  is  considerable  and  "fumigation"  can  occur  as 


198 


Stability  Category  A-C;  Looping 


Stability  Category  D;  Coning 


Stability  Category  E-G;  Fanning 


I  i.  ts&—iL   .  ■  u  I  .I'M 


Stability  Categories  As  Noted, 
Lofting 


E-G 


Stability  Categories  As  Noted; 
Fumigation 


E-G 


A-C 


Stability  Categories  As  Noted; 
Trapping  Inversion 


Figure  4.5-1 

i 

Typical  Plume  Behavior 


E-G 


A-D 


Plume  behavior  influenced  by  the  temperature  lapse  rate  above  and  below  the 
release  height.  The  dashed  lines  in  the  profiles  are  the  adiabatic  lapse 
rates,  included  for  reference,  while  the  solid  lines  indicate  the  actual 
lapse  rate.  The  Pasquill  stability  categories  are  also  provided. 

199 


emissions  from  elevated  sources  are  brought  rapidly  to  the  sur- 
face creating  maximum  ground-level  concentrations.  Examples  of 
large  elevated  pollutant  sources  which  could  potentially  impact 
BLM  lands  include  power  plants  and  other  large  industrial  sources 
as  well  as  large  forest  fires. 

Finally,  neutral  atmospheric  stability,  characterized  by 
a  windy,  well-mixed  atmosphere,  and  generally  indicative  of  good 
atmospheric  dispersion,  can  result  in  locally  high  ground-level 
concentrations  for  stacks  of  intermediate  height  or  stacks  whose 
height  is  not  substantially  greater  than  the  height  of  surround- 
ing buildings.  Most  moderate  sized  industrial  complexes  are 
indicative  of  this  source  type;  refineries  and  other  processing 
industries  serve  as  typical  examples.  In  such  cases,  strong 
winds  can  bring  the  plume  rapidly  to  the  surface,  resulting  in 
high  gound-level  pollutant  concentrations  in  a  condition  known  as 
"downwash".  Neutral  conditions  may  also  result  in  the  re-en- 
trainment  of  loose  dust  and  soil  particles  associated  with  des- 
erts and  overgrazed  arid  lands.  Reduced  visibility  and  increased 
atmospheric  particulate  loading  may  occur  in  nearby  populated 
areas  as  a  resul t . 

The  following  discussion  provide  seasonal  and  annual 
distributions  of  atmospheric  stability  which,  combined  with  a 
knowledge  of  source  types,  can  be  used  to  identify  probable 
periods  of  maximum  impact.  Seasonal  and  annual  stability  fre- 
quency distributions  for  various  site  locations  throughout  the 
Ukiah  District  are  provided  in  Figures  4.5-2  through  4.5-4.  At 
Areata,  neutral  conditions  dominate  the  stability  distribution 
during  all  seasons  of  the  year.  On  an  annual  basis,  neutral 
conditions  acccount  for  60.9%  of  the  distribution  while  stable 
conditions  account  for  25.9%  of  the  distribution.  Unstable 
conditions  at  Areata  are  fairly  infrequent.  The  frequency  of 
neutral  conditions  in  Areata  is  highest  in  the  summer  months 
coinciding  with  the  high  frequency  of  occurrence  of  fog  and 
stratus.  Unstable  conditions  also  reach  the  highest  frequency  of 
occurrence  during  this  season  when  surface  heating  effects  tend 
to  become  most  intense.  As  a  result,  the  frequency  of  stable 
conditions  is  at  a  low  during  the  summer  months.  Fall  tends  to 
be  the  season  with  the  lightest  wind  speeds  and  the  highest 
frequency  of  clear  skies  in  Areata.  Accordingly,  the  frequency 
of  stable  conditions  reaches  a  seasonal  maximum  at  34.2%  of  the 
distribution. 

At  Ukiah,  the  frequency  of  neutral  conditions  is  greatly 
diminished  over  that  observed  at  Areata.  The  inland  more  conti- 
nental nature  of  this  station  results  in  a  greatly  enhanced 
frequency  of  stable  conditions.  On  an  annual  basis,  neutral 
conditions  occur  just  26.3%  of  the  time  while  stable  conditions 
account  for  34%  of  the  distribution.  Seasonally,  neutral  condi- 
tions are  highest  in  winter  when  the  frequency  of  migratory  low 
pressure  systems  reaches  a  peak.  This  is  the  rainy  season  in 
California  and  neutral  conditions  are  generally  associated  with 
inclement  weather.   Stable  conditions  occur  more  frequently  than 


200 


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UNSTABLE    NEUTRAL    STABLE 
Figure  4.5-2 
Seasonal/Annual  Distribution  of  Atmospheric  Stability  at  Areata,  Ca, 

201 


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0    UNSTABLE    NEUTRAL    STABLE 


49.4 


NEUTRAL    STABLE 

Figure  4.5-3 
Seasonal/Annual  Distribution  of  Atmospheric  Stability  at  Ukiah,  Ca 

202 


70 

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70 


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NEUTRAL 

STABLE 

UNSTABLE    NEUTRAL   STABLE 
Figure  4.5-4 

Seasonal/Annual  Distribution  of  Atmospheric  Stability 
Sacramento,  California 

203 


either  neutral  or  unstable  conditions  during  all  seasons  of  the 
year.  The  frequency  of  stable  conditions  reaches  a  peak  during 
fall  when  it  accounts  for  35.6%  of  the  seasonal  distribution. 
This  is  in  agreement  with  the  distribution  of  stable  conditions 
seasonally  at  Areata.  Throughout  northwestern  California,  fall 
is  the  season  with  lightest  wind  speeds  accompanied  by  a  high 
frequency  of  occurrence  of  poor  ventilation  conditions.  Unstable 
conditions  reach  a  maximum  frequency  during  summer  when  they 

of  the  distribution.  This  is  the  only  season 
unstable  conditions  occur  more  frequently  than 
stable  conditions.  Unstable  conditions  domi- 
season  as  surface  heating  becomes  intense  re- 
sulting in  considerable  convective  activity.  This  is  also  the 
season  with  the  maximum  number  of  thunderstorms  occur  in  this 
area  ,    once  again,  indicative  of  an  unstable  atmosphere. 


account  for  43.8% 
of  the  year  when 
either  neutral  or 
nate  during  this 


Finally,  the  Sacramento  data  presented  in  Figure  4.5-4 
present  an  indication  of  stability  distributions  within  the 
Sacramento  Valley  portion  of  the  Ukiah  District.  At  this  loca- 
tion, considerable  variation  exists  between  seasons.  On  an 
annual  basis,  stable  conditions  dominate  the  distribution  ac- 
counting for  41.1%  of  the  distribution  with  neutral  conditions 
occurring  with  the  next  highest  frequency  of  occurrence.  Season- 
ally, neutral  conditions  dominate  the  winter  distribution  due  to 
a  combination  of  the  frequent  occurrence  of  low  clouds  and  fog  as 
well  as  the  passage  of  storm  systems.  During  this  season,  neu- 
tral conditions  account  for  53.7%  of  the  distribution  at  Sacra- 
mento. During  all  other  seasons  of  the  year,  stable  conditions 
dominate,  once  again,  reaching  the  highest  frequency  of  occur- 
rence of  48%  of  the  fall  distribution.  Once  again,  this  is 
indicative  of  the  pattern  observed  throughout  the  Ukiah  District 
during  the  fall  months.  Unstable  conditions  reach  their  peak  in 
summer  accounting  for  38.9%  of  the  distribution. 


4.5.2 


Diurnal  Stability  Distributions 


The  diurnal  distribution  of  stability  provides  a  means 
of  determining  the  probability  that  any  one  category  will  occur 
at  any  given  hour  of  the  day.  This  information,  together  with 
the  seasonal  and  annual  stability  distributions,  provides  a  com- 
plete picture  of  the  stability  characteristics  at  any  given 
station.  Since  most  human  and  industrial  activity  is  generally 
concentrated  during  the  daylight  hours,  the  diurnal  stability 
distributions  allow  for  intensified  study  of  the  dispersion 
conditions  prevalent  during  those  and  other  pertinent  periods. 

The  diurnal  stability  distributions  for  the  four  sta- 
tions for  which  digitized  data  were  available  are  presented  in 
Table  4.5-1  and  Figure  4.5-5.  These  data  were  averaged  over  the 
respective  periods  of  record  for  each  station,  and  as  such  are 
representative  of  an  annually  averaged  day;  seasonal  -variations 
are    not  expected  to  be  significant  on  a  diurnal  basis. 


204 


Table  4.5-1 

Diurnal  Frequency  Distribution 

of  Stability  in  the  Ukiah  District 


Hour 

Areata 

Ukiah 

U 

N 

S 

U 

N 

S 

1 

0 

56.2 

43.8 

0 

19.1 

80.9 

2 

* 

0 

20.6 

79.4 

3 

• 

0 

21.5 

78.6 

4 

0 

59.1 

40.9 

0 

22.3 

77.7 

5 

* 

0 

24.3 

75.8 

6 

• 

0 

25.6 

74.3 

7 

11.6 

63.2 

25.3 

12.4 

28.6 

59.0 

8 

38.7 

28.8 

32.6 

9 

56.5 

29.4 

14.0 

10 

35.2 

64.8 

0.0 

72.8 

27.3 

0 

11 

75.5 

25.5 

0 

12 

77.2 

22.8 

0 

13 

40.4 

59.6 

0.0 

77.5 

22.5 

0 

14 

76.0 

24.0 

0 

15 

70.9 

29.1 

0 

16 

18.1 

76.8 

5.1 

64.6 

35.5 

0 

17 

50.6 

40.3 

9.1 

18 

29.2 

42.7 

28.2 

19 

0 

56.4 

43.6 

13.6 

38.1 

48.3 

20 

0 

24.2 

75.8 

21 

0 

21.3 

78.7 

22 

0 

51.4 

48.6 

0 

20.1 

79.9 

23 

0 

18.4 

81.6 

24 

0 

19.0 

81.0 

U  =  Unstable 
N  =  Neutral 
S  =  Stable 


205 


O 
O 


o 


o         o        o         o 

^J-  CO  C\J  r— 


jQ 
+-> 

CD 


4-> 

o 


Q. 

S_ 

cu 

CO 

+J 

r—    r— 

CD 

O 

CO 

J3     fO  QJ 

1 

F 

•i — 

TO      S-r- 

Lfi 

+-> 

Q 

+->    -PJ3 

. 

<C 

CO     Z5   <T3 

•St 

-£Z 

C     (D-P 

4- 

fO 

ZD    ZOO 

O) 

O 

■r™ 

S- 

-^i 

ZJ 

C 

ZZ> 

• 

CT. 

o 

1   ; 

•  i — 

•1 — 

CD 

«      , 

Ll_ 

4-> 

3 

i : 

JZ) 

•  i— 

c 

S- 

•i— 

co 

Q 
fO 


o 

o 

o 

o 

o 

o 

o 

o 

o 

o 

o^ 

00 

1^ 

CO 

in 

«=j- 

ro 

CNJ 

206 


As  can  be  seen  from  the  table,  both  stations  exhibit 
very  sharp  increases  in  stable  conditions  after  about  1600  PST 
and  very  sharp  decreases  at  0800  PST.  These  times  correspond 
with  the  average  limits  of  sunset  and  sunrise,  respectively,  on 
an  annual  basis.  The  maximum  frequency  of  stable  conditions 
occurs  during  the  middle  of  the  night  at  both  stations. 

The  onset  of  unstable  conditions  closely  matches  the 
rapid  decay  of  stable  conditions  near  sunrise.  Conversely, 
unstable  conditions  decay  rapidly  at  the  onset  of  stable  con- 
ditions near  sunset.  The  overlaps  evident  in  the  stable  and 
unstable  categories  in  Table  4.5-1  are  a  result  of  the  annual 
variations  in  the  onsets  of  sunrise  and  sunset;  seasonal  plots  of 
the  diurnal  stability  distributions  would  serve  to  reduce  these 
overlaps.  The  maximum  frequency  of  unstable  conditions  occurs 
at  1300  PST  at  both  stations.  Again,  as  would  be  expected  from 
the  definition,  unstable  conditions  do  not  occur  at  any  station 
after  radiational  sunset  and  before  radiational  sunrise. 

Neutral  conditions  are  shown  to  occur  at  all  hours  of 
the  day,  showing  a  tendency  to  occur  more  frequently  during  the 
late  afternoon  hours  at  both  stations. 


4.5.3 


Stability  Persistence 


Stability  persistence  tables  give  an  indication  of  the 
tendency  of  a  stability  category  to  persist  for  extended  periods 
of  time.  This  information  can  be  used  to  identify  the  frequency 
of  the  persistence  of  adverse  dispersion  conditions.  For  exam- 
ple, long  periods  of  very  stable  conditions,  will  maximize  the 
impact  of  vehicular  emissions.  In  this  way,  adverse  dispersion 
conditions  can  be  related  to  specific  pollutant  sources. 

Table  4.5-2  presents  the  stability  persistence  tables 
for  Ukiah,  the  only  station  for  which  suitable  hourly  data  are 
available.  These  tables  are  representative  of  a  typical  annual 
period.  The  values  in  the  tables  reveal  the  percentage  of  time 
that  a  given  stability  class  persisted  for  a  given  number  of 
hours  at  each  station. 


4.5.4 


Stability  Wind  Roses 


Stability  wind  roses  provide  information  useful  for 
determining  land  use  alternatives  in  terms  of  the  probable  trans- 
port and  dispersion  of  airborne  pollutants.  The  data  are  pre- 
sented for  three  major  classes  which  represent  a  combination  of 
the  Pasquill  categories;  (1)  unstable  (A-C),  (2)  neutral  (D)  and 
(3)  stable  (E-G).  As  noted  earlier,  maximum  ground  level  pol- 
lution impacts  vary  with  each  stability  category  as  well  as  with 
source  emission  types  and  levels. 

Once  again,  stable  conditions  are  generally  character- 
ized by  light  winds,  hence,  wind  roses  for  this  stability  cate- 
gory are  valuable  in  determining  probable  levels  and  areas  of 


207 


Table  4.5-2 
Persistence  of  Stability  Class 
(Percentage  of  Total  Observations) 
at  Ukiah,  CA  (1955-1964) 


No.  of  Hours 

Stability 

Persisted 

U 

N 

S 

1 

31.0 

23.2 

45.8 

2 

22.7 

20.7 

42.7 

3 

14.9 

18.8 

40.5 

4 

9.8 

17.3 

38.9 

5 

6.0 

16.0 

37.8 

6 

3.7 

15.0 

36.6 

7 

1.7 

14.1 

35.5 

8 

0.4 

13.2 

34.4 

9 

0.1 

12.5 

32.9 

10 

0.1 

11.7 

30.4 

11 

0 

11.0 

27.4 

12 

0 

10.3 

22.1 

13 

0 

9.9 

17.1 

14 

0 

9.5 

13.0 

15 

0 

9.0 

9.5 

16 

0 

8.6 

5.5 

17 

0 

8.3 

2.8 

18 

0 

7.8 

0 

19 

0 

7.4 

0 

20 

0 

6.7 

0 

21 

0 

6.4 

0 

22 

0 

5.9 

0 

23 

0 

5.6 

0 

24 

0 

5.3 

0 

25 

0 

4.91 

0 

or  more 

Unstable 

Neutral 

Stable 


208 


maximum  impact  from  the  low-level,  non-buoyant  emissions  associ- 
ated with  many  rural  land  uses,  such  as  grazing  and  farming. 
Alternatively,  neutral  conditions  with  high  wind  speeds  or  un- 
stable conditions  can  result  in  maximum  impacts  from  elevated 
plume  sources  associated  with  heavier  industrial  activity. 

Figures  4.5-6  and  4.5-7  provide  stability  wind  roses  as 
well  as  the  annual  wind  rose  for  Areata  and  Ukiah.  As  indicated 
earlier,  stability  class  I  refers  to  unstable  conditions,  stabil- 
ity class  II  refers  to  neutral  conditions,  and  stable  conditions 
are  represented  by  stability  class  III.  Each  of  the  stability 
wind  roses  can  be  summed  for  comparison  with  the  annual  wind  rose 
also  depicted  on  each  figure. 

Figure  4.5-6  provides  stability  wind  roses  as  well  as 
the  annual  wind  rose  for  Areata,  California.  The  figure  shows 
that  stable  conditions  are  almost  exclusively  associated  with 
nocturnal  drainage  flow  from  higher  terrain  lying  east  of  the 
city.  Neutral  conditions,  on  the  other  hand,  are  well  distrib- 
uted and  are  represented  by  flow  from  each  of  the  tertiary  maxima 
that  make  up  the  annual  wind  rose.  North- northwesterl  y  flow  is 
most  frequently  associated  with  neutral  conditions  and  is  indica- 
tive of  general  maritime  flow  of  air  down  the  northern  Califor- 
nian  coast  in  this  region.  Unstable  conditions  occur  ^ery  infre- 
quently at  Areata  and  are  almost  exclusively  associated  with  flow 
from  the  northwest  quadrant.  This  primarily  occurs  during  situa- 
tions when  sunny  skies  prevail  associated  with  a  light  onshore 
f  1  ow. 


The  stability  and  annual 
form' a  are  provided  in  Figure  4.5- 
that  stable  flow  is  once  again  assoc 
wind  conditions  associated  with  down 
the  Russian  River  Valley.  Accord  in 
quadrant  dominates  for  stable  flow 
tions  are  generally  associated  wi 
which  is  indicative  of  conditions  as 
system  passage.  Finally,  unstable 
uted  between  both  the  southeaster 
observed  at  this  site.  Unstable  co 
high  frequency  during  the  warmer  mon 
directions  are    well  distributed. 


wind  roses  for  Ukiah,  Cali- 
7.  The  wind  roses  indicate 
iated  with  nocturnal  drainage 
valley  flow  along  the  axis  of 
gly,  flow  from  the  northwest 
conditions.  Neutral  condi- 
th  south- southeasterl y  flow 
sociated  with  migratory  storm 
conditions  are  well  distrib- 
ly  and  northwesterly  maxima 
nditions  occur  with  a  fairly 
ths  of  the  year  when  the  wind 


209 


i  FREQUENCY   OF  OCCURRENCE   (I) 
ANNUA!  WIND  ROSE 

SITE: 
ARCATA 

NNK-^"^ 

"---\NNE 

\ne 

NU/ 

^/^ 

"""/^      Xs 

WNl/              /             /\|          \^* 

\          \fNE 

\k/   \^\ 

\               \ 

wsw\          \        A^J 

/           /ESE 

\X    ^16/ 

Sw\              y-^^__ 

/SE 

\2e   / 

SSw 

5 SSE 

AIL  WIND  SPEEDS 

PERIOD 
YEARS   1968-1972 

FREQUENCY  OF  OCCURRENCE    (%) 
ANNUAL  WIND  ROSE 

wNi/     /    yc     \ 

~^NNE 

SITE: 
ARCATA 

N,NE 

\       3ENE 

WSw\           \        /\o2/ 

Sw\             ^-~-^_ 

SSW         ' 
ALL  WIND  SPEEDS 
STABILITY   CLASS   1 

S SSE 

/             /ESE 

/SE 

PERIOD 
YEARS  1968-1972 

FREQUENCY  OF  OCCURRENCE   [%) 
ANNUAL  WIND  ROSE 

SITE: 
ARCATA 

NNW^ ' 

\NNE 

nu(              J*r 

\nE 

wni/       /       y(      fvV" 

\  3ene 

-~ti*/     v^^\ 

wsw\         \ 

/  \w 

/    /ESE 

\/        \46  / 

swV            y^_^_ 

/SE 

\§e   / 

ssw                ' 

S SSE 

ALL  WIND  SPEEDS 
STABILITY   CLASS  2 

PERIOD 

YEARS  1968-1972 

FREQUENCY   OF   OCCURRENCE    (%) 
ANNUAL  WIND  ROSE 

SITE: 
ARCATA 

NNk^- — """ 

-^NNE 

\nE 

NW/                    Jr 

/"^v 

/^l     / 

wni/     /     yc     V— — 

—fi*/       V^- \ 

\  3fNE 

N 

w 

sw\           \       /No?/ 

/    /£SE 

\X   \l£/ 

Sw\                    y^->^__ 

SS£ 

\20     / 

SSW^~~" 

S "          SSE 

ALL  WIND  SPEEDS 
STABILITY  CLASS  3 

PERIOD 
YEARS  1968-1972 

Figure  4.5-6 
Stability  Wind  Roses  for  Areata,   California 


210 


FREQUENCY  OF   OCCURRENCE    (%) 
ANNUAL  WIND  ROSE 

SITE: 
UKIAH 

-^NNE 

^2         yK                \ 

WNl/            / 

/\    \  3fNE 

Sw  / 

y&f^~  \ 

wsw\ 

sw^ 

//      NJ2/ 
\J6  / 

/*\  /    /ese 
\     v/^E 

ALL  WIND  SF 

EEDS 

\20    / 

ssw ""— — 

SSE 

PERIOD 
YEARS  1955-1964 

FREQUENCY  OF  OCCURRENCE   {%) 
ANNUAL  WIND  ROSE 

SITE: 
UKIAH 

hlU^-"^~ 

A\20 

nu/          J><r    ' 

7"%?       / 

\nE 

WNl/            /           y*\           \~— 

\  3ene 

~~M./  \^*^\ 

WSw\        \     yv    / 

/ese 

NC             \J6  / 

Sw\                 ^^^ 

/SE 

\2e  / 

SSW 
ALL  WIND  SPEEDS 
STABILITY  CLASS  1 

5 '        SSE 

PERIOD 
YEARS  1955-1964 

FREQUENCY  OF  OCCURRENCE   (%) 
ANNUAL  WIND  ROSE 

SITE: 
UKIAH 

NNW--- " 

~\NNE 

\nE 

NiK 

^/^v 

7^1   /^ 

WNl/           /          /C           \-_ 

rLf        v-^X 

\        J^NE 

u 

w 

sw\ 

yW 

/        /ese 

\y    \j6  / 

Sw\                 ^^^ 

/SE 

\26    / 

SSW        ' 

S SSE 

ALL  WIND  SPEEDS 
STABILITY  CLASS  2 

PERIOD 
YEARS  1955-1964 

FREQUENCY  OF  OCCURRENCE   (%) 
ANNUAL  WIND  ROSE 

SITE: 
UKIAH 

NNU^-^^" 

ogNE 
/Sje 

\nE 

Nix 

y^6 

"""""/^    / 

WNl/ 

\fii/      \^-^\ 

\  3ene 

\       ^\^    /vj/ ' 

WSw\            \       /Nog/ 

/    /ese 

\X        \J6  / 

SwV                 7^^_ 

/s£ 

\?0    / 

ssw       " 

5 ^SSE 

ALL  WIND  SPEEDS 
STABILITY  CLASS  3 

PERIOD 

Figure  4.5-7 
Stability  Wind  Roses  for  Ukiah,  California 


211 


4.6 


MIXING  HEIGHTS  AND  INVERSIONS 


The  entire  atmosphere,  is  not  available  for  the  dilution 
of  pollutants  released  near  the  surface.  Only  the  mixing  layer 
which,  in  many  situations  may  be  only  several  hundred  feet  thick, 
can  serve  this  function.  Section  4.2.3  describes  mixing  heights 
and  inversions  in  considerable  detail  relative  to  their  role  in 
dispersion  meteorology. 

I  This  section  shall   investigate  the  characteristics  of 

the  mean  mixing  layer  throughout  various  areas  of  the  Ukiah 
District.  In  addition,  inversion  statistics  will  be  presented 
for  various  locations  in  the  study  area,  and  the  subsequent  dis- 
cussions shall  provide  a  review  of  inversion  types  and  their 
frequency  in  the  Ukiah  District. 


4.6.1 


Mixing  Height 


Considerable  variation  in  mean  mixing  heights  occurs  on 
a  seasonal  basis.  Throughout  the  United  States,  mixing  heights 
vary  from  several  hundred  feet  on  winter  mornings  to  well  over 
13,000  feet  on  summer  afternoons.  In  California,  the  mean  annual 
range  is  roughly  between  several  hundred  feet  and  approximately 
10,000  feet.  The  variation  in  mixing  heights  over  a  given  area 
can  play  a  major  role  in  pollutant  dispersion  for  certain  types 
of  sources.  For  example,  power  plant  siting  is  very  dependent  on 
regional  dispersion  characteristics.  An  area  with  a  history  of 
shallow  or  low  mixing  heights  would  tend  to  trap  pollutants 
emitted  by  such  a  facility.  Such  an  area  would  therefore  be 
rated  as  unfavorable  for  power  plant  siting. 

Mixing  depths  can  be  characterized  for  each  air  basin  in 
the  district  using  data  prepared  by  Holzworth  (1972).  Annual 
morning  mixing  heights  within  the  Ukiah  District  generally  range 
from  500  meters  along  the  coast  to  less  than  400  meters  in  por- 
tions of  the  Sacramento  Valley.  During  the  afternoons,  mixing 
heights  remain  at  about  500  meters  along  the  coast  on  an  annual 
basis  and  decrease  with  inland  progression  toward  the  Sacramento 
Valley.  Seasonally,  morning  mixing  heights  tend  to  be  most 
restrictive  during  summer  and  fall  with  mixing  heights  decreasing 
from  around  500  meters  along  the  coast  to  nearly  300  meters  in 
the  Sacramento  Valley.  Mixing  heights  are  greatest  during  the 
spring  months  when  morning  values  reach  800  meters  along  the 
coast  and  600  meters  in  the  Sacramento  Valley.  During  the  after- 
noon hours,  annual  mixing  heights  increase  with  progression  from 
the  coastline  ranging  from  around  800  meters  to  over  1200  meters 
in:the  Sacramento  Valley.  Seasonally,  spring  is  again  the  best 
season  with  mixing  heights  ranging  from  1200  meter  along  the 
coast  to  over  1600  meters  in  the  Sacramento  Valley.  A  ^jery  steep 
gradient  in  afternoon  mixing  heights  exist  during  the  summer  and 
fall  afternoons.  In  summer,  mixing  heights  range  from  £00  meters 
near  the  coast  to  1600  meters  in  the  Sacramento  Valley.   This 


212 


reflects  a  situation  where  a  marine  air  at  coastal  stations 
results  in  a  very  shallow  stable  layer  while  inland  surface 
heating  effects  tend  to  erode  the  stable  layer  near  the  surface 
and  result  in  ample  mixing  heights. 

The  CARB  (1974)  has  conducted  upper  air  observations  for 
winds  and  temperatures  aloft  at  Sacramento,  Red  Bluff,  Salinas, 
Fresno,  Ukiah,  Thermal  and  Riverside.  The  length  of  the  data 
base  presented  in  this  report  is  less  than  three  years  in  every 
case.  The  Ukiah  data  provide  additional  information  relative  to 
mixing  height  characteristics  in  the  Ukiah  District.  Figures 
4.6-1  and  4.6-2  provide  a  comparison  of  the  mean  spring  morning 
mixing  heights  as  defined  using  CARB  and  Holzworth  data,  respec- 
tively. Additional  data  from  Sacramento,  Red  Bluff  and  Ukiah 
provide  very  useful  additional  information  for  the  Ukiah  Dis- 
trict. The  Holzworth  data  which,  once  again,  was  based  on  a  very 
limited  availability  of  upper  air  data  indicates  a  linear  de- 
crease of  mixing  heights  on  spring  mornings  from  800  meters  along 
the  coast  to  around  600  meters  at  Sacramento  and  Red  Bluff.  The 
ARB  data,  however,  indicates  that  this  is  not  indicative  of 
conditions  in  this  area.  The  ARB  data  indicates  that  mixing 
heights  are  on  the  order  of  400  meters  along  the  coastline  of 
Mendocino  County  decreasing  to  300  meters  in  the  Sacramento 
Valley  portion  of  the  Ukiah  District.  Higher  mixing  heights  are 
observed  in  the  San  Francisco  Bay  region.  The  CARB  data  provide 
a  better  resolution  in  the  Ukiah  District  as  they  are  based  upon 
the  use  of  available  data  from  Ukiah,  Sacramento  and  Red  Bluff. 
The  data  are  only  available  for  the  morning  hours  and  conclusions 
cannot  readily  be  made  relative  to  the  utility  of  the  Holzworth 
data  for  the  afternoon.  In  addition,  the  additional  resolution 
provided  by  the  CARB  data  is  only  valid  for  the  southern  portion 
of  the  district  and  does  not  provide  additional  clarification 
relative  to  northern  portions  of  the  district.  The  CARB  data 
provides  the  following  highlights  relative  to  morning  mixing 
heights  in  appropriate  portions  of  the  district: 


(1)   The  lowest   average 
summer  at  Red  Bl  uf f , 


mixing   heights   occur 
Ukiah  and  Sacramento. 


during   the 


(2)   During  other  seasons, 
are    unremar kabl e . 


mixing  heights  at  these  locations 


(3)   Highest  average  mixing  heights  occur  at  Ukiah 
and  Sacramento  during  winter. 


Red  Bluff 


Table  4.6-1  provides  seasonal  and  annual  mean  morning 
and  afternoon  mixing  height  values  for  selected  stations  through- 
out the  Ukiah  District.  It  is  evident  from  these  data  that 
mixing  heights  tend  to  be  higher  along  the  coast  during  the 
morning  hours  and  in  the  interior  valleys  during  the  afternoon. 

Long-term  mixing  height  and  inversion  data  are  not 
currently  available  for  the  mountain  areas.  As  a  result,  inter- 
polative  estimates  must  be  made  from  meteorological  data  from 
nearby  locations  in  order  to  provide  a  reasonable  evaluation  of 
mixing  height  levels  over  mountainous  terrain. 


213 


Figure  4.6-1 

Isopleths  of  Mean  Spring  Morning 

Mixing  Heights  (m)  (with  ARB  Data) 


214 


800         6  00 

700       50  0 


8  0  0    700 


60  0    5  0  0 


Figure  4.6-2 
Isopleths  of  Mean  Spring  Morning 
Mixing  Heights  (m)  (from  Holzworth) 


215 


Table  4.6-1 
Mean  Morning  and  Afternoon  Values  of 
Mixing  Height  (Meters)*  in  the  Ukiah  District 


Morni  ng/Af ternoon 

Winter 

Spring 

Summer     Fall 

Annual 

Eureka 

500 

780 

500      480 

565 

800 

1150 

700      850 

875 

Santa  Rosa 

430 
300 

700 
1 24"0 

465      425 
800      960 

504 
950 

1  2 
Ukiah  '»* 

487 

369 

286      434 

394 

800 

1320 

900     1000 

1005 

1  2 

Sacramento  ' 

300 

282 

223      2^9 

263 

950 

1900 

1700     1400 

1488 

*  meter  =  3.28  feet 


Mixing  heights  determined  from  interpolation  of  seasonal   mixing 
height  analysis  from  Holzworth's   "Mixing  Heights,  Wind  Speed, 
and  Potential    for  Urban  Air  Pollution  Throughout  the  Continguous 
United  States". 

Morning  mixing  heights  based  on  Air  Resources  Board  data  covering 
a  five  year  period  from  July  1,   1972  to  December  31,    1977. 


216 


The  steepness  of  windward  mountain  slopes  and  numerous 
meteorological  parameters  such  as  wind  velocity,  wind  direction 
and  atmospheric  stability  impact  mixing  height  depths  and  their 
variability  over  rugged  complex  terrain.  Figures  4.6-3  through 
4.6-5  illustrate  mixing  layer  alterations  due  to  mountain  flow 
for  three  hypothetical  scenarios  which  vary  atmospheric  stabili- 
ty. As  depicted  in  Figure  4.6-3,  when  the  lower  atmosphere  is 
neutrally  stratified,  the  inversion  layer,  which  is  the  major 
determinant  of  the  local  mixing  depth,  tends  to  follow  the  con- 
tour of  the  local  terrain.  Hence,  mixing  height  depths,  as 
defined  earlier,  remain  unchanged  or  tend  to  be  slightly  shallow- 
er over  the  mountainous  area. 

On  the  other  hand,  when  a  stable  surface  air  mass  is 
capped  by  an  elevated  inversion  and  is  forced  to  rise  over  abrupt 
mountainous  terrain,  considerable  variations  in  the  characteris- 
tic mixing  depth  develop.  The  low  lying,  stable  air  is  not 
easily  displaced  upward  and  over  the  mountain  ridge;  consequent- 
ly, the  surface  air  mass  tends  to  pile  up  along  the  windward 
mountain  slopes,  thus  forming  a  bulge  in  the  atmospheric  mixing 
layer  just  upwind  of  the  mountain  ridge.  Under  these  conditions, 
as  depicted  in  Figure  4.6-4,  the  mixing  depth  tends  to  be  larger 
along  the  windward  slope  than  along  the  valley  floor  or  the 
leeward  side  of  the  mountain  range. 


Figure  4.6-5  presents  the  situation  in  which  a  sur 
unstable  layer  is  isolated  from  the  upper  atmosphere  by  a  li 
inversion.  As  flow  moves  over  rugged  terrain,  dramatic  cha 
in  the  mixing  layer  can  occur.  Basically,  the  low  lying, 
stable  air  is  forced  to  ascend  into  and  through  the  inhibi 
inversion  layer  as  surface  air  flow  is  swept  up  the  steep  wes 
the  Coast  Ranges.  This  forced  convective  acti 
has  the  potential  to  completely  wipe  out  the  1 
layer  (or  considerably  weaken  the  stable  layers) 
considerable  mixing  of  the  lower  lying  air  mas 
conditions,  considerable  cloudiness  can  develop 


si  opes  of 
somet i  mes 
inversion 
promot  i  ng 
Under  such 


at  times,  much  precipitation.  This  is  indicative  of  su 
season  conditions  resulting  in  convective  thundershower  activ 
As  the  flow  passes  over  the  mountain  ridge  and  descends  down 
leeward  slopes,  the  stable  layer  can  once  again  develop. 


face 
fted 
nges 

un- 
ting 
tern 
vity 
oca! 
thus 
ses  . 
and  , 
mmer 
i  ty . 

the 


The  above  discussion  qualitatively  depicts  mean  mixing 
height  characteristics  when  flow  is  forced  over  mountainous 
terrain  features  such  as  the  Coast  Ranges.  However,  definitive 
analyses  are  needed  to  support  the  qualitative  review  presented 
for  this  area.  Therefore,  estimates  and  assessments  of  mixing 
layer  depths  over  these  areas  are  presently  best  determined  by 
(1)  the  Holzworth  document  entitled:  "Mixing  Heights,  Wind 
Speeds,  and  Potential  for  Urban  Air  Pollution  Throughout  the 
Contiguous  United  States"  and  (2)  the  CARB  data  summarized  in 
"Meteorological  Parameters  for  Estimating  the  Potential  for  Air 
Pollution  in  California."  Seasonal  and  annual  mixing  depth 
contour  maps  provided  by  the  Holzworth  publication  are  depicted 


217 


E-3 


0 


$ 


& 


<■<!£ 


TOP 


?  INVERSION  .$^Vr>  J^^  ^^ 
FLAYER  fe@^Svfe§^ 


BASE 


NEUTRAL 


vwwv^r 


**S*§3&5&«W<* 


^xTT^T^T^^r 


Figure  4.6-3 
Depth  of  the  Mixing  Layer  in  Mountainous  Terrain  with  Neutral  Flow 


E-4 


TOP 


BASE 


•^STRONG    "'/-'-v.  —  V  < V-"^ 
3  INVERSION  «LV  ^-S" 


STABLE 


£*>- 


AVsWVWA 


Figure  4.6-4 
Depth  of  the  Mixing  Layer  in  Mountainous  Terrain  with  Stable  Flow 


E-5 


TOP    *&s^-?3£gk&$2&Mj 


.« INVERSION 

?,  ST  AB  LE  LA  YE  R  \St}. 

BASE  *ET*" 


UNSTABLE 


ZONE  OF 
FORCED  ATM 
CONVECTION 


WARMER  BUT 
UNSTABLE  TO  NEUTRAL 


Figure  4.6-5 
Depth  of  the  Mixing  Layer  in  Mountainous  Terrain  with  Unstable  Flow 


218 


in  Appendix  C.  These  figures 
comparing  California  mixing 
areas  of  the  United  States. 


also  present  an  excellent  means  for 
depth   characteristics   with   other 


4.6.2 


Inversion  Types  and  Frequencies 


The  type  and  frequency  of  temperature 
an  important  role  in  the  overall   description 
dispersion  meteorology  of  the  Ukiah  District. 
si.ons  are  either  surface  based  or  elevated  with 
on  potential  pollutant  sources.   Surface  based 
in  a  layer  of  stable  air  close  to  the  ground 


inversions  plays 

of  the  regional 

Basically,  inver- 

differing  impacts 

inversions  result 

usually  with  very 


light  wind  speeds.  This  type  of  situation  tends  to  maximize  the 
impact  of  ground  level  non-buoyant  sources  such  as  vehicles  (e.g. 
off  road  vehicles  [ORV])  and  fugitive  sources  (e.g.  storage 
tanks,  dirt  roads,  etc).  Elevated  inversions  tend  to  limit  the 
volume  of  air  available  for  the  mixing  of  pollutants  and  tend  to 
maximize  the  impact  of  buoyant  elevated  sources,  such  as  power 
facilities,  refineries,  etc.  The  following  paragraphs  provide  a 
review  of  the  type  and  frequency  of  inversions  experienced  in  the 
Ukiah  District. 

As  indicated  earlier,  upper  air  data  are  only  routinely 
available  for  Oakland,  California.  These  data  have  been  sup- 
plemented by  special  studies  conducted  largely  by  the  CARB  at 
Ukiah  in  the  Ukiah  District. 

Table  4.6-2  summarizes  the  available  historical  inver- 
sion data  for  the  Ukiah  District.  These  data  include  soundings 
taken  at  Areata,  Eureka,  Ukiah  and  Sacramento.  With  the  excep- 
tion of  a  brief  period  of  record  available  from  Areata,  all  the 
data  are  representative  of  the  early  morning  hours.  The  data 
indicate  the  very  high  frequency  of  surface  inversions,  particu- 
larly at  Ukiah  and  Sacramento.  The  frequency  of  times  when  there 
were  no  inversions  present  is  quite  rare  with  the  exception  of 
Areata.  At  Areata,  no  inversions  existed  during  a  substantial 
number  of  soundings.  While  the  period  of  record  is  brief  at 
Areata,  this  does  point  to  the  fact  that  dispersion  conditions 
near  the  surface  tend  to  be  somewhat  less  restrictive  along  the 
well  exposed  northern  coast  of  the  Ukiah  District  where  the 
influx  of  maritime  air  tends  to  be  accompanied  by  brisk  winds  and 
reasonable  mixing  heights.  At  valley  locations,  such  as  Ukiah 
and  Sacramento,  conditions  tend  to  be  more  restrictive,  particu- 
larly during  the  fall  and  summer  periods.  These  data  are  further 
summarized  in  Figures  4.6-6  and  4.6-7. 


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4.7 


TYPICAL  AND  WORST-CASE  CONDITIONS 


Previous  sections  have  thoroughly  examined  and  discussed 
the  factors  affecting  the  atmospheric  dispersion  characteristics 
of  the  Ukiah  District.  This  permits  the  identification  of  typi- 
cal and  worst-case  conditions  for  a  variety  of  typical  sources 
found  in  the  Ukiah  District.  This  analysis  will  provide  a  basis 
for  determining  an  initial  evaluation  of  the  typical  and  worst- 
case  impact  of  various  land  use  alternatives  using  simplistic 
modeling  techniques  as  described  in  Section  4.9. 


4.7.1 


Typical  Dispersion  Conditions 


Typical  dispersion  conditions  define  the  most  commonly 
occurring  combination  of  the  key  dispersion  parameters,  i.e., 
wind  speed,  wind  direction  and  atmospheric  stability  class.  This 
information  is  useful  particularly  in  first  cut  or  screening 
level  of  effort  air  quality  modeling  analyses  as  described  in 
Section  4.9.  In  such  cases,  it  is  desirable  to  have  a  rough 
estimate  of  the  most  commonly  occurring  dispersion  conditions  in 
order  to  get  an  indication  of  the  typical  impact  of  an  existing 
or  proposed  source. 

Table  4.7-1  provides  a  description  of  the  most  frequent- 
ly occurring  dispersion  parameters  for  sites  in  the  Ukiah  Dis- 
trict for  which  the  necessary  data  are  available.  These  include 
Ukiah,  Areata  and  Sacramento. 

The  data  in  Table  4.7-1  provide  the  most  frequently 
occurring  wind  direction,  wind  speed  and  stability  category 
information  suitable  for  characterizing  dispersion  meteorological 
conditions.  As  such,  it  is  suitable  for  use  in  screening  level 
of  effort  or  simplistic  modeling  calculations  to  provide  a  pre- 
liminary estimate  of  existing  or  proposed  pollutant  source  im- 
pacts. The  reader  is  cautioned,  however,  that  dispersion  analy- 
ses require  site  specific  meteorological  data  and  a  more  thorough 
review  than  that  provided  by  the  type  of  information  contained  in 
the  table . 


4.7.2 


Worst-Case  Dispersion  Conditions 


Worst-case  dispersion  conditions  are  used  by  dispersion 
meteorologists  in  a  screening  level  of  effort  to  determine  the 
probable  maximum  impact  of  an  existing  or  proposed  facility.  The 
results  of  such  a  review  provide  an  indication  as  to  whether  more 
detailed  and  sophisticated  analyses  are  required.  Once  again,  as 
with  typical  conditions,  the  worst-case  can  be  defined  in  terms 
of  the  primary  dispersion  parameters,  atmospheric  stability 
class,  wind  speed  and  wind  direction.  The  reader  is  again  cau- 
tioned in  the  use  of  the  following  information  as  s i t e- spec i f i c 
data  and  more  detailed  analyses  are  desireable  to  accurately  gage 
pollutant  impact. 


223 


Table  4.7-1 
Description  of  Typical  Meteorological   Conditions   *    ' 
Throughout  the  Ukiah  District 


Wind 

Wind 

Stability 

Station 

Direction 

Speed  (MPH) 

Category  (2) 

Sacramento 

SSW 

7.5 

3 

Ukiah 

SSE 

3.6 

3 

Areata 

E 

6.8 

2 

1.  As  defined  by  the  most  frequently  occurring  value  on  an  annual  basis  - 
parameters  are  not  interrelated,  i.e.,  the  indicated  wind  speed  is  for 
the  total  data  base  and  is  not  the  average  for  the  most  frequently 
occurring  wind  direction. 

2.  1  -  Unstable  (Pasquill  Classes  A,  B,  C) 

2  -  Neutral  (Pasquill  Class  D) 

3  -  Stable  (Pasquill  Classes  E,  F,  G) 


224 


In  an  effort  to  identify  the  historical  worst-case 
conditions  occurring  in  California,  it  was  necessary  to  create  a 
table  of  five  pollutant  sources  with  typical  exit  characteris- 
tics. Table  5.4-1  summarizes  typical  emission  characteristics 
for  fugitive  dust,  automobiles,  oil  recovery  operations,  oil 
refineries  and  large  power  plants.  In  addition,  a  traditional 
worst-case  scenario  often  used  by  dispersion  meteorologists  is 
described.  Although  the  primary  pollutants  generated  from  each 
of  these  sources  may  vary,  the  short-term  characteristics  of 
these  gases  and/or  particulates  in  the  atmosphere  may  be  assumed 
to  be  highly  similar.  The  five  sources  listed  in  Table  5.4-1 
represent  ground  level,  non-buoyant;  ground  level,  slightly 
buoyant;  low-level,  buoyant;  i nt ermed i ate- 1  ev el  ,  buoyant;  and 
elevated,  buoyant  emissions,  respectively.  Table  4.7-2  lists  the 
worst-case  dispersion  conditions  for  each  of  these  sources. 

Table  4.7-3  provides  the  annual  frequency  of  the  se- 
lected worst-case  scenarios  for  stations  throughout  the  Ukiah 
District.  The  table  indicates  that  the  selected  scenarios  for 
the  cross  section  of  sources  occur  with  considerable  variability 
across  the  area.  In  addition,  the  frequency  of  the  scenario 
selected  for  one  type  of  source  may  occur  with  a  substantially 
different  frequency  than  that  selected  for  another  source.  This 
highlights  the  importance  of  attaching  the  probability  of  occur- 
rence to  the  selected  worst-case  meteorological  condition  for  the 
source  in  question  and  the  need  to  involve  professional  disper- 
sion meteorologists  in  such  programs. 

Mixing  height,  an  important  parameter  in  the  definition 
of  both  typical  and  worst-case  conditions  has  not  been  included 
in  the  above  analysis.  This  is  often  difficult  to  do  as  real 
time  mixing  height  data  are  not  generally  available  concurrently 
with  surface  wind  speed,  wind  direction  and  atmospheric  stability 
class  data  to  provide  for  meaningful  analysis.  However,  typical 
mixing  heights  can  be  obtained  from  the  data  presented  in  Section 
4.6.1,  while  historical  worst-case  mixing  heights  are  discussed 
by  Holzworth  in  his  publication  "Meteorological  Episodes  of 
Slowest  Dilution  in  Contiguous  United  States". 


225 


Table  4.7-2 
Worst-Case  Dispersion  Conditions 
For  a  Cross-Section  of  Typical  Sources 


-c             0) 
•Source 

Wind  Speed 
(MPH) 

Stability  Class    ,,,> 
(Pasquill    Class)Uj 

Fugitive  Dust 

1.1 

D 

Automobiles 

1.1 

D 

Oil   Recovery  Operations 

26.8 

C 

Oil   Refinery 

6.7 

A 

Power  Plant 

6.7 

A 

(3) 
Traditional      'Worst-Case 

2.3 

F 

1.  Reference  Table  5.4-1  for  a  description  of  the  exit  characteristics 
for  the  sources  listed  below. 

2.  Section  4.5  provides  a  complete  discussion  of  atmospheric  stability 

3.  In  theoretical  or  "back  of  the  envelope"  calculations,  this  case  is 
often  used  by  meteorologists  to  describe  worst-case  conditions. 


226 


Table  4.7-3 
Annual    Frequency  (%)  of  Worst-Case  Meteorological    Conditions   *    ' 

Throughout  the  Ukiah  District 


Worst-Cast  Condition 


(St. Class/Wind  Speed(MPH) 

Areata 

Ukiah 

Sacramento 

F  and  2.3 

10.0 

36.0 

13.9 

D  and  1.1 

13.0 

9.4 

2.9 

C  and  26.8 

Neg.+ 

0.0 

Neg.+ 

A  and  6.7 

0.2 

0.8 

0.6 

1.     As  defined  for  the  sources   indicated  in  Table  4.7-2 
and  described  in  Table  5.4-1 

+       Neg.   =  Negligible  but  non-zero 


227 


4.8 


AIR  BASIN  ANALYSIS 


The  State  of  California  encompasses  an  extremely  large 
land  area  which  exhibits  a  wide  variety  of  geographic  and  topo- 
graphic features  (see  Section  2).  As  air  masses  migrate  into 
California,  the  prevailing  winds  and  dispersion  characteristics 
are  greatly  influenced  by  terrain.  The  degree  and  nature  of  the 
influence  can  be  characterized  for  geographically  and/or  meteor- 
ologically homogeneous  areas.  Such  zones  of  similar  atmospheric 
dispersion  characteristics  can  be  identified  as  air  basins. 
Figure  4.8-1  provides  the  results  of  an  air  basin  analysis  for 
California  while  Figure  4.8-2  presents  a  summary  map  of  the  air 
basins  located  within  the  Ukiah  District  of  California.  The 
figures  represent  an  original  analysis  independent  of  political 
boundaries  and  are,  therefore,  slightly  different  than  the  CARB 
air  basin  map  for  the  State.  The  latter  figure  is  also  provided 
as  Overlay  F. 

Air  basins  provide  a  means  of  isolating  particular  areas 
of  the  state  that  generally  exhibit  similar  atmospheric  flow, 
ventilation  mechanisms  and  dispersion  potential.  As  presented  in 
the  figure,  these  areas  include: 


North  Coastal  Air  Basin 

North  Coastal  Mountain  Air  Basin 

North  East  Hills  Ai  r  Basi  n 

Mountain  Area  Air  Basin 

Sacramento  Valley  Air  Basin 

San  Joaquin  Valley  Air  Basin 

San  Francisco  Bay  Area  Air  Basin 

Central  Coast  Air  Basin 

Central  Coastal  Mountains  Air  Basin 

South  Coastal  Air  Basin 

South  Coastal  Mountains  Air  Basin 

Great  Basin  Valley  Air  Basin 

South  East  Desert  Air  Basin 


The  development  and  use  of  an  air  basin  classification 
scheme  requires  one  to  visualize  the  atmosphere  as  a  moving  fluid 
washing  over  mountain  ridges  and  spilling  into  valleys  and 
through  canyon  areas.  As  indicated  above,  physically  and  meteor- 
ologically homogeneous  areas  can  be  then  identified  and  used  in 
dispersion  analyses.  Regional  terrain  characteristics  generally 
establish  the  boundaries  of  such  areas.  Terrain  features  are 
dominant  in  establishing  air  basins  as  mountain  ranges  and  val- 
leys obstruct  or  alter  regional  flow  and,  hence,  dispersion 
co-nditions.  Figure  4.8-1  illustrates  the  importance  of  terrain 
fe.atures  in  defining  meaningful  air  basins. 

While  air  basins  are  characteristically  defined  by  major 
regional  terrain  features,  the  climatological  and  -dispersion 
meteorological  conditions  existing  in  the  area  in  question  also 
provide  considerable  information  relative  to  the  identification 
of  homogeneous  air  basins.   An  area  can  be  homogeneous  from  a 


228 


"~|  NORTH  COASTAL 

«|J  NORTH  COASTAL  MOUNTAINS 
NORTH  EAST  HILLS 
SACRAMENTO  VALLEY 
SAN  FRANSCISCO  BAY  AREA 

Vj    SAN  JOAQUIN  VALLEY 
||5£j5j    CENTRAL  COAST 

^    CENTRAL  COASTAL  MOUNTAINS 
MOUNTAIN  AREA 
GREAT  BASIN  VALLEY 
SOUTH  EAST  DESERT 
|  SOUTH  COASTAL  MOUNTAINS 
SOUTH  COASTAL 


Figure  4.8-1 
California  Air  Basins 


229 


terrain  standpoint  but  may  vary  s  i  gni  f  i  cant  1 1  y  in  terms  of  the 
actual  dispersion  meteorology.  For  example,  in  California,  a 
case  could  be  made  for  including  the  Moj  ave  Desert  and  Owens 
Valley  into  one  air  basin  as  defined  by  the  terrain  characteris- 
tics of  this  general  region.  However,  it  is  known  that  the 
dispersion  meteorology  is  considerably  different  in  the  lee  of 
the  Sierra  Nevada  in  the  Owens  Valley  as  opposed  to  that  experi- 
enced in  the  Mojave  Desert.  As  a  result,  the  Great  Basin  Valley 
has  been  delineated  as  a  separate  entity  from  the  South  East 
Dessert  air  basin.  Substantially  different  dispersion  meteoro- 
logical characteristics,  such  as  important  differences  in  pre- 
vailing winds,  wind  speed,  atmospheric  stability,  and  mixing 
heights  dictated  this  decision  in  the  absence  of  important  ter- 
rain considerations. 

An  air  basin  analysis  provides  considerable  insight  into 
the  potential  impact  of  air  pollutant  emissions  within  certain 
regional  areas.  Particular  air  basins  may  ventilate  air  pollut- 
ants very  slowly  while  others  do  so  quite  quickly.  A  detailed 
discussion  of  the  dispersion  characteristics  for  each  air  basin 
in  the  Ukiah  District  follows. 

The  Ukiah  District  includes  portions  of  4  of  the  13 
California  air  basins  as  depicted  in  Figure  4.8-2.   They  include: 

•  North  Coastal 

•  North  Coastal  Mountains 

•  Sacramento  Va 1 1 ey 

•  San  Francisco  Bay  Area 

The  North  Coastal  Air  Basin  comprises  the  bulk  of  the 
Ukiah  District  in  Mendocino,  Humboldt,  and  Del  Norte  Counties. 
The  air  basin  is  generally  comprised  by  good  ventilation  poten- 
tial with  strong  onshore  winds.  Except  for  the  immediate  coast- 
line, the  area  is  one  of  fairly  rugged  terrain  and  ventilation  is 
further  enhanced  by  surface  roughness  induced  mixing  effects. 
Air  quality  in  this  region  tends  to  be  good,  reflecting  a  strong 
maritime  influence  and  good  ventilation  potential.  The  ventila- 
tion potential  is  particularly  good  during  the  rainy  season  when 
the  frequent  passage  of  migratory  storm  systems  results  in  strong 
winds,  active  weather  and  excellent  dispersion.  Poorest  disper- 
sion generally  occurs  during  late  summer  and  early  fall  when  wind 
speeds  become  lighter  and  marine  inversions  are  fairly  shallow 
an.d  restrictive.  However,  air  quality  is  still  generally  good  in 
this  region  in  the  absence  of  important  air  pollutant  sources. 

The  North  Coastal  Mountains  Air  Basin  comprises  the  Lake 
County  and  Northern  Napa  County  portions  of  the  Ukiah  District  as 
well  as  a  small  portion  of  eastern  Mendocino  County.  The  area  is 
characterized  by  fairly  rugged  terrain  with  several   inland 


230 


RAFAEL  f U 


Figure  4.8-2 
Air  Basins  in  the  Ukiah  District 


231 


valleys.  The  maritime  influence  in  the  Pacific  Ocean  tends  to  be 
decreased  at  this  location  and  the  ventilation  potential  is 
slightly  poorer.  Ukiah,  for  example,  experiences  fairly  light 
wind  speeds  during  many  occasions  and  in  summer  and  fall  the 
mixing  heights  tend  to  be  fairly  restrictive.  Under  such  condi- 
tions, the  potential  for  pollutant  buildup  does  exist.  The 
ventilation  potential  is  excellent  at  higher  elevations  within 
this  air  basin,  however,  the  potential  is  very  poor  at  sheltered 
valley  sites.  This  area  is  an  active  geothermal  region  and 
considerable  studies  have  been  conducted  relative  to  the  pollu- 
tion potential  of  Lake  County. 

Colusa,  Yolo  and  Solano  Counties  are  located  within  the 
Sacramento  Air  Basin.  Ventilation  potential  in  this  region  tends 
to  improve  as  one  moves  northward.  The  area  is  subject  to  the 
maritime  influence  of  Pacific  Air  moving  into  the  Carquinez 
Straits  and  diverging  both  north  and  south  into  the  Sacramento 
and  San  Joaquin  Valleys,  respectively.  The  ventilation  potential 
can  be  restricted,  particularly  during  the  fall  and  winter  months 
when  winds  are  light  and  mixing  heights  are  shallow.  Under  such 
conditions,  fog  and  low  clouds  can  develop  and  persist  for  days 
with  the  concomitant  potential  for  a  significant  buildup  of 
pollutants.  During  the  summer  season,  wind  speeds  tend  to  be 
strong  and  the  maritime  influence  of  Pacific  air  moving  into  the 
region  tends  to  inhibit  significant  pollutant  buildups. 

Finally,  the  San  Francisco  Bay  Area  has  been  isolated  as 
a  separate  air  basin.  Marine  flow  from  the  west  and  west-north- 
west is  channeled  directly  inland  over  the  San  Francisco  area. 
As  marine  flow  enters  the  area,  it  is  channelled  along  the  two 
major  axes  of  the  San  Paolo  and  San  Francisco  Bays.  The  San 
Paolo  Bay  loops  eastward  through  the  Carquinez  Straits  into  the 
San  Joaquin  Valley  while  the  San  Francisco  Bay  points  southeast- 
ward into  the  Santa  Clara  Valley.  It  is  also  noted  that  marine 
air  tends  to  turn  northwestward  and  northward  into  the  Santa  Rosa 
area  and  further  to  the  north,  Ukiah.  Ventilation  potential  can 
become  restricted  in  these  inland  valleys  north  of  the  San  Fran- 
cisco Bay  region. 


4.9 


FIRE  WEATHER 


The  primary  purpose  for  the  utilization  of  open  burning 
is  to  quickly  eliminate  choking  underbrush,  for  example,  in  the 
management  of  forested  lands,  or  to  dispose  of  waste  vegetative 
growth  in  the  management  of  agricultural  areas.  These  goals  must 
be  accomplished  while  causing  a  minimum  impact  upon  ambient  air 
qu-ality  in  the  surrounding  region.  For  this  reason,  it  is  desir- 
able to  achieve  a  quick,  hot  burn  which  will  result  in  a  minimum 
burn  time,  while  maximizing  the  atmosphere's  dispersive  capabil- 
ities by  getting  the  resulting  smoke  well  above  the  surface 
1 ayer  . 


232 


Meteorology  plays  a  very  important  role  in  the  identifi- 
cation of  proper  periods  during  which  to  burn  with  a  minimum 
impact  on  surrounding  air  quality.  Burn  versus  no-burn  days  are 
forecasted  daily  by  the  CARB  for  each  of  the  designated  air 
basins  in  California.  Forecasts  for  the  following  day  are  usu- 
ally available  by  1500  PST.  If  the  issuance  of  a  forecast  is 
delayed,  they  are  to  be  available  by  no  later  than  0745  PST  on 
the  day  in  question.  The  CARB  uses  some  very  basic  criteria  in 
making  decisions  relative  to  open  burning  in  each  of  California's 
air  basins.  The  forecasting  criteria  are  designed  to  isolate 
those  days  on  which  the  burning  of  large  surface  areas  will  have 
a  minimum  impact  on  local  air  quality,  based  upon  the  atmos- 
phere's ability  to  disperse  pollutants.  Factors  which  impact 
this  are  the  stability  of  the  atmosphere,  the  presence  of  either 
surface  or  elevated  inversions  and  the  mean  wind  speed  and  wind 
direction.  Previous  sections  have  provided  a  review  of  the 
dispersion  meteorology  of  the  Ukiah  District  and  reference  is 
made  to  that  discussion  for  more  details  relative  to  these  para- 
meters . 

The  dispersion  of  smoke  generated  from  open  burning  is 
restricted  by  such  features  as  stable  atmospheric  conditions,  an 
elevated  inversion  which  restricts  the  volume  of  air  available 
for  mixing,  as  well  as  low  wind  speeds  which  result  in  little 
movement  of  the  pollutants  once  they  are  emitted.  These  mete- 
orological considerations  work  hand  in  hand  with  the  nature  of 
the  local  terrain.  Areas  which  are  in  a  valley  or  a  bowl  and  are 
surrounded  by  important  terrain  features  tend  to  trap  emitted 
pollutants  near  the  source  particularly  when  restrictive  meteor- 
ological conditions  combine  with  such  terrain  effects.  Accord- 
1 n  9 1 y  >  the  CARB  forecasting  criteria  include  a  review  of  the 
anticipated  strength  of  the  morning  surface  inversion,  the  rela- 
tive stability  of  the  atmosphere  from  the  surface  to  roughly 
3,000  feet,  the  wind  speed  at  the  expected  plume  height,  as  well 
as  the  probable  wind  direction.  Burning  is  not  permitted  on  days 
when  wind  speeds  are  light,  the  atmosphere  is  stable,  strong 
surface  or  elevated  inversions  exist,  or  if  wind  directions  will 
tend  to  blow  smoke  toward  populated  areas. 

Section  6.5.2  will  provide  a  review  of  the  regulatory 
constraints  involved  in  open  outdoor  burning  including  the  acqui- 
sition of  permits.  Once  a  permit  is  obtained,  the  basic  decision 
whether  or  not  to  burn  is  based  upon  acquiring  the  burn/no-burn 
forecast  from  the  CARB  in  Sacramento.  In  addition  to  this,  local 
rules  of  thumb  should  be  used  to  provide  proper  management  of  the 
burn  in  terms  of  meteorological  conditions.  The  following  pro- 
vides an  example  of  typical  considerations: 

•  The  wind  direction  at  the  probable  plume  height 
should  be  such  that  the  plume  will  move  away  from 
Smoke  Sensitive  Areas  (SSA).  The  California  Divi- 
sion of  Forestry  (CDF)  has  designated  SSA's  in 
California  which  should  not  be  impacted  by  any  burn 


233 


contemplated  by  BLM  managers.  Figure  4.9-1  pro- 
vides a  review  of  the  location  of  such  areas  in  the 
state.  These  regions  include  most  of  the  populous 
areas  of  the  state,  as  well  as  areas  in  rugged 
terrain  subject  to  considerable  recreational  use. 


Low  wind  speeds  should  be 
where  SSA's  may  be  impacted. 


avoided,   particularly 


Wind  speeds  should  generally  be  greater 
miles  per  hour  to  maximize  dispersion. 


than  15 


Surface  inversions  should  be  avoided  due  to  the 
potential  for  trapping  the  smoke  near  the  surface. 
However,  if  the  plume  is  carried  above  the  inver- 
sion, the  downward  dispersion  of  contaminants  will 
be  inhibited  by  the  surface  based  inversion. 

If  the  burn  will  be  less  than  12  hours,  it  is 
beneficial  to  start  in  the  morning  as  this  will 
tend  to  maximize  the  buoyant  effects  associated 
with  the  burn. 

If  the  burn  is  to  last  more  than  12  hours,  it  may 
be  beneficial  to  start  at  night  as  this  may  mini- 
mize adverse  smouldering  effects,  experienced 
following  the  burn. 

Burning  in  precipitation  is  advantageous  from  an 
air  quality  viewpoint  as  much  of  the  contaminants 
will  tend  to  be  washed  out  of  the  plume. 

Burning  should  not  be  conducted  when  visibility  is 
less  than  11  miles  at  the  site  or  at  a  nearby  SSA. 

Burning  should  never  be  conducted  when  fire  danger 
exists  and  the  manager  should  be  cognizant  of 
forest  fire  weather  forecasts  provided  by  the  NWS. 

The  manager  should  be  able  to  respond  to  deteri- 
orating conditions  so  that  the  burn  can  be  down- 
graded should  dispersion  conditions  become  poor. 

Unlimited  burning  is  never  recommended  unless  the 
wind  direction  is  away  from  a  SSA,  or  a  SSA  is 
located  more  than  100  miles  away,  or  if  the  burn  is 
to  be  conducted  during  precipitation.  Even  in 
these  instances,  a  quota  should  be  established  for 
the  amount  of  dry  fuel  to  be  burned  during  the  day. 

Burning  should  not  be  conducted  when-  the  wind 
direction  will  result  in  the  movement  toward  a  SSA 
if  the  area    is  within  30  miles. 


234 


"7" 


SUSANVILLE 
DISTRICT 


UKIAH 
DISTRICT 


CALIFORNIA  AIR  BASINS 


SCALE  IN  MILES 


100 


FOLSOM 
DISTRICT 


BAKERSFIELD 
DISTRICT 


I 


FOREST  SERVICE  DESIGNATED 
SMOKE  SENSITIVE  AREAS 


L^ 


SMOKE  SENSITIVE  AREAS 


RIVERSIDE 
DISTRICT 


Figure  4.9-1 
235 


Figures  4.9-2  and  4.9-3  provide  a  review  of  typical 
atmospheric  conditions  experienced  over  California  during  the 
afternoon  and  nighttime  hours.  Figure  4.9-2  displays  the  terrain 
of  California,  including  the  Coast  Range,  the  Sacramento  Valley 
and  the  Sierra  Nevada.  As  indicated  in  the  figure,  the  prevail- 
ing wind  in  this  area  is  from  west  to  east.  The  atmosphere, 
close  to  land  areas  tends  to  be  unstable  during  the  afternoon 
hours,  while  over  the  ocean  and  above  the  unstable  air,  a  \/ery 
stable  regime  exists  as  part  of  the  marine  layer  induced  by  the 
nearby  ocean.  This  generally  extends  up  to  nearly  a  thousand 
feet  during  the  afternoon.  Above  that  point,  the  atmosphere  is 
generally  slightly  stable.  Three  potential  burns  are  illustrated 
on  the  figure;  one  in  the  Coast  Range,  one  near  the  Coast  Range, 
and  one  in  the  Sierra  Nevada.  In  addition,  the  figure  depicts  a 
SSA  in  the  populous  Sacramento  Valley  region. 


Coast 
to  the  east 
an  unstabl e 
that  of  the 
not  have  an 


The  fire 
Range  woul d 


illustrated  in  the  higher  elevations  of  the 
have  a  very  limited  impact  in  the  SSA  located 
The  plume  is  initially  buoyant  and  is  emitted  into 
atmosphere  and  will  tend  to  reach  an  elevation  above 
stable  layer.  As  such,  in  most  instances,  it  will 
important  impact  on  the  SSA  as  downward  dispersion 
will  be  inhibited.  The  burn  illustrated  in  the  lee  of  the  Coast 
Range  at  a  relatively  low  elevation  would  have  to  be  managed  very 
carefully  as  it  is  in  relatively  close  proximity  to  the  SSA. 
Here,  the  plume  is  emitted  into  an  unstable  atmosphere,  but  is 
limited  from  continued  dispersion  aloft  by  the  presence  of  a  very 
stable  elevated  inversion.  As  such,  the  plume  does  have  the 
potential  to  impact  the  SSA  and  would  have  to  be  regulated  very 
closely.  The  final  burn  indicated  in  the  figure  is  well  up  into 
the  Sierra  at  a  location  where  it  should  have  an  acceptable 
impact  on  local  air  quality.  The  plume  is  moving  away  from  the 
SSA  and  is  benefiting  from  excellent  dispersion  effects  due  to 
the  unstable  surface  layer  as  well  as  the  effects  imparted  by 
orographic  lifting  over  the  higher  terrain. 


Typical  meteorological  conditions  in  California  at  night 
are  displayed  in  Figure  4.9-3.  In  this  instance,  very  stable  air 
tends  to  accumulate  over  the  SSA,  and  burning  would  not  be  recom- 
mended in  the  zone.  Burning  at  mountaintop  locations,  however, 
would  still  be  acceptable  as  they  are  being  emitted  into  a 
slightly  stable  atmosphere  and  the  very  stable  layer  below  would 
prohibit  the  downward  dispersion  of  the  plume  into  the  SSA. 
These  figures  provide  only  idealized  descriptions  of  typical 
meteorological  effects  on  potential  burn  situations.  It  is 
emphasized  that  the  decision  should  be  based  upon  burn/no-burn 
forecasts  available  from  the  CARB,  even  in  areas  which  are  out- 
side the  jurisdiction  of  regulatory  agencies  due  to  elevation  as 
described  in  Section  6.5.2. 


236 


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4.10 


GENERAL  DISPERSION  MODELING 


Dispersion  modeling  is  a  mathematical  representation  or 
simulation  of  transport  processes  that  occur  in  the  atmosphere. 
There  are  numerous  dispersion  modeling  techniques  available,  all 
of  which  aim  to  calculate  ground  level  concentrations  of  pol- 
lutants that  result  from  industrial,  agricultural,  transportation 
and  urban  emissions.  It  is  important  to  realize  that  there 
exi-sts  no  single  modeling  technique  capable  of  properly  depicting 
all  conceivable  dispersion  situations  that  occur  in  the  atmos- 
phere. Likewise,  meteorological  conditions  impacting  dispersion 
are  complex  and  depend  on  the  interaction  of  numerous  physical 
processes.  Therefore,  any  successful  modeling  effort  must  be 
directed  by  individuals  with  broad  knowledge  and  experience  in 
air  pollution  meteorology,  as  well  as  expertise  in  data  proces- 
sing techniques.  The  judgement  of  well  trained  professional 
analysts  is  essential  to  properly  evaluate  the  ground  level 
impact  of  pollutant  emissions.  Without  detailed  validation/- 
calibration  efforts,  air  quality  modeling  results  are  generally 
felt  to  be  good  only  within  an  order  of  magnitude  under  many 
circumstances,  such  as  applications  in  areas  of  rugged  terrain. 

Air  quality  models  have  been  widely  used  to  identify 
potential  violations  of  National  Ambient  Air  Quality  Standards 
(NAAQS).  Modeling  studies  of  the  atmosphere  are  useful  in  deter- 
mining emission  limits  for  industrial  development  in  specified 
areas.  Hence,  dispersion  models  are  vital  to  the  timely  and  cost 
effective  development  of  air  pollution  .ontrol  strategies  for 
most  regions.  Ideally,  mathematical  modeling  of  the  dispersion 
potential  of  the  atmosphere  would  allow  optimum  planning  for 
proposed  land  use  development  in  terms  of  minimizing  the  air 
pollution  impact.  Dispersion  models  provide  a  technique  which 
can  be  used  to  help  ensure  attainment  and  maintenance  of  air 
quality  standards  and  to  prevent  significant  air  quality  deter- 
ioration due  to  future  development. 

This  section  is  designed  to  present  a  basic  understand- 
ing of  dispersion  modeling  approaches  to  air  qualtiy  problems. 
The  subsections  to  follow  will  alllow  the  reader  to  understand 
the  concepts  of  mathematical  air  quality  modeling.  Numerous 
models  are  described  as  well  as  techniques  for  selecting  the 
optimum  approach.  English  units,  which  have  been  employed  in 
previous  sections  of  this  document,  will  not  be  used  here. 
Calculations  must  be  performed  in  metric  units,  as  dictated  by 
the  equations  and  figures  commonly  used  in  dispersion  modeling. 
English  conversions,  however,  have  been  placed  on  figures  as  a 
convenient  reference  for  the  reader. 

4. 10.  1    Classes  of  Model s 


Basically, 
model s  available, 
acteri  zed  as  : 


there  are  four  general  types  of  air  quality 
These  types  of  dispersion  models  are  char- 


239 


•  Gauss  i  an 

•  Numeri  ca 1 

•  Statistical 

•  Physi  cal 


or  Empirical 


Within  each  of  these  classes,  there  exists  a  large 
number  of  individual  computational  algorithms,  each  with  its  own 
specific  application.  For  example,  numerous  air  quality  models 
have  been  developed  based  upon  the  Gaussian  or  log-normal  solu- 
tion to  the  fluid  transport  equation.  Each  particular  model  or 
algorithm  is  designed  to  handle  a  specific  air  quality  and  atmos- 
pheric scenario  while  computing  pollution  impacts  through  the  use 
of  the  Gaussian  diffussion  equation.  The  models  may,  for  ex- 
ample, consider  different  atmospheric  parameters,  terrain  fea- 
tures, and  various  degrees  of  data  resolution.  The  well-known 
EPA  dispersion  models  such  as  the  CI  imatol ogi cal  Dispersion  Model 
(CDM),  the  Air  Quality  Display  Model  (AQDM) ,  the  Valley  Model, 
and  the  Texas  CI  imatol ogi cal  Model  (TCM)  are  commonly  referred  to 
as  individual  models  but  in  fact  are  all  variations  of  the  basic 
Gaussian  model.  In  many  cases,  the  only  real  difference  between 
models  is  the  degree  of  detail  considered  in  the  input  and  output 
of  data  . 

Gaussian  models  are  considered  to  be  the  state  of  the 
art  technique  for  estimating  the  impact  of  non-reactive  pollut- 
ants. These  types  of  models  assume  instantaneous  transport  of 
effluents  downwind  of  the  emission  source.  However,  numerical 
models  are  more  appropriate  than  Gaussian  models  for  source 
applications  which  involve  reactive  pollutants.  Most  numerical 
models  employ  numerous  interactive  steps  allowing  for  downwind 
adjustments  to  time  dependent  chemical  and  thermal  processes  that 
take  place  in  the  plume.  Statistical  or  empirical  techniques  are 
frequently  employed  in  situations  where  an  incomplete  scientific 
understanding  of  the  physical  and  chemical  processes  of  the  plume 
behavior  makes  the  use  of  the  Gaussian  and  numerical  modeling 
approaches  impractical.  Physical  modeling,  the  fourth  generic 
type,  involves  the  use  of  a  wind  tunnel  or  other  fluid  modeling 
facilities  necessary  to  investigate  dispersion  in  very  confined, 
specialized  environments  isolated  to  only  a  few  square  kilo- 
meters. Physical  modeling  is  a  complex  process  which  requires  a 
high  level  of  technical  expertise. 

4.10.2   Model  Suitability  and  Application 

The  level  of  analysis  for  which  a  particular  dispersion 
model  is  well  suited  depends  on  several  factors.   These  include: 

•  The  detail  and  accuracy  of  the  data  base  (i.e., 
emission  inventory,  baseline  air  quality  and  mete- 
orologicaldata) 

•  The  local  topographic  and  meteorological  complexi- 
t  i  es 

•  The  technical  competence  of  the  individuals  direct- 
ing the  modeling  effort 


240 


•    Available  financial  and  computational  resources 

Air  quality  models  require  a  data  base  which  includes 
emission  source  characteristics,  meteorological  parameters  and 
baseline  air  quality  levels  (and  at  times,  local  topographic  data 
and  temporal  statistics).  Models  that  require  detailed  and 
precise  input  data  should  not  be  applied  when  such  data  are 
una vai 1 abl e  . 

Most  dispersion  models  are  intended  for  use  only  in 


areas  of  relatively  simple 
ses  for  major  topographic 
scenarios  may   start   with 
analyses  using  the  Gaussian 
define  the  level  of  impact 


topography.  Specific  modeling  analy- 
features  and  complex  meteorological 
a  simplistic  preliminary  screening 
or  other  straightforward  approach  to 
If  these  analyses  point  to  a  po- 
tentially important  impact  then  more  sophisticated  modeling 
approaches  must  be  implemented. 


various  levels  of 
general  techniques 
t i  ve  estimates  of 
source  category, 
understanding  of 


Applications  of  the  various  classes  of  air  quality 
models  previously  mentioned  require  a  two  step  approach  with 

sophistication.  The  first  level  consists  of 
that  provide  relatively  simple  and  conserva- 
air  quality  impact  of  a  specific  source  or 
This  initial  screening  level,  provides  an 
air  pollution  impact  due  to  a  particular 
source(s)  in  the  area  in  question.  The  major  objective  at  this 
stage  is  to  identify  potential  violations  of  air  quality  stan- 
dards. This  is  done  by  using  simple  analytical  techniques  to 
isolate  areas  of  projected  maximum  ground  level  concentrations 
for  comparison  with  the  most  limiting  standards,  and  is  the  level 
of  effort  the  District  Offices  should  strive  to  accomplish. 

The  second  level  of  effort  involves  the  use  of  analy- 
tical techniques  which  provide  a  more  detailed  treatment  of 
physical  and  chemical  processes  once  a  potential  problem  has  been 
identified.  This  step  requires  a  more  detailed  and  precise  data 
base  which  will  result  in  a  more  accurate  estimate  of  source 
impact.  At  this  point,  an  exhaustive  data  base  specific  to  the 
study  area  is  incorporated  into  the  modeling  analysis.  For 
example,  temporal  variations  in  the  baseline  meteorology,  air 
quality  and  emissions  data  can  be  input  to  the  model.  Emission 
inventory  data  can  also  be  more  accurately  assessed  in  terms  of 
such  aspects  as  temporal  variability. 

The  screening  level  approach  to  air  quality  modeling  is 
hig-hly  recommended  in  all  initial  applications  of  dispersion 
models.  If  a  problem  is  identified,  then  more  sophisticated 
analyses  are  indicated.  In  any  case,  a  multi-step  approach  to 
modeling  is  vital  in  accurately  establishing  regional  air  quality 
impact.  ; 

A  specific  plan  of  attack  is  required  for  each  disper- 
sion problem  that  is  encountered.  It  is  not  the  purpose  of  this 
section  to  recommend  specific  models  for  specific  air  quality 


241 


impact  situations,  but  rather  to  provide  a  foundation  or  frame- 
work in  which  to  approach  the  basic  air  quality  modeling  problem, 
which  may  be  used  as  a  screening  level  to  determine  if  further 
anal ysi  s  is  needed  . 

4.10.3    The  Gaussian  Model 

Gaussian  based  models  are  considered  to  be  the  state  of 
the  art  technique  for  estimating  concentrations  of  non-reactive 
pollutants  such  as  sulfur  dioxide  and  particulate  matter  for  most 
point  source  emissions.  Numerous  experiments  have  been  conducted 
to  study  the  shape  of  plumes.  The  publication  "Meteorology  and 
Atomic  Energy"  lists  over  twenty  experiments,  many  of  which  have 
been  conducted  by  the  Atomic  Energy  Commission  (now  ERDA-Energy 
Research  and  Development  Administration).  In  general,  most 
investigators  have  been  satisfied  that  a  Gaussian  distribution  is 
a  good  mathematical  approximation  of  plume  behavior  over  time 
periods  on  the  order  of  five  minutes  to  one  hour.  Figure  4.10-1 
illustrates  the  Gaussian  plume  distribution  in  the  horizontal  and 
the  vert  i  cal  . 

The  Gaussian  model  provides  reasonable  estimates  in  flat 
or  gently  rolling  terrain.  However,  Gaussian  based  models  are 
extremely  inaccurate  for  air  quality  impact  assessments  in  areas 
comprised  of  extremely  rugged  and  varying  terrain,  such  as  hilly 
or  mountainous  regions.  For  such  situations,  statistical  or 
physical  modeling  methods  are  best  employed,  since  the  dispersion 
potential  of  the  atmosphere  can  then  be  characterized  by  empiri- 
cal data  obtained  by  local  monitoring  programs. 

Properly  used,  a  Gaussian  model  is  unequalled  as  a 
practical  diffusion  modeling  tool  in  terms  of  simplicity,  flexi- 
bility and  the  successful  correlation  between  predicted  and 
measured  values.  For  these  reasons,  the  Gaussian  model  is  used 
in  this  section  to  illustrate  several  simple  modeling  problems. 
All  variables  which  will  be  used  to  solve  the  Gaussian  equation 
wi 1 1  now  be  def i ned  : 


C(x,y,z) 


a   o 


is  the  concentration  at  a  point  (x,y,z). 

is  the  mean 

are  the  standard  deviations  in  the  y  and  z 
directions 


i  s  the  emi  ssi  on  rate 

is  the  mean  wind  speed  and 

is  the  height  of  the  plume  centerline  when  it 
becomes  essentially  level. 


242 


fa 

o 

•i— 

+-> 

s- 

O) 

> 

■a 

c 

ro 

,_ 

c^ 

fO 

c 

4-J 

*r— 

C 

5 

o 

o 

N 

1 — 1 

-C 

•r— 

1 

co 

S- 

o 

o 

1— I 

E 
CD 

in 

«a- 

■M 

CD 

CO 

sz 

o> 

5^ 

-M 

s_ 

00 

Z3 

c 

CD 

OJ 

•r- 

•r— 

4-> 

U_ 

rO 

£Z 

C 

O 

•r™ 

»r— 

■D 

4-> 

S_ 

3 

o 

X) 

o 

•  i — 

C_> 

i- 
+J 
00 

Q 

¥— t 

oo 

CO 

el 

243 


The  normal  or  Gaussian  frequency  curve  is  given  by: 


C  (x)  = 


(2tt)   a 


exp 


(x  -  x)' 

9   2 

2o 


4.10-1 


Where  C  is  the  concentration,  x,is  the  mean,  and  o  is  the 
standard  deviation.  (  2tt  )  1^ 2  makes  the  area  under  the  curve,  from 
x  =  _  oo  to  =  +  °°,  equal  to  1  (See  Figure  4.10-2). 


C(x) 


-3o- 


2o- 

-1(7 

R 

ler 

2a 

2% 

161 

50% 

Bui 

98* 

Figure  4. 10- 2 
Gaussian  or  Log-Normal   Distribution 


When    a    distribution    is    bi normal     in    the    two    dimensions    x    and 
y,    the    probability    density    function    is: 

1 


exp 


C  (x,y)  = 


(x  -  x)2 


2tt  a       a 

x     y 


(y  -  y)2 


y 


4.10-2 


If  there  is  a  continuous  emission,  Q,  of  gas  or  aerosols 
from  a  point,  H,  above  the  ground,  a  3  dimensional  coordinate 
system  must  be  defined  so  that  the  origin  is  on  the  ground  be- 
neath the  point  of  emission,  x  is  in  the  direction  of  the  mean 
wind,  u,  y  is  crosswind  and  z  is  vertical. 

Likewise,  it  is  assumed  that  the  diffusion  in  the  crosswind 
and  vertical  dimensions  will  occur  in  a  Gaussian  manner,  so  that 
the  pollution  will  move  downwind  with  the  mean  speed  of  the  wind, 
and  that  the  diffusion  in  the  downwind  direction  is  negligible 
compared  with  the  transport. 


The  concentration,  C,  at  any  point  (x,y,z)  can  be  written 


as 


exp  - 


C   (x, 

y> 

Q 

z)    u       _ 

1 

2tt  o       o 

y     z 

1 

r    2 

y 

j_ 

(z  -  H)2 

2 

2 

0 

L    y 

2 

J 

4.10-3 


Here  y  is  assumed  to  be  0,  and  z  assumed  to  be  H.  In  this 
equation,  C  has  units  of  mass  per  volume;  u,  velocity  or  length 
per  time;  Q,  mass  per  time;  a  and  o  length;  and  y,z,  and  H, 
length.  y 

Because  diffusion  in  the  z  direction  is  bounded  by  the 
earth's  surface,  equation  4.10-3  cannot  be  strictly  used.  If  it 
can  be  assumed  that  the  ground  acts  as  a  perfect  reflector, 
therefore,  source  at  z  =  H  is  assumed  to  have  a  virtual  "image" 
source  at  z  =  -H  and 


C  (x,  y,  z)  u 
Q 


exp 


1 


2tt  oy  az 


<z  -  f     +  ex 
2a 


P  ~ 


(z  +  H) 
2 
2a 


exp 
2 


-y 


4.10-4 


This  is  the  generalized  diffusion  equation.  We  cannot 
expect  to  obtain  instantaneous  concentrations  from  this  equation, 
but  concentrations  averaged  over  at  least  a  few  minutes  time. 
There  are  several  reasons  to  expect  this  equation  to  be  valid  for 
the  atmosphere.  It  obeys  the  equation  of  continuity,  i.e.,  the 
conservation  of  mass.  The  mass  Q/l  second  is  found  between  any 
two  planes  perpendicular  to  the  x-axis  at  a  distance  u  / 1  second 
apart.  Secondly,  diffusion  is  a  random  process  and  the  distri- 
bution of  material  from  such  motion  may  be  expected  to  be  in  some 
statistical  form;  in  this  case,  according  to  the  Gaussian  curve. 

one  theoretical  reason  why  one  would  not  expect 
apply.  Diffusion  can  only  occur  at  a  finite 
concentration  of  released  material  should  drop 
distance  from  the  x  axis  because  it  has  not 
point.  The  Gaussian  distribution  assumes  the 
material  to  be  spread  from  -  °o  to  +  °o  crosswind.  This  is  not  of 
practical  importance,  however,  as  the  Gaussian  distribution  drops 
off  extremely  rapidly  within  a  few  a  crosswind.  One  practical 
limitation  is  that  the  Gaussian  distribution  does  not  allow  for 
any  wind  shear  in  the  surface  layer. 


However ,  there  is 
this  equat  i  on  to 
speed,  i.e.,  the 
to  zero  at  some 
di  f fused  to  this 


ti  ons 


Interest  is 
i.e.,  C ( x , 


generally  focused  upon  ground  level  concentra- 
Y,  0).   Substituting  z  =  0  in  (4.10-4)  yields: 


C(x,  y,  0)  u  _ 
Q 


4.10-5 


ti  c   a 

y  z 


exp 


2a 


,2  -i 


2o 


245 


1  s 


It  will  be 
eliminated  in 


noted  that  the  2  in  the  denominator  in  (4.10-4) 
(4.10-5)  because  of  the  2 


resulting  from 
numerator . 


2  exp  - 


H 


2o 


occurring  in  the 


If  the  source  is  at  ground  level  (H  =  0),  there  is  further 
simplification.  Similarly,  if  one  is  interested  only  in  center- 
line  concentrations  (directly  downwind)  then  y  =  0,  and  equation 
(4.10-5)  may  again  be  simplified. 


This  (4.10-5)  is  the  basic 
ground  level  concentration  from  a 
usual  units  for  the  variables  are: 


(x,  y,  0) 


y 


y,  h, 


equation  for  calculating 
continuous  point  source. 

/  3 
gms/m 

m/sec 

gms/sec 

meters 


the 
The 


As  seen  from  Equation  4.10-5,  the  plume  concentration 
(C)  at  various  downwind  distances  (x)  from  the  emission  source  is 
largely  dependent  upon  horizontal  and  vertical  dispersion  coeffi- 
cients (sigma  y  or  sigma  z).  Figure  4.10-1  illustrates  the 
coordinate  system  for  a  typical  plume  and  visually  describes  the 
significance  of  the  dispersion  coefficients  in  the  y  and  z 
directions. 


Stability 

The  values  of  both  oy  and  oz  will  depend  upon  the  turbu- 
lent structure  of  the  atmosphere.  If  measures  of  horizontal  and 
vertical  motions  of  the  air  are  made  as  with  a  bivane,  the  re- 
sulting records  may  be  used  to  estimate  a  and  oz 
quill,  1961).   If  wind  fluctuation  measurements  are 


( see  Pas- 
not  avail- 


able, estimates  of  °y  and  °z  may  be  made  by  first  estimating  the 
stability  of  the  atmosphere  from  wind  measurements  at  the  stan- 
dard height  of  10  meters,  and  estimates  of  net  radiation  (Pas- 
quill,  1951).  Stability  categories  (in  six  classes)  are  given  in 
Table  4.10-1  in  terms  of  insolation  during  daytime  (radiation 
received  from  the  sun)  and  amount  of  cloud  cover  at  night. 
Strong  insolation  corresponds  to  a  solar  altitude  (above  the 
horizon)  greater  than  60  with  clear  skies,  and  slight  insolation 
corresponds  to  a  solar  altitude  from  15  to  35  with  clear  skies. 
Table  170,  Solar  Altitude,  and  Azimuth  in  the  Smithsonian  Meteor- 
ological Tables  (List,  1951)  is  a  considerable  aid  in  determining 
insolation.  Cloudiness  will  generally  decrease  insolation  and 
should  be  considered  along  with  a  solar  altitude  in  determining 
insolation.  Insolation  that  would  be  strong  with  clear  skies  may 
be  reduced  to  moderate  with  broken  middle  clouds  and  to  slight 
with  broken  low  clouds.  Night  refers  to  the  period  from  one  hour 
before  sunset  to  one  hour  after  sunrise.  The  neutral  category, 
(D),  should  be  assumed  for  overcast  conditions  during  day  or 
ni  ght . 


246 


Table  4.10-1 
Key  to  Stability  Categories 


Night 

Surface  Wind 
Speed  (at  10  m) 
m/sec 

Strong 

Insolation 
Moderate 

Slight 

Thinly  Overcast 

or 
>  4/8  Low  Cloud 

<  3/8 
Cloud 

<     2 

A 

A-B 

B 

- 

- 

2-3 

A-B 

B 

C 

E 

F 

3-5 

B 

B-C 

C 

D 

E 

5-6 

C 

C-D 

D 

D 

D 

>     6 

C 

D 

D 

D 

D 

The  neutral  category,  D,  should  be  assumed  for  overcast  conditions  during 
day  or  night. 


247 


Estimation  of  Vertical  and  Horizontal  Dispersion 


Having  determined  the  stability  class 


the  measures 
zontal  , 
from  the 


sou 


of  diffusion  in  the 
may  be  estimated  as 


from  Tabl e  4. 10-1 , 
vertical,  az  ,  and  in  the  hori- 


rce  , 
and 


a  function  of  downwind  distance 
(x),  using  Figures  4.10-3  and  4.10-4.   These 
ov/  are    valid  for  concentrations,  (C),  averaged 


Val UeS   Of   Oz   aim    u» 

over  a  few  minutes  time,  and  apply  to  open  level  country  with  no 
allowance  made  for  turbulence  due  to  buildings  or  topography. 
With  yery  light  winds  on  a  clear  night,  the  vertical  spread  may 
be  less  than  the  values  for  class  F. 


tempe 
ti  on , 
allow 
conve 
still 
be  as 
(2x  ) 
earth 
to  0. 
tance 
trat  i 
pi  ume 


When  conditions  are  such  that  the  vertical  structure  of 

rature  indicates  a  definite  limit  to  the  vertical  convec- 

particularly  under  unstable  conditions,  the  oz      should  be 


ed  to  increase  only  to  0.47h,  where  h,  is  the  limit  of 
ction.   At  the  distance  x,  where  oz  =  0.47  h,,  the  plume  is 

assumed  to  have  a  Gaussian  vertical  distribution.  It  can 
sumed  that  by  the  time  the  plume  travels  twice  this  distance 
,  the  plume  has  become  uniformly  distributed  between  the 
's  surface  and  the  limit  of  convection.  A  value  of  az  equal 
8h,  may  be  used  and  the  exponential  term  dropped  at  dis- 
s  equal  to  or  greater  than  2x,  and  will  make  the  concen- 
on  value  computed  by  the  equation,  equal  to  that  from  a 

uniformly  distributed  in  the  vertical. 


Estimation  of  Wind  Speed 

For  mean  wind  speed,  (u),  the 
meters  elevation  (surface  wind)  should  be 
1  km  for  surface  sources  or  short  stacks, 
or  elevated  sources,  a  mean  speed  through 
the  plume  (about  2  az  )  should  be  used, 
the  surface  and  geostrophic  speeds  should 


val ue  measured  at  10 

used  for  x  up  to  about 

For  greater  distances 

the  vertical  extent  of 

A  speed  midway  between 

be  reasonable. 


Calculation  of  Centerline  Concentration  From  a  Ground  Level 
Source 

For  most  practical  purposes  it  will  be  sufficient  to 
calculate  the  centerline  concentration  for  the  distances  100  m,  1 
km,  10  km,  and  100  km  and  plot  these  against  downwind  distance  x, 
on  log/log  graph  paper  for  interpolation  of  concentration  for 
other  distances.  (For  unstable  or  stable  cases  it  is  desirable 
to  include  several  other  distances.)  This  may  be  done  using  the 
equat i  on  : 


3.18  X 


10  -1  Q 


4.10-6 


u 


248 


I  10 

DISTANCE  DOWNWIND,  km 

Figure  4.10-3 

Vertical  Dispersion  Coefficient  as  a  Function 
of  Downwind  Distance  from  the  Source 


249 


10,000 


1,000 


I  10 

DISTANCE  DOWNWIND,  km 

Figure  4.10-4 
Horizontal    Dispersion  Coefficient  as  a  Function  of 
Downwind  Distance  from  the  Source 


100 


250 


The  zero  subscript  of  C,  concentration,  indicates  emis- 
sion from  a  ground- 1  eve!  source.  If  there  is  a  limit  to  convec- 
tion (h),  concentrations  should  also  be  calculated  for  distances 
Xi  and  x~  using  oz  =  0 . 47 h ,  and  o  z  =  0.8  h,  respectively.  Line 
segments  connecting  the  calculated  concentrations  for  the  various 
distances  will  give  a  plot  of  concentration  with  distance. 


Calculation  of  Ground-Level  Center! ine  Concentration  From  an 
E 1 e vated  Source 


from : 


Concentrations  from  an  elevated  source  may  be  calculated 

,2 


C  = 


7T  U   O    O 

y  z 


exp  - 


H' 


2  O: 


4.10-7 


where  H  is  the 
pi  us  pi ume  ri  se 


effective  height  i.e.,  the  physical 
of  the  elevated  source. 


stack  height 


Values  of  exp  -  Wc  H  °z  c  are  found  in  Table  4.10-2.  A 
is  the  ratio  of  H/ o2  and  B,  the  expression  in  the  body  of  the 
table,  is  the  computed  value  of  the  exponential.  The  E  repre- 
sents x  10  to  the  power  indicated  by  the  following  two  digits. 
For9exampl e  ,  if  A  =  3.55,  the  value  of  the  exponential  is  0.183  X 
10   . 

It  is  possible  under  light  wind  situations  at  nights 
that  the  plume  from  an  elevated  source  will  remain  aloft  with  no 
significant  vertical  diffusion,  in  which  case  the  ground-level 
concentrations  would  be  zero.  Vertical  spread  can  then  be 
started  at  a  downwind  position  corresponding  to  the  wind  speed 
and  the  estimated  time  for  breakdown  of  the  stable  situation. 

Graphs  for  Estimation  of  Diffusion 

Hilsmeier  and  Gifford  (1952)  have  presented  graphs  of 
relative  concentration  times  wind  speed  (Cu/Q)  below  the  plume 
centerline,  versus  downwind  distance  for  various  stability 
classes.  Figure  4.10-5  give  Cu/Q  as  a  function  of  x  for  a 
ground-level  source  whereas  Figures  4.10-6  through  4.10-8  are  for 
the  indicated  elevated  sources. 


Calculation  of  Off  Axis  Concentrations 


4.10-1, 

by  the  factor: 


Off-Axis  concentrations  may  be  calculated  from  equation 
or  by  correcting  ground- 1 evel  centerline  concentrations 


exp  -  (y  /2o      ).   This  may  be  obtained  from  Table 


4. 10-3  for  val ues  of  y/ o 

Plotting  Ground-Level  Concentration  Isopleths 


251 


Table  4.10-2 


Values  of  Exp  - 


2a. 


0.00 


0.01 


o.ao 
o.io 
o.?o 

0.30 

c.»o 
o.»o 

0.60 

O.'O 

o.bo 

0.90 

.00 

.10 

1.20 

I.JO 

.*o 
.so 

.60 
.70 
.80 
.90 

.00 

.10 

.20 
.50 

.*o 

.50 
.60 
.70 
.80 
.90 

.00 
.10 
.20 
.30 
.*0 

.50 
.60 
.70 
.80 
■  90 

.00 

.10 
.20 
.30 


'.50 
>.6C 

.to 

.90 


C.lOOf 

01 

0 

.1001 

J   01 

0 

.loot 

C.995I 

:  oo 

0 

,99*1 

:  oo 

0 

,993E 

0.980! 

:  oo 

0 

.9781 

■    00 

0 

.976£ 

C.9S6I 

:  oo 

0 

,953( 

:  oo 

0 

.950E 

C.923! 

00 

0 

,9191 

'    00 

0 

,916E 

0.8821 

00 

0 

,8781 

00 

0 

>87*E 

0.8351 

■    00 

0 

,e30( 

■   00 

0 

.825E 

0.7831 

■   00 

0 

,777( 

00 

0 

,772f 

0.726! 

00 

0 

,720( 

•   00 

0 

71*f 

0.667( 

00 

0 

,661( 

.  oo 

0 

,655! 

0.607( 

00 

0 

.6001 

00 

0 

,59*E 

C  .ifc-sE 

00 

0 

,5*0( 

00 

0 

33*E 

C.*87[ 

00 

0 

*■  6  1 E 

00 

0 

*75E 

0.4301 

00 

0 

,424f 

00 

0 

*m 

0.3751 

00 

0 

3701 

00 

0 

365E 

0.3251 

00 

0 

3201 

00 

0 

313E 

0.2781 

00 

0 

,27*E 

00 

0 

269E 

C.2361 

00 

0 

2321 

00 

0 

228E 

C.I98! 

00 

0 

19*E 

00 

0 

191E 

C.  16*1 

00 

0 

161E 

00 

0 

158E 

0.133E 

00 

0 

133E 

00 

0 

130E 

0.1101 

00 

0 

108E 

00 

0 

106E 

C.8B9E 

.01 

0 

870E 

.01 

0 

851E 

0.7101 

.01 

c 

69*E 

.01 

0 

678E 

0.561E 

.01 

0 

3*8E 

.01 

0 

S35E 

0.*39E 

.01 

0 

»2ee 

-01 

0 

418£ 

0.3*0E 

.01 

0 

332E 

.01 

0 

323E 

0.261E 

.01 

0 

23*! 

.01 

0 

2*7£ 

C.  198E 

.01 

0 

193E 

.01 

0 

1881 

0.149E 

.01 

0 

t*5E 

-01 

0, 

U1E 

0.111E 

.01 

0, 

108E 

-01 

0 

105E 

C.819E 

.02 

0 

79kE 

-02 

0 

769E 

C.598E 

.02 

0 

579E 

-02 

0, 

560E 

0.432E 

-02 

0 

*18E 

-02 

0 

«0*E 

C.309E 

.02 

0 

299E 

-02 

0, 

289E 

0.21 qE 

.02 

0. 

2tlE 

-02 

0, 

20*E 

0.153E 

.02 

0 

USE 

-02 

0, 

U3E 

0.106E 

.02 

0 

10JE 

-02 

0 

989E 

0.732f 

.03 

0. 

70*f 

-03 

0. 

67«E 

0.498! 

-03 

0, 

47«f 

-03 

0, 

*60f 

0.333! 

-01 

o, 

322E 

-03 

0, 

310? 

0.224! 

.03 

0 

21»E 

-03 

0. 

206E 

0.1*8E 

.03 

c 

1*2E 

.03 

0 

136E 

0.966! 

.0* 

0 

925E 

.0* 

0 

866E 

C.625E 

.0* 

0 

598E 

.0* 

0 

372c 

C.401E 

.0* 

0 

»•}( 

.0* 

0 

366E 

0.24*! 

.0* 

0 

2*3E 

.0* 

0 

232E 

0.  160( 

.0* 

e 

13*j 

.0* 

0 

u»r 

0.993! 

.05 

0 

9*61 

.05 

0 

9C2f 

C.fcl It 

.05 

c 

9«K 

-05 

0, 

»5*r 

0.02 


00 
00 
HO 
00 

no 
oo 
oo 
oo 

00 

00 
00 
00 
00 

00 

00 
00 
00 
00 
00 

00 

00 

.01 

.01 

.01 

.01 
.01 
.01 
.01 
.01 

-01 

-02 
-02 
-02 
.02 

-02 
.02 

.03 
-03 
-93 

.13 
.03 
.03 
.0* 
.0* 


.0* 
.0* 
C5 

05 


0.03 

0.100E  01 

0.992E  00 

0.97*f  00 

0.9*7E  00 

0.912E  00 

0.869E  00 
0.820F  00 
0.766c  00 
0.709E  00 
0.6*9F    00 

0.588E  00 
0.528E  00 
9.469F  00 
0.413E  00 
0.360F    00 

P.J10E  00 
0.265E  00 
0.224E  00 
0.1B7E  00 
0.155E    00 

0.127E  00 
0.103E  00 
0.832F.01 
0.662F-01 
0.522E-01 

0.607E.01 
0.313E.01 
0.241E-01 
0.1B2E.01 
0.137E-01 

0.101E-01 
0.7*6E-02 
0.5*3E-02 
0.391E-02 
0.27gE-02 

0.197E-02 
0.13BF-02 
0.932E-03 
O.653F-03 
0.443F-03 

0.297F-03 

0.198C-03 
0.130E-03 
0.8*9E-0* 
0.5*Bt -0* 

0.350E-04 
D.221E.0* 
0.139E-9* 
*  .  8  5  9  :  .  '  5 
0.52«f .05 


B     •    exp 
U.O* 


-   1(A)' 


0.05 


0.06 


0.07 


0.08 


0 

.999f 

0 

.990E 

0 

,972r 

0 

,9**F 

0 

,9P8f 

0 

>86*E 

0 

,815r 

0 

760r 

0 

,703f 

0 

,6*3f 

0 

,»82c 

0 

,522E 

0 

,*6*F 

0 

,*C7r 

0 

355E 

0 

306F 

0 

26lF 

0 

220E 

0 

1B*F 

0 

152E 

0 

123F 

c 

101E 

0 

ei*E 

c 

6*7E 

0 

510E 

0 

397E 

0 

3C7E 

0 

23*E 

0 

177E 

0 

133E 

0 

9B*E 

0 

723E 

0 

525E 

0 

378E 

0 

269E 

0, 

190E 

0 

133r 

0 

918E 

0, 

628r 

0 

*26r 

0 

286r 

0. 

190r 

0 

125F 

c 

813r 

I 

52*E 

0, 

33. r 

c 

211F 

c 

132r 

c 

Bl9t 

0, 

5"2F 

00 
00 
00 
00 
00 

00 
00 
00 
00 
00 

00 
00 
00 
00 

00 

00 
00 
00 
00 
00 

00 

00 

-01 

-01 

-01 

.01 
-01 
-01 
-01 
-01 

•  02 
-02 
-02 
-02 
-02 

-02 
-02 

-03 
-03 
-03 

-03 

-03 
.03 
-0* 
.0* 

.0* 


."5 

."5 


0.999E 

0.989E 
0.969E 
0.9ME 

0.90*£ 


0.860E  00 
0.810E  00 
0.755£  00 
0.697E  00 
0.637£  00 


0.576E 
0.516E 
0.458E 


0.402E  00 
0.350E  00 

0.301E  00 
0.236E  00 
0.216E  00 

o.ieiE  00 

0.1*9£  00 

0.122E  00 

0.991E-01 
0.796E-01 
0.632E-01 
0.497£.01 

0.387E.01 
0.299E.01 
0.228E.01 
0.172E-01 
0.129E.01 

0.955E.02 

0.700E.02 
0.309E.02 
0.366E.02 
0.260E.02 

0.183E.02 
0.128E-02 
0.8B*E-03 

0.60ȣ.03 
0.609E-03 

0.276E-03 
0.182E-03 
0.120E.03 

0.77BE-0* 
0.501E.0* 

0.32CE-0* 
0.2C2E.D* 

0.126E.0* 
C.76CE.C5 
0.*78E-05 


0.998E 

0.987E 
0.967E 
0.937E 

0.900E 


0.998E 
0.986E 


0.855E  00 
0,BO*E  00 
0.T69E  00 
0.691  E  00 
0.631E  00 

0.S70E  00 
O.SlOE  00 
0.4S2E  00 
0.397E  00 

C.3**E  00 

0.296E  00 
0.232E  00 
0.213E  00 
0.177E  00 
0.146E  00 

0.120E  00 
0.970E-C1 
0.77JE.01 
0.617E-01 
0.485E-01 

0.377E.01 
0.291E-01 
0.222E.01 
0.167E.01 
0.12JE-01 

0.92&E.02 
0.679E-02 
0.692E-02 
0.33*E-02 
0.231E.02 

0.177E-02 
0.123E-02 
0.851E.03 
0.382E-03 
0.S93E-03 

0.263E-03 

0.175E-03 

0.113E-03 
0.74SE-04 
0.479E-04 

0.303E-0* 
0.193E.C* 
0.120E-0* 
0.7*3E-r3 
0.*55E-O5 


00 
bE  00 
0.964E  00 
0.93*E  00 
0.893E  00 

O.ISOE  00 
0.799E  00 
0.743E  00 
0.68SE  00 
0.625E  00 

0.»6*E  00 
0.30*E  00 
0.**6E  00 
0.S91E  00 
0.S39E  00 

0.292E  00 
0.248E  00 

0.209E  00 
0.174E  00 

0.1**E    00 

0.U7E  00 
0.949E-01 
0.760E-01 
0.603E-01 
0.473E-01 

0.368E-01 
O.283E-01 
0.216E-01 
0.163E.01 

0.  121E-01 

0.898E-02 
0.65BE-02 
0.677E-02 
0.»42E-02 
0.263E-02 

0.1T1E-02 

0.119F-02 
0.I20E-03 

0.560f-0J 

0.S78E-03 

0.253F-03 
0.16BE-03 
0.U0E-03 
0.713E-0* 
0.458E-04 

0.292E-0* 

0.18*E-0* 
0.115E-0* 
0.7C8E.05 
0.433E-05 


0.997 
0.98* 
0.962 
0.930 
0.891 

0.8*3 
0.79* 
0.738 
0.679 
0.619 

0.S58 
0.*98 
0.**1 
0,386 
0.33* 

0.287 
0,2** 
0.203 
0.171 
0.1*1 

0.115 
0.929 
0.7*3 
0.589 
0.462 

0.339 
0.276 
0.210 
0.158 
0.118 

0.871 
0.637 
0.*6l 
0.331 
0.233 

0.163 
0.115 
0.789 
0.938 
0.363 

0.2*3 

0.161 
0.105 
0.683 
0.438 

0.279 
0.1TS 

0.109 
0.6'* 
0.412 


E    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

E    0  0, 

0. 

E    00 

0, 

E    00 

0, 

E    00 

0. 

£    00 

0. 

E    00 

0, 

£    00 

0. 

£    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

E    00 

0. 

£.01 

0. 

£.01 

0. 

£.01 

0. 

£.01 

0. 

£-01 

0. 

E.01 

0. 

E-01 

0. 

£.01 

0. 

E-01 

0. 

£.02 

0. 

E-02 

0. 

E.02 

0. 

E.02 

0. 

E.02 

0. 

E-02 

0. 

£-02 

0. 

£-03 

0. 

£-03 

0. 

E-03 

0. 

f-03 

0. 

E-03 

0. 

£.03 

0. 

£.0* 

0, 

E-04 

0. 

E.04 

c. 

£.0* 

0. 

E.04 

0. 

E-OJ 

0. 

f  .03 

* 

0.09 

996E  00 
9*2E  00 
959E  00 
927E  00 
887E  00 

840£  00 

7B6E  00 

732£  00 

673E  00 

613E  00 

S52E  00 

493E  00 

435E  00 

381E  00 

330E  00 

283E  00 

24QE  00 

2C1E  00 

168E  00 

138E  00 

113E  00 
909E.01 

727E.01 
375E.01 
450E.01 

349E-01 
268E.01 

204E.01 
134E.01 

1UE-C1 

845E-02 
617E-C2 
446E-02 
320E.02 
227E-02 

159E-02 
110E-02 
760E-03 
SlBE-03 
349E.03 

233E-03 

134E-03 

101E-03 
653E.0* 
419E-0* 

266E.0* 
167E.0* 
10»E.O* 
6*2E.05 
392E-05 


252 


Table  4.10-2  (Continued) 


B    •     exp  -  i  (A)2 

* 

0, 

00 

0.01 

0. 

02 

0.03 

0.06 

0.05 

0.06 

0.07 

0.08 

0.09 

5.00 

0.575( 

•  05 

e. 

»5»f.0S 

0 

SS7( 

.05 

0. 

>:.<-:* 

0.503r-05 

0.29CE-05 

0.276E-05 

0.262f*05 

0.2»9f-05 

0.237E-03 

5.10 

0.2251 

-05 

0. 

-...--:■ 

0 

203! 

.05 

0. 

193F-03 

0.  1(J*-C5 

0.176E.05 

0.165E-03 

0.157E-05 

0.169E-05 

0.162E-05 

5.20 

0.13»! 

.05 

0. 

;•    -:■ 

0 

121! 

.05 

0. 

115E-05 

o.rc9f-:5 

0.103E.03 

0.982E-06 

0.932E>06 

0.(8*E«06 

0.(38E>06 

5.50 

0.7951 

.06 

0. 

r5*E-06 

c 

715E 

.06 

0. 

k7(E-06 

0.6* Jf-06 

0.609E.06 

0.577E-06 

0.5*7£-06 

0.S19E.06 

0.691E-06 

5.*0 

0.666! 

.06 

0. 

k*lt-06 

0 

918! 

.06 

0. 

I96E-06 

0.37SC.06 

0.1S5E.06 

0.336E.06 

0.J18E.06 

0.301E-06 

0.285E.06 

5.50 

e.2701 

.06 

0. 

r55E-06 

0 

262! 

.06 

0. 

J29E-06 

0.216E.06 

0.20SE.06 

0.196E-06 

0.18JE-06 

0.17JE.06 

0.16*E-06 

5.60 

e.i55( 

.06 

0. 

L67E.06 

0 

159E 

.06 

0. 

13  IE. 0  6 

0.126E-06 

0.117E-06 

0.111E.06 

0.106E.06 

0.987E-07 

0.932E.07 

5.70 

O.BIll 

.07 

0. 

U2E-07 

0, 

786E 

.07 

0. 

»*2E-07 

0.701f.07 

0.662E.07 

0.625E-07 

0.590E.07 

0.556E-07 

0.325E.07 

5.50 

-.--'■ 

.07 

0. 

k68£-07 

0 

*• 

.07 

0. 

H6E-07 

0.393f.07 

0.370E-07 

0.369E.07 

0.S29E-07 

0.311E-07 

0.29JE.07 

5.90 

C.276! 

-07 

0. 

160E-07 

0 

265E 

-07 

0. 

f3lE-07 

0.2HE-07 

0.203E.07 

0.K3E-07 

0.K2E-07 

0.172E-07 

0.162E-07 

6.00 

0.15?! 

-07 

0. 

l*SE-07 

0 

1S5E 

.07 

0. 

127E-07 

0.120F-07 

0.11SE-07 

0.106E-07 

0.998E-08 

0.939E-08 

0.((*E«08 

6.10 

:.•-'- 

.08 

0. 

»8?E-08 

0, 

7J6( 

.08 

0. 

b92E-08 

0.631E.Q8 

0.612E-08 

0.576E-08 

0.561E-08 

0.509E-06 

0.678E-08 

6.?0 

:.."■ 

.0| 

0. 

k2SE«08 

0 

S97E 

-08 

0. 

I7SE-08 

0.53lE-0( 

0.529E.0( 

0.309E.08 

0.291E-0J 

0.273E-0B 

0.2S6E-OS 

6.30 

0.2*  l  ( 

-Og 

0. 

J26E-0B 

0, 

212E 

.08 

0. 

199E-08 

0.187E-08 

0.175E-0( 

0.165E.08 

0.156E-0( 

0.165E-08 

0.136E.08 

6.»0 

c. i2a* 

-08 

0. 

120E-08 

0, 

H2E 

.08 

0. 

I05r.08 

0.987r.09 

0.925£.09 

O.B67E-09 

0.(15E-09 

0.762E-09 

0.7UE-09 

6.50 

0.669( 

-09 

0. 

•  27r-09 

0 

»B7( 

.09 

0. 

ISO*. 09 

0.516r-09 

0.6ME-09 

0.632E-09 

0.*2*E-09 

0.J97f.09 

0.371E-09 

6.6C 

O.S6({ 

.09 

0. 

I25E.09 

0 

»" 

.09 

0. 

M5E-09 

0.267E.09 

0.230E.09 

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253 


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5 

2 

10° 

s 

2 

a 

C  u        2 

Q    SO'2 


K) 


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10 


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Figure  4.10-5 


Values  of  ^r  for  a  Ground  Level  Source 


254 


K>" 


10 


C  u 

Q 


C 


K) 


-5 


H  • 

10  m 

Y^\ 

<m     ■ 



y 

"           k     .          L 

V  ^ 

k     ^ 

/    \    V  i\      \ 

k     \ 

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1 

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10' 


10- 


2      5 

m  (m«tefi) 


10' 


10" 


Figure  4.10-6 


Values  of  -If-  for  H  =  10  meters 
1  meter  =  39.37  inches 


255 


10 


10 


C  u 
Q 


-4 


K> 


-5 


10 


-6 


I 

H   -30  m 

1    /    \ 

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s 

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1  i 

A 

10' 


io- 


2  5 

/(meters) 


10' 


10: 


Figure  4.10-7 
Values  of  -^  for  H  =  30  meters 
1  meter  =  39.37  inches 


256 


10 


-4 


to 


-5 


C  u 

Q 


♦0 


K) 


-7 


— , ,_ 



*$V\ 

H- 

100  m 

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2  5 


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Figure     4.10-8 
Values  of  ^  for  H  =   100  meters 
1  meter  =  39.37  inches 


257 


Table  4.10-3 


2    2 
Values  of  Exp  (y  /2a  )  for  y/o 


y/ay 

exp  (y2/2oy2) 

0 

1.00 

0.1 

1.01 

0.2 

1.02 

0.3 

1.05 

0.4 

1.08 

0.5 

1.13 

0.6 

1.20 

0.7 

1.28 

0.8 

1.38 

0.9 

1.50 

1.0 

1.65 

1.2 

2.05 

1.4 

2.66 

1.5 

3.08 

1.6 

3.60 

1.8 

5.05 

2.0 

7.39 

2.15 

10 

3.04 

10? 

3.72 

103 

4.29 

104 

4.80 

105 

258 


It  may  be  of  interest  in  a  given  application  to  plot  the 
position  of  the  centerline  of  the  plume  and  to  determine  areas 
covered  by  concentrations  greater  than  a  given  magnitude.  First 
the  axial  position  of  the  plume  must  be  known.  The  mean  wind 
direction  will  determine  the  position.  The  surface  wind  may  be 
used  up  to  1  km.  Between  1  km  and  100  km,  the  average  of  the 
surface  direction  and  the  geostrophic  direction  backed  (counter- 
clockwise change  in  direction)  by  10  will  give  a  close  approxi- 
mation. The  wind  direction  should  be  a  mean  through  the  vertical 
extent  of  the  plume  (about  2  a). 


easi 

c   ) 

cent 

off- 

corr 

3)  a 

4.10 

the 

thes 

draw 

assu 

If  t 

over 

the 

wi  dt 

the 


In  order  to  draw  lines  of  equal  concentration,  it  pis 
est  to  locate  the  centerline  concentration,  that  is  exp  (y  /  2 

times  the  concentration  desired,  on  a  log/log  plot  of 
erline  concentrations  against  distance.  The  value  of  y  (the 
axis  distance),  can  then  be  found  by  knowing  the  y/°v  value 
esponding  to  the  appropriate  exp  (y  /2  a  )  (See  TablTa  4.10- 
nd  the  value  of  for  this  particular  distance  (from  Figure 
-4).  The  position  corresponding  to  the  downwind  distance  and 
off-axis  distance  can  then  be  plotted.  After  a  number  of 
e  points  have  been  plotted,  the  concentration  isopleth  may  be 
n  and  the  area  determined  by  using  a  planimeter.  This 
mes  that  the  plume  has  a  Gaussian  distribution  across  wind, 
here  is  a  systematic  veering  or  backing  of  the  wind  direction 

a  range  that  is  large  compared  to  the  width  of  the  trace, 
plume  may  be  assumed  to  be  uniform  in  distribution  across  the 
h  (4.3  o  )  of  the  plume  and  the  concentration  will  be  0.58  of 
calculated  centerline  concentration. 


Areas  Within  Concentration  Isopleths 

Figure  4.10-9  gives  areas  within  ground-level  concentra- 
tion isopleths  in  terms  of  Cu/Q  for  a  ground-level  source  for 
various  stability  categories  (Hilsmeier  and  Gifford,  1962). 


Rapid  Determination  of  Maximum  Concentration 

The  maximum  concentration  of  pollutants  will  occur  along 
the  centerline  of  the  plume  where  y  is  zero,  as  indicated  in 
equation  4.10-7  above.  The  distance  downwind,  at  which  the 
maximum  concentration  occurs  at  ground  level,  is  a  function  of 
effective  source  height  and  stability.  Figure  4.10-10  is  a 
nomogram  from  which  the  relative  value  of  the  maximum  concentra- 
tion can  be  determined  given  the  stability  and  effective  source 
height.  If  the  relative  value  of  that  concentration  is  multi- 
plied by  Q/u  ,  the  maximum  concentration  for  a  specific  set  of 
conditions  is  obtained.  The  nomogram  is  designed  for  source 
strength  expressed  in  grams/sec  and  wind  speed  in  meters/sec. 


Accuracy  of  Computations 

The  method  will,  in  general,  give 
estimates  of  concentrations,  especially  if 
measurements  are  not  available  and  estimates 


only  approximate 

wind  fluctuation 

of  dispersion  are 


259 


I/Ill 

i 

m           i 

J 

J          t 

J             *            £ 

r 

f        f 

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/ 

J    / 

r    I    * 

/ 

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f  /     / 

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t                J 

1  I 

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/ 

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/      / 

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u. 

UJ          o 

U           CD 

< 

9> 
O 


CD 
O 


o 


O 


o 


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(2w)  v3av 


Figure  4.10-9 
Area  Within  Ground  Level  Concentration  Isopleths  for 
Values  of  Cu/Q  and  Atmospheric  Stability 


I 
O 


in 


CM 


ro 
I 
O 


\r> 


cm      —- 


i 
o 


If) 


CM 


I 
O 


to 


CM 


ID 


O 


260 


Distance  in  meters  from  source  to  maximum 
ground  level  concentration 


o 

1 — I 

o 


CD 


CD 


5- 
O 


OO 

c 
o 


TO 

C  OO 

CD  CD 

U  00 

C  CO 

O  (T 

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s:  jo 

ro 

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(0 


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rO 


CD 
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CD 


CD  CD 

C£  U 
5- 

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C  O 

TO  0O 

CD  to 

O  3 

S-  O 

13  -r- 

O  S- 


o 


CD 

o 
e 
ro 
+-> 

Q 


00 

CU 


U 

c 


1-^ 


CI 
00 


S- 
CD 

CD 


261 


obt ai  n 
stabl e 
travel 
within 
tances 
neut ra 
ki 1 ome 
above 
10  km 
genera 
i  n  d  e  f  i 
the  pi 
al lowe 
of  sta 
km  cal 
by  an 
c  o  n  d  i  t 
of  5  o 


ed  from  Figures  4.10-3  and  4.10-4.    In  the  unstable  and 

cases,  errors  of   a   of  several  fold  may  occur  for  longer 

distances.   There  are    cases  where  o   may  be  expected  to  be 

a  factor  of  2.   These  are:  1)  alf  stabilities  for  dis- 

of  travel  of  a  few  hundred  meters  in  open  country;  2) 

1  to  moderately  unstable  conditions  for  distances  of  a  few 

ters;  and  3)  unstable  conditions  in  the  first  1000  meters 

ground  with  a  marked  inversion  thereafter  for  distances  of 


a 


yr 


are  l  n 


or  more.  Uncertainties  in  the  estimates  of 
1  less  than  those  of  az  except  when  the  wind  "field  is 
nite.  In  this  case,  the  estimate  of  concentrations  from 
ume  would  be  the  same  except  that  a  wind  range  should  be 
d  for  the  direction  of  the  plume,  up  to  360  .  For  extremes 
ble  and  unstable  conditions  at  distances  between  50  and  100 
culated  concentrations  may  differ  from  true  concentrations 

order  of  magnitude.    For  these  distances,  under  neutral 


ions,  calculated  concentrations  should  be  within  a 
f  true  concentrations. 


factor 


EXERCISES  WITH  DIFFUSION  PARAMETERS 


1.  What  stability  category  would  be  most  likely  to  occur  when 
the  wind  is  6  -  8  m/sec?  (D) 

2.  If  the  sky  is  overcast  -  synonymous  with  cloudy  -  what  would 
the  stability  category  most  likely  be?  (D) 

3.  What  would  the  stability  category  most  likely  be  on  a  sunny 
April  afternoon  when  the  wind  is  3  m/sec?  (A  or  B) 

4.  If  the  surface  wind  at  night  is  3  m/second  there  is  5/8 
coverage  of  low  clouds,  what  is  the  most  likely  stability 
category?  (D  or  E) 

5.  What  are  o  and  a  at  150  m  from  a  source  under  B  stability? 
(oy  =  2  7.5 nt ,  az  =  15.5m) 

6.  How  much  difference  is  there  in  az  at  5  km  under  D  and  F 
stability?  (55m) 

7.  What  is  the  value  of  a   at  30  km  under  C  stability?  (2200m) 

8.  At  300  m  how  many  times  larger  is  cy  under  B  stability  than 
under  D  stabi 1 i ty?  (2.4) 

9.-  Under  E  stability  how  much  greater  is  the  horizontal  disper- 
sion factor  than  the  vertical  dispersion  factor  at  300m? 
(7.7) 

10.  If  the  value  of  H/  a  is  1.8,  what  is  the  value  of  exp  - 
-  1/2  (H/o2)2?  (1.6) 

11.  The  value  of  exp  -  l/2(H/o  )2  is  2.2  x  10"3.  What  is  H/ o  ? 
(3.49)  z  z 


262 


12.  Under  D  stability  and  a  wind  speed  of  5  m/sec,  a  plume  is 
emitted  at  100  m  above  the  ground.  What  is  the  value  of  C/Q 
at  4  km?   fi      7 

(1.4  x  10"°  sec/m"3) 

13.  What  is^the^area  enclosed  by  an  isopleth  whose  Cu/Q-value  is 
4  x  10'   m   ,  when  the  stability  category  is  B?  (10  m) 

I  EXAMPLE  DIFFUSION  COMPUTATIONS 


#1  A  power  plant  burns  10  tons  per  hour  of  3%  sulfur  coal, 
releasing  the  effluent  from  a  single  stack.  On  a  sunny  summer 
afternoon,  the  wind  speed  at  10  meters  is  4  m/sec  from  the  north- 
east. The  morning  radiosonde  run  in  the  vicinity  has  indicated 
that  a  frontal  inversion  aloft  will  limit  the  convection  to  1500 
meters.  The  1200  meter  wind  is  from  30°  at  5  m/sec.  The  effec- 
tive height  of  emission  is  150  meters.  What  is  the  maximum 
concentration  and  where  does  it  occur? 


Solution:   On  a  sunny,  summer  afternoon  the  insolation 

should  be  strong.    From  Table  4.10-1,  strong  isolation  and  4 

m/sec  wind  yields  class  B  stability.   The  amount  of  sulfur  burned 
i  s  : 


Sulfur  = 


10  tons 
hour 


2000  lbs 


ton 


0.03  sulfur  =  600  lbs/hr 


Sulfur  has  a  molecular  weight 
molecular  weight  of  32; 
burned,  there  results  two 


Q  = 


2  SO 


2 


of  32  and  combines  with  0~ 
therefore,  for  e\/ery  pound  of 
pounds  of  SO 


600  lbs.  S 


hr. 


2* 
453.6  gms/1 b. 

3600  sec/hr 


with  a 
sul fur 


=  151  gms.  SO  /sec. 


The  maximum  concentration  may  be  found  by  using  Figure 
4.10-10.   Given  stability  class  B  and  effective  source  height  of 
one  may  enter  the  nomogram  and  read  the  Cu/Q  value  of  8  x 


150  m 

10    from  the 
usi  ng 


abscissa, 
the  wind 
strength,  Q,  of  151  gms 


(max) 


=  8  x  10 


Solving  for  the  maximum  concentration,  C 
speed,  u,  of  4  m/sec  and  the  source 
SOp/sec  yields. 


151  qms/sec  =  3  x 
4  m/sec 


10 


-4 


gm/rrf 


The  distance  from  the  power  plant  at  which  the  maximum 

concentration  occurs  under  these  meteorological  conditions  can  be 

read  from  the  ordinate  in  Figure  4.10-10.  This  distance  is 
1000m. 


263 


#2  Using  the  conditions  in  the  above  problem,  draw  a  graph 
of  centerline  sulfur  dioxide  concentrations  beneath  the  plume 
with  distance  from  100  meters  to  100  km. 


vection  to 
700  meters 
2  x,  =  11.0 
usea  to  find 


Sol ut i  on :   Since  the  frontal  inversion  limits  the  con- 
=  1500  meters,  the  distance  where   o   =  0.47  h,  = 
5.5  km.   At  distances  equal  to  orz greater  tnan 
j  =  0.8  hl    =  1200  meters.   Equation  4.10-7  is 
concentration  as  a  function  of  distance. 


."1 

1  s  X-, 

km , 


C  = 


151 


tt  u  a 


exp 


In  this  case  H  =  150  meters.  Solutions  for  this  equa- 
tion are  given  in  Table  4.10-4.  The  values  of  concentrations  in 
Table  4.10-4  are  plotted  against  distance  in  Figure  4.10-11. 


#3  Draw  a  graph  of  concentration  versus  cross-wind  distance 
at  a  downwind  distance  of  800  meters  for  the  conditions  of  prob- 
1  ems  1  and  2 . 


Solution:  From  probJem  2,  -,the  centerline  concentration 
at  800  meters  is  2.9  X  10"  gms/m  .  To  determine  the  concen- 
trations at  distances  y  from  the  x  axis,  the  centerl i ne  Oconcen- 

oy  = 


X  aXIS,  UIIC  bCIUCI       I       I     ME       ry 

tration  must  be  multiplied  by  the  factor  exp  -l/2(y/aM) 


120  meters  at 
gi  ven  in  Table 


x  =  800 
4.10-5. 


meters.   Values  for  this  computation  are 


The  preceeding  exercises  illustrate  one  of  the  simplest 
approaches  to  air  quality  modeling.  Numerous  levels  of  sophis- 
tication can  be  incorporated  into  the  basic  Gaussian  modeling 
approach  to  determine  pollution  concentrations  at  downwind  recep- 
tor locations.  As  mentioned  before,  the  next  level  incorporates 
mathematical  simulations  of  plume  rise.  Plume  rise  is  mainly  a 
function  of  momentum  and  thermal  buoyancy.  Terms  related  to  one 
or  both  of  these  factors  are  included  in  nearly  all  plume  rise 
formulas.  For  cold  stacks  (JETS),  those  with  emissions  of  less 
than  10  to  20  F  above  ambient,  momentum  is  probably  the  most 
important  factor.  On  the  other  hand,  for  hot  stacks,  when  gases 
are  warmer  than  200  F,  buoyancy  is  the  most  important  aspect  of 
the  plume  rise  formula.  Numerous  plume  rise  formulas  have  been 
proposed  by  a  multitude  of  qualified  investigators.  No  one 
formula  provides  the  best  estimate  for  all  types  of  stacks  and 
atmospheric  conditions.  The  most  widely  accepted  plume  rise 
formulas  were  derived  by  Holland  (1953)  and  Briggs  (1969).  The 
basics  of  their  plume  rise  simulation  formulae  are  applied  by 
most  Environmental  Protection  Agency  (EPA)  accepted  air  quality 
model s  . 


264 


Table  4.10-4 
Solutions  for  Problem  #2 


Col. 

Col. 

Col. 

Col. 

Col. 

Col. 

Col. 

a 

b 

c 

d 

e 

f 

g 

X 

(km) 

u 

(m/sec) 

y 

m 

a 
z 

m 

z 

-  -  <€> 

C 

gms  /m 

0.  3 

4 

52 

30 

5.0 

-6 
3     X  10 

2. 3    x  io"8 

0.  5 

4 

77 

53 

2.83 

_9 

1.7     X  10   " 

5.0     X  io" 

0.8 

4 

120 

93 

1.61 

0.27 

2.9     X  10 

1 

4 

150 

125 

1.20 

0.48 

3.  1     X  IO"4 

2.8 

4.5 

375 

700 

0.21 

0.98 

4.0     X  10_: 

5.6 

4.  5 

700 

1200 

0.  125 

0.98 

1.25  X  io"5 

10 

4.5 

1200 

1200 

0.  125 

0.98 

7.3     X  IO"6 

100 

4.5 

8400 

1200 

0.  125 

0.98 

1.04  X  10'6 

Col.  c  from  Figure  4.10-4 

Col.  d  from  Figure  4.10-3 

Col.  e  150  m  over  value  in  Col.  d 

Col.  f  Value  in  Table  4.10-2  corresponding  to  H/oz  in  Col.  e 

Col.  g  Solution  to  equation  4.10-7 


Table  4.10-5 


y 

(m) 

y/a 

y 

exp  -  {  (y/a    ) 

C(y) 

gms  /m 

+  1C0 

0.  834 

0.7 

2.03  X  IO*4 

+  200 

1.67 

0.  25 

7.25  X  io'5 

+  300 

2.  5 

4. 2     X  10 

1.22  X  jo 

+  400 

3.  33 

3.  7     X  io""3 

c 

1.  07  X   ]0" 

This  is  graphed  in  Figure  4.10-12 


265 


1  m  =  3.281  feet 

1  km  =  0.6214  miles 

1  m/s  =  3.281  feet/second 

1  gm/m3  =  6.243x10-7  lbs/feet3 


10 


10" 


■3 


Concentration 

so2 

gm»  /m 


10 


io- 


.5 


10 


-7 


10' 


-+ 

, 

rz=a 



- 

- 

- 

, 

- 

_ 

c= 

■ 

V- 

— 

., 

^ 

4- 

: 

-  T—  *d.~ 



1  , 

V 

^^ 

— p- 

\ 

- 

._ 

- 

. 

1  1  . 

1 

- 

-h 

I 

'  1  "' 

. 

-H 

-  ". 



T^ 

1 

\- 

• 

i 

-- 

— 



i 

0   1 


10 


Di»t»nce  (Km    ) 


100 


Figure  4.10-11 
3 
Concentration  of  S0o  (gms/m  )  as  a  Function  of  Distance 

(km). (Problem  2) 


1  gm/   3  =  6.243  x   10"7  lbs/ft3 
3     m 

1  km  =  0.6214  mi 


2  x  10"1 

sc2 

Concentration 
gm/m 


io- 


10 


.5 


-400      -300     -200     -100  0  100        200        J00       400 

y   Di»t»nce  (  Mete  r  •  ) 


Figure  4.9-12 
Concentration  of  S02  (gms/m3)  Across  Wind  at  a  Distance  of  800  Meters 


(Problem  3) 


266 


1  gm/  3  =  6.243  x  10"7  lbs/ft3 
3  m 

1  m  =  1.094  yds 


Briggs  in  his  recent  publication,  PI ume  Ri  se  (1969),  has 
presented  both  a  critical  review  of  the  subject  and  a  series  of 
equations  applicable  to  a  wide  range  of  atmospheric  and  emission 
conditions.  These  equations  are  being  employed  by  an  increasing 
number  of  meteorologists  and  are  used  almost  exclusively  within 
EPA.  An  important  result  of  this  study  is  that  the  rise  of 
buoyant  plumes  from  f  ossi  1 -?-f  uel  plants  with  a  heat  emission  of  20 
me-gawatts  (MW)  -  4.7  x  10  cal/sec  -  or  more  can  be  calculated 
from  the  following  equations  under  neutral  and  unstable  condi- 
t i  ons . 


where  : 


AH 


AH 


1.6  F 


1  .6  F 


1/3 


1 


2/3 


1/3   -1 


(10 


hs) 


2/3 


4.  10-8 


4.  10-9 


H  =  plume  rise 

F  =  buoyancy  flux 

u  =  average  wind  at  stack  level 

x  =  horizontal  distance  downwind 

_  =  physical  stack  height 


of  the  stack 


Equation  4.10-8  should  be  applied  out  to  a  distance  of 
10  h  from  the  stack  and  equation  4.10-9  can  be  used  for  greater 
distances. 

The  buoyancy  flux  term,  F,  may  be  calculated  from: 


F  = 


g  Q 


-  c  p  pT 


-  3.7  x  10 


4.   3 
m  /sec 

cal/sec 


4.10-10 


where 


g 

Qh 

c 

p 

T 


gravitational  acceleration 

heat  emission  from  the  stack,  cal/sec 

specific  heat  of  air  at  constant  pressure 

average  density  of  ambient  air 

average  temperature  of  ambient  air 


:  Alternatively,  if  the  stack  gases  have  nearly  the  same 
specific  heat  and  molecular  weight  as  air,  the  buoyancy  flux  may 
be  determi  ned  from : 


F  = 


A  T 


4.10-11 


Notation  has  been  previously  defined. 

267 


In  stable  stratification, 
a  di  stan 
stabi 1 i  ty  parameter : 


_e,q ua tion  4.10-8  holds  approxi- 
mately to  a  distance  x  =  2.4  us  "  '  .   S  may  be  defined  as  a 


s  =  S. 
T 


d  e 


3  Z 


4.10-12 


where 


3  9 

9  z 


;  lapse  rate  of  potential  temperature 

eyond  this  point  the  plume  levels  off  at  about 

c       \   1/3 


A  H  =  2.4 


4.10-13 


u  s 


However,     if    the    wind     is     so     light    that    the    plume    rises 
vertically,    the    final    rise    can    be    calculated    from: 


AH    =    5.0    F1/4    s"3/8 


4.10-14 


For  other  buoyant  sources,  emitting  less  than  20  MW  of 
heat,  a  conservative  estimate  will  be  given  by  equation  4.10-8  up 
to  a  di  stance  of : 


x  =  3x' 


4.10-15 


where  : 


=  0.52 


sec 


ft 


6/5  1 


6/5 


p2/5  h  3/5= 


4.10-16 


which  is  the  distance  at  which  atmospheric  turbulence  begins  to 
dominate  entrainment. 

Sophisticated  modeling  more  complex  than  the  simple 
Gaussian  are  often  required.  These  sophisticated  algorithms 
applied  to  the  basic  Gaussian  approach  include  the  computation  of 
downwind  ground  level  concentrations  as  a  function  of  stability 
class  and  wind  speed.  Such  an  approach  would  incorporate  wind 
speeds  as  a  function  of  stability  class.  Further  sophistication 
in  the  Gaussian  modeling  approach  would  incorporate  relative 
frequency  distributions  of  wind  speeds,  wind  direction  and  sta- 
bility class.  This  type  of  model  would  be  useful  in  isolating 
long-term  air  pollution  concentrations  in  the  study  area. 


There  is  a 
with  regard  to  the 
of  each  generation 


limitless  number  of  levels  of  sophistication 

Gaussian  model.   The  accuracy  and  refinement 

of  the  model  depends  upon  the  quality  and 


268 


resolution  of  the  data  base  used.  As  the  problem  becomes  more 
complex,  more  sophisticated  numerical  models  must  be  employed 
particularly  in  instances  where  terrain  or  conversion  effects 
become  important.  Such  modeling  is  beyond  the  scope  of  this 
document,  however  the  EPA  may  be  contacted  for  more  information 
on  dispersion  models  such  as  the  CI imatol og i cal  Dispersion  Model 
(CDM),  the  Air  Quality  Display  Model  (AQDM) ,  the  Valley  Model, 
and  the  Texas  CI imatol og i cal  Model  (TCM). 


269 


4.11      ASSISTANCE  IN  DISPERSION  METEOROLOGICAL  PROBLEMS 
References 
t   Abstracts 


Meteorological  and  Geoast rophysi cal  Abstracts 
American  Meteorological  Society 
45  Beacon  Street 
Boston  8,  Mass. 

Peri  od  i  cal s 

Bulletin  of  the  American  Meteorological  Society 
American  Meteorological  Society  (See  above) 

Journal  of  Applied  Meteorology 

American  Meteorological  Society 

Journal  of  the  Atmospheric  Sciences  (formerly 
Journal  of  Meteorology) 

American  Meteorological  Society 

Monthly  Weather  Review 

U.S.  Dept.  of  Commerce 

Weather  Bureau,  Washington,  D.C. 


Quarterly  Journal  of  the  Royal  Meteorological 
Soci  ety 

Royal  Meteorological  Society 

49  Cromwel 1  Road 

London  ,  S. W.  7 

•   Books 

American  Meteorological  Society,  On  Atmospher i  c 
Pollution, 

Meteorological  Monographs,  1,  4,  Nov.  1951. 

Geiger,  R.  (Transplanted  by  Scripta  Technica  Inc.) 
The  Climate  Near  the  Ground. 

Rev.  ed.,  Harvard  University  Press 

Cambridge,  Mass.   1965. 

Professional  Meteorological  Consultants 

Professional  meteorologists  advertise  their  services  in 
the  Professional  Directory  section  of  the  Bulletin  of  the  Ameri- 
can Meteorological  Society.  In  the  May  1979  Bulletin,  83  such 
firms  and  individuals  were  listed.  The  American  Meteorological 
Society  has  in  the  last  several  years  instituted  a  program  of 


270 


certifying  consulting  meteorologists, 
services  listings  in  the  Bulletin,  40 
Meteorologists. 


Of  the  83  professional 
list  Certified  Consulting 


Local  U.S.  National  Weather  Service  Office 

A  wealth  of  meteorological  information  and  experience  is 
available  at  the  local  city  or  airport  Weather  Service  Office 
pertaining  to  local  climatology,  pecularities  in  local  micro- 
meteorological  conditions  including  topographic  effects,  and 
exposure  and  operating  characteristics  of  meteorological  instru- 
ments. The  Air  Stagnation  Advisories  are  received  here  by  tele- 
type from  the  National  Meteorological  Center.  Often  the  public 
telephones  the  Weather  Service  with  air  pollution  complaints 
which  the  meteorologists  may  have  traced  back  to  a  specific 
source  by  examining  local  wind  circulations.  Through  personal 
contact  with  the  meteorol og i st- i n-charge  (MIC),  specific,  local- 
ized forecasts  may  be  arranged  to  support  a  short-term  air  pol- 
lution investigation  or  sampling  program. 

Contract  Work 

Many  universities  do  contract  work  for  private  organi- 
zations and  for  government  agencies  on  meteorological  problems. 


271 


4.12 


GLOSSARY  OF  TERMS 


Ad  i  abat  i  c 


Ad'i  abat  ic 
Di  agram 


Advect  i  on 
I nversi  on 


Aerodynamic 


Air  Basi  n 


Air  Flow  Pattern 
Air  Parcel 

Al gori  thm 

Backi  ng 


A  thermodynamic  change  of  state  of  a  system  in 
which  there  is  no  transfer  of  heat  or  mass 
across  the  boundaries  of  the  system.  In  an 
adiabatic  process,  compression  always  results 
in  warming,  expansion  in  cooling. 

A  thermodynamic  diagram  with  temperature  as 
abscissa  and  pressure  to  the  power  0.286  as 
ordinate,  increasing  downward. 

A  type  of  inversion  which  occurs  over  an  area 
due  to  the  horizontal  transport  of  a  stable 
layer  (e.g.,  marine  inversion  noted  along 
coastal  California  are  the  result  of  the 
advection  of  cool,  stable  air  from  the  nearby 
Pacific. 

Pertaining  to  forces  acting  upon  any  moving 
solid  or  liquid  body  other  than  a  stationary 
object  relative  to  a  gas  (especially  air). 

An  area  created  by  topographic  boundaries 
which  serves  to  contain  air  pollutants  emitted 
into  the  area  by  pollution  sources  and  to 
restrict  air  exchange  with  other  air  basins. 

The  typical  movement  of  air  currents  as 
graphed  on  wind  roses. 

An  imaginary  body  of  air  to  which  may  be 
assigned  any  or  all  of  the  basic  dynamic  and 
thermodynamic  properties  of  atmospheric  air. 

A  procedure  for  solving  a  problem  (as  in 
mathematics)  that  frequently  involves  repeti- 
tion of  an  operat  i  on  . 

According  to  general  internationally  accepted 
usage,  a  change  in  wind  direction  in  a  coun- 
tercl oc  kwi  se  sense  . 


B  i  m  o  d  a  1 
Black  Body 

Buoyancy  Fl ux 


A  distribution  having  two  maxima. 

A  body  which  absorbs  all  incident  electro- 
magnetic radiation;  i.e.,  one  which  neither 
reflects  nor  transmits  any  incident  radiation. 

An  empirical  term  used  in  plume  rise  calcula- 
tions to  define  the  heat  content  of  an  indus- 
trial source. 


272 


Burn/No-Burn 


Calm 


Centerl ine 
Concentrat  i  on 

Channel i  ng 


Cold  Stacks 
(Jets) 


Condensation 
Level s 


Used  to  determine  when  weather  conditions 
Forecasts  favor  the  rapid  dispersion  of  pollu- 
tants created  by  the  burning  of  agricultural 
wastes  and  other  industrial  operations. 


A  period  when  the 
United  States,  the 
it  has  a  speed  of 
( or  one  knot)  . 


air  is  motionless.   In  the 

wind  is  reported  as  calm  if 

less  than  one  mile  per  hour 


The  concentration  of  gaseous  pollutants  or 
aerosols  at  the  center  of  the  plume. 

The  effect  of  terrain,  particularly  valleys, 
in  modifying  the  prevailing  winds  along  the 
path  of  lowest  terrain  heights. 


Cold,  non-buoyant  sources  with 
peratures  less  than  10  to  20°F 
temperatures  . 


emission  tern- 
above  ambient 


The  1 evel 
1 i  f ted  dry 
rated  . 


at  which  a  parcel   of  moist  air 
adiabatically  would  become  satu- 


Coning 


Constant  Level 
Ball oons 

Convective 
Thundershowers 

Diffusion 


Digitized  Data 


Dispersion 
Model i  ng 


Di  spersion 
Potent i  al 


When  the  vertical  temperature  gradient  is 
between  dry  adiabatic  and  isothermal,  slight 
instability  occurs  with  both  horizontal  and 
vertical  mixing.  An  industrial  plume  tends  to 
become  cone  shaped,  hence  the  name. 


A  ball oon  des  i  gned 
pressure  level  . 

Showers  caused  when 
to  rise  rapidly. 


to  float  at  a  constant 


layers  of  air  are  forced 


In  meteorology,  the  exchange  of  fluid  parcels 
between  regions  in  space,  in  the  apparently 
random  motions  of  a  scale  too  small  to  be 
treated  by  the  equations  of  motion. 

Data  which  is  recorded  in  a  computer  accep- 
table format  (as  opposed  to  analog  or  strip 
chart  dat a) . 

The  mathematical  representation  or  simulation 
of  transport  precesses  that  occur  in  the 
atmosphere . 

The  ability  of  a  system  such  as  the  atmos- 
phere, to  dilute  the  concentration  of  a  sub 
stance  or  pollutant  by  molecular  and  turbulent 
motion;  e.g.,  smoke  in  the  air. 


273 


Di  urnal 


Downwash 


Dra  i  nage  Fl ow 


Dry  Adiabatic 
Rate 


Effective  Stack 


El evated 
Inversion 


Empi  r i  cal 


Daily,  especially  pertaining  to  actions  which 
are  completed  within  twenty-four  hours  and 
which  recur  every  twenty-four  hours. 

The  condition  resulting  when  strong  winds  push 
a  plume  rapidly  to  the  surface,  resulting  in 
high  ground-level  pollution  concentrations. 
The  phenomenon  is  usually  observed  in  the  lee 
of  b  u  i  1  d  i  ngs  . 

The  movement  of  cold  air  off  high  ground, 
caused  by  gravity  and  typical  of  mountainous 
reg  ions  . 

The  rate  of  decrease  of  temperature  with  Lapse 
height  when  dry  air  is  lifted  ad  i  abat  i  cal  1  y 
(due  to  expansion  as  it  is  lifted  to  lower 
pressure) . 

The  physical  stack  height  plus  plume  rise, 
i.e.,  the  point  above  ground  at  which  the 
gaseous  effluent  becomes  esentially  level. 

An  inversion  layer  above  the  immediate  sur- 
face. Such  an  inversion  inhibits  dispersion 
of  bouyant  pollutants,  such  as  those  given  off 
by  power  facilities  and  refineries. 

An  approach  based  upon  observation  and  experi- 
mentation. 


Env  i  ronmental 
Lapse  Rate 

Exit 
Characteristics 


Fann  i  ng 

Fire  Management 
Fire  Weather 

Fluid  Dynamics 


The  actual  rate  of  decrease  of  temperature 
with  elevation  at  at  given  time  and  place. 

Parameters  pertaining  to  a  gas  exiting  from  a 
stack  including  gas  temperature,  exit  veloci- 
ty, emission  rate,  stack  height,  and  stack 
d  i  ameter . 

When  the  atmosphere  is  stabily  stratified,  an 
industrial  plume  will  spread  horizontally  but 
little  if  any  vertically. 

The  practice  of  controlling  range  undergrowth, 
such  as  chapparal,  through  controlled  burning. 

The  state  of  the  weather  with  respect  to  its 
effect  upon  the  kindling  and  spreading  of 
forest  f i  res . 

The  level  of  physics  that  treats  the-  action  of 
force  on  fluids  and  gases  in  motion  or  at 
rest . 


274 


Freezing  Level 


Front 


Frontal 
Inversion 


Fugitive  Dust 


Fug  i  t i  ve  Source 


Fumigation 


Gaussi  an 
Diffusion 
Equat  i  on 

Hori  zontal 
Di  spersi  on 
Coefficient 


Induced    Flow 

Insolation 

Inversion 


Inversion  Layer 


Isopl  eth 


I sothermal 


The  lowest  altitude  in  the  atmosphere  over  a 
given  location  at  which  the  air  temperature  is 
32°F. 

The  transition  zone  between  two  air  masses  of 
different  densities. 

A  temperature  inversion  encountered  in  the 
atmosphere,  upon  vertical  ascent  through  a 
sloping  front. 

Solid  air  borne  particles  emitted  from  any 
source  other  than  a  stack. 

A  source  emitting  pollutants  other  than  from  a 
stack. 

The  rapid  mixing  of  a  fanning  plume  down  to 
the  ground,  such  as  during  inversion  breakup. 

An  equation  used  to  evaluate  the  concentration 
of  gases  or  aerosols  assuming  a  Gaussian  or 
normal  di  str i  but  i  on . 

The   horizontal   standard  deviation  of  plume 

pollutant  concentration.   The  parameter  varies 

as  a  function  of  downwind  distance  and  atmos- 
pheric stability. 

A  flow  of  air  caused  by  uneven  heating  of 
terrain  and  its  associated  air  parcels. 

Solar  radation  received  at  the  earth's  sur- 
face . 

A  departure  from  the  usual  decrease  or  in- 
crease with  altitude  of  the  value  of  an  atmos- 
pheric property  (almost  always  of  tempera- 
ture). In  a  temperature  inversion,  tempera- 
ture increases  with  altitude.  A  temperature 
inversion  is  stable,  allowing  little  turbulent 
exchange  to  occur. 

That  layer  of  air  which  departs  from  the  usual 
decrease  in  temperature  with  increasing 
al t  i  tude . 

A  line  of  equal  or  constant  value  of  a  given 
quantity,  with  respect  to  either  space  or 
time. 

Of  equal  or  constant  temperature,  with  respect 
to  either  space  or  time. 


275 


Jet  (Low-Level ) 

K -Theory 

Land  Breeze 

Lapse  Rate 
Line  Source 

Loft  i  ng 


Loopi  ng 

Mixing  Height/ 
Depth 


Mixing  Layer 


Momentum  Exchange 


Mountain  Flow 


Neutral 
Atmospher i  c 
S  t  a  b  i  1  i  t  y 


Nocturnal  Ai  r 
Fl  ow 


A  high-speed  wind  that  attains  its  velocity 
through  channeling  due  to  terrain  configura- 
tion such  as  a  narrow  mountain  pass  or  canyon. 

K-theory  or  gradient  transport  theory  assumes 
that  turbulent  diffusion  is  proportional  to 
the  local  mean  concentration  gradient. 

A  coastal  breeze  blowing  from  land  to  sea, 
caused  by  the  temperature  difference  when  the 
sea  surface  is  warmer  than  the  adjacent  land. 

The  decrease  of  an  atmospheric  variable  (al- 
most always  temperature)  with  height. 

A  source  of  pollutants  occurring  at  a  reason- 
ably continuous  rate  along  a  fixed  line  (e.g., 
h  i  ghway ) . 

Lofting  of  an  industrial  plume  occurs  when 
there  is  a  superadiabatice  layer  above  a 
surface  inversion.  It  is  a  condition  which 
encourages  diffusion  upward  but  not  downward 
because  of  the  presence  of  a  stable  layer 
bel ow. 

The  looping  of  an  industrial  plume  occurs  with 
a  superad i abat i c  lapse  rate. 

Height  (Depth)  of  the  layer  of  air  where  well- 
mixed  conditions  exist,  usually  the  height  of 
the  first  significant  inversion  above  the 
surface . 

That  thin  layer  of  the  troposphere  available 
for  the  dispersion  of  pollutants  released  near 
the  surface  . 

The  turbulent  transfer  of  momentum;  the  pro- 
duct of  mass  and  velocity. 

The  regular  flow  of  air  around  portions  of 
raised  terrain.  Air  will  stream  toward  and  up 
mountain  slopes  during  the  day  and  downward 
and  away  during  the  night. 

Neutral  stratification  of  the  atmosphere, 
i.e.,  the  lapse  rate  is  equal  to  the  dry- 
adiabatic  lapse  rate,  therefore,  a  parcel  of 
air  displaced  vertically  will  experience  no 
buoyant  acceleration. 

A  flow  pattern  characteristic  of  clear  nights 
and  rapid  radiational  cooling,  which  tends  to 
stabilize  the  atmosphere  promoting  air  flow 
from  higher  terrain  towards  low  lying  areas. 


276 


Nucleation 

Numeri  cal 
Model i  ng 

Orographic 

Pasqui 1  1  '  s 

Stability 

Categories 


The  condensation  out  of  molecules  on  airborne 
part  i  cl es  . 

The  development  of  a  means  of  computing  the 
future  state  of  the  atmosphere  from  the  basic 
theoretical  equations  which  govern  that  state. 

Of,  pertaining  to,  or  caused  by  mountains. 

Stability  classes  as  defined  by  Dr.  F.  Pas- 
quill  of  the  British  Meteorological  Service, 
including  extremely  unstable,  unstable, 
slightly  unstable,  neutral,  slightly  stable, 
and  st abl e  . 


Persistence 


Time  period  over  which  a  certain  parameter  is 
mai  ntai  ned . 


Phys  i  cal 
Model i ng 


Physical  modeling  is  based  uopon  the  actual 
simulation  of  events  in  the  real  atmosphere  or 
in  a  seal e  model  . 


Physical  Stack 
Height 

PI  ume 


PI ume  Rise 


Positive  Net 
Radiation 

Prevail i  ng 
Wind(s) 

Prof i 1 e 


Pseudo-Adiabatic 
Lapse  Rate 


Radi  at i  onal 
Cool i  n  g 


Actual  height  of  a  stack,  i.e.,  a  pollutant 
source . 

A  large,  conspicuous  cloud  of  smoke,  dust,  or 
water  vapor  arising  from  a  stack. 

The  velocity  and  heat  of  an  industrial  source 
will  cause  it  to  rise  to  a  certain  height. 
The  difference  between  this  height  and  the 
physical  stack  height  is  called  plume  rise. 

Amount  of  incoming  solar  radiation  in  excess 
of  outgoing  terrestrial  radiation. 

The  wind  direction(s)  most  frequently  observed 
during  a  given  period. 

A  graph  of  the  value  of  a  scalar  quantity 
(such  as  temperature)  versus  a  horizontal, 
vertical,  or  time  scale. 

The  rate  of  decrease  of  temperature  with 
height  of  an  air  parcel  lifted  at  saturation 
through  the  atmosphere.  Less  than  the  dry 
adiabatic  lapse  rate. 

Cooling  of  the  earth's  surface  and  surrounding 
air  accomplished  (mainly  at  night)  whenever 
the  earth's  surface  experiences  a  net  loss  of 
heat . 


Rad  i  at  i  onal 
I nversi  on 


An  inversion  at  the  surface  due  to  radiation 
cool i  ng. 


277 


Radiosonde 
Re-entrainment 

Regime 

» 

Screening  Level 

Sky  Cover 
SI  ope  Winds 


Smoke  Sensitive 
Area 


Sol ar  Al ti  tude 
Sol ar  Insolation 
Sorpt  i  on 
Sounding 

Stability 
Stabl e 


STAR  (STability 
ARray) 


A  balloon-borne  instrument  used  for  measuring 
and  transmitting  weather  data,  such  as  pres- 
sure, temperature  and  humidity. 

The  mxing  of  environmental  air  into  an  organ- 
ized air  current  of  which  it  formally  was  a 
member . 

The  character  of  the  seasonal  distribution  of 
a  weather  phenomenon  at  any  place;  e.g.,  the 
summer  sea  breeze  regime. 

A  simplistic  approach  designed  to  determine 
the  need  for  additional,  more  detailed  ana- 
lyses . 

The  amount  of  sky  covered  or  concealed  by 
clouds  or  other  obscuring  phenomena. 

Winds  caused  by  uneven  surface  heating  and 
cooling  in  areas  of  rugged  terrain. 

An  area  which,  due  to  high  population  density, 
recreational  value  or  scenic  beauty,  is  con 
sidered  particularly  sensitive  to  smoke  plumes 
from  forest  management  burning. 

The  elevation  angle  of  the  sun  above  the 
hori  zon  . 

Solar  radiation  received  at  the  earth's  sur- 
face . 

The  deposition  of  molecules  due  to  collision 
with  an  obj  ect  . 

Any  penetration  of  the  natural  environment  for 
scientific  observation.  In  meteorology,  com- 
monly refers  to  the  environmental  lapse  rate. 

A  measure  of  the  extent  to  which  vertical  and 
horizontal  mixing  will  take  place.  Commonly 
measured  as  unstable,  neutral  or  stable. 

The  lapse  rate  is  less  than  the  dry  adiabatic 
lapse  rate  and  vertical  motion  is  suppressed. 

A  description  of  a  type  of  meteorlogical 
program  developed  by  the  National  Climatic 
Center  in  Asheville,  North  Carolina.  The 
program  provides  joint  frequency  d  i  s-t  r  i  but  i  on  s 
of  wind  speed,  wind  direction,  and  atmospheric 
stabi 1 i  ty  class. 


278 


Stability  Wind 
Roses 


Stack 


Statistical 
Model i  ng 


Sub-Ad iabatic 


Subsidence 
I nver si  on 


Super-Ad iabatic 


Surface  Based 
I nversi  on 


Surface  Boundary 
Layer 

Surface  Data 


Surface  Roughness 


Synoptic  Scale 
Winds 


Temperature 
Prof i 1 e 

Temperature 
Soundi  ng 

Thermal  Buoyancy 


Diagrams  designed  to  show  the  distribution  of 
wind  direction  experienced  at  a  given  location 
over  a  desired  time  period  for  a  given  atmos- 
pheric stability  class. 

Any  chimney,  flue,  conduit,  or  duct  arranged 
to  conduct  emissions  to  the  outside  air. 

Statistical  modeling  is  based  upon  the  sto- 
chastic nature  of  turbulence  and  describes 
diffusion  as  an  ensemble  average  of  many 
particles  emitted  from  a  source. 

A  lapse  rate  which  is  less  than  the  dry  adia- 
batic  lapse  rate  (5.5°F  per  1,000  feet). 

A  temperature  inversion  produced  by  the 
warming  of  a  layer  of  descending  air.  The 
effect  is  the  creation  of  a  limited  mixing 
volume  below  the  stable  layer. 

A  lapse  rate  which  is  greater  than  the  dry 
ad iabatic  lapse  rate. 

An  inversion  layer  of  stable  air  close  to  the 
ground.  Such  an  inversion  inhibits  dispersion 
of  fugitive  dust  and  other  non-buoyant  sources 
of  pol 1 utants  . 

The  thin  layer  of  air  immediately  adjacent  to 
the  eart  h ' s  surface . 

Observations  of  the  weather  from  a  point  at 
the  surface  of  the  earth,  as  opposed  to  upper- 
air  or  winds-aloft  observations. 

Irregulatities  of  the  earth's  surface  (pro- 
vided by  trees,  buildings,  etc.)  which  in- 
creases air  turbidity,  and  consequently, 
pollutant  dispersion. 

Strong  winds  created  by  weather  patterns  of 
high  and  low  pressure  systems  in  the  lower 
troposphere  . 

A  graph  of  temperature  versus  a  horizontal, 
vertical,  or  time  scale. 

Upper-air  observations  of  temperature  as  taken 
by  a  radiosonde. 

The  impetus  provided  by  heat  for  an  emission 
to  rise  or  remain  suspended  in  the  atmosphere. 


279 


Thermal  Low 


Trans  port 


Trappi  ng 


Tra j  ectory 
Anal yses 


Tropopause 
Troposphere 


Typi  cal 
Conditions 


Unstabl e 

Val 1 ey  Wi  nds 
Veering 
Vent  i 1  ate 


Vert  i  cal 
Ci  re ul at i  on 


An  area  of  low  atmospheric  pressure  due  to 
high  temperatures  caused  by  intensive  heating 
at  the  earth's  surface. 

The  rate  by  which  a  substance  or  quantity, 
such  as  heat,  suspended  particles,  etc.,  is 
carried  past  a  fixed  point. 

When  an  inversion  occurs  aloft  such  as  a 
frontal  or  subsidence  inversion,  a  plume 
released  beneath  the  inversion  will  be  trapped 
beneath  it . 

The  depiction  of  regional  wind  direction 
patterns  at  the  surface  of  the  earth,  as 
generated  from  the  most  frequent  wind  direc- 
tion occurring  at  each  of  several  stations  in 
an  area  for-  selected  averaging  periods. 


The  boundary  between  the  troposphere 
stratosphere  . 


and  the 


The  lowest  10  to  20  km  (  6-12  miles)  of  the 
atmosphere.  It  is  characterized  by  decreasing 
temperature  with  height,  appreciable  vertical 
wind  motion,  appreciable  water  vapor  content, 
and  weather. 

The  most  commonly  occurring  combination  of  the 
key  dispersion  factors  -  wind  speed,  wind 
direction,  and  atmospheric  stability  class. 
Knowledge  of  the  most  commonly  occurring 
dispersion  condidtions  provides  some  indica- 
tion of  the  effect  of  an  existing  or  proposed 
pol 1 ut  i  on  source  . 


The  environmental  lapse  rate  is 
the  dry  adiabatic   lapse   rate 
turbulence  is  enhanced. 


greater  than 
and   vertical 


A  wind  which  ascends  a  mountain  valley  during 
the  day. 

According  to  general   international   usage,  a 
change  in  wind  direction  in  a  clockwise  sense. 

To  cause  to  circulate  as  in  the  dispersion  of 
air  pollutants. 

The  movement  or  mixing  of  air  along  a  vertical 
axis. 


280 


Vertical  Dispel 
Coefficient 


Vertical  Temp- 
erature Profile 

Vertical  Wind 
Prof i le 

Virtual  Source 


Wind  Tunnel 
Winds  Aloft 


Worst-case 
Conditions 


The  vertical  standard  deviation  of  plume  sion 
pollutant  concentration.  The  parameter  varies 
as  a  function  of  downwind  distance  and  atmos- 
pheric stability. 

A  graph  of  temperature  versus  altitude. 


A  graph  of  the  variation  of  mean  wind  speed 
with  height  in  the  surface  boundary  layer. 

The  theoretical   location  of  a  point  source 

with  respect  to  an  actual  area  source  which 

would  result  in  plume  dispersion  at  the  actual 

point  of  emission  indicative  of  the  area 
source . 

A  small  scale  model  of  the  atmosphere  which 
permits  experimentation  in  the  laboratory. 

Wind  speeds  and  directions  at  various  levels 
in  the  atmosphere  above  the  surface. 

That  combination  of  wind  speed,  wind  direc- 
tion, and  atmospheric  stability  class  that 
would  result  in  the  greatest  possible  pollu- 
tant impact  of  an  existing  or  proposed  source. 


281 


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283 


5.0  BASELINE  AIR  QUALITY  EMISSION  LEVELS 

5.1  FORMATION  OF  AIR  POLLUTANTS 

5.1.1     I  ntroduct i on 

Polluted  atmospheres  generally  are  associated  with  man's 
industrial  and  domestic  activities.  However,  many  of  the  major 
gaseous  pollutants  are  also  emitted  by  nature.  Taken  on  a  world- 
wide basis,  the  total  mass  of  trace  gases  emitted  by  nature 
exceeds  those  emitted  by  man  by  several  orders  of  magnitude. 
Nonetheless,  man's  activities  do  adversely  affect  the  quality  of 
the  atmosphere,  particularly  in  dense  urban  areas  and  near  large 
emission  sources.  For  many  of  the  pollutants,  serious  long-term 
worldwide  effects  are  feared.  The  effects  may  be  immediate  and 
obvious,  such  as  poor  visibility,  eye  irritation,  and  objection- 
able odors;  or  the  effects  may  be  noticeable  only  through  longer 
periods  of  observation,  such  as  in  corrosion.  More  subtle  ef- 
fects require  sophisticated  statistical  studies  to  determine  such 
things  as  human  health  effects  and  changes  in  the  earth's  energy 
bal ance . 

Table  5.1-1  compares  typical  concentrations  of  pollu- 
tants (Cadle,  1970)  with  those  found  in  uncontami nated  areas.  It 
can  be  seen  that  the  ratio  of  concentration  of  polluted  air  to 
clean  air  ranges  from  fractional  to  1000-fold.  Table  5.1-2  by 
Robinson  and  Robbins  (1972)  summarizes  the  worldwide  sources, 
atmospheric  concentrations,  residence  times,  and  removal  reac- 
tions for  eight  principal  gaseous  air  pollutants.  Except  for 
sulfur  dioxide,  emissions  from  natural  sources  exceed  those  from 
pollution  sources.  Figure  5.1-1  and  5.1-2  show  the  relationship 
between  outdoor  and  indoor  pollution  levels  for  sulfur  dioxide 
and  carbon  monoxide.  Measurements  such  as  these  indicate  serious 
penetration  into  homes  near  strong  pollution  sources  (Benson,  et . 
al.,  1972). 


5.  1.2 


The  Gaseous  Compounds  of  Carbon 


The  gaseous  compounds  of  carbon  found  in  natural  and 
polluted  atmospheres  comprise  a  broad  spectrum  of  the  compounds 
of  organic  chemistry.  Because  carbon  can  form  bonds  with  ele- 
ments such  as  hydrogen,  oxygen,  nitrogen,  and  sulfur  and  at  the 
same  time  combine  with  itself  to  form  a  series  of  straight  and 
branched  chain,  cyclic,  and  combined  cyclic-chain  systems,  an 
almost  infinite  number  of  compounds  are  possible.  Many  gaseous 
carbon  compounds  such  as  methane  (marsh  gas),  carbon  dioxide, 
carbon  monoxide,  the  terpenes  (Table  5.1-3  [Rasmussen,  1972]), 
and  other  volatile  plant  materials  are  emitted  in  nature  through 
biological  processes,  volcanic  action,  forest  fires,  natural  gas 
seepage,  etc.  In  areas  inhabited  by  man,  the  emissions  of  com- 
merce, industry  and  transportation  are  largely  concentrated  in 
urban  areas  and  generate  high  local  concentrations  of  volatile 
solvents  and  fossil  fuel  combustion  products. 


284 


Table  5.1-1 
Comparison  of  Trace  Gas  Concentrations  (ppm) 


Ratio 

CUan  air 

Polluted  air 

■polluted-to-clean 

CO, 

320 

400 

1.3 

CO 

0.1 

40-70 

400-700 

CH4 

1.5 

2.5 

1.3 

N,0 

0.2j 

(?) 

— 

NO,(NO.) 

0.001 

0.2 

200 

0, 

0.02 

0.5 

25 

SO, 

0.0002 

0.2 

1000 

NH, 

0  01 

0.02 

2 

285 


Table  5.1-2 
Summary  of  Sources,   Concentrations,  and  Major  Reactions  of  Atmospheric  Trace  Gases 


Calculated 

Mi,or 

\aturol 

Ettimnted  emiwoni  {tons) 

Atmoiphtrtr 

background 

atmoepheric 
retidence 

Be  moral 
reaction* 

Contaminant 

$OU"tl 

$ourre» 

Pollution               Satural 

concentration* 

time 

and  ninks 

Remark* 

o, 

fombu'tion 

Volcanoes 

146  X   10«         No  estimate 

0   2  ppb 

4  days 

Oxidation  to 

Photochemira  1 

<>'  coal  and 
ml 

sulfate  by 
otone  or,  a 
absorption, 
solid  and  li 
aerosols 

fter 

by 

quid 

oxidation  »ith 
NOi  and  1IC 
may  he  the 
process  needed 
to  give  rapid 

Hts 


CO 


NO   NOt 


Ml, 


NV) 


Hydrocarbons 


COi 


Chemical 
liriirewM. 

Sew  age 

treat  nient 

Auto  -  (ha  ■ 
an  I  other 
combustion 

(  "Ti'.'jstion 


None 


(  ombostion 
ei  haust, 
rhernical 
protsaaes 

Comhuation 


Volcanoe" 
biological 
action  in 
•  »  amp 
area« 

forest  fire*. 
oceans 
ter|.pne 
rear' ions 

Rartenal 
action  in 
BOll   (') 


Waste  Biological 

treatment  decay 


Biological 

action  in 
■oil 


llmlogical 
processes 


Biological 
dersy 
release 
Irnm 
oceans 


3  X  I0» 


301  X  10" 


53  X  10« 


100  X  I0» 


33  X  10> 


NO: 

430  X  10* 
NO-: 

6-i8  X  10« 


0  2  ppb 


0  1  ppm 


NO:  0  2-2  ppb 
NOi:  0  5-4  ppb 


4  X  10«     1 100  X  10i    6  pph  to  20  ppb 


None 


500  X    !"• 


88  y    10«         CM. 

I    ft  X   10' 
Terpenes. 
2<MI   X    10« 


1    4   X   10'« 


10" 


0   25  ppm 


CM.:  1    5  ppm 
non  Clli    <  1  ppb 


320  ppm 


2  days         Oxidation  to  SOi 


<3  years 


5  days 


7  da> 


4  years 


4  years 
(CH.) 


2-4  years 


Probably  soil 
organisms 


Oxidation  to 
nitrate  after 
sorption  by 
•olid  and  lupjid 
aerosols, 
hydrocarbon 
photochemical 
reactions 

Reaction  w  ith 
SOi  to  form 
(Nll.i-Sn. 
oxidation  to 
nitrate 

Photodi«sociation 
in  stratosphere, 
biological 
action  in  soil 

Photochemical 
react  ion  w  it  h 
NO    NO;.  Of, 
large  sink 
necessarv  for 
CM. 

Biological 

adsorption  and 
photosynt  he*is. 
absorption  in 
oceans 


transformntion 
of  SO;  —  SO, 
Only  one  set  of 
background 
concentrations 
available 

Ocean  contributions 
to  natural  source 
probably  low 

Very  little  work 
done  on  natural 
processes 


Formation  of 
ammonium 
salt*  is  major 
NMi  sink 

No  information 
on  proposed 
absorption  of 
N,()  h\ 
vegetation 

"Rearm  t" 
hydrocarbon 
emissions  from 
pollution  — 
27  X   10"  tons 

Atmospheric 
concentrations 
increasing  by 
0.7  ppm   year 


286 


10 


Ouidoo'  c»rt>on  monpaide  cor>centr»lion  |A)  ppm 
20  30  40 


50 


60 


**     80 


c 

c 

I     60 


40  - 


20  - 


2  poinls 
A      400%  @  0  2  pphm 
1600%  ©  0  2  pphm 


_l_ 


-j_ 


_i_ 


_l_ 


10  20  30  40 

Ouldooi  m'tu'  diomde  coocf rural. on  <•    pphm 


50 


60 


Figure  5.1-1 

Indoor  concentrations  of  sulfur  dioxide 
and  carbon  monoxide  as  a  function  of 
outdoor  concentrations. 


287 


60 


1  I  ! 

Car  being  put  in  garage 


1 1 1 

C»r  being  taken  from  garage 


-L- 


1200   1700   2200   300    800    1300   1800   2300    400    900   '400 

Mar  S       '  Mar  6  '         Ma'  7 

Time  hours 


-I- 


Figure  5.1-2 

Carbon  monoxide  concentrations  in  house  with  gas  range 
and  furnace  and  with  attached  garage.  Solid  line, 
kitchen;  dashed  line,  family  room;  dotdashed  line,  outside 


288 


Table  5.1-3 
Worldwide  Terpene  Emission  Estimates 


Investigator 


Method 


Estimate  in  tons 


WeDt' 


Rasmussen  and  Went* 


Ripperton,  White,  and 
Jeffries' 


Sum  of  sagebrush  emission  and 
terpenes  as  percentage  of 
plant  tissues 

1.  Bagging  foliage 
1  liter/lOcm' 

2.  Knclosure  forbs  0.6o  m'/m* 
3  Direct  »n  titu  ambient  con". 
Reaction  rate  ()|/pinene 


175  X  10' 


23  4  X  10" 

13  5  X  10" 
432  X  10' 
2  to  10  X  previous 
estimates 


•  F.  W.  Went,  Proc.  A  at.  Aead.  Sci.  46,  212  (19G0). 

'  R  A.  Rasmussen  and  F.  W.  Went,  l'roe.  Sal   Acad.  Set.  63,  215  (190.'.). 
'  L-  A.  Ripperton,  O.  White,  and  II.  K.  Jeffries,  "Cias  Phase  Drone- Pinene  Reactions," 
PP   54-56.  Div.  of  Water,  Air,  and  Waste  Chemistry,   147th    Nat.  Meeting  Amor. 
Chem.  Soc,  Chicago,  Illinois,  1967. 
Not  corrected  for  vertical  foliage  area  over  ground  area. 


Table  5.1-4 
Estimates  of  Hydrocarbon  Emissions,  1940-1970  (10  tons/year) 

(United  States) 


Source  category 

1940 

1950 

1980 

1968 

1989 

1970 

Fuel  combustion  in 

1.4 

13 

1.0 

10 

0.9 

0.6 

stationary  sources 

Transportation 

7.5 

118 

18.0 

20  2 

19.8 

19  5 

Solid  waste  disposal 

0  7 

0  9 

1.3 

2  0 

2.0 

2.0 

Industrial  process  losses 

3.3 

5.2 

4.3 

4.4 

4.7 

5.5 

Agricultural  burning 

19 

2.1 

2  5 

2.8 

2.8 

2.8 

Miscellaneous 

4.5 

4.2 

4  4 

4.9 

5.0 

4.4 

Total 

19.1 

25.6 

31.6 

35.2 

35.2 

34  7 

Total  controllable" 

14.7 

21.4 

27.2 

30.3 

30.2 

30.3 

•  Miscellaneous  sources  not  included. 


289 


5.1.2.1  The  Hydrocarbons 

Table  5.1-4  shows  the  emissions  of  hydrocarbons  in  the 
United  States  since  1940  (Cavender  et  al  ,  1973).  Transportation 
is  by  far  the  principal  emitting  source,  and  these  data  indicate 
that  its  emissions  seem  to  have  peaked  starting  in  1968.  Table 
5.1-5  gives  the  average  concentration  for  about  30  hydrocarbon 
compounds  identified  and  measured  in  Los  Angeles,  California  air 
(LAAPCD,  1970-72).  More  than  60  hydrocarbons  have  been  identi- 
fied, but  the  total  number  possible  is  yery  large  and  is  limited 
only  by  the  sensitivity  and  selectivity  of  the  analytical  method 
used  (USEPA,  1970).  The  compounds  are  classified  into  four  major 
functional  types:  alkanes  (paraffins),  al kenes  (olefins),  acety- 
lenes, and  aromatics.  The  concentrations  are  expressed  in  both 
parts  per  million  (ppm)  and  parts  per  million  as  carbon  (ppm  C). 
The  latter  is  calculated  by  multiplying  the  former  by  the  number 
of  carbon  atoms  in  the  respective  compound.  Parts  per  million  as 
carbon  is  considered  to  be  more  representative  of  the  hydrocarbon 
burden  of  the  ai  r . 

In  themselves,  the  hydrocarbons  in  air  have  relatively 
low  toxicity.  They  are  of  concern  because  of  their  photochemical 
activity  in  the  presence  of  sunlight  and  nitrogen  oxides  (Tues- 
day, 1971;  Gordon  et  al ,  1968).  They  react  to  form  photochemical 
oxidants  of  which  ozone  is  predominant  (Table  5.1-6).  Oxidants, 
including  peroxyacyl  nitrate  (PAN),  are  responsible  for  much  of 
the  plant  damage  and  eye  irritation  associated  with  smog.  Meth- 
ane has  ^ery  low  photochemical  activity.  As  a  consequence, 
hydrocarbon  concentrations  are  often  measured  separately  as 
methane  on  the  one  hand  and  non-methane  hydrocarbons  on  the  other 
(Figure  5.1-3).  Methane  will  vary  from  40%  to  80%  of  the  total 
hydrocarbons  in  an  urban  atmosphere  (Figure  5.1-4  (Altshuller  et 
al  ,  1973). 

Strictly  speaking,  hydrocarbons  are  the  compounds  of 
hydrogen  and  carbon.  At  least  two  of  the  techniques  used  for 
measuring  "total"  hydrocarbons  in  air  include  many  other  classes 
of  organic  compounds.  The  nondi spers i ve  infrared  method  (NDIR), 
for  example,  measures  compounds  containing  carbon- hydrogen  bonds. 
This  includes  most  organic  compounds.  The  flame  ionization 
method  measures  anything  that  reacts  to  form  ions  in  a  hydrogen 
flame.  Pure  hydrocarbons  give  higher  specific  responses,  but 
without  prior  separation;  the  longer  chain  alcohols,  aldehydes, 
esters,  acids,  etc.,  also  give  responses. 

5.1.2.2  The  Oxygenated  Hydrocarbons 

The  oxygenated  hydrocarbons,  like  the  hydrocarbons, 
include  an  almost  infinite  number  of  compounds.  They  are  classi- 
fied as  alcohols,  phenols,  ethers,  aldehydes,  ketones,  esters, 
peroxides,  and  organic  acids  (Roberts  and  Caserio,  1967). 

Some  minor  amounts  of  oxygenated  hydrocarbons  are  emit- 
ted as  solvent  vapors  from  the  chemical,   paint  and  plastics 


290 


Table  5.1-5 
Average  Hydrocarbon  Composition  from 
218  Ambient  Air  Samples  Taken  in  Los 
Angeles,  California 


Concentration 

Compound 

ppm 

ppm  (at  carbon) 

Methane 

3  22 

3.22 

Ethane 

0.09S 

0.20 

Propane 

0.049 

0.15 

Isobutane 

0  013 

0.05 

n-Butane 

0  064 

0.26 

Isopentane 

0  043 

0.21 

n-Pentanc 

0.035 

0.18 

2,2-Dimethylbutane 

0.0012 

0  01 

2,3-Dimethylbutane 

0.014 

0  08 

Cyclopentane 

0.004 

0  02 

3-Methylpentane 

O.OOS 

0.05 

n-Hexane 

0.012 

0  07 

Total  alkanes  (excluding  methane) 

0.3412 

1  28 

Ethylene 

0  060 

0  12 

Propene 

0.018 

0.05 

1-Butane  +  isobutylcne 

0  007 

0  03 

(rons-2-Butene 

0.0014 

0.01 

cw-2-Butene 

0  0012 

Negligible 

1-Pentene 

0.002 

0  01 

2-Methyl-l-butcnc 

0.002 

0  01 

<rans-2-Pentenc 

0.003 

0.02 

cts-2-Pentenc 

0.0013 

0.01 

2-Methyl-2-butene 

0  004 

0.02 

Propadiene 

0  0001 

Negligible 

1,3-Butadicnc 

0.002 

0.01 

Total  alkenes 

0  1020 

0.29 

Acetylene 

0.039 

O.OS 

Methylacetylene 

0.0014 

Negligible 

Total  acetylenes 

0.0404 

0  OS 

Benzene 

0.032 

0  19 

Toluene 

0.053 

0  37 

Total  aromatirs 

0.085 

05C 

Total 

3.788G 

5  43 

291 


Table  5.1-6 

Ozone  Levels  Generated  in  Photooxidation  of  Various 
Hydrocarbons  with  Oxides  of  Nitrogen 


Hydrocarbon 

Ozone  level,  ppm 

Time,  min 

Isobutenc 

1.00 

28 

2-Mcthyl-l,3-butadienc 

OHO 

45 

fran*-2-Butene 

0  73 

35 

3-Heptenc 

0  72 

60 

2-Ethyl-l-buteno 

0  72 

80 

1,3-Pentadiene 

0  70 

45 

Propylene 

0.68 

75 

1,3-Butadiene 

0.65 

45 

2,3-Dimethyl-l,3-butadiene 

0.65 

45 

2,3-Dimethyl-2-butene 

0  64 

70 

1-Pentene 

0.62 

45 

1-Butene 

0.5K 

45 

eta-2-Butenr 

0  55 

35 

2,4,4-Tnmethyl-2-pentene 

0  55 

50 

1,5-Hexadienc 

0.52 

85 

2-Methylpentanc 

0.50 

170 

1 ,5-Cy  clooctadiene 

0  48 

65 

Cyclohexene 

0  45 

35 

2-Methylheptane 

0  45 

180 

2-Methyl-2-butene 

0  45 

38 

2,2,4-Tnmethylpentanr 

0.2G 

80 

3- Methyl  pen  lane 

0  22 

100 

1,2-Butadiene 

0  20 

60 

Cyclohexane 

0.20 

80 

Pentane 

0   18 

100 

Methane 

0  0 

— 

•  Hydrocarbon  concentration  (initial;  3  ppm  ,  oxide  of  nitrogen  (NO 
or  NOj,  initial;  1  ppm. 


292 


1.5 
10 
0.5 

0 

1.5 

1  0 

05 

0 
20 

1  5 

1  0 

05 

0 

10 

05 


1 1 1  I  I  I  I  l  l 

Chicago,  Illinois       .^•«»» 


X 


(May  through  August  »nd  October) 
J I I I  I I  '  ' L_ 


St 

T 
Louis. 

-I 
Missour 

T 

\ 

1 1 

— i r 

1            1 

^ 

T 

i 

~ 

•^ 

■ 

i 

' 

(May 

-I 

th 

rough  July 

.  September 

.  and  October  1 

_L 

~ 

1— 

Denver, 

r 1 1 

Colorado 

1 

— r- 

' 

T 1               1 

— r 

/         \ 

/ 

^ 





>s 

"V. 

^^•. 

i 

(January  through  March 
iiii 

May 

September 

i 

.  and  October  1 
J 1 L 

_i_ 

-         1 

Washington 

1            1 
(January 

1            1 
through  April 

-t r      — i r 

and  August  through  Octobe') 
iiii 

-1 

1— 

-^ 

12 

h 


12 


6 
■  p  m 


1? 


Local  time 


Figure  5.1-3 

Nonmethane  hydrocarbons  as  measured  by 
a  flame  ionization  analyzer,  averaged 
by  hour  of  day  over  several  months  for 
various  cities. 


293 


4  5  6 

Total  hyOrocjrtxxv  PP"> 


10 


Figure  5.1-4 

Nonmethane  hydrocarbon  fraction  to  total  hydrocarbon  for  selected 
locations.  O:  Los  Angeles,  California,  1967;  D:  Azusa,  California, 
1967;  A:  Los  Angeles,  California,  1968;  V:  Los  Angeles,  Calif- 
ornia, 1968---Sundays;  +   Brooklyn,  New  York,  1069;  ■   Bayonne, 
New  Jersey,  1968 


294 


industries.  The  greater  quantities  of  primary  emissions  are  more 
usually  associated  with  the  automobile.  Table  5.1-7  (Seizinger 
and  Dimitriades,  1972)  lists  some  typical  oxygenates  found  in 
automobile  exhaust.  The  aldehydes  are  the  preponderant  oxygen- 
ates in  emissions  but  are  emitted  in  minor  amounts  when  compared 
to  hydrocarbon,  carbon  dioxide,  carbon  monoxide  and  nitrogen 
oxide  emissions.  Many  oxygenated  compounds  are  formed  as  second- 
ary products  from  photochemical  reactions  (Tuesday,  1971). 

5.1.2.3   The  Oxides  of  Carbon 

Carbon  Dioxide 

Carbon  dioxide  is  not  generally  considered  an  air2pollu- 
tant.  It  is  non-toxic,  and  immense  quantities  of  it  (  10  tons) 
are  cycled  through  the  biosphere  annually  (Robinson  and  Robbing, 
1972).  It  is  an  essential  ingredient  of  plant  and  animal  life 
cycles.  Through  photosynthesis,  it  is  converted  to  plant  tis- 
sues; oxygen  is  produced  as  a  by-product.  Without  photosynthe- 
sis, the  world's  supply  of  oxygen  would  reduce  drastically  to 
that  formed  by  lightning  and  photolytic  processes  acting  on  water 
(Mason,  1966;  Riehl  ,  1972). 

The  concentration  of  carbon  dioxide  in  air  is  variable 
and  depends  upon  whatever  sources  or  sinks  are  present  and  such 
factors  as  the  growing  season  when  plants  tend  to  deplete  the 
amounts  present.  Callendar  (1958)  studied  carbon  dioxide  meas- 
urements from  1870  to  1955  (Figure  5.1-5).  A  nineteenth  century 
base  value  of  290  ppm  was  established  and  is  generally  accepted. 
Present  day  values  have  been  set  at  320  ppm  with  an  annual  growth 
rate  of  about  0.7  ppm  (Robinson  and  Robbins,  1972). 


Worldwide  combustion  of  fossil  fuel  is  a 
of  the  relatively  rapid  increase  in  carbon  dioxide 

and  Robbins  (1972)  have  reviewed 
of  carbon  dioxide.   Table  5.1-8 
projected  to  the  year  2000.    A 
3  00%  in  emissions  over  those  of 
and  Robbins  (1972)  assume  that 
dioxide  emitted  remains  in  the  atmosphere.   This 
an  increase  to  about  370  ppm. 


phere.   Robinson 
sinks  and  effects 
dioxide  emissions 
crease  of  nearly 
dieted.   Robinson 


primary  cause 

in  the  atmos- 

the  sources  , 

shows  carbon 

rel at  i  ve  i  n- 

1965  is  pre- 

hal  f  the  carbon 

woul d  resul t  i  n 


295 


Table  5.1-7 
Oxygenates   in  Exhaust  from  Simple  Hydrocarbon  Fuels 


Ozygrnatr 

Concentration  range,  ppm" 

Acelaldehyde 

0.8-4  9 

Propionaldehydc  (+  acetone)' 

2.3-14.0 

Acrolein 

0.2-5  3 

Crotonaldehyde  (+  toluene)' 

0.1-7.0 

TiRlaldehydc 

<0  1-0.7 

Bcnzaldchyde 

<0  1-13.0 

Tolualdehydc 

<0. 1-2.6 

Ethylbenzaldehydc 

<0. 1-0.2 

o-Hydroxybenzaldehydc  (+  Cio  aromatic)* 

<0. 1-3.5 

Acetone  (+  propionaldehydc)' 

2.3-14.0 

Methyl  ethyl  ketone 

<0.1-1   0 

Methyl  vinyl  ketone  (+  benzene)' 

0   1-42  6 

Methyl  propyl  (or  iaopropyl)  ketone 

<0   1-0  8 

3-Mcthy]-3-buten-2-one 

<0   1-0  8 

4-Methyl-3-penten-2-one 

<0  1-1.5 

Acetophenonc 

<0. 1-0.4 

Methanol 

0  1-0  6 

Ethanol 

<0  1-0.6 

Ci  alcohol  (+  Ci  aromatic)' 

<0   1-1.1 

2-Buten-l-ol  (  +  C»H,(J) 

<0  1-3  6 

Benzyl  alcohol 

<0  1-0  6 

Phenol  -+-  cresolfsj 

<0. 1-6.7 

2,2,4,4-Tetramethyltctrahydrofuran 

<0.1-C  4 

Benzofuran 

<0  1-2  8 

Methyl  phenyl  ether 

<0   1 

Methyl  formate 

<0   1-0  7 

Nitromethane 

<0. 8-5.0 

C.H.O 

<0   1 

c»h«o 

<0. 1-0.2 

C,1I,0<> 

<U   1-0  3 

•  Values  represent  concentration  levels  in  exhaust  from  all  test  fuels 

1  Data  represent  unresolved  mixture  of  propionaldehydc  ■+■  acetone  Chroma- 
tographic peak  shape  suppests  acetone  to  be  the  predominant  component. 
'  Toluene  is  the  predominant  component. 

*  The  Cio  aromatic  hydrorarlton  is  the  predominant  component. 
'  Benzene  is  the  predominant  component. 

'  The  aromatic  hydrocarbon  is  the  predominant  component 


296 


340 


320  - 


I  310  - 

d 
u 

300  (- 


290 


280 
1870 


- 

1 

1 

1 

T 

T 

— 1 1 1 

1 

/ 
/ 
/ 

'/      ' 

- 

0 

0                         > 

So 

- 

o  ^r 

- 

- 

0 

O 

O         S 

- 

_o 

0 

19lh  Century  b»» 

y»luf  ■  290  ppm 

0 

0 

__L   . 

0 

' 

1                  1                  J 

i 

1 

1890 


1910  1930 

Ye.r 


1950 


1970 


Figure  5.1-5 
Average  C09  concentration  in  North  Atlantic  region  1870-1956 


297 


Table  5.1-8 
Projected  C02  Emissions:     1965-2000 


Emissions,  10'  tons 

t'y((ir 

1965 

1970 

1980 

1990 

£000 

Coal 

7.33 

7.40 

7 .  55 

7.70 

7 . 8.-. 

Petroleum 

4  03 

5 .  28 

H .  57 

13.90 

22  50 

Natural  gas 

1    19 

1  62 

2  79 

4.80 

8.27 

Incineration 

0  4C 

0.51 

0  61 

0.73 

0  88 

Wood  fuel 

0  68 

0  68 

0  68 

0  68 

0.68 

Forest  fires 

0  39 

0  39 

0.39 

0  39 

0  39 

Total 

14  OS 

15  88 

20  59 

28  20 

40  57 

Relative  chanpe 

100% 

113  % 

146% 

200% 

288  7c 

298 


Ulirrviolet    Vmole 


Infrared 


60 


Iff5 


Iff3 


1ffJ 


T 1 1 1 1 

.tlacfcbody  radiation  at  1000*  K  Qjly/rrunl 

,t  «im«rrrur l*  km*  radiation  (3 A  ry/min) 


Dtraci  baam  eatar  radiation 
*i  — it»'»  aurfaoa  (O  ry/m>n) 


Abaorption 
of 


0  1       0? 


05         10       20  5         10        20 

Wa»»l«r<orh .  microm 


SO        100 


Figure  5.1-6 
Spectra  of  Solar  and  Earth  Radiation 


299 


greenhouse,  effect.   The  temperature  increase  theoretically 

resulting  from  an  increase  of  concentration  to  370  ppm  would  be 

0.5  C  (Manabe  and  Wetherald,   1967).    In  reality 

energy  balance  is  much  more  complicated.    Water 

absorbs  strongly  in  the  infrared,  the  amount  of 

reflect  sunlight,  and  global  atmospheric  circulation 

play  important  roles  (Robinson  and  Robbins,  1972;  Sellers,  1965). 

An  increase  in  the  reflectivity  of  the  earth's  atmosphere  caused 

by  an  increase  in  suspended  particulate  matter  (McCormick  and 

Ludwig,  1967)  or  an  increase  in  cloud  cover  could  offset  the 

warming  tendency  of  carbon  dioxide. 


the  earth ' s 
vapor,  which 
clouds  which 

patterns  al 


Carbon  Monoxide 


Carbon  monoxide  is  a  colorless,  odorless,  and  tasteless 
gas  which  is  slightly  lighter  than  air.    It  is  considered  a 
asphyxiant  because  it  combines  strongly  with  the  hemo- 
the  blood  and  reduces  the  blood's  ability  to  carry 
cell  tissues.    Untold  numbers  of  deaths  have  been 
carbon  monoxide  in  coal  mines,  fires  and  non-ventilated 
healthy  working  person  can  work  eight  hours  a  day,  40 


dangerous 
gl obi  n  of 
oxygen  to 
caused  by 
pi  aces  .   A 


hours  a  week,  without  noticeable  adverse  effects  at  carbon  monox 
ide  concentrations  of  25  ppm  (the  threshold  limit  value). 


Carbon  monoxide  is  a  product  of  incomplete  combustion  of 
carbon  and  its  compounds.  It  is  emitted  by  fossil  fuel  combus- 
tion sources  in  greater  quantities  than  all  other  pollutant 
sources  combined.  Table  5.1-9  summarizes  the  estimates  of  emis- 
sions in  the  United  States  (Cavender  et  al  ,  1973).  The  automo- 
bile is  by  far  the  largest  single  pollution  emission  source. 
Figure  5.1-7  shows  that  maximum  carbon  monoxide  concentrations 
found  at  eight  Continuous  Air  Monitoring  Program  (CAMP)  stations 
in  the  United  States  (Chang  and  Weinstock,  1973). 


The  background  concentration  of  carbon  monoxide  is 
estimated  from  data  gathered  in  the  Pacific  (Robinson  and 
Robbins,  1972;  1970)  to  be  approximately  0.1  ppm.   Table  5.1-10 


300 


Table  5.1-9 

Estimates  of  Carbon  Monoxide  Emissions 
(United  States)  1940-1970  (106  tons/year) 


Source  category  1940  1960  1960  1968  1969  1970 

Fuel  combustion  in  62  5.6  2.6  2.0  1.8  0.8 

stationary  sources 

Transportation  34  9  55.4  83  5  113  0  112  0  111.0 

Solid  waste  disposal  1.8  2.6  5.1  8.0  7.9  7.2 

Industrial  process  losses        14.4  18.9  17.7  8.5  12  0  11.4 

Agricultural  burning  9.1  10  4  12.4  13.9  13  8  13.8 

Miscellaneous  19.0  10  0  6.4  5.0  6  3  3.0 


Total 

85.4 

103  0 

128  0 

150.0 

154.0 

147.0 

Total  controllable" 

66  4 

92  9 

121.0 

145  0 

148  0 

144  0 

*  Miscellaneous  sources  not  included. 


301 


Cart  plus  truckt   millions 


Figure  5.1-7 

Maximum  CO  concentrations  at  Continuous  Air  Monitoring  Program 
(CAMP)  stations.  1962-196S  maxima  vs  cars  plus  trucks.  Denver 
(Den.),  Colorado;  Cincinnati  (Cin.),  Ohio;  Washington  (Wash.), 
D.C.;  St.  Louis  (S.L.),  Missouri;  San  Francisco  (S.F.),  California; 
Philadelphia  (Phil.),  Pennsylvania;  Chicago  (Chi.),  Illinois; 
Los  Angeles  (L.A.),  California. 


302 


Table  5.1-10 
Carbon  Monoxide  Concentrations  in  Representative  United  States  Cities 
Hourly  Maxima  in  ppm.   1962-1967 


Yearly 

maxima 

Theoret 

ical  geometric 

Highest 

Lowest 

mean  (17,  61) 

Chicago,  Illinois 

59 

28 

13.2 

Cincinnati,  Ohio 

34 

20 

4.8 

Denver,  Colorado 

55 

40 

6.7 

Los  Angeles,  California 

47 

35 

9.7 

Philadelphia,  Pennsylvania 

54 

37 

6  9 

St.  Louis,  Missouri 

29 

25 

5.5 

Ran  Francisco,  California 

3S 

22 

4   R 

Washington,  DC. 

41 

25 

3  5 

303 


shows  the  range  of  maximum  hourly  average  values  for  the  years  of 
1962-1967  for  eight  major  United  States  cities  (USEPA,  1970; 
Faith  and  Atkisson,  1972).  The  theoretical  geometric  mean  hourly 
concentrations  for  the  entire  period  are  also  shown.  CO  concen- 
trations are  more  than  ten  times  the  level  of  concentrations  of 
other  major  pollutants. 

5.1.3    The  Gaseous  Compounds  of  Sulfur 

5.1.3.1   The  Sulfur  Oxides 


If7 


Sulfur  forms  a  number  of 


oxides  (SO, 
and  sul fur 


SO 


2  '   2  JL' 
tri  oxide  (ST)-, ) 


so3, 

but  only  sulfur  dioxide  (SO-)  and  sulfur  tr  i  oxide  *"(  St)  3 )  are 
any  importance  as  gaseous  air  pollutants.  The  peroxide,  So0  7 » 
has  been  suggested  as  existing  in  the  lower  stratosphere  where  a 
layer  of  sulfate  particles  has  been  found  (Bigg  et  al  ,  1970; 
Junge  and  Manson  1961). 


emitted  with  S0o  at  about 


Sulfur  trioxide  is  generally  cmiwucu  mm  ^w- 
l%-5%  of  the  S02  concentration  (Cholak  et  al ,  1958;  Tice,  1962). 
A  few  industries  such  as  sulfuric  acid  manufacturing,  electro- 
plating and  phosphate  fertilizer  manufacturing  may  emit  higher 
relative  amounts  (USEPA,  1972).  Sulfur  trioxide  rapidly  combines 
with  water  in  air  to  form  sulfuric  acid  (^SO^)  which  has  a  low 
dew  point.   An  aerosol  or  mist  is  easily  formed,  and  S03  or  FUSO* 

haze  and  poor  visibility  in  air 
for  S03  or  HUSO*  in  air  is  quite 
to  be  interpreted  with  some  care 


is  frequently  associated  with 
(Figure  5.1-8).   The  analysis 
difficult,  and  the  data  have 
(USEPA,  1972). 


Sulfur  dioxide  is  a  colorless  gas  with  a  pungent,  irri- 
tating odor.  Most  people  can  detect  it  by  taste  at  0.3  to  1  ppm 
(780  to  2620  ug/ni  ).  It  is  highly  soluble  in  water:  11.3  gm/100 
ml  as  compared  to  0.169  gm/100  ml  for  carbon  dioxide,  forming 
weakly  acidic  sulfurous  acid  ( H « S  0  -  ) .  In  clean  air,  it  oxidizes 
slowly  to  sulfur  trioxide.  It  is  oxidized  more  readily  by  atmos- 
pheric oxygen  in  aqueous  aerosols.  Heavy  metal  ions  in  solution 
catalyze  the  reaction  which  stops  when  aerosols  become  acidic. 
Atmospheric  ammonia  neutralizes  the  acid  to  form  ammonium  sul- 
fate, which  is  commonly  found  in  atmospheric  particles  (Johnstone 
and  Coughanowr,  1958,  1960).  In  moist  air  and  in  the  presence  of 
nitrogen  oxides,  hydrocarbons,  and  particulates,  sulfur  dioxide 
reacts  much  more  rapidly  (Urone,  1972;  Urone  and  Schroeder, 
1969). 

Today,  sulfur  dioxide  remains  one  of  the  major  atmos- 
pheric pollutants.  Its  worldwide  emissions  have  been  estimated 
at  146  megatons/year  by  Robinson  and  Robbins  (Table  5.1-2)  and 
more  recently  as  100  (150  as  sulfate)  megatons  per  year  by 
Kellogg  et  al  .  (1972)  who  predict  emissions  of  about  275  megatons 
per  year  for  the  year  of  2000.  Estimated  United  States  sulfur 
dioxide  emissions  for  1970  were  33.9  megatons  (Table  5.1-11). 
Fuel  combustion  and  stationary  sources  and  industrial  emissions 
accounted  for  70%  and  18%  of  this  figure,  respectively  (Cavender, 


304 


10'  10" 

Sulfuric  •cid  mijt  concentration,  pg  m' 


Figure  5.1-3 

Calculated  visibility  (visual  range)  in  miles  at  various  sulfuric  acid 
mist  concentrations  and  different  relative  humidities. 


305 


Table  5.1-11 

Estimates  of  Sulfur  Oxide  Emissions  (United  States) 
1940-1970  (106  tons/year) 


Source  category 

1940 

1950 

1960 

1968 

1969 

1970 

Fuel  combustion  in 

16  8 

18.3 

17.5 

24  7 

25  0 

26.5 

stationary  sources 

Transportation 

0  7 

1.0 

0.7 

1.1 

1.1 

1.0 

Solid  waste  disposal 

Neg" 

0  1 

0  1 

0.1 

0.2 

0.1 

Industrial  process  losses 

3  8 

4.2 

4.7 

5   1 

5  9 

6.0 

Agricultural  burning 

Neg 

Neg 

Neg 

Neg 

Neg 

Neg 

Miscellaneous 

0  2 

0.2 

0.3 

0.3 

0.2 

0  3 

Total 

21.5 

23.8 

23  3 

31.3 

32.4 

33  9 

Total  controllable' 

21  3 

23  6 

23  0 

31  0 

32.2 

33.6 

•  Negligible  (less  than  0.05  X  10*  ton6/yearJ. 

*  Miscellaneous  sources  not  included. 


Table  5.1-12 

Sulfur  Dioxide  Concentrations   in  Representative 
'united  States  Cities  Hourly  Maxima,  ppm,   1962-1967 


Yearly  maxima 
High  si         Lowest 


Theoretical  geometric 
mean  (17,  61) 


Chicago,  Illinois 

1   69 

0.86 

0.111 

Cincinnati,  Ohio 

0  57 

0  41 

0  018 

l)cnvcr,  Colorado 

0  36 

0  17 

0  014 

Los  Angeles,  California 

0.29 

0.13 

0  014 

Philadelphia,  Pennsylvania 

1  03 

0.66 

0  oco 

St.  Louis,  Missouri 

0.96 

0 .  55 

0.031 

San  Francisco,  California 

0.26 

0  11 

0.006 

Washington,  DC. 

0 .62 

0.35 

0.042 

306 


et  al ,  1973).  Intensive  efforts  are  being  made  to  control  sulfur 
dioxide  emissions  by  either  removing  sulfur  from  coal  and  oil  or 
removing  sulfur  dioxide  at  the  combustion  source  (USEPA,  1969). 

Ambient  air  concentrations  of  sulfur  dioxide  are  rou- 
tinely measured  in  many  cities  and  have  been  the  subject  of  a 
large  number  of  studies.  Table  5.1-12  give  typical  data  obtained 
from  the  United  States  Continuous  Air  Monitoring  Program  (CAMP). 
Figure  5.1-9  shows  the  frequency  distribution  of  sulfur  dioxide 
measurements  made  in  selected  United  States  cities.  An  approxi- 
mate log-normal  distribution  is  shown  by  the  straight  portions  of 
the  lines.  This  confirms  to  some  extent  the  model  developed  by 
Larsen  and  others  (Larsen,  1969;  USEPA,  1969;  Larsen,  1971). 

5.1.3.2   Reduced  Sulfur  Compounds 

Hydrogen  Sulfide 

Hydrogen  sulfide  (H«S)  is  a  toxic,  foul  smelling  gas 
well  known  for  its  rotten  egglike  odor.  -It  can  be  detected  at 
concentrations  as  low  as  0.5  ppb  (7  yg/m  )  (A.D.  Little,  Inc., 
1968).  Its  natural  emission  sources  include  anaerobic  biological 
decay  processes  on  land,  in  marshes  and  in  the  oceans.  Volcanoes 
and  natural  hot  water  springs  also  emit  hydrogen  sulfide.  A 
total  of  approximately  100  megatons  (268  when  expressed  as  sul- 
fate) is  estimated  to  be  emitted  in  nature  (Table  5.1-2)  (Kellogg 
et  al  ,  1972).  However  this  estimate  has  been  made  with  strong 
reservations.  The  analysis  of  very  low  concentrations  in  air  is 
subject  to  error  because  some  of  the  hydrogen  sulfide  is  oxidized 
to  sulfur  dioxide  during  the  sampling  process  (Kellogg  et  al , 
1972). 

Approximately  three  megatons  of  HpS  are  estimated  to  be 
emitted  each  year  by  pollution  sources  fRobinson  and  Robbins, 
1972)  (Table  5.1-2).  One  of  the  larger  single  sources  is  the 
kraft  pulp  industry  which  uses  a  sulfide  process  to  extract 
cellulose  from  wood  (Blosser,  1972).  Because  of  the  strong  odor 
of  sulfides,  such  facilities  can  be  detected  by  their  odor  40 
miles  or  more  downwind,  unless  emissions  are  carefully  con- 
trolled. Other  hydrogen  sulfide  pollution  sources  include  the 
rayon  industry,  coke  ovens  and  the  oil  refining  industry.  The 
processing  of  "sour"  crude  oil  results  in  the  emission  of  hydro- 
gen sulfide  and  other  volatile  organic  sulfides.  Hydrogen  sul- 
fide emissions  from  industrial  processes  are  sometimes  used  as 
fuel  for  boilers  or  are  released  in  burning  flares.  In  either 
case,  they  are  burned  to  sulfur  dioxide  and  emitted  to  the  air. 
Today,  many  modern  refineries  recover  their  sour  gasses  and 
process  them  to  form  sulfuric  acid  or  elemental  sulfur  (Faith  et 
al  ,  1965). 


Hydrogen  sulfide  concent  rat i ons 
higher  than  0.1  ppm  (140  yg/m  ).   Cholak 
nati  air  over  a  period  of  five  years~and 
sulfide  to  exceed  0.01  ppm  (14  yg/m  ). 


in  urban  air  are  rarely 

(1952)  analyzed  Cincin- 

rarely  found  hydrogen 

A  s  urvey  in  Houston , 


307 


0  01     006  0  1  0?    05     1       2  5         10  20      X    40    50    60 

PERCENT  OF  TIME  CONCENTRATION  IS  EXCEEDED 


Figure  5.1-9 

Frequency  distribution  of  sulfur  dioxide  levels  in  selected  United  States 
cities,  1962-1967.  v,  Chicago,  Illinois;  ▼,  Philadelphia,  Pennsylvania; 
D,  St.  Louis,  Missouri;  ■.  Cincinnati,  Ohio;  O,  Los  Angeles,  California; 
#.  San  Francisco,  California. 


308 


Texas  showed  average  values  of  0.02  ppm  in  the  most  highly  pollu- 
ted sectian  of  the  city.  The  highest  level 
(390  yg/nT)  (Faith  and  Atkisson,  1972;  SRI 
found  relatively  high  levels  in  Windsor, 
concentration  of  approximately  0.1  ppm  and 
(835  u  g/V). 


measured  was  0.28  ppm 

,  1957).   Katz  (1955) 

Ontario  with  a  mean 

a  maximum  of  0.6  ppm 


Hydrogen  sulfide  blackens  lead-based  paints.  A  level  of 
0.1  ppm  is  said  to  produce  blackening  of  such  paints  within  1 
hour  (Faith  and  Atkisson,  1972).  In  air,  hydrogen  sulfide  is 
oxidized  to  sulfur  dioxide  within  hours,  adding  to  the  ambient 
sulfur  dioxide  level  (Kellog  et  al ,  1972). 

Mercaptans  and  Sulfides 

Other  sulfur  compounds  that  are  of  interest  in  air 
pollution,  principally  because  of  their  strong  odors,  are  methyl 
mercaptan  (ChUSH),  dimethyl  sulfide  (CH^SChU),  dimethyl  disulfide 
(ChUSSCH-,),  and  their  higher  molecular  homologs  (Blosser,  1972). 
They  have  odors  similar  to  those  emitted  by  skunks  and  rotting 
cabbage.  Total  emissions  of  these  compounds  are  unknown.  A 
number  of  studies  have  been  concerned  with  their  evaluation 
(Schmall,  1972)  and  their  measurement  in  air  (Figure  5.1-10 
(Rasmussen  ,  1972 ) . 


5.  1.4 


The  Gaseous  Compounds  of  Nitrogen 


N. 


whi  ch 


Nitrogen  forms  the  very  stable  diatomic  gas,  no 
makes  up  over  78%  of  the  atmosphere  and,  fortunately,  helps 
temper  the  oxidative  power  of  atmospheric  oxygen.  It  also  forms 
a  large  number  of  gaseous  and  nongaseous  compounds,  many  of  which 
are    essential  to  living  matter. 


They  are  produced  by  such  natural  processes  as  bacterial 
fixation,  biological  growth  and  decay,  lightning,  and  forest  and 
grassland  fires.  To  a  lesser  extent,  but  in  higher  local  urban 
concentrations,  nitrogen  compounds  are  produced  by  man  through  a 
wide  number  of  agricultural,  domestic,  and  industrial  activities. 
In  the  reduced  state,  nitrogen  forms  such  compounds  as  ammonia, 
amides,  amines,  amino  acids  and  nitriles.  In  the  oxidized  state, 
it  forms  seven  oxides  and  a  large  number  of  nitro,  nitroso, 
nitrite  and  nitrate  derivatives  (Cotton  and  Wilkinson,  1966). 

5.1.4.1   The  Oxides  of  Nitrogen 


The  oxides  of  nitrogen  include  nitrous  oxide  (N^O), 
nitric  oxide  (NO),  nitrogen  dioxide  (N0?),  nitrogen  trioxide 
(N0o),  nitrogen  sesquioxide  (N2O3),  nitrogen  tetroxide  (NoO^), 
and  nitrogen  pentoxide  (NoOc)*  'hey  and  two  of  their  hydrates, 
nitrous  acid  ( H  N  0  ~  )  and  nitric  oxide  (NO),  and  nitrogen  dioxide 
(NOg)  are  found  in  appreciable  quantities.  The  latter  two,  NO 
and  N02>  are  often  analyzed  together  in  air  and  are  referred  to 
as  "nitrogen  oxides"  and  given  the  symbol  "NO  ".   Nitrous  oxide 


309 


100 


s: 


GC 


40   - 


K 


'Hydrogen  fcjlfirje 


,  Dimethyl  fcjUiO* 


J 


D it>p t>^ v  i  Oiujii.cv 


-i l  I  l 


'  i l i_ 


01?34£6789!0 

MINUTES 


Figure  5. 1-10 
Sulfur  Gases   in  Ambient  Air,    In-Situ  Analysis 


310 


(N«0)  is  not  included  in  the  "NO  "  measurement,  but  it  is  pos- 
sible for  the  higher  oxides  to  be  included  if  they  happen  to  be 
present  (APHA,  1972). 


concentrations  of 

methane,  and  the 

minor  surgery  and 

produces  a  loss  of 
di  sappear .   It  i  s 

some  conditions  it 


Nitrous  oxide  (N„0)  is  a  colorless,  slightly  sweet, 
nontoxic  gas  present  in  the  natural  environment  in  relatively 
large  amounts  (0.25  ppm)  when  compared  to  the 
the  other  trace  gases  except  carbon  dioxide, 
noble  gases.  It  is  used  as  an  anesthetic  in 
dentistry.  When  mixed  with  air  and  inhaled  it 
feeling.  Its  effects  are  not  severe  and  soon 
commonly  called  "laughing  gas"  because  under 
can  cause  those  who  inhale  it  to  laugh  violently.  The  major 
natural  source  of  nitrous  oxide  is  biological  activity  in  the 
soil  and  possibly  in  the  oceans.  A  worldwide  production  rate  of 
10  tons  per  year  and  a  residence  time  of  four  years  has  been 
estimated  (Robinson  and  Robbins,  1972;  Craig  and  Gordon,  1963). 
Nitrous  oxide  has  been  associated  with  photochemical  reactions  in 
the  upper  atmosphere  (Bates  and  Hays,  1967),  but  because  of  its 
low  reactivity  in  the  lower  atmosphere  it  is  largely  ignored  in 
air  pollution  studies.  There  are  no  known  significant  pollution 
sources  (Robinson  and  Robbins,  1972). 


As  a  pollutant,  nitric  oxide  is  produced  largely  by  fue 
combustion  in  both  stationary  and  mobile  sources  such  as  the 
automobile.  In  the  high  temperatures  of  the  combustion  zone, 
nitrogen  reacts  with  oxygen  to  form  nitric  oxide: 


N, 


NO 


(5.1-1) 


The  reaction 
temperatures, 
completely  to 


is  endothermic  and  proceeds  to  the  right  at  high 
At  low  temperatures,  the  equilibrium  lies  almost 

the  left,  but  the  rate  of  recombination  is  extreme- 
ly slow.  Consequently,  the  amount  of  NO  emitted  is  a  function  of 
the  flame  structure  and  temperature  as  well  as  the  rate  at  which 
the  combustion  mixture  cools.  If  the  cooling  rate  is  rapid, 
equilibrium  is  not  maintained  and  the  NO  concentration,  although 
thermodynami cal ly  unstable,  remains  high  (Trayser  and  Creswick, 
1970;  Hall  and  Blacet,  1952).  The  proper  catalyst  can,  of 
course,  expedite  its  decomposition  to  nitrogen  and  oxygen.  In 
exhaust  gases,  where  higher  concentrations  and  temperatures 


311 


prevail,  some  of  the  nitric  oxide  is  oxidized  to  nitrogen  diox- 
ide. This  generally  varies  from  0.5%  to  10%  of  the  nitric  oxide 
present  (USEPA,  1971). 


oxide 

aut  om 

used 

tures 

hydro 

oxide 

m  i  x  t  u 

the  n 

than 

exces 


tons 
est  im 

State 
accou 
year 
mum  h 


Figure  5.1-11  shows  the  relative  amounts  of  nitrogen 
s,  hydrocarbons,  and  carbon  monoxide  in  the  exhaust  of  an 
obile  as  a  function  of  the  ratio  of  the  air-to-fuel  mixture 
for  the  engine.  At  low  air-to-fuel  ratios  ("rich"  mix- 
),  flame  temperatures  are  low,  combustion  is  incomplete, 
carbon  and  carbon  monoxide  emissions  are  high,  and  nitrogen 
s  emissions  are  low.  At  higher  air-to-fuel  ratios  ("lean" 
res)  the  temperature  of  the  combustion  flame  becomes  hotter, 
itrogen  oxides  increase  until  the  air-fuel  ratio  is  greater 
the  stoichiometric  point  and  then  decrease  rapidly  as  the 
s  air  cools  the  flame  (Trayser  and  Creswick,  1970). 


Worldwide  pollution 
per  year  of  NO  and  N0? 


sources  emit 
combined  (NO 
NO   emission's  expressed  as 
s.   Fuel  combustion  in  stationary 


approximately  53  X  10 

)  .   Tabl e  5.1-13  gives 

NOo  for  the  United 

transportat  i  on 

emitted  per 

Table  5.1-14  shows  maximum  and  mini- 

in  several  United  States  cities. 


sources  fiand 
nt  for  more  than  95%  of  the  22.7   X  10   tons 
i  n  the  Uni  ted  States . 
our! y  averages  of  NO 


In  a  polluted  atmosphere,  nitric  oxide  is  oxidized  to 
nitrogen  dioxide  primarily  through  photochemical  secondary  reac- 
tions. Figure  5.1-12  shows  the  diurnal  variations  of  NO,  N02  and 
0o  in  a  typical  photochemical  pollution  situation.  Nitric  oxide 
reaches  a  maximum  during  the  early  morning  traffic  rush  hours. 
The  rising  sun  initiates  a  series  of  photochemical  reactions 
which  convert  the  nitric  oxide  to  nitrogen  dioxide.  Within  a  few 
hours  the  nitrogen  dioxide  reaches  a  maximum  during  which  it 
photochemi ca 1 1 y  reacts  to  form  ozone  and  other  oxidants.  Both 
the  nitrogen  dioxide  and  the  ozone  eventually  disappear  through 
the  formation  of  nitrated  organic  compounds,  peroxides,  aerosols, 
and  other  terminal  products.  The  cycle  is  repeated  the  following 
day.  If  the  air  mass  is  not  swept  away  or  is  brought  back  by  a 
reversing  wind,  the  residual  gases  add  to  the  new  day's  pollu- 
tants (Tuesday,  1971). 

Nitrogen  dioxide  is  a  redd i sh- brown  gas  with  a  pungent, 
irritating  odor.  At  concentrations  higher  than  those  found  in 
the  atmosphere,  it  forms  a  colorless  dimer,  nitrogen  tetroxide 
(N?0.).  Natural  emissions  are  due  primarily  to  biological  decay 
involving  nitrates  being  reduced  to  nitrites,  followed  by  conver- 
sion to  nitrous  acid  (HNOo).  decomposition  to  nitric  oxide  and 
oxidation  to  ryitrogen  dioxride.  Natural  emissions  are  estimated 
to  be  658  X  10   tons  per  year. 

Nitrogen  dioxide  is  one  of  the  more  invidious  pollu- 
tants. It  is  irritating  and  corrosive  in  itself,  but  more  im- 
portantly, it  serves  as  an  energy  trap  by  absorbing  sunlight  to 
form  nitric  oxide  and  atomic  oxygen: 


312 


— I 1         I — 

I 

STOICHIOMETRIC 


10 


14  16  IB 

AIR-FUEL  RATIO 


22 


Figure  5.1-11 

Effects  of  air-fuel  ratio  on  exhaust  composition 
(approximate  ranges,  not  to  scale). 


313 


Table  5.1-13 

Estimates  of  Nitrogen  Oxide  (NO  )  Emissions 
(United  States),  1940-1970  (106  tons/year) 


Source  category 

191,0 

1950 

I960 

196S 

1969 

1970 

Fuel  combustion  in 

3  5 

4 

3 

5  2 

9  7 

10  2 

10  0 

stationary  sources 

Transportation 

3  2 

."> 

2 

s  o 

10.6 

112 

11   7 

Solid  waste  dispos.il 

0   1 

0 

2 

0  2 

0  4 

0  4 

0  4 

Industrial  process  Itwtsc* 

Neg° 

0 

1 

0    1 

0  2 

0  2 

0.2 

Agricultural  burninc 

0  2 

0 

•  ) 

0  3 

0  3 

0  3 

0.3 

Miscellaneous 

0  K 

0 

4 

0  2 

0  2 

0  2 

0   1 

Total 

7.9 

1(1 

4 

14   0 

21   3 

22  5 

22  7 

Total  controllable' 

7    1 

10 

0 

13  R 

21    1 

22  3 

22  6 

"Negligible  (less  than  0.0.1  X  10' ton.-  year  J 
s  Miscellaneous  sourro  not  included 


Table  5.1-14 

Nitrogen  Oxide  (NO  )  Concentrations  in  Representative 
United  States  Cities  Hourly  Maxima,  ppm,  1962-1968 


Yearly 

maxima 

Geometric 

Highest 

Lowest 

mean 

Chicago,  Illinois 

1.06 

0.69 

0.75 

Cincinnati,  Ohio 

1  42 

0  4') 

0  S3 

Denver,  Colorado" 

0.72 

0.56 

0.62 

Los  Anfreles,  California 

1.35 

0  98 

1.24 

Philadelphia,  Pennsy 

Ivania 

1.79 

0.97 

1.53 

St.  Louis,  Missouri' 

0  92 

0  44 

O.o7 

Washington,  D.C. 

1  30 

0.68 

0  83 

•  1 965-1 96 ^ 

♦  1964-1968 


314 


• 


Hour  of  d»v 


it.. 


Figure  5 

Typical  diurnal  variation  of  NO,  N02,  and  O3  concentrations  in 
Los  Angeles,  California.  Solid  line,  ozone;  long  dashed  line, 
nitrogen  dioxide;  dotted  line,  nitric  oxide. 


40000  KOOO 


KOOO  KOOO 


*lSOl.V(D  ABSOO'HON  S*(CT««»  Of  NO.   »NDN,0. 


^^h^^^_ 


JbOO  «0X 


Figure  5.1-13 
Absorption  coefficients  (1/pl  log1Q  |Q/|)  of  N02  and  N204 
vs  wavelength  and  wave  number,  measured  at  25^C. 


315 


N02  + 


hv 


NO 


0 


(5.1-2) 


The 

and 

t  i  on 

bl  ue 

Figu 

trum 

cate 

-  mi 

ppm 

more 

the 

more 

hove 

and 


atomic  oxygen  is  very  reactive,  forming  ozone  with  oxygen, 

initiating  a  number  of  secondary  photochemical  chain  reac- 

s.   Nitrogen  dioxide  absorbs  light  strongly  in  the  yellow  to 

end  of  the  visible  spectrum  and  the  near  ultraviolet. 

re  5.1-13  (Hall  and  Blacet,  1952)  shows  the  absorption  spec- 

of  nitrogen  dioxide,  and  Figure  5.1-14  (USEPA,  1971)  indi- 

s  the  amount  of  light  absorbed  in  terms  of  parts  per  million 


A  mile  thick  layer  of  air  containing  0.1 
ultraviolet  light  reaching  the  ground  by 
through  a  horizontal  layer  of  10  miles, 
reduces  the  blue  and  ultraviolet  light 
.1-14).   The  yellow-brown  haze  often  seen 
in  a  large  part  due  to  nitrogen  dioxide 
the  aerosols  it  helps  generate  (Carlson  and  Ahlquist,  1969). 


le  concentrations, 
of  N0?  reduces  the 
than  25%.   Viewed 
same  concentration 
than  90%  (Figure  5 
ring  over  a  city  is 


have 

t  i  on 

Gay 

monl 

diff 

var  i 

1  yze 

vapo 

spec 

trat 

from 

meas 

pher 

repo 


Nitrogen  trioxide  ( N  0  3 )  and  nitrogen  pentoxide  ( N  ?  ^  5  ) 
been  postulated  as  intermediates  in  the  photochemical  oxida- 
of  hydrocarbons  and  sulfur  dioxide  (Urone,  1972;  Louw,  1973; 

and  Bufalini,  1971;  Schuck  et  al ,  1966).   They  are  not  com- 

y  observed;  their  concentrations  are  expected  to  be  small  and 

icult  to  measure  in  air  in  the  presence  of  NO,  N0~  and  their 

ous  photochemical  reaction  products.   The  pentoxide  hydro- 

s  readily  with  water  vapor  in  the  air  to 

r  (HN(K)  which  has  been  detected  in  the 

troscopic  means  (Cadle  and  Allen,  1970). 

e   (PAN),  an  eye- i rr i tat i ng  photochemical 
hydrocarbons  and  nitrogen  oxides,  has  been 

ured  in  air  (Hall  and  Blacet,  1952;  Hanst, 

ic  concentrations  as  high  as  0.1  ppm  (500  yg/md)  have  been 

rted  (JSEPA,  1971). 


form  nitric  acid 

stratosphere  by 

Peroxyacetyl  ni- 

reaction  product 

identified  and 

19731).    Atmos- 


5.  1.5 


Ozone  and  Ox  i  dant s 


Ozone,  O3,  is  a  bluish  gas  about  1.6  times  as  heavy  as 
air  and  highly  reactive.  It  is  formed  at  high  altitudes  by 
photochemical  reactions  involving  molecular  and  atomic  oxygen 
(Cotton  and  Wilkinson,  1966).  Its  concentration  in  the  atmos- 
phere depends  upon  the  altitude;  being  greatest  in  the  stratos- 
phere. At  20  km,  its  concentration  is  0.20  ppm.  Its  concentra- 
tion in  rural  areas,  away  from  pollution  sources,  is  approxi- 
mately 0.02  ppm  (USEPA,  1970).  Very  minor  amounts  of  ozone  are 
formed  during  lightning  and  thunderstorms.  Ozone  strongly  ab- 
sorbs ultraviolet  light  in  the  wavelength  region  of  2000-3500  A 
and  very  weakly  at  about  6000  A.  Its  absorption  of  the  energetic 
portion  of  the  ultraviolet  light  prevents  serious  damage  to 
living  tissues  (USEPA,  1970). 


Ozone  and  other  oxidants 
and  hydrogen  peroxide  (Bufalini  et 
luted  atmospheres  as  a  result  of  a 
chemical  reactions  (Tuesday,  1971; 
levels  have  been  found  not  only  in 


such  as  PAN  (Stephens,  1961) 
al ,  1972)  are  formed  in  pol- 

rather  wide  variety  of  photo- 
Leighton,  1961).   High  ozone 

urban  areas,  where  it  follows 


316 


80 

_ 

1                 1                 1___ 

60 

0  1  ppm  ■  mile 

f      _ 

50 

- 

40 

- 

30 

- 

20 

- 

10 

_ 

8 

- 

6 

Ippm-miie                    / 

- 

5 

- 

4 

1 

3  ppm-  mile  / 
1                  1         /        1 

/   10  ppm  -  mile 
/               I                1 

- 

3600       4000       4500       5000      5500       6000       6500       7000 
VIOLET    BLUE    GREEN   YELLOW   ORANGE       RED 

WAVELENGTH.  A 


Figure  5.1-14 

Transmittance  of  Visible  Light  at  Different  N02 

Concentrations  and  Viewing  Distances 


317 


a  trend  of  build-up  during  the  day 
night,  but  also  in  rural  areas.   It  is 
precursors  are    being  transported  long 
be  a  nautral  source  within  rural  areas 


and  break-down  during  the 

believed  that  ozone  or  its 

distances  or  there  may  may 


The  overall  effect  of  ozone  is  a  stinging  of  the  eyes 
and  mucous  membranes.  This  reaction  was  first  noticed  in  Pasa- 
dena, California,  a  suburb  of  Los  Angeles.  Shortly  thereafter, 
polluted  atmospheres  were  labeled  as  "Los  Angeles"  type  because 
of  their  general  oxidative  character.  "London"  (England)  type 
smogs  (i.e.,  smoke  plus  fog)  were  reductive  in  nature  because  of 
their  higher  concentrations  of  sulfur  dioxide  and  soot  from  the 
burning  of  coal.  Figure  5.1-12  shows  the  diurnal  variation  of 
nitrogen  oxides  and  ozone  in  a  typical  Los  Angeles  type  of  photo- 
chemical pollution.  However,  since  London  has  cleared  its  air 
with  a  vigorous  smoke  abatement  program,  it  is  experiencing  Los 
Angeles  type  of  pollution  as  shown  by  Figure  5.1-15  (Derwent  and 
Stewart,  1973). 

To  prevent  possible  serious  health  effects,  an  ambient 
air  quality  standard  maximum  1-hour  concentration  of  240  9/m3 
(C.12  ppm)  has  been  adopted.  Alert  levels  were  set  at  200  g/m 
(0.1  ppm).  Figure  5.1-16  shows  the  number  of  times  that  the 
alert  level  was  exceeded  in  Los  Angeles,  California  for  1967  thru 
1971  (Sagersky,  1973).  A  study  of  oxidant  levels  in  the  San 
Francisco,  California  Bay  Area  show  a  trend  to  smaller  annual 
oxidant  levels  (Cramer,  1973).  However  greater  efforts  are 
needed  to  reduce  these  values.  Two  studies  have  shown  that 
indoor  air  follows  outdoor  air  concentrations  rather  closely 
(Mueller,  et  al,  1973;  Thompson  et  al,  1973). 

A  number  of  areas  have  been  measuring  total  oxidant  and 
ozone  concentrations  above  the  alert  levels  (USEPA).  There  is 
reason  to  believe  that  the  "oxidative"  conditions  in  these  in- 
stances are  not  the  same  as  those  found  in  larger  cities.  Rip- 
perton,  et  al.  (1971),  for  example,  have  found  evidence  for 
tropospheric  photochemical  production  of  ozone. 

Chesick  (1972)  and  others  (IDA,  1973)  have  been  con- 
cerned over  the  effect  that  high-flying  jet  planes  would  have  on 
the  upper  atmosphere.  Water  vapor  and  nitrogen  oxides  emitted 
from  the  jet  exhausts  conceivably  could  react  with  ozone  and 
reduce  its  insulating  quality  for  strong  ultra-violet  rays. 


5.1.6 


Pa  rt  i  cul ate  Matter 


The  particulate  matter  commonly  found  dispersed  in  the 
atmosphere  is  composed  of  many  substances:  flour  ides,  beryllium, 
lead,  and  asbestos  (all  toxic),  aerosols,  dust  and  other  matter 
such  as  wood  waste  generated  by  forest  fires.  Combustion  also 
produces  particles.  Particles  larger  than  10  m  result  from  many 
mechanical  processes  such  as  wind  erosion,  grinding  and  spraying. 
Trees  produce  terpenes  which  can  result  in  organic  particles  and 
oceans  produce  salt  particles  as  well.  Only  three  general  class- 
es of  physical  properties  can  reasonably  be  said  to  apply  to  all 
particulate  matter.   These  properties  all  involve  the  interface 

318 


00    04    08     12     16    20    00    CM    08    12     16    20     00    04    08    12     16    20    00 
July  12.  1972  July  13,  1972  July  14    1972 

Time  of  day 


Figure  5.1-15 

Diurnal  variations  of  air  pollutants  measured  in  London,  England  from 
July  12  to  July  14,  1972.  ■,  Ozone,  ppb;  #.  nitric  oxide,  ppb; 
□  ,  nitrogen  dioxide,  ppb;  O,  hydrocarbons,  ppm. 


319 


JAN     FEB    MAR     APR    MAY     JUN     JUL     AUG     SEP     OCT    NOV   DEC 
MONTH 


Figure  5.1-16 

The  number  of  days  each  month  in  Los  Angeles 
County,  California  during  which  the  ozone 
concentration  has  risen  to  0.1  ppm  or  above. 
Solid  line:  1967;  short  dashed  line:  1968; 
long  dashed  line:  1969,  dashed-dotted  line: 
1970;  dotted  line:  1971. 


320 


between  particles  and  their  surroundings,  and  include  (1)  surface 
properties,  (2)  motion,  and  (3)  optical  properties. 

Surface  properties  include  sorption,  nucleation  and 
adhesion,  among  others.  Sorption  is  the  deposition  of  molecules 
due  to  collision  with  an  object.  If  the  molecules  are  in  a 
supersaturated  atmosphere,  the  deposited  molecules  can  attract 
other  molecules  causing  them  to  condense  out  around  the  original 
deposit.   This  is  nucleation. 


Optical  properties  cover  the  behavior  of  particles 
toward  light.  This  affects  visiblity,  particularly  when  par- 
ticles larger  than  1  urn  are  involved.  These  particles  intercept 
or  scatter  light  in  proportion  to  their  cross- sect i onal  area. 
Smaller  particles  also  scatter  light,  but  according  to  far  more 
complicated  scattering  laws. 


The  concentration  of~suspended  particulate  matter 
ranges  from  less  than  60ug/m   to  1700 ug/m   in  various  Ame 
cities  often  shows  a  notable  annual  variation.   Levels  are  1 
in  summer  and   highest  in  autumn  and  winter.   Losses  of 
radiation  occur  due  to  these  concentrations,  and  can  run  as 
as  one-third  in  the  summer  and  two-thirds  in  the  winter, 
is  also  a  correlation  between  particle  concentrations  and 
fall,  and  particulates  and  visibility.    The  EPA  is  pres 
considering  a  standard  for  fine  particulates  which  are  felt 
the  most  important  in  terms  of  (1)  the  respirable  fraction 
the  catalytic  conversion  to  secondary  contaminants  and  (3) 
bi 1 i  ty  impai  rment . 


whi  ch 
ri  can 
owest 
sol  ar 
high 
There 
rai  n- 
ently 
to  be 
,  (2) 
vi  si  - 


Although  raw  auto  exhaust  contains  some  particulate 
matter  (smoke  particles),  this  is  not  sufficient  to  degrade 
visibility  significantly  when  diluted  several  thousandfold  with 
air.  However,  aerosols  can  be  formed  by  irradiation  of  dilute 
auto  exhaust  or  of  hydrocarbon/NO  mixtures.  Aerosol  formation 
is  much  enhanced  by  the  addition  of  sulfur  dioxide  to  the  mix- 
ture. This  suggests  that  sulfuric  acid  plays  a  role  since  H^SO. 
is  not  only  \/ery    nonvolatile  but  it  also  will  absorb  water. 


5.1.7 


Atmospheric  Chemistry  of  Air  Pollution 


The  solution  of  many  air  pollution  problems  involves 
knowledge  of  the  chemistry  of  the  atmosphere,  when  it  may  be 
termed  "clean"  and  when  it  is  "dirty."   Also,  the  nature  of  air 


321 


pollutants  as  they  react  as  a  whole  must  be  determined.  In 
general,  the  two  classes  of  polluted  smogs  are  called  either  the 
London  type  -  a  reducing  smog  where  contaminants  form  nuclei  for 
condensation  of  water  vapor  into  fogs--or  the  Los  Angeles  type  - 
an  oxidizing  smog  where  contaminants  are  photolysed  to  irritants. 

•   Solar  Radiation 

boj 


The  sun  approaches  a  perfect  black  body 
closely  in  the  region  of  6000°K  (12,}00°F). 


radiator  most 
Its  maximum 
energy  per  wavelength  occurs  at04500A,  while  its  maximum 
photon  emission  occurs  at  6 0  00 A.  Photons  produce  many 
chemical  and  energy  changes  in  matter  at  the  molecular 
level  upon  absorption,  by  upsetting  vibrational,  rota- 
tional and  electronic  balance.  Vibrational  and  rota- 
tional changes  occur  mainly  in  the  infrared  region  while 
electronic  shifts  need  the  higher  energy  of  the  ultra- 
violet range. 

Photochemical  Reactions 


There  are  four 
which  occur  in 
sorption,  ( 3 ) 
react  i  ons .   We 
absorb  photons 
bl e  range ) . 

Absorbers 


main  steps  in  a  photochemical  reaction 

time  sequence:    (1)  Radiation,  (2)  Ab- 

Primary  Reactions,  and  (4)  Secondary 

are    mainly  interested  in  substances  which 

in  the  3000-7000A  spectral  region  (visi- 


Non- absorbers 


j 

j 

N( 

SOp 

Hn6?  -  HNO. 

rch6     -* 

RCO 

RCOO 

Parti  cul ates 


N2 

CO 
CO- 

N(r 

SO-,  - 
RCR 
RCOH 
RCOOH 


H2S04 


(R  denotes  a  rad  i  cal ) 

Oxygen 

The  most  important  photochemical  reactions  involve  the 
very  reactive  single  oxygen  atom. 


0 
0 

J 
J 


0 


0 


OLEFINS — ►Several    Fragments 


NO 


SO 


NO 

SO 


0 


322 


These  atoms  are  produced  by  two  main  reactions 


N02   +   hv 

0,    +   hv 


NO   +   0 


Major  fragments  of  photO' 
chemical  reaction  in  the 
atmosphere   where    h   • 
Plank's  constant  and  v 


the  frequency  of 
t  i  on . 


the  radi  a 


1 


Oxygen  atoms  are  produced  at  the  rate  of  150  pphm  hr' 
but  because  of  their  reactivity,  their  stationary  con- 
centration in  air  is  usually  only  1-2  ppht  (parts  per 
hundred  thousand) . 

Ozone 

Ozone  is  yery  important  as  a  reactant  in  photochemical 
type  smog.  It  is  produced  through  the  photolysis  of 
nitrogen  dioxide  and  the  reactive  oxygen  atom. 


NO, 


0 


hv 

0o 


NO 
0-, 


0 


Ozone  is  a  strong  oxidizer  and  its  main  atmospheric 
reactions  are: 


90% 
Equal  Rate 

Sulfur  Dioxide 


0 


NO 
NO 


■NO 


2 

NO. 


0 


01  ef  i  ns  -►Free  radicals, 
other  organic  fragments 


Sulfur  dioxide  is  the  major  sulfur  containing  compound 
formed  during  fuel  combustion.  Hydrogen  sulfide  is  easily  oxi- 
dized to  sulfur  dioxide  in  air,  especially  in  the  presence  of 
sunlight.  In  sunlight,  sulfur  dioxide  reacts  with  either  atomic 
or  molecular  oxygen  to  form  an  aerosol,  particularly  if  water 
vapor  is  present.  This  aerosol  is  dilute  sulfuric  acid  when 
uncontaminated  with  particulates,  which  are  found  in  reducing 
type  smogs.  Sulfur  dioxide  also  reacts  with  organics  to  form 
various  sulfonic  acids  which  are  also  irritants.  Relative  humid- 
ity plays  a  very  important  role  in  the  photochemical  reactions  of 
sulfur  dioxide  by  determining  part i cul ate-aerosol  formations. 

Organic  Compound  Reactions 

The  range  of  classes  of  organic  compounds  emitted  from 
various  processes  and  industries  is  very  wide.  Most  of  the 
higher  molecular  weight  products  settle  rapidly,  but  short  carbon 


323 


chain  molecules  tend  to  be  more  reactive  as  ionic  character 
outweighs  the  usual  covalent  nature  of  organic  materials  and  they 
are  very  important  as  irritant  precursors.  Absorption  of  photons 
often  leads  to  dissociation  into  free  radicals  -  short  fragments 
with  extra  electrons  which  are  extremely  reactive.  Olefins, 
aldehydes,  ketones,  peroxides,  are  classes  which  easily  absorb 
photons  and  form  free  radicals,  and  are  among  the  usual  products 
of  combustion,  especially  from  oil  base  fuels. 

Nitrogen  Oxide  Reactions 

Oxides  of  nitrogen  are  formed  in  practically  all  combus- 
tion processes  in  air,  but  the  diurnal  peaks  and  valleys  of 
concentration  are  a  matter  of  concern  in  air  pollution  studies 
due  to  the  high  buildup  in  the  morning  hours  within  urban  areas 
as  vehicular  traffic  reaches  a  peak.   The  sequence  of  reactions 


NO 


NO 


hv 

0 


2 


0 


NO 

°3 

NO 


0 


2 


0 


is  the  fastest,  most  important,  and  results  in  the  highest  con- 
centrations of  actual  and  potential  irritant  concentrations  in 
air  pollution  -  atmospheric  chemistry.  Second  in  importance, 
photochemically,  is  olefin  photolysis  and  ozone  -  organic  mole- 
cule interaction.  Other  nitrogen  oxide  reactions  of  less  im- 
portance are  : 

N02   + 
NO    + 
N2°5   +   H20-*-2HN03 
Non-photochemical  Reactions 

A  secondary  reaction  following  photochemical   reaction 
which  is  very    important  is  : 

On   +   Olefins  -^-free  radical  fragments 

Olefins  are  the  most  important  beginning  class  of  organic  com- 
pounds for  production  of  irritants  and  phytotox i cants . 

Reaction  with  water  vapor: 

NOx   +   H2°"*"HN02   "   HN03 
S03   +   H20-»-H2S04 


324 


Other  inorganic  and  organic  classes  of  compounds  are 
also  emitted  to  the  atmosphere  such  as  flourides  which  quickly 
react  with  various  surfaces,  ammonia  which  forms  acids,  hydrogen 
sulfide  which  reacts  with  organics  and  forms  sulfates,  carbon 
monoxide  which  slowly  oxidizes  to  carbon  dioxide  and  organic 
amines  which  oxidize  to  acids.  The  above  reactions  are  generally 
not  of  importance  except  in  small  localized  areas. 

Particulate  Material  Reactions 

Particulate  matter  consists  of  an  entirely  different 
size  category  than  we  have  examined  thus  far.  As  such,  it  pro- 
vides reactive  surfaces  and  can  act  as  a  third  body  and  catalyst. 
Interaction  with  a  particulate  surface  can  cause  either  an  energy 
level  change  or   complete  chemical  change. 


Examples  of  the  former  are: 

*■      M-*^0^22   +  M  Change  in  absorption 


0X12 


CH3   + 


M 


CHn   +   M  Termination  of  free  radical 


Examples  of  the  latter  are 
Zn  0(M)   +   H20   vapor-^ 
where  : 


-H202   + 


X  =  is  the  wavelength  and 

M  =  represents  an  energy- accept i ng  third  body 


Catalyzed  by  photons 
S02   +   H20   drop — » 


■H2S03 


drop 


H2S04»  H20   drop  +   Ca  C03-»-CaS04   +   C02  +  H20  Change 
i  n  part icul ate 

Kinetics  in  Atmospheric  Chemistry 

Without  becoming  involved  in  the  rigors  of  kinetic 
theory,  a  few  elementary  definitions  should  be  stated.  The  basis 
for  determining  the  importance  of  any  photochemical  reaction, 
stationary  concentration,  rate  of  reaction,  etc.,  is  the  Stark- 
Einstein  Law  which  states  that  one  photon  must  be  absorbed  to 


ini ti ate  photol ysi  s. 
equat i  on  : 


From 


this 
I 


theory  is  derived  the  important 


Where  k   is  the  specific  absorption  rate, 


of  absorption,  j  is  a  conversion  factor, 
tion  of  the  absorbing  substance.    k 


I  is  the  rate 
and  c  is  the  concentra- 
represents  the  average 


fraction  of  absorbing  molecules  which  receive  photons  per  unit 


325 


is  given  by : 


time.  Primary  quantum  yield  is  very  important  as  it  tells  us 
what  percent  of  molecules  that  absorb  photons  will  acutally  react 
to  the  absorbed  energy  via  a  specific  process.  Absorption  of  a 
may  result  either  in  energy  level  change,  shown  by  flores- 
or  chemical  change,  shown  by  dissociation  or  direct  reac- 
The  rate  of  formation  of  excited  molecules  A 

d  (A1). 

1  a  a 

c,   the  concentration  of  the  absorber. 
For  secondary  photochemical  reactions  rate 
important.   For  a  bimolecular  reaction  A   +   B — ►C 
decrease  in  concentration  of  A  will  be: 


photon 
cence  , 
t  i  on . 


(A) 


dt 


=  I   =  k   (A)  = 


kac 


where 


constant 
+   D, 


1  s 

the 


d  (A)  _ 


dt 


kj  (A)  (B) 


where  K,  is  the  rate  constant  of  the  reaction.  In  general,  the 
larger  the  rate  constant,  the  more  probable  and  more  important 
part  the  reaction  plays  in  the  atmosphere. 


Thus,  a  knowledge  of  what  general  reactions  take  p 
in  the  atmosphere  under  different  meterol og i cal  conditions, 
help  answer   questions   concerning   the   relative   importance 
contaminating  substances.   From  a  meteorological  point  of  v 
relative  humidity  and  percent  possible  sunshine  are  the 
important   parameters  to  consider.    This   is  because  nitr 
dioxide- ol efi n  photolysis  and  the   reactions  which  follow 
sunshine  dependent  and  the  sulfur  di ox i de- part i c u 1  ate  react 
are  largely  humidity  dependent.   Further  consideration  invo 
precipitation  which  functions  as  a  removal  method,  and  low 
speed  which  causes  the  atmosphere  to  function  as  a  stable  r 
tion  vessel.   Extremes  of  temperature  either  help  catalyze  ph 
chemical  reactions,  as  in  los  Angeles,  or  enhance  fog  forma 


1  ace 

can 

of 

i  ew , 

most 

ogen 

are 

ions 

1  ves 

wi  nd 

eac- 

oto- 

t  i  on 


of  part icul ate 


S0?  reactions,  as  in  London. 


The  state  of  knowledge  of  atmospheric  chemical  reactions 
and  interactions  leaves  a  good  bit  to  be  desired  as  the  subject 
is  ^ery  complex.  Experiments  in  all  the  areas  discussed  are 
increasing  our  knowledge  and  the  total  picture  is  slowly 
emergi  ng . 


326 


5.2 


AIR  POLLUTION  EFFECTS  ON  AIR  QUALITY  RELATED  VALUES 


A  pollutant  can  be  roughly  defined  as  a  harmful  chemical 
or  waste  material  which  is  discharged  into  the  atmosphere  or 
water.  Pollutants  add  stress  to  the  biosphere,  thereby  affecting 
the  quantity,  quality  or  diversification  of  populations.  State 
and  local  governments  have  regulated  air  pollutants  for  many 
years,  but  the  first  federal  legislation  was  not  seen  until  1955, 
with  the  establishment  of  an  air  pollution  research  program. 
Public  awareness  of  air  pollutant  hazards  has  increased  tremen- 
dously since  that  time,  and  culminated  in  the  enactment  of  the 
1977  Clean  Air  Act  Amendments.  As  stated  in  the  Act,  the  purpose 
of  this  legislation  is  "to  protect  and  enhance  the  quality  of  the 
Nation's  air  resources  so  as  to  promote  the  public  health  and 
welfare"  (CAAA,  1977).  Falling  under  the  umbrella  of  public 
health  and  welfare  is  not  only  man,  but  all  air  quality  related 
values,  including  soils,  vegetation,  wildlife,  watersheds,  arch- 
aeology, and  visibility.  In  general,  all  aquatic  and  terrestrial 
flora  and  fauna  and  their  habitats  must  be  evaluated  to  determine 
threshhold  levels,  or  the  point  at  which  a  pollutant  can  no 
longer  be  tolerated  by  a  population.  Section  5.1  detailed  the 
formation  of  air  pollutants.  This  section  will  describe  the 
effect  of  these  pollutants  on  the  environment. 

As  depicted  in  Section  2,  the  majority  of  BLM  lands  are 
situated  within  the  500-3000  foot  elevation  range;  however,  areas 
as  low  as  sea  level  and  as  high  as  6000  feet  are  also  found 
within  the  Ukiah  District.  The  major  vegetation  types  concen- 
trated in  these  areas  include  redwood,  Douglas  fir,  fir,  pine, 
woodland,  plains  grass,  chaparral,  saltbush  and  marsh.  While 
pollutant  effects  have  been  felt  severely  by  California's  agri- 
cultural crops,  these  will  not  be  discussed  to  the  extent  of  the 
aforementioned  vegetation  types,  as  they  are  not  of  primary 
importance  to  the  BLM.  Effects  on  fisheries  and  native  animals 
will  also  be  discussed  to  the  extent  that  they  have  been  re- 
searched. It  is  also  valuable  to  note  that  effects  of  air  pol- 
lutants have  been  seen  in  arc heol og i c a  1  sites,  such  as  ancient 
Grecian  ruins,  and  in  geology  throughout  Europe  and  the  Eastern 
United  States.  Although  these  later  effects  have  not  been  seen 
or  researched  in  California,  they  may  become  a  serious  future 
concern  . 

Part i  cul ates 

Within  the  BLM  lands  in  the  Ukiah  district,  man-made 
emission  densities  for  particulates  range  from  0-12,000  tons  per 
year,  with  the  highest  emissions  density  being  found  in  Humboldt 
County.  Particulates  may  be  defined  as  dispersed  matter  in  the 
liquid  or  solid  phase.  A  few  of  the  wide  variety  of  chemical 
constituents  of  particulate  matter  are  listed  in  Table  5.2-1. 
Individual  particles  range  from  0.005  to  500  ym  in  diameter. 
While  emission  control  devices  can  remove  up  to  99%  of  stack 
particulate  emissions,  their  efficiency  becomes  considerably 


327 


lower  for  particles  in  the  size  range  of  0-5  urn.  These  parti- 
cles, therefore,  are  more  readily  emitted  and  can  be  transported 
over  great  distances.  Also,  this  size  range  is  easily  passed 
into  the  lungs  of  man  and  animals,  making  these  smaller  particles 
the  most  deleterious. 

The  effect  that  particulate  matter  will  evoke  depends 
largely  on  its  chemical  composition.  In  general,  most  trace 
elements  deposited  on  soil  will  remain  in  the  surface  layers, 
except  in  very  acidic  or  sandy  soils.  While  this  accumulation 
serves  to  protect  groundwaters  from  contamination  in  the  short 
term,  in  time,  natural  processes  such  as  surface  runoff,  erosion, 
and  windblown  dust  may  serve  to  contaminate  aquatic  biota.  One 
of  the  most  important  factors  in  determining  potential  soil 
effects  is  the  concentration  of  naturally  occurring  endogenous 
trace  elements.  Impacts  of  added  particulates  will  be  more 
severe  in  areas  where  endogenous  concentrations  are  currently 
close  to  the  tolerance  limit  for  any  population  member.  On  the 
other  hand,  benefit  in  a  deficient  area  may  be  gained  by  the 
addition  of  essential  trace  elements,  such  as  copper,  boron, 
molybdenum,  zinc  and  manganese,  (Dvorak,  1978). 

Effects  on  vegetation  will  ^ary  considerably.  Visible 
effects  range  from  chlorosis,  necrosis  and  discoloration  to 
stunting  and  deformation.  These  may  be  linked  to  changes  in 
enzymatic  reactions  or  metabolic  processes,  such  as  photosynthe- 
sis and  respiration  and  will  depend  not  only  on  the  chemical 
composition  of  the  particulate  matter,  but  also  on  the  exposure 
concentration,  and  plant  species.  In  a  natural  vegetation  area, 
such  as  the  forests  of  the  Ukiah  District,  where  the  majority  of 
the  vegetation  is  recycled  rather  than  consumed,  concentration 
build-up  will  exceed  that  found  in  agricultural  areas. 

As  trace  elements  collect  in  the  edible  plants  the 
entire  food  chain  will  be  impacted.  Herbivorous  wildlife  are 
affected  through  ingestion  and  also  by  the  loss  of  sensitive 
plant  species  within  their  habitat.  These  factors  may  contribute 
to  reduced  numbers  of  wildlife  species  or  possibly  the  elimina- 
tion of  certain  species  from  the  affected  environment.  Inges- 
tion, along  with  inhalation,  are  the  two  modes  of  entry  of  trace 
elements  into  animals.  Several  effects  of  these  elements  are 
detailed  in  Table  5.2-1. 

Sulfur  Dioxide 

All  areas  monitoring  SO?  levels  within  the  Ukiah  Dis- 
trict have  S02  concentrations  below  one-tenth  pphm  as  shown  in 
Figure  5.3-7  and  are  classified  either  as  better  than  national 
standards  or  unclassified.  However,  this  cl ass i f i cai ton  does  not 
preclude  effects  from  being  seen  within  this  area.  Sources  of 
SO?  and  sulfur  compounds  include  high  sulfur  fuel  combustion 
(SO?),  anaerobic  decompostion  of  plants  material  (H?S),  and  the 
industrial  production  of  sulfuric  acid.  Coal-fired  power  plants 
alone  account  for  40%  of  total  U.S.  sulfur-compound  emissions. 


328 


Table  5.2-1 
General  Manifestations  of  Trace  Elements  in  Animals 


Target  organs  or  characteristics 

Element 

of  toxicity 

Comments 

Arsenic 

Has  been  associated  with  increased 

Non-accumulative  in  animals  but  has 

incidence  of  lung  cancer. 

affinity  for  hair,  nails,  and  skin. 

Bar- .. 

Has  strong  stimulating  effect  on  all 

Poorly  absorbed  with  generally  little 

muscles  in  acute  poisoning. 

retention  in  tissue. 

Beryll ium 

Characteristic  granuloniatous  changes  of 

Via  inhalation,  beryllium  is  corre- 

lung tissue  is  brought  about  by  long- 

lated  with  an  interference  in  the 

term  exposure. 

passage  of  oxygen. 

CdC- 

Is  linked  with  the  incidence  of  hyper- 

Accumulative in  all  animals  and  toxic 

tension  in  experimental  animals. 

to  all  systems  and  functions  in  humans 
and  animals. 

Cobal t 

Causes  changes  in  lungs  typical  of 

With  increasing  age,  the  body  burden 

pneumoconiosis.  Also  causes  induction 

of  cobal t  diminishes . 

of  polycythemia  in  many  species. 

Copper 

Associated  with  induction  of  haemolytic 

In  excess,  results  in  some  accumulation 

disease,  especially  in  certain  species. 

in  the  tissue,  especially  in  the  liver. 

Chrc  " j 

hexavalent  corpounds  extremely  toxic  to 

In  particular,  the  respiratory  tract 

body  tissue.   Insolutle  forms  retained 

and  fat  tissue  accumulate  this  metal. 

in  lung  tissue. 

Fluoride 

Contributes  to  dental  fluorosis  in 
2  n  i  ma  1  s . 

Deposits  in  bone  tissue. 

Lead 

".-;.'..  absorbed  lead  is  mostly  retained 

Has  strong  affinity  to  accumulate  in 

in  trie  body  as  lead  triphosphate,  espe- 

bone  tissue. 

cia""     liver,  kidneys,  pancreas, 

and  aoi  " 

Manganese 

Acute  intoxication  involves  changes  in 

Most  amounts  taken  into  the  body  are 

the  respiratory  system,  whereas  chronic 

retained,  especially  in  liver  and 

poisoning  affects  the  central  nervous 

lymph  nodes. 

system. 

Mercury 

Organic  forms  have  effects  on  brain 

Can  bioaccumulate  in  tissues  of 

tissue.  The  inorganic  form  is  more 

animal s. 

linked  to  damage  to  liver  and  kidneys. 

1 

Associated  with  degenerative  changes 
in  1 iver  eel  1 s. 

Can  accumulate  in  tissues. 

Nicl 

Associated  with  cancer  of  lungs. 

Very  poorly  absorbed  from  gut. 

Selenium 

Associated  with  alkali  disease  in 

Is  converted  in  the  body  into  a 

cattle. 

volatile  compound  which  is  eliminated 
through  breatn  and  sweat. 

Vanadiu 

Is  found  to  inhibit  the  synthesis  of 

Vanadium  salts  are  poorly  absorbed 

cholesterol  and  other  lipids.  Other 

from  the  gastrointestinal  tract. 

compl ications  leading  to  cardiovas- 

cular diseases  are   also  prevalent. 

Zi  nc 

Intoxication  produces  either  lung  or 

Absorbed  or  injected  zinc  is  incor- 

intestinal tract  manifestations. 

porated  at  varying  rates  into  dif- 
ferent tissue,  indicating  varying 

— — _ — _____ 

rates  of  zinc  turnover. 

Source:  Dvorak,  1978 


329 


Highest  levels  of  exposure  from  such  plants  may  be  expected  in 
the  Western  U.S.,  where  scrubbers  are  not  used  (Dvorak,  1977). 
Since  many  BLM  land  areas  contain  major  coal  reserves,  this  may 
be  an  area  of  great  concern  in  the  future. 

The  effects  of  gaseous  air  pollutants  such  as  S0~  on 
plants  and  animals  are  typically  classified  according  to  the 
exposure.  Acute  effects  are  those  related  to  exposures  of  short 
duration  (up  to  one  month)  and  comparatively  high  concentrations. 
Chronic  effects  are  evoked  when  organisms  are  exposed  to  low- 
level  concentrations  for  periods  of  one  month  to  several  years. 
Long-term  effects  are  the  result  of  exposures  lasting  for  decades 
or  longer.  These  are  characterized  by  abnormal  changes  in  the 
ecosystem  or  subtle  physiological  changes  in  the  organism.  Acute 
injury  to  vegetation  from  SOo  exposured  is  characterized  by 
collapsed  marginal  or  intercostal  leaf  areas,  which  later  become 
dried  and  bleached  to  an  ivory  color  in  many  species,  or  brownish 
red  or  brown  in  other  species.  Chronic  injury  is  seen  as  leaf 
yellowing  from  the  margins  to  intercostal  areas.  Both  acute  and 
chronic  injuries  can  result  in  death  of  the  plant.  Long-term 
injury  may  also  occur  without  visible  symptoms,  but  may  be  im- 
plied by  subtle  changes  in  the  ecosystem  (Dvorak,  1976). 

Sensitivity  to  SO,-,  will  vary  according  to  the  plant 
species  and  microclimate  in  which  it  exists.  Several  vegetation 
types  native  to  BLM  lands  in  the  Ukiah  District  have  been  listed 
in  Table  5.2-2,  according  to  the  sensitivity  level  as  determined 
by  the  reference.  Plants  may  also  be  affected  in  the  following 
ways:  increased  respiration,  decreased  protein  content  and 
metabolism,  decreased  sugar,  vitamin  and  starch  content,  de- 
creased glucosidase  activity  and  altered  terpene  activity. 


Studies 


and  S0o  with   N0o  effects 


on 


concerning  S0?  u..u  ^w~  »,  iuh  mw~ 
desert-type  vegetation  of  the  Southwestern  U.S.  have  been  con- 
ducted by  Hill,  et.al.  (1974).  The  area  studied  included  Utah 
and  New  Mexico  at  elevations  of  4500  to  6500  feet.  Using  con- 
centrations of  0.5  to  11  ppm  S0o  +  0*1  to  5  ppm  N 0 «  for  2-hour 
fumigation  periods,  the  study  ranked  sensitivity  according  to 
Table  5.2-3.  Studies  have  been  ranked  together  as  no  synergistic 
effects  were  found.  Common  injuries  appeared  as  leaf  necrosis 
and  interveinal  patches  of  necrotic  tissue  on  broad  leaves. 
Color  of  injured  tissue  varied  from  tan,  gray  brown  and  yellow  to 
rusty  brown  depending  on  the  species.  With  desert  plants,  often 
the  entire  leaf  was  injured.  Results  of  the  study  suggested  that 
middle-aged  and  older  leaves  were  more  sensitive  than  younger, 
expanding  leaves  and  years  with  unusually  high  rainfall  could 
cause  more  severe  injury  to  desert  type  vegetation  (Hill,  1974). 

Caldwell,  et  al  (1976)  also  studied  S02  effects  on 
southwestern  U.S.  desert  vegetation.  Fumigation  studies  were 
conducted  in  the  Catalina  Mountains  near  Tucson  at  7700  ft. 
Results  were  similar  to  those  by  Hill,  et .  al .  (1974);  however, 
Caldwell  noted  that  SO-  will  injure  vegetation  to  a  maximum 
distance  of  30  to  40  miles.   Past  that  point,  the  plume  will  be 


330 


Table  5.2-2 
SCL  Injury  to  California  Native  Vegetation 


Common  Name 

Sensitivity 

Reference 

Pine,  Jack  &  Red 

Sensitive 

Davi 

s  &  Wilhour 

(1976) 

Douglas  Fir 

Intermediate 

Dav 

s  &  Wilhour 

(1976) 

Fir,  Basalm  &  Grand 

Intermediate 

Dav 

s  &  Wilhour 

(1976) 

Pine,  Lodgepole 

Intermediate 

Dav 

s  &  Wil hour 

(1976) 

Pine,  Ponderosa 

Intermediate 

Dav 

s  &  Wilhour 

(1976) 

Pine,  Western  White 

Intermediate 

Dav1 

s  &  Wilhour 

(1976) 

Fir,  Silver 

Resistant 

Dav 

s  &  Wilhour 

(1976) 

Fir,  White 

Resistant 

Davis  &  Wilhour 

(1976) 

Pine,  Limber 

Resistant 

USDA  (1973) 

Pine,  Mugs 

Resistant 

Davis  &  Wilhour 

(1976) 

Pine,  Pinton 

Resistant 

Davis  &  Wilhour 

(1976) 

Fir,  Subalpine 

Sensitive 

Davis  &  Wilhour 

(1976) 

Pine,  Short  Leaf 

Intermediate 

Treshow  (1970) 

Sagebrush,  Big 

Intermediate 

Davis  &  Wilhour 

(1976) 

Source:  Dvorak,  1978 


331 


Table  5.2-3 
Percent  of  the  Total   Leaf  Area   Injured  by  Different  Concentrations 
of  SO2  in  Two-Hour  Field  Fumigation  Studies 


Average  percent  injury 


Number  of  replications 


Species 


SO; 

.5 
ppm 

1 
ppm 

2 

ppm 

4 
ppm 

6 

ppm 

10 
ppm 

0 

0 

0 
0 

22 

0 

10 

60 

0 

0 

0 

16 

38 

0 

0 

10 

15 

0 

0 

0 
20 

78 

0 

0 

0 

1 

1 

0 

0.2 

3 

0 

22 
0 
0 

33 

80 

0 

0 

21 

0 

4 

9 

2 

0 

0 

1 

5 

2 

0 

30 
0 
0 

50 

50 
0 
0 

0 

0 

0 

0 
0 

0 

0 

0 

13 

96 
0.6 

0 

0 
5 

0 
0.4 

10 
25 

0 

2 

5 

7 

0 

1 

40 

0 

0 

0 

5 

» 

0 

6 
0 
0 

14 
0.2 

0 

3 

0 

15 

80 

0 

0.4 

8 
0 

16 

40 

0 

0 
0 

0 

0 

0 

43 

2 

0 

19 

95 

.5124  6  10 

ppm     ppm      ppm       ppm       ppm      ppm 


Abies  concolor 

(White  fir) 
Abies  lasiocarpa 

(Alpine  fir) 
Acer  glabrum 

(Rocky  Mountain  maple) 
Achillea  millefolium 

(Yarrow) 
Agoseris  glauca 

(Mountain  dandelion) 
Agropyron  caninum 

(Wheatgrass) 
Agropyron  desertorum 

(Crested  wheatgrass) 
Ambrosia  sp. 

(Ragweed) 
Amelanchier  utahensis 

(Utah  serviceberry) 
Antennana  sp. 

(Pussytoes) 
Arabis  pulchra 

(Rockcress) 
Artemisia  ludoviciana 

(Louisiana  sage) 
Artemisia  tridentata 

(Big  sagebrush) 
Aster  chilensis 

(aster) 
Astragalus  utahensis 

(Locoweed) 
Atriplex  canescens 

(Fourwing  saltbush) 
Atriplex  confertifolia 

(Shadscale) 
Betula  occidentals 

(River  birch) 
Bouteloua  barbata 

(Six-weeks  grama  grass) 
Bouteloua  gracilis 

(Elue  grama  grass) 
Bromus  ciliatus 

(Fringed  brome) 
Bromus  inermis 

(Smooth  brome) 
Bromus  tectorum 

(Cheatgrass) 
Cercocarpus  ledifolius 

(Curl-leaf  mountain  mahogany) 
Cercocarpus  montanus 

(Mountain  mahogany) 
Chenopcaium  fremontn 

(Goosefoot) 
Chrysothamnus  nauseosus 

(Big  rubber  rabbitbrush) 
Chrysothamnus  stenophyllus 

(Little-leaf  rabbitbrush) 
Chrysothamnus  viscidiflorus 

(Sticky-flower  rabbitbrush) 
Cirsium  undulatum 

(Thistle) 
Clematis  ligusticifolia 

(Western  virgin's  bower) 
Cleome  sp. 

(Beeplant) 
Cowama  mexicana 

(Cliffrose) 
Cryptantha  humilis 

(Catseye) 
Cynoglossum  officinalis 

(Houndstongue) 
Descurainia  californica 

(Tansy  mustard) 
Ephedra  viriais  (Mormon  tea) 
Equisetum  sp.  (Horsetail) 
EriC/gCnum  tacemosum 

(Buckwheat) 
Euphoroia  serp/lhfoha 

(Spurge) 
Eurotia  lanata  (Wmterfat) 
Geranium  ricnardsonn 

(Vvhite  geranium) 
Gilia  sggregata  (Scarlet  f  Hia) 


12 

6 

7 


15 

0 
86 

14 


1 

1  1 

3  2 


1  1 


3  2 


2  3 


2 

5 
3 

1 
1 
4 
1 

1 

1 

15 

1 

2 
2 

2 


10 

2 
2 


9 

1 

2 

1 

1 

3 

1 

5 

1 

1 

1 

1 

2 

7 

1 

4 

1 

1 

3 

Table  5.2-3   (cont.) 


Average  percent  m|ury  Number  of  replications 


SO: 


.5  1  2  4  6  10  .5  1  2  4  6  10 


Species  ppm  ppm  ppm  ppm  ppm  ppm  ppm      ppm      ppm       ppm        ppm 


ppm 


0 

100 

0 

0 

40 

75 

0 

0 
0 

0 

0 

0 

28 

0 

0 

25 

2 

1 

1 

1 

2 

5 

1 

9 

1 

1 

2 

1 

4 

1 

1 

1 

2 

2 

7 

9 

3 

1 

1 

14 

17 

1 

Gutierrezia  sarothrae  0  0  21  78  4  2  13 

(Snakeweed) 
Hackelia  floribunda  0  0  11 

(Stickseed) 
Haplopappus  nuttalln 

(Goldenweed) 
Hedysarum  boreale 

(Sweet  vetch) 
Hjlaria  jamesii  0 

(Galleta) 
Hymenoxys  richardsonii 

(Hymenoxys) 
Juniperus  osteosperma 

(Utah  juniper) 
Juniperus  scopulorum  0  0  0  25  1 

(Rocky  Mountain  juniper) 
Lepidium  sp.  0  1 

(Peppergrass) 
Machaerantbera  canescens  25 

(Spiny-leafed  aster) 
Mahonia  repens  0  0  0  1 

(Oregon  grape) 
Malacothnx  sonchoiaes  0 

(Desert  dandelion) 
Munroa  squamosa  0  0  0  0  3  2 

(False  buffalograss) 
Oenothera  sp.  6  12  5  3  3  1 

(Evening  primrose) 
Opuntia  sp.  0 

(Prickly  pear  cactus) 
Oryzopsis  hymenoides  0.2  2  2  17  29  90  4  9  8 

(Indian  ricegrass) 
Oryzopsis  micrantha  4 

(Ricegrass) 
Pachystima  myrsinites  0  1 

(Mountain  lover) 
Penstemon  sp.  15  70  1 

(Penstemon) 
Phacelia  corrugata  0  2 

(Scorpion  weed) 
Picea  pungens  0  0  0  12  3 

(Blue  spruce) 
Pmusedulis  0  0.06  2  4  9 

(Pinyon  pine) 
Pinus  ponderosa  0  0  1  2  3 

(Ponderosa  pine) 
Poa  pratensis  0  0  7  15  3 

(Kentucky  blue  grass) 
Populus  angustifolia  002  11  20  36252 

(Narrowleaf  cottonwood) 
Populus  tremuloides  0  0  012  7  0  123  11  8 

(Quaking  aspen) 
Pseudotsuga  taxifolia  0  0.8  5  4 

(Douglas  fir) 
Quercus  gambelii  0  8  1 

(Gambel  oak) 
Rhus  trilobata  0.3  0  1 

(Squawbush) 
Rosa  woodsii  0  1  15  90  60  6  3  5  2 

(Wild  rose) 
Salsola  kali  7  3  3  2 

(Pussian  thistle) 
Senecio  streptanthifolius  0  8  3  1 

(Groundsel) 
Silene  menziesii  (Catchfly)  0  1 

Sitanion  hystrix  0  1 

(Squirreltail) 
Sphaeralcea  sp.  0  0.03  17  40  2  4  3 

(Cutleaf  globe  mallow) 
Sphaeralcea  parvifolia  20  22  43  38  30  2  7  3  7  2 

(Globe  mallow) 
Sporobolus  cryptandrus  000  0  0  3287 

(Sand  dropseed) 
Stipa  occidentalis  0  73  4 

(Needlegrass) 
Symphoncarpos  oreophilus  0.3  6  18  32  4  4  6  3 

(Snowberry) 
Tragopoeon  dub'us  0  4  8  2  2  3 

(GoatSLearc') 
Tnsetum  spicatum  (Tnsetum)  90 

Viola  sp.  (Viola)  25  2 

Yucca  sp  (Yucca)  0 

Zygadenus  paniculatus  0  0  13  1  1  2 


(Deatn  camas) 


333 


too  dilute  to  cause  any  effects.  The  most  resistant  species 
(Douglas  Fir,  Pinon  Pine,  and  Arizona  Ponderosa)  all  grow  in 
higher  elevations  and  the  three  most  sensitive  species,  (Good- 
ding's  Willow,  Cocklebury,  and  Sunflower),  all  grow  in  low,  wet 
areas.  Humidity  plays  a  role  in  determining  the  threshhold  value 
for  SOp  injury.  Higher  humidities  tend  to  lower  the  SO-  levels 
needed  to  create  a  response.  Generally,  injury  was  proportional 
to  new  growth  and  smaller,  less  developed  individuals  were  more 
sensitive.  Symptoms  were  visible  within  one  and  one-half  days 
after  fumigation.  High  temperature  and  wind  increased  symptom 
maturation  (Caldwell,  1976). 


Plants,  in  general, 
SOp  injury;  however,  animals 
in  habitat  or  food  species, 
occur.    Sulfur  is  known  to 
protein  synthesis.    Enzymes 
catalase  are    particularly  sensitive, 
increased  airway  resistance,  decreased 


are    more  sensitive  than  animals  to 

are  impacted  indirectly  by  changes 

Direct  effects  in  animals  also 

inactivate  enzymes,  thus  altering 

such  as  diastase,  peroxidase  and 

In  man,  the  effects  may  be 

mucus  flow  rate,  increased 


susceptibility  to  respiratory  infection  and  chronic  respiratory 
disease.  Six  to  ten  exposures  of  0.2  ppm  for  10  seconds  each  has 
produced  altered  e  1  ect r o- e nee pha 1 o grams  .  Recent  population 
studies  indicate  that,  at  lower  concentrations,  inhaled  sulfuric 
acid  and  specific  sulfates  produce  even  greater  irritability  than 
from  S09  (Coffin  and  Knel son  1976). 


Studies  by  Colucci  (1976) 
pulmonary  function  in  laboratory 
6.75  ppm  for  two  to  three  hours, 
with  chronic  concentrations  of 
Epidemiological  studies  indicate 
ppm  can  adversely  affect  human 
animals  with  higher  ventilation 
tissue  per  body  size  would  be 
Results  of  Colucci 's  studies  may 


show  deleterious  effects  to 

animals  with  acute  exposures  of 

Pulmonary  dysfunction  occurred 

4.86  ppm  for  several   months. 

that  chronic  exposures  of  0.04 

populations.    It  follows  that 

rates  or  more  exposed  mucosal 

more  sensitive  (Dvorak,  1976). 

be  reviewed  in  Table  5.2-4. 


Another  integral  part  of  SO^  emissions  concerns  the 
combination  of  S02  and  nitric  oxide  as  acid  precipitation.  The 
acidification  of  many  freshwater  lakes  and  streams  has  become  an 
area  of  extreme  concern  in  Northern  Europe  and  Northeastern  North 
America.  The  acidity  of  precipitation  has  been  on  the  rise  in 
this  area  since  the  early  190  0's  because  of  increased  emissions 
of  acid-forming  sulfur  and  nitrogen  compounds.  This  acidic 
precipitation  can  lower  the  pH  of  soils  and  natural  waters  caus- 
ing mineral  leaching  and  damage  to  many  aspects  of  the  biosphere. 

Studies  by  Hendrey,  et .  al  .  (1976)  show  that  the  acidi- 
fication of  freshwaters  produces  many  changes  in  the  aquatic 
environment.  In  six  Swedish  lakes,  where  pH  had  decreased  by  1.4 
to  1.7  units  during  a  forty-year  period,  bacterial  activity  had 
apparently  decreased,  leaving  dense  amounts  of  fungal  hyphai  on 
sediment  surfaces.  Decreased  pH  was  believed  to  be  the  cause  for 
the  shift  in  dominance  of  organisms  from  bacteria  to  fungi,  with 
the  consequent  decrease  in  oxygen  consumption  and  interference 
with  nutrient  recycling  by  microdecomposers  (Hendry,  1976). 


334 


Table  5.2-4 


Summary  of  Toxicological  Experiments  with  Sulfur  Dioxide  ( SOp )' 


Concentration 

S~ecies 

(10-  _c 

Duration 

Effects 

'•'on  key 

<0.034 

78  weeks 

None 

•  ey 

<0.078 
.7 

None 

Impaired  bronchial  clearance 

Dog 

0.13 

21  hours/day  for  620  days 

None 

- 

0.13 

78  weeks 

None 

Guinea  | 

<0.13 

22  hours/day  for  365  days 

None 

Dog 

0.13 

21  hours/day  for  225  days 

Increased  pulmonary  resistance 

:;: 

0 

.026-0.079 

12  hours/day  for  4  months 

None 

Mouse 

c 

.18  -0.26 

7  days 

Increased  sensitivity  to  pneumonia 
infection 

:  : :  : 

0.26 

3-10  days 

Increased  S-sulfonate  clearance 

Mouse 

Up  to  72  hers 

Lesions  in  respiratory  tract 

'■  3t 

6  hours/day,  5  days/week 
for  11 3  days 

None 

-  c 

6  hours/day,  5  days/week, 
for  22  days 

40r  mortality 

6  hours/day,  5  days/week, 
for  12  days 

--90  mortality 

• ==  pig 

6  hours/day.  for  2C  days 

None 

' 

0.52 

Increase  in  pulmonary  flow 
resistance 

-  DO  i  X 

14  and  62  hours 

Formation  of  S-sulfcnate 

":  .se 

13 

5  min/day,  5  days/week 
for  300  days 

Accelerated  onset  of  neoplasia 

-=~ster 

14 

3  hours/day  for  75  days 

Increased  pulmonary  infection 

13-14 

2  hours/2  tines/week  for 
4  to  5  months 

Change  in  goblet  cells  of  bronchi 
and  bronchioles 

13-78 

Change  in  goblet  cell  release 

Rat 

26 

Up  to  6  weeks 

None 

52 

Up  to  6  weeks 

Bronchial  damage 

104 

Up  to  6  weeks 

Death  within  22  days 

- 

78 

6  hours/day  for  10  days 

Increased  acid  phosphatase  activity 

- 

78 

2  hours 

Gastric  inhibition 

.se 

:7£ 

10  exposures  of  10  min- 
utes, with  3  or  7  min- 
utes recovery  between 
exposures 

Initial  decrease  in  respiratory 
rate,  then  progressive  return  to 
preexposure  rate;  desensi tization 
to  successive  exposures. 

Mouse 

Various 

Sensitized  mice  to  pneumonia 

infection 

Data  extracted  ir"    sumnary  of  Colluci  (1976)  and  presented  in  order  of  increasing  concentra- 
tion, except  ^rere  there  is  more  than  one  entry  for  a  single  experiment. 


Source:  Dvorak,  1973 


335 


The  interference  with  microdecom poser  activities  impacts 
on  invertabrates,  as  food  availability  and  variety  is  decreased 
(Hendrey,  1976).  Devastating  effects  have  been  seen  in  fish 
species.  In  Norway,  huge  amounts  of  adult  salmon  and  trout  have 
been  killed  in  connection  with  spring  snow  melt  or  heavy  autumn 
rains.  Sweden  has  reported  the  extinction  of  the  salmonid  popu- 
lation, and  severe  effects  in  the  roach,  perch,  and  pike  communi- 
ties. Metal  smelters  in  Sudbury,  Canada,  which  emit  2.64  million 
tons  of  SOp  annually,  have  been  thought  to  be  the  cause  of  the 
rapid  disappearance  of  lake  trout,  lake  herring,  white  suckers, 
and  other  species  in  the  La  Coche  mountain  region  during  the 
1960's.  PH  values  as  low  as  4.5  were  not  uncommon  in  this  re- 
gion. In  the  Adirondack  Mountains  of  New  York  State,  intensive 
studies  revealed  pH  levels  less  than  five  to  be  present  in  51%  of 
the  higher  elevation  lakes,  and  90%  of  these  lakes  were  devoid  of 
fish  life.  Species  such  as  brook  trout,  lake  trout,  white  suck- 
er, brown  bullhead  and  several  cyprinid  species  were  completely 
eliminated  over  a  period  of  forty  years.   Cause  of  death  at  pH 

be  the  result  of  a  coagulation  of 

subsequent  anoxia.   At  pH  levels  of 

be  a  disturbance  of  the  normal  ion 

appears  that  small   fish  are  more 

the  same  species.   Smaller  fish 

per  unit  weight,  which  hastens 


levels  less  than  three  may 
mucous  on  gill  surfaces  and 
four  to  five, 
and  acid-base 
sensitive  than 
have  a  1 arger 


the  cause  may 
bal ance  .  It 
1 arger  members  of 

gill  surface  area 


ion  fluxes.  Age-specific  mortality  has  not  been  clearly  defined 
although  there  are  indications  that  age  may  play  a  role  in  some 
species  (Schofield,  1976). 


precipitation   on  soils  may  be  bene- 
Because  it  increases  the  amounts  of 
benefit  may  outweigh  any 
of  valuable  soil  miner- 
other  cations,  has  been 
as  soil  structure,  tex- 
so  widely,  it  is  diffi- 
that  increased  acid  will 


The  effect  of  acid 
ficial  as  well  as  harmful, 
sulfur  and  nitrogen,  the  added  nutrient 
deleterious  effects.  However,  leaching 
als,  such  as  Calcium  and  Manganese,  and 
linked  to  acid  precipitation.  Inasmuch 
ture,  and  cation  exchange  capacity  vary 
cult  to  determine  completely  the  effect 
create  without  first  classifying  the  soil  type.  Susceptibility, 
as  discussed  by  Maimer  (1976),  varies  as  follows.  Natural  soils 
with  high  pH  and  base  saturation  are  usually  highly  resistant, 
along  with  soils  rich  in  clay  and  organic  colloids.  On  the  other 
hand,  acid  and  sandy  soils  and  soil  types  that  are  transitional 
between  brown  earths  and  podsals  will  be  more  seriously  affected 
by  increased  acidity.  It  is  relevant  also  to  bear  in  mind  that 
acid  precipitation  may  carry  many  other  pollutants  to  the  soil, 
which  may  increase  or  counteract  expected  effects  (Maimer,  1976). 


As  soils  are  affected,  biological  effects  will  be  seen 
on  forest  vegetation.  Some  species  of  lichens,  which  have  the 
capacity  to  fix  molecular  nitrogen  from  the  air,  are  quite  sensi- 
tive to  S0~  and  lose  their  nitrogen-fixing  ability  when  subjected 
to  acid  precipitation.  However,  this  may  not  be  harmful  to 
forest  trees  as  they  are  not  obligate  nitrate  plants.  The  addi- 
tion of  acid  rain  is  also  expected  to  cause  the  release  of  alumi- 
num and  heavy  metal  ions  from  the  soil,  which  are    toxic  to  many 


336 


plants.  It  is  also  felt  that  nitrogen  is  accumulating  in  forest 
soil,  and  this  accumulated  nitrogen  is  expected  to  be  transformed 
to  nitrate  and  leached  after  clearfelling  or  forest  fires.  The 
results  of  this  net  acidification  during  a  short  period  of  time 
is  not  clearly  known.  However,  it  is  expected  that  this  condi- 
tion will  contribute  to  a  decreased  growth  rate  of  trees  (Tamm, 
1976).  Although  effects  of  acid  precipitation  have  not  been 
established  in  California,  it  is  being  monitored  presently  in  the 
Ukiah  District  in  order  to  evaluate  trends  for  future  considera- 
tion. 

Nitrogen  Oxides 


n  i  t  r 

tota 

atmo 

fert 

cal 

t  i  on 

bact 

sour 

Di  st 

with 

and 

(12, 


Like  SCU,  coal-fired  power  plants  are  a  major  source  of 
ogen  oxides.  These  plants  are  responsible  for  11%  of  the 
1  nitrogen  oxide  emissions  in  the  U.S.  Other  sources  of 
spheric  nitrogen  include  ammonia  (NH.)  from  biodecay  and 
ilizers,  nitrogen  oxides  (chiefly  NO  and  N02)  from  biochemi- 
reactions  within  the  soil,  and  also  h ig h- t emperat ure  combus- 
processes.  Taken  on  a  global  scale,  most  NO  is  produced  by 
eria,  about  50  x  10  tons  per  year  as  compared  to  man-made 
ces  which  account  for  5  x  10  tons  per  year.  In  the  Ukiah 
rict,  typical  emissions  densities  for  oxides  of  nitrogen  are 
in  the  range  of  5,000  to  12,000  tons  per  year  (TPY).  Sonoma 
Solano  Counties  exhibits  the  highest  level  of  NO  emissions 
000-18,000  TPY). 


Soils  and  plant  life  have  not  shown  any  detrimental 
effects  of  increased  atmospheric  nitrates  at  their  present  level 
(Noggle,  et  .  al  .  ,  1978).  In  fact,  atmospheric  nitrate  is  bene- 
ficial because  it  restores  the  small  quantities  of  nitrates  lost 
in  a  mature  ecosystem. 

Animals  and  man,  however,  can  be  adversely  affected  by 
nitrous  oxides  as  they  are  quite  destructive  to  lung  tissue.  NO^ 
is  relatively  insoluble  in  water  and  therefore  is  not  scrubbed  by 
tracheal  and  bronchial  linings.  This  results  in  greater  penetra- 
tion into  the  lungs,  interference  with  bacterial  activity  of 
macrophages,  increased  susceptibility  to  infection,  bronchial 
inflammation,  and  loss  of  cilia.  Long-term,  low-level  doses  may 
result  in  an  emphysema- type  injury,  decreased  pulmonary  compli- 
ance, and  increased  lung  weight  (Kavet  and  Brown). 


Predicted  worst-case  NO  emissions  from  a  2100  MWe 
generating  station  within  about  a  one-half  mile  radius  exceed  5.3 
ppm  for  a  short  time  period.  Table  5.2-5  gives  an  indication  of 
the  adverse  effects  possible  even  at  this  level.  Epidemiological 
studies  indicate  that  humans  may  be  adversely  affected  by  chronic 


exposures  to  0.53  of  NO 


2* 


The  effectiveness  of  extrapolating 


these  data  to  wildlife  in  the  region  is  uncertain  (Dvorak,  1978). 


It  is  known  that  N0o  in  combination 
severe  effects  at  levels  where  S0~  or  N0~ 
a  visible  response.   Since  coal  combustion 


counts  for  approximately  40%  of  total 


with  S0o  can  produce 
alone  would  not  produce 
i n  power  pi  ants  ac- 
sulfur  compound  emissions 


337 


Table  5.2-5 


Summary  of  Toxicological  Experiments  with  Nitrogen  Oxides  (NO  V 

A 


Species 

Concentration 
(105  ug/m3) 

Duration 

Effects 

Acute  exposures 

Guinea  pig 

0.01-0 

20 

4  to  24  hours/day  for 
up  to  14  days 

Elevated  protein  in  urine 

Guinea  pig 

0.04 

Up  to  21  days 

Increased  average  area  per  alveolar 
wall  cell 

Mouse 

0.02-0 

30 

Up  to  17  hours 

Impaired  bacterial  defense 

Monkey 

0.2  -1. 

0 

2  hours 

Decreased  tidal  volume,  progressive 
histopathclcgical  damage 

Rat 

0.30-0. 

34 

48  hours 

Increase  in  Type  II  pneumocytes 

Rabbit 

0.16-1. 

2 

3  hours 

Impaired  bacterial  defense  at  all 
levels  of  exposure 

Hamster 

0.60-0. 

70 

7  to  10  days 

Chronic  exposures 

Bronchiol itic  lesions 

Mouse 

0.01 

Up  to  12  months 

Reduction  of  functional  lung  tissue 

Monkey 

0.02 

493  days 

Slight  to  moderate  emphysema 

Monkey 

0.04 

14  months 

Hypertrophy  of  bronchiolar  epithe- 
1  iur,  in  bronchiole 

Rat 

0.02 

14  months 

Marginal  changes  in  epithelium 

Guinea  pig 

0.02 

6  months 

Higher  mortal ity 

Rat 

-.0.06 

9  months 

Decrease  in  lung  compliance 

Rat 

0.04 

Li  fetime 

"Emphysema-like"  injury  suggested 

Rat 

0.04 
0.34 

Up  to  360  days 
Up  to  7  days 

Increase  in  number  of  cells  prepar- 
ing to  divide 

Rat 

0.12 

6  weeks 

Interstitial  edema,  vascular 
congestion 

Rat 

0.20 

90  days 

Decreased  body  size 

Rat 

0.30 

90  days 

Decreased  body  size 

Mouse 

--0.80 

Up  to  8  weeks 

Epithelial  damage  near  terminal 
bronchioles 

Hamster 

0.9-1  .1 

10  weeks 

Respiratory  rate  increased,  hyper- 
plasia and  hypertrophy  in  termi- 
nal and  respiratory  bronchioles 

'Data  extracted  from  summary  of  Ziskind  and  Hausknecht  (1976)  and  presented  in  order  of 
increasing  concentration,  except  where  there  is  more  than  one  entry  for  a  single  experiment. 


Source:  Dvorak,  1978 


338 


and  about  11%  of  total  nitrogen  oxide  emissions  in  the  continen- 
tal U.S.,  it  is  important  to  look  to  these  immediate  areas  for 
pollutant  responses. 

Carbon  Monoxide 

Within  the  Ukiah  District,  BLM  lands  in  Yola,  Napa, 
Marin  and  southern  parts  Solano  and  Sonoma  Counties  are  in  non- 
attainment  areas.  Other  BLM  lands  are  situated  in  areas  that  are 
unclassified  or  better  than  national  standards  as  shown  in  Figure 
5.3-4. 

The  toxic  properties  of  carbon  monoxide  have  been  known 
to  man  for  quite  some  time.  Unfortunately,  studies  involving 
environmental  aspects  such  as  soils,  wildlife,  vegetation  and 
archaelogy  have  not  been  published  to  the  same  extent  as  many 
other  air  pollutants.  For  this  reason,  carbon  monoxide  effects 
on  man  and  mammals  alone  will  be  discussed. 

Ninety-five  percent  of  carbon  monoxide  emissions  may  be 
attributed  to  automobile  exhaust  and,  because  they  are  released 
near  the  ground,  these  emissions  do  not  undergo  substantial 
diffusion.  This  fact  coupled  with  CO's  lack  of  involvment  in 
further  atmospheric  reactions  to  form  secondary  pollutants, 
accounts  for  the  very  high  levels  in  urban  areas.  The  situation 
is  complicated  further  in  that  CO  measurements  in  urban  areas  may 
be  critically  underestimated.  Studies  were  conducted  by  Cortese 
and  Spengler  (1976)  in  the  Boston  area  to  determine  the  ability 
to  represent  carbon  monoxide  exposure  by  fixed  monitoring  sta- 
tions. In  this  experiment,  66  non-smoking  individuals  carried 
portable  CO  samplers  at  breathing  levels  for  the  period  October 
1974  through  February  1975.  Results  showed  that  four  of  the  66 
volunteers,  who  commuted  to  work  daily,  were  exposed  to  37  ppm  CO 
because  of  faulty  automobile  exhaust  systems.  This  level  is  in 
excess  of  the  National  Ambient  Air  Quality  Standard  for  one-hour 
35  ppm.  Considering  the  other  volunteers,  concentration  of  5  to 
20  ppm  occurred  85%  of  the  time,  5%  were  greater  than  23  ppm  and 
1%  were  over  31  ppm.  Comparison  of  these  levels  to  fixed  loca- 
tion monitors  in  the  area,  show  that  the  mean  one-hour  personal 
exposure  concentration  (25.3  ppm)  was  1.6  times  greater  than  the 
fixed  monitoring  concentration  (15.6  ppm)  for  all  area  stations. 
This  difference  may  be  due  to  the  fact  that  CO  concentrations  at 
breathing  level  may  diminish  by  5  to  15%  by  the  time  they  reach 
the  usual  monitoring  height  of  15  feet  (Cortese,  et 
This  study  would  indicate  that  CO  concentrations,  as 
may  actually  be  significantly  higher  in  urban  areas  or 
travel ed  roadways . 


al,  1976). 
moni  tored , 
on  heav  i 1 y 


Effects  on  small  mammals  may  be  derived  through  studies 
by  Mordelet-Dambrine  (1978)  and  Finelli,  et.  al.  (1976). 
Mordelet-Dambrini  ventilated  guinea  pigs  and  rats  with  2.84%  CO. 
After  two  minutes,  tracheal  pressure  variations  were  seen  and 
blood  pressure  and  heart  rate  decreased  within  one  to  two  min- 
utes, respectively.    Rats  appeared  to  be  more  sensitive  than 


339 


guinea  pigs  to  CO  inhalation.  It  was  postulated  that  their 
higher  heart  rate  could  trigger  the  higher  sensitivity  level 
(Mordelet-Dambrini ,  1978). 

Finelli,  et.  al  .  (1976)  studied  the  effects  of  clean 
air,  exhaust  emissions  with  a  catalytic  converter,  and  carbon 
monoxide  emissions  on  20  male  rats  for  ^a  period  of  four  weeks. 
CO  levels  of  57.5,  172.5  and  517.7  mg/m  were  used.  During  the 
exposure  period,  18  animals  were  killed,  and  there  was  a. dramatic 
loss  in  heart,  spleen  and  body  weight.  A  trend  of  lower  serum 
cholesterol  levels  was  significant  in  the  rats  exposed  to  the 
highest  CO  levels.  These  effects  were  not  seen  in  the  group 
exposed  to  the  exhaust  equipped  with  the  catalytic  converter  as 
CO  amounts  had  been  greatly  reduced  (Finelli,  1976). 

Parallel  studies  have  shown  that  adult  rats  exposed  to 
automobile  exhaust  without  catalytic  converters  may  also  exhibit 
elevated  hematocrit  and  hemoglobin,  cardiac  hypertrophy,  loss  in 
body  weight  and  increased  levels  of  serum  lactate  dehydrogenase. 
Low  levels  have  also  caused  increased  serum  and  aortic  cholester- 
ol in  rabbits.  This  may  be  a  factor  in  the  development  of  arter- 
iosclerosis in  humans  (Finelli,  1976).  Also  in  humans,  it  is 
known  to  affect  the  heart,  brain  and  muscle  tissue  most  seriously 
because  CO  has  a  high  affinity  for  hemoglobin  and  thus  limits  the 
amount  of  oxygen  available  to  all  body  tissues,  these  three  being 
extremely  sensitive  to  oxygen  deficiencies.  CO  has  also  been 
associated  with  reduced  ability  to  perform  vigilance  tasks  and 
reduced  exercise  tolerance  (Cortese,  1976). 

Any  of  these  symptoms  may  also  be  seen  in  species  native 
to  the  Ukiah  District.  Possibly,  symptoms  may  be  more  severe  in 
animals  with  higher  heart  rates  and  more  lung  tissue  relative  to 
body  weight.  However,  care  should  be  taken  in  extrapolation  of 
data  . 

Hydrocarbons 

Hydrocarbon  emissions  are  below  25,000  tons  per  year  in 
all  areas  of  the  Ukiah  District  with  the  exception  of  Sonoma 
County  where  emissions  reach  26,000  tons  per  year.  As  in  the 
case  for  carbon  monoxide,  studies  involving  hydrocarbons  as  an 
air  pollutant  are  not  as  numerous  as  those  concerning  many  other 
ai  r  pol 1 ut ants  . 


There  are    three  basic  sources  of  hydrocarbons:  animal, 
mineral  and  vegetable,  such  as  municipally  operated  sewage  treat- 


ment systems,  industrial 
and  decaying  vegetation, 
leum  hydrocarbons  escape 
marine  facilities  and 
(Boyd,  1976). 


discharges  from  oil-dependent  industries 

Over  90%  of  major  discharges  of  petro- 

from  pipelines,  tank  ships,  tank  barges, 

onshore  production  storage  facilities 


340 


At  the  1977  American  Petroleum  Oil  Spill  Conference,  it 
was  reported  that  in  California,  concentrations  of  petroleum 
hydrocarbons  were  found  in  almost  all  benthic  and  sandy  interti- 
dal  sediment  samples  collected  in  the  Southern  California  border- 
land (Reed,  1977).  As  hydrocarbons  collect  in  soils  and  water, 
an  effect  will  be  seen  on  algae  and  photopl ankt on .  Retardation 
of  algae  growth  and  inhibition  of  photosynthesis  has  been  linked 
to  the  presence  of  petroleum  hydrocarbons.  A  reported  growth 
stimulation  in  photopl ankt on  may  be  due  to  the  slight  carcino- 
genic stimulatory  activity  of  low  HC  levels  (Vandermuelen,  1976). 

Effects  of  hydrocarbons  on  fish  have  been  well  docu- 
mented by  Adams  (1975).  Studies  indicate  that  recreational 
vehicles,  such  as  snowmobiles  and  motor  boats,  add  dangerously 
high  amounts  of  hydrocarbons  to  lakes.  Death  of  fish  may  occur 
at  levels  of  a  few  ppm  and  feeding,  homing  and  reproduction  are 
disrupted  at  levels  of  10  to  100  ppb.  These  exhaust  hydrocarbons 
concentrate  in  fatty  tissue  such  as  lateral  line  muscle  and 
visceral  fat.  These  compounds  remain  in  the  tissues  and  are 
passed  to  higher  animals  through  the  food  chain  (Adams,  1975). 
Further  discussion  of  hydrocarbon  effects  on  fish  will  be  inclu- 
ded in  a  subsequent  section,  as  this  experiment  also  involved 
1  ead  val ues  . 

Ozone 

Hydrocarbons  and  nitric  oxides  in  the  presence  of  sun- 
light are  known  to  produce  ozone.  Automobile  exhaust,  therefore, 
may  be  considered  as  a  primary  source  of  the  precursors  which 
give  rise  to  oxidant.  High  ozone  levels  have  been  found  not  only 
in  the  urban  environment  but  also  in  rural  areas,  on  mountain 
tops,  and  at  night.  The  reason  for  this  ozone  build-up  is  not 
fully  known;  however,  it  is  believed  that  ozone  or  its  precursors 
are  being  transported  long  distances  or  there  may  be  a  natural 
source  of  hydrocarbons  and  nitric  oxides  within  forests  and 
swamps,  such  as  terpenes  and  methane.  Within  the  Ukiah  District, 
areas  in  the  southeastern  section  of  the  District  have  been  in 
violation  of  the  federal  one-hour  standard  for  oxidant  levels  as 
seen  in  Figure  5.3-11;  however,  these  violations  are  on  the  order 
of  less  than  one  percent  of  all  observations  per  year. 

Ozone  is  known  to  reduce  photosynthesis  in  plants, 
thereby  reducing  the  nutrient  value  of  the  plant.  Studies  of  air 
pollution  damage  to  the  forests  of  the  Sierra  Nevada  Mountains  by 
Williams  et  al  (1974),  indicated  widespread  oxidant-caused  injury 
to  conifers.  Especially  susceptible  were  the  ponderosa  and 
Jeffery  pine  as  measured  by  the  extent  and  intensity  of  chloratic 
mottle  on  current  year  needles.  Since  ozone  is  dose- ace umul  at i ve 
for  a  variety  of  sensitive  plants,  a  concentration  of  0.06  ppm 
over  a  five-month  growing  season  would  produce  chlorotic  mottle 
on  current  year  needles  of  the  ponderosa  pine.  It  should  be 
noted  that  this  quoted  level  is  within  the  federal  standard  of 
0.12  ppm  (Williams,  1977). 


341 


Results  of  the  1974  Sierra  Nevada  field  survey  showed 
ozone  injury  to  be  most  abundant  in  the  mixed  conifer  forest 
types  located  from  6000-8000  ft.  in  elevation.  However,  injuries 
at  mid-elevation,  (4000-6000  feet),  where  many  BLM  lands  are 
located,  tended  to  be  more  severe.  These  studies  indicate  that 
ozone  injury  is  dependent  on  elevation.  At  mid  elevations,  where 
inversion  levels  are  often  found,  injuries  will  be  most  severe. 
At  higher  levels,  where  ozone  is  quite  abundant,  injuries  are 
more  prevalent  (Williams,  1977).  Injuries  to  other  species  are 
detailed  in  Table  5.2-6. 

The  California  Department  of  Agriculture  yearly  assesses 
damage  to  vegetation  as  caused  by  air  pollution.  In  their  1970 
summary,  Millecan  (1971)  details  the  history  of  ozone  damage  to 
California  forests.  In  the  early  1950's  in  the  San  Bernardino 
National  Forest,  several  pines  began  to  turn  chloratic  and  drop 
needles.  Ponderosa  and  Jeffery  pine  were  particularly  involved. 
In  1963,  it  was  first  suggested  that  ozone  might  be  the  cause. 
Later,  in  1969,  aerial  surveys  by  the  Forest  Service  and  Uni- 
versity of  California  at  Riverside  revealed  the  extent  of  ozone 
damage.  More  than  161,000  acres  of  the  ponderosa  and  Jeffery 
pines  in  the  San  Bernardino  National  Forest,  an  estimated  two- 
thirds  of  the  trees,  were  damaged  by  ozone.  Of  these,  3%  were 
dead,  another  15%  were  severely  affected,  and  82%  were  moderately 
or  lightly  affected  (Millecan,  1971).  Damage  estimates  have  also 
been  assessed  by  the  Statewide  Air  Pollution  Research  Center  of 
the  University  of  California.  Figure  5.2-1  reveals  the  extent  of 
oxidant  injury  as  seen  in  1974.  Elevations  over  8000  feet  were 
not  considered  in  this  study. 

The  Forest  Service  has  been  assessing  ozone  injury  since 
1974.  A  recent  survey  by  Pronos  et  al  (1978)  revealed  the  extent 
of  ozone  injury  in  the  Sierra  and  Sequoia  National  Forests  as 
depicted  in  Figure  5.2-2.  The  worst  injuries  found  were  consid- 
ered to  be  moderate  and  these  were  generally  found  at  elevations 
of  4000  to  7000  feet  on  the  Front  Range  mountains  west  of  the  San 
Joaquin  Valley  and  along  major  river  drainages.  However,  a  quick 
comparison  of  this  data  to  photochemical  levels  found  in  the  San 
Bernardino  National  Forest  show  that  the  ozone  levels  of  the 
southern  Sierra  do  not  even  approach  the  levels  found  in  Southern 
California  forests  as  shown  in  Table  5.2-7  (Pronos,  1978). 
Presently,  no  evidence  of  ozone  injury  has  been  seen  or  docu- 
mented in  the  forests  of  the  Ukiah  District,  but  it  is  valuable 
for  the  BLM  Manager  to  be  aware  of  the  potential. 

Impacts  of  ozone  on  man,  animals  and  other  air  quality 
related  values  have  not  been  studied  to  the  same  extent  as  with 
vegetation.  However,  ozone  has  been  found  to  attack  the  cell 
membrane,  breaking  double  bonds  and  removing  hydrogen  atoms.  In 
humans,  this  process  acts  as  a  bronchoconst ri ctor ,  whereby  less 
air  reaches  the  lungs.  There  is  increased  coughing  and  breath- 
lessness,  and  lung  elasticity  is  decreased.  Also,  there  is 
damage  to  alveolar  macrophages  in  the  presence  of  high  concentra- 
tions of  ozone,  increasing  the  susceptibility  to  infection  and 


342 


Table  5.2-6 
Site  Characteristics  and  Extent  of  Ozone   Injury 


1 

Elevation 

Si 

>eues  w  it!i 

Local    in 

(meters) 

lopog 

rapra 

Site 

s 

\.  niptonis 

Land  use 

Delilah  1  0 

15  64 

Ridge 

Flat, 

Ponderosu  (PPj 

National  Forest 

Dry 

(N  F) 

Mt.  Sam;i>on 

1623 

Ridge 

Steep 
Dry 

PP 
BL-. 

ck  Oak  (BO j 

NF,  Private 

McKensic  Rid-e 

1600 

Ridge 

Flat, 
Dry 

PP, 

BO 

NT 

Converse  Basin 

157T 

Basin 

Mesic 

PP. 

Sugar  Pine 

NF 

(SP) 

Giant  Sequoia 

(GS) 

Hume  Luke 

1577 

Basin 

Mesic 

PP. 
P 

SP.  Jeflery 
ine(JP) 

NF 

Boy  den  Ca\r 

970 

Qjnvon 

Bottom 

Dr\, 
Steep 

PP 

NT, 

Nat  ional  Park 
(NF) 

Pi.-.-,  k.jre 

2199 

Ridge 

Steep, 

PP. 

JP.SP 

Ro.  :ky. 

W'h 

ite  Fir  (WT  | 

NP 

Moist 

Buck  R^ck 

25'^ 

Ridge 

Steep. 
Rockv 

JP 
Lo 

igepole  Pine' 

NT 

Weaver  Lj.-.; 

2oc9 

Fiat 

Dn 

JP. 
P 

Lod'gepole 

mt? 

NF 

■ 

1638 

We   :  - 

i>e 

Moist 

PP, 

BO.W'F,  SP, 

L'niv.  of  Calif. 

F  jre^t 

GS 

-     1 

' 

West  Sio 

pe 

Dry 

PP. 

BO.  W  F 

NT  ,  Private 

.  •  .-  S 

lO^u 

Fia: 

Dry 

PP. 

BO 

NF,  County,  Pri- 
vate 

Sierra  I  "«;enn 

970 

Flat 

Dry 

PP 

Private.  County , 
State 

-     ■ 

1517 

Variable 

Moist 

PP. 

BO 

NF 

:       :m  Point 

1517 

Rid,;t 

Dry 

PP, 

BO 

NT 

Sk.  eway  Grove, 

1517 

Fiat 

Moist, 

JP 

NT 

Muir  Crc\e 

Rocky 

Lod;;epe.e  RS 

2038 

Flat 

Moist, 

Ro.  k\ 

JP. 

LP 

NP 

Crystal  Cave 

141-f 

Flat 

Mesic 

PP. 

BO,  WT 

NT 

G.j:."   Fc  '-  S! 

191  i 

Flat 

Mesic 

J  P. 

BO 

NP 

Co!on\  Mi!!  RS 

. 

Ridee 

Dry 

PP. 

WT,  BO 

NP 

Moro  Rov  k 

1SS0 

South  S 

ope 

Mesic 

PP 

NT 

Cr                    !ow 

1914 

Meadow 

Mesic 

JP 

NT 

1    Milk  Ranch  Peak 

1897 

South  J 

ope 

Drv 

PP, 

WF.SP, 

NT 

1 

BO 

j    Mineral  K 

2254 

Canvon 

Bottom 

Mesic 

JP 

NT 

Source:     Williams,   1977 


343 


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344 


Figure  5.2-2 
Location  of  Ozone  Injury  in  the  Sierra  and  Sequoia  National  Forests,  1977 


Source:  Pronos,  1978 


345 


Table  5.2-7 

Comparison  of  Ozone  Concentrations  in  the 

San  Bernardino  National  Forest  (Sky  Forest,  5640  feet) 

With  Concentrations  in  the  Southern  Sierra  Nevada  (Whitaker's  Forest,  5400  feet) 

June  -  September  1977 


LOCATION 

JUNE 

JULY 

AUGUST 

SEPTMEBER 

MAX. 
HRLY. 
AVER, 
(pphm) 

MEAN 
of  MAX. 

HOURS 
(pphm) 

MAX. 
HRLY. 
AVER, 
(pphm) 

MEAN 
of  MAX. 

HOURS 
(pphm) 

MAX. 
HRLY. 
AVER, 
(pphm) 

MEAN 
of  MAX. 

HOURS 
(pphm) 

MAX. 
HRLY. 
AVER, 
(pphm) 

MEAN 
of  MAX. 

HOURS 
(pphm) 

Sky  Forest 

32 

20 

30 

22 

33 

19 

24 

14 

Whitaker's 
Forest 

14 

10 

15 

11 

14 

11 

13 

9 

(Concentrations  are  expressed  as  maximum  hourly  averages  and  means  of  maximum  hourly 
averages,  and  are  shown  as  parts  per  hundred  million.) 


346 


cases  of  pulmonary  edema.  With  wildlife,  we  can  expect  these 
effects  to  be  seen  to  an  even  greater  degree,  as  injury  in  most 
cases  is  more  severe  in  animals  with  more  respiratory  tissue  per 
body  wei  ght . 

Lead 

3 
The  thirty-day  standard  for  lead  is  1.5  yg/m  .   Near  the 

city  of  San  Rafael  in  Marin  County,  violations  of  this  standard 

may  be  expected  6  times  per  year.   Environmental  sources  of  lead 

include  the  petroleum,  paint  and  ceramic  industries,  and  coal 

combust  i  on . 

Lead  has  become  a  serious  environmental  pollutant  to  the 
agricultural  industry  and  is  a  major  concern  in  the  vicinity  of 
major  roads,  as  lead  collects  and  accumulates  in  the  soil.  To 
date,  plants  show  no  toxic  effects,  and  lead  absorbtion  by  plants 
is  insignificant.  Concern,  however,  stems  from  the  rise  in  lead 
content  of  plants  and  in  animal  feed,  for  these  accumulations 
will  affect  the  entire  food  chain  (Keller,  1977) 

As  lead  accumulates  in  the  soil,  long-term  changes  in 
productivity,  decomposition,  nutrient  cycling,  and  insect  and 
mycrobial  activities  may  be  seen.  In  the  case  of  the  Hubbard 
Brook  Experimental  Forest  in  Central  New  Hampshire,  lead  is 
accumulating  at  the  rate  of  0.67  pounds  per  half  acre  per  year. 

measured  include  precipitation,  winter  snow  and 
The  soil  and  especially  forest  floor  humus  was 
major  sink  for  lead,  while  lead  uptake  in  vege- 
low.  The  entire  system,  however,  is  functioning 
from  the  atmosphere  and  hydrologic  systems  and 
soil  system.  With  this  current  input  rate,  the 
doubling  time  for  lead  concentration  in  forest  humus  would  be 
only  50  years  and  since  lead  deposits  from  the  atmosphere  have  a 
mean  residence  time  of  5000  years,  long-term  concentration  should 
be  carefully  evaluated  (Siccama,  et.  al.,  1978). 


Sources  of  lead 
stream  water, 
found  to  be  the 
tat  i  on  was  quite 
to  remove  lead 
pi  ace  it  in  the 


Effects  of  lead  accumulations  on  fish  have  been  studied 
by  several  investigators.  Hodsons,  et  al  (1978)  has  shown  that 
lead  uptake  in  rainbow  trout  is  a  function  of  the  pH  of  the 
water.  Blood  lead  concentrations  increased  by  a  factor  of  2.1  as 
pH  decreased  by  1.0  unit.  Consequently,  lead  sensitivity  in- 
creased with  low  pH  levels.  The  author  suggested  that  low  pH 
increases  the  permeability  of  the  gills.  Sublethal  concentration 
of  lead  for  a  period  of  three  to  six  months  may  cause  spinal 
deformities.  Lead  is  also  known  to  cause  behavioral  changes  in 
fish  at  70  ppb  and  death  at  0.3  ppm.  Therefore,  pH  should  be 
monitored  in  streams  known  to  have  high  lead  values  (Hodson, 
1978) . 

Badsha  and  Sainsbury  (1977)  have  studied  first  year 
whitings  in  the  Severn  Estuary  and  feel  that  bi oaccumul at i ons  are 
functions  of  the  food  chain  rather  than  respiration  and  gills. 
Therefore,  bottom  feeders  would  be  expected  to  accumulate  rela- 
tively higher  lead  amounts  than  other  types  of  predators.   Once 


347 


ingested,  lead  is  not  rejected  and  slowly  increases  (Badsha,  et . 
al.,  1977).  Effects  on  fresh  water  fish  may  be  quite  similar 
according  to  experiments  by  Rehwoldt,  et .  al  .  (1978)  in  the  fresh 
water  stretch  of  the  Hudson  River  system.  In  this  study  several 
species  of  fish  were  caught  and  lead  levels  were  compared  to 
those  of  preserved  samples.  Results  are  given  in  Table  5.2-8  and 
indicate  that  lead  levels  are  time  independent  in  a  relatively 
clean  system  such  as  the  Mid-Hudson  (Rehwoldt,  1978). 

Studies  by  Adams  (1975)  involve  the  effects  of  lead  and 
hydrocarbons  on  brook  trout.  Increasing  amounts  of  these  two 
pollutants  are  released  to  the  aquatic  environment  by  snowmobiles 
and  outboard  motors  each  year  and  are  attracting  much  attention. 
Towle's  Pond  in  Freeport,  Maine,  served  as  the  site  for  several 
experiments.  Water  samples  in  November  1971  showed  4.1  ppb  lead 
and  no  detectable  hydrocarbons  as  a  baseline  concentration. 
Through  the  winter  seasons  of  1971  and  1972,  56.8  liters  of 
gasoline  were  burned  in  snowmobiles  operating  on  the  pond. 
During  ice-out,  lead  levels  increased  to  88  ppb  in  1972  and  135 
ppb  in  1973.  These  lead  levels  decreased  rapidly  within  72  hours 
of  ice-out  and  returned  to  near  normal  within  six  days.  Lead 
levels  in  exposed  fish  were  15.7  and  8.8  times  those  of  control 
fish  in  1972  and  1973,  respectively.  Four  fish  died  during  the 
first  six  hours  of  the  1973  experiment.  Cause  of  death  has  been 
attributed  to  low  oxygen  levels  in  the  pond  during  that  period. 
Hydrocarbon  levels  ranged  from  1  to  10  ppm  and  an  oil  slick  was 
visible  on  the  pond  for  one  week  after  ice-out  each  year.  Levels 
in  exposed  fish  ranged  from  0.1  to  1  ppm.  Laboratory  study 
revealed  highest  lead  levels  occur  in  the  digestive  tract  (3.3 
times  that  in  control  groups)  and  lowest  in  the  gills,  which  may 
further  indicate  that  bottom  predators  may  be  seriously  affected 
by  increasing  lead  levels.  Elevated  lead  levels  were  also  found 
in  muscle  skin  and  gills  (Adams,  1975). 


soil  , 
lead 
vege- 
coul  d 
5.2-9 


The  pathological  effects  of  lead  in  small  mammals  are 
detailed  in  reports  by  Roberts,  et .  al  .  (1978).  Two  abandoned 
metaliferous  mines  in  Wales  were  chosen  as  the  sites  for 
vegetation  and  mammal  tissue  measurements  to  determine 
accumulations.  The  area  was  typified  by  sparse  natural 
tation,  with  a  limited  range  of  species,  as  few  populations 
survive  the  heavy  metal  concentrations  in  the  soil.  Table 
indicates  the  lead  amounts  found  in  the  soil,  vegetation  and 
invertebrate  populations.  Small  mammals  were  caught  in  the  area 
and  examined  for  lead  content.  Vegetarian  feeders  were  found  to 
have  the  highest  level  concentrations  and  insectivorous  mammals 
the  least.  In  these  mammals,  bone  and  kidney  tissues  had  the 
highest  lead  concentration,  and  the  liver,  brain,  and  muscle 
tissues  had  the  least.  This  supports  the  generally  accepted  idea 
that  the  skeleton  is  the  main  long-term  storage  site  for  lead 
(Roberts,  1978). 


Mice  were  fed  lead  acetate  at  levels  of  0.1%  and  4.0%  in 
experiments  by  Eyden ,  et .  al  .  (1978),  to  determine  toxicity.  The 
animals  suffered  weight  reductions,  increased  sperm  abnormal  ti es , 


348 


Table  5.2-8 
Average  Values  (m/g)  for  Lead  in  Dry  Weight 


Common  Name 

Source 

Pb 

Alewife 

MC  10  (1976) 
VC  2  (1953) 

0.30 
0.61 

Atlantic  Sturgeon 

MC  (1976) 
NYS  5  (1924) 

0.82 
0.71 

Fundulus 

MC  21  (1976) 
VC  4  (1953) 
NYS  3  (1936) 
AMNH  (2)  (1973) 

0.51 
0.62 
0.41 
1.10 

Small  Mouth  Bass 

MC  11  (1976) 
NYS  3  (1936) 

1.06 
0.99 

Spottail  Shiner 

MC  17  (1936) 
VC  5  (1953) 
AMNH  2  (1973 

0.59 
0.69 
0.77 

Striped  Bass 

MC  14  (1976) 
NYS  2  (1936) 
AMNH  5  (1973) 

0.92 
0.40 
0.21 

Sunfish 

MC  23  (1976) 

0.25 

White  Perch 

MC  26  (1976) 
VC  2  (1953) 
NYS  1  (1936) 

1.06 
1.02 
0.80 

*  MC  Marist  College 

VC  Vassar  College 

NYS  New  York  State  Museum  and  Science  Service 

AMNH  American  Museum  of  Natural  History 


Number  after  source  is  sample  size 
Number  in  paranthesis  is  year  caught 


Source:  Rehwoldt,  et.al.,  (1978) 


349 


Table  5.2-9 

LEAD  CONCENTRATIONS  (yg/g  dry  weight)  IN  SOIL,  VEGETATION 
AND  INVERTEBRATES  (mean  +  standard  error,  number  of 
samples  in  brackets) 


Mine  A 

Vegetation 
Lead 

Invertebrates 
Lead 

Surface  Soil 
Lead 

120  +  5.40(8) 

61.9  +  14.5(6) 

8430  +  2050(9) 

Control 

20.8  +  3.89(8)t 

18.4  +  1.87(6)+ 

96.3  +  24.4(10)1- 

Mine  B 

249  +  33.7(9) 

81.7  +  18.6(5) 

14010  +  6160(7) 

Control 

28.9  +  2.73(9)t 

22.3  +  4.79(6)+ 

78.0  +  10.1(8)+ 

+  Denotes  statistical  significance  at  p  <  0.001  (NS  =  p>0.05) 


Source:  Roberts,  1978 


350 


early  hair  loss,  lethargy  and  reductions  in  mean  survival  time. 
Symptoms  were  dose- dependent  and  the  authors  suggested  that  death 
may  be  attributed  to  internal  organ  malfunction  resulting  from 
enzyme  interference,  lack  of  nervous  or  hormonal  infection  from 
depressed  immunological  competence  (Eyden,  1978). 

Lead  is  also  known  to  accumulate  in  humans  within  the 
blood,  bones,  urine,  aorta,  teeth,  kidneys  and  liver.  It  has 
been  associated  with  anemia,  arter i ocl erosi s  ,  diseases  of  the 
central  nervous  system,  bone  deterioration,  kidney  failure, 
chromosome  abberations,  and  brain  damage.  It  is  also  known  that 
lead  will  pass  through  the  placenta  in  pregnant  women.  Most 
serious  effects  may  be  seen  in  young  children,  ages  one  to  four, 
as  this  is  the  time  for  normal  development  of  the  central  nervous 
system  and  bone  tissue.  Yankel  et .  al  .  (1977)  observed  blood 
lead  levels  in  young  children  living  near  a  lead  smelter  in 
northern  Idaho  and  found  amounts  as  high  as  70  mg  Pb/lOOml. 
Ambient  air,  soil  and  dust  lead  levels  were  attributed  to  be  the 
major  cause  for  the  elevated  lead  levels.  Air  exposure  alone 
explained  55%  of  the  variance  (Yankel,  1977). 

This  section  has  detailed  the  effects  of  various  pollu- 
tants on  air  quality  related  values.  Whenever  possible,  envir- 
onmental concerns  typical  of  the  Ukiah  District  were  stressed. 
Where  data  was  lacking,  similar  species  or  areas  were  described. 
Relating  these  data  to  the  Ukiah  District  may  help  to  point  out 
critical  areas  for  immediate  study  or  future  areas  of  concern. 

Hydrogen  Sulfide 

The  southern  portions  of  the  Ukiah  District  are  located 
within  a  natural  geothermal  area.  Therefore,  hydrogen  sulfide 
(H?S)  is  emitted  to  the  atmosphere  and  most  likely,  these  natural 
emissions  have  caused  violations  of  the  California  standard  (0.03 
ppm)  for  the  past  50,000  years.  Development  of  the  geothermal 
potential  of  this  area,  while  decreasing  natural  emissions,  has 
at  the  same  time  increased  man-made  emissions. 

1979  data  from  geothermal  sources,  as  reported  by  the 
State  Energy  Commission,  show  HoS  controlled  emissions  to  be  1600 
tons  per  year  and  unabated  emissions  of  3100  tons  per  year. 
Geothermal  processes  also  release  very  low  concentrations  of 
radon-222,  mercury,  arsenic,  S0~,  ammonia  and  boron.  Presently, 
all  fifteen  operating  geothermal  power  units  are  located  in 
Northern  Sonoma  County;  however,  the  potential  for  development 
also  exists  in  Lake,  Mendocino,  and  Napa  Counties.  Violations  of 
the  standard  may  be  expected  on  the  order  of  a  few  hours  per 
year.  Studies  in  the  Geyser s-Cal i stoga  Geothermal  Area  have 
noted  unabated  HUS  maximum  concentrations  of  1.0  ppm  and  average 
levels  of  0.2  ppm  during  an  8-hour  period.  The  worst  known  hUS 
accumulation  occurred  at  the  Big  Sulphur  Creek  watershed  during  a 
nocturnal  inversion  and  averaged  0.1-0.2  ppm.  Fumigation  studies 
by  Coyne  and  Bingham  (1978)  using  H~S  concentrations  of  0.74  ppm 
showed  a  ten  percent  increase  in  photosynt het i c  rates  for  field 


351 


snap  bean . 
significant 
fore  ,  i  t  i  s 
not  harmful 
there  is  no 
mal  s  ,  and 
(Malloch,  1979). 


Further  studies  by  Shinn,  et.  al.  (1976)  also  found  a 
increase  in  photosynthet i c  rates  for  lettuce.  There- 
assumed  that  H~S  levels  found  in  the  geysers  area  are 

to  vegetation  types.   According  to  Malloch  (1979), 

evidence 
ambient 


of  HoS  effects  on  water  quality  or  on  ani- 
H  ~  S   revels  are  beneficial  to  vegetation 


However,  vegetation  stress  and  damage  has  been  noted 
near  the  Geyser s-Cal i stoga  Known  Geothermal  Resource  Area  (KGRA) 
since  1973.  Symptoms  such  as  needle  tip  burn,  leaf  bronzing, 
glazing,  chlorosis,  necrosis,  reduced  vigor  and  decreased  lichen 
abundance  and  diversity  have  been  observed.  Malloch,  et .  al . 
(1979)  have  studied  the  vegetation  injury  in  this  area.  High 
concentrations  of  boron  have  been  found  in  circulating  water, 
surface  soils  and  leaf  tissues  and  it  is  believed  these  harmful 
effects  may  be  attributed  to  boron  toxicity  rather  than 
(Malloch,  1979). 


H2S 


352 


5.3 


BASELINE  AMBIENT  AIR  QUALITY 


The  Ukiah  District  encompasses  portions  of  four  air 
basins  as  described  in  Section  4.8  -  North  Coastal,  North  Coastal 
Mountains,  San  Francisco  Bay  Area  and  Sacramento  Valley.  Air 
quality  monitoring  in  the  district  is  concentrated  in  major 
cities  for  most  of  the  pollutants,  with  an  expanded  network  for 
the  monitoring  of  total  suspended  particulates  (TSP).  The  exist- 
ing monitoring  network  is  shown  in  subsequent  figures  in  conjunc- 
tion with  the  pol 1 utant- speci f i c  attainment  status  for  each 
county  . 

The  California  Air  Resources  Board  (CARB),  in  accordance 
with  the  requirements  of  the  Clean  Air  Act  Amendments  of  1977, 
has  classified  each  county  in  terms  of  attainment  of  the  National 
Ambient  Air  Quality  Standards  (NAAQS).  Air  quality  regulations 
are  discussed  in  considerable  detail  in  Section  6;  however,  a 
review  of  the  attainment  status  of  counties  within  the  Ukiah 
District  provides  an  excellent  means  for  defining  baseline  am- 
bient air  quality.  Figures  5.3-1  through  5.3-4  show  the  current 
status  for  each  pollutant  as  designated  for  counties  in  the  Ukiah 
District.  The  figures  illustrate  which  areas  have  been  desig- 
nated as  non-attainment,  cannot  be  classified,  or  better  than 
national  standards  for  total  suspended  particulates  and  sulfur 
dioxide.  For  oxidant,  carbon  monoxide,  and  nitrogen  dioxide, 
areas  with  sufficient  data  and  poor  air  quality  have  been  desig- 
nated as  non-attainment.  Those  areas  with  good  air  quality  or 
insufficient  data  have  been  categorized  as  "cannot  be  classified 
or  better  than  national  standards."  Since  the  unclassified  areas 
denote  the  lack  of  sufficient  baseline  air  quality  data,  these 
maps  also  indicate  which  counties  require  additional  monitoring 
stations  to  determine  their  status  and  thus  their  problem  areas. 

Baseline  Levels 

Ambient  air  quality  values  for  1977  for  selected  sta- 
tions can  be  found  in  Appendix  D  while  long-term  baseline  data 
are  presented  in  Appendix  E.  The  values  cover  all  of  the  major 
pollutants,  although  every  station  does  not  measure  all  pollut- 
ants of  interest.  The  listings  include  the  number  of  observa- 
tions, the  yearly  high,  the  arithmetic  and  geometric  means  with 
their  standard  deviations  and  the  seasonal  means  and  highs.  The 
frequency  with  which  standards  are  equalled  or  exceeded  is  also 
provided  for  each  station. 

Baseline  ambient  air  quality  data  from  Appendix  D  have 
been  summarized  in  Figures  5.3-5  and  5.3-6  for  total  suspended 
particulates  and  sulfur  dioxide,  respectively.  These  parameters 
have  been  selected  for  graphical  presentation  and  detailed  analy- 
sis as  they  comprise  the  most  readily  available  air  quality  data. 
They  also  provide  a  good  representation  of  the  effects  of  both 
industrial  and  agricultural  (or  outdoor)  sources. 


353 


ELK  VALLEY 


ARCATA 


7~3 


[v 


D 


Does  Not  Meet  Primary  Standards 
Does  Not  Meet  Secondary  Standards 

Cannot  Be  Classified 

Better  Than  National  Standards 


Figure  5.3-1 
Ukiah  District  TSP  Classifications 


W.SACRAMENTO 


354 


ELK  VALLEY 


.    SMITH  RIVER  A\ 

CRESCENT  CITYV 
\\\NV\v\\\\V^ 
NDEL  NORTE 


HOOPA      ,Os 

BLUE  LAKE    \\\ 
.        .   KORBELNN 

v\\\\»    KNEELAND 
FORTUNA  \\V0 
SCOTIA       «  \A\\  .     BRIDGEVILLE 


ARCATA 


Be 


Un 


tter  Than  Primary  Standards 
classified 


W.SACRAMENTO 


Figure  5.3-2 
Ukiah  District  S02  and  N02  Classifications 


355 


ELK  VALLEY 


ARCATA 


.    SMITH  RIVER 
CRESCENT  CITY 

DEL  NORTE 

KLAMATH 

i 

I 

ORICK 

HUMBOLDT 

HOOPA      . 

BLUE  LAKE 
.        .   KORBEL 
EUREKA 

*     KNEELANO 


.      FORTUNA 
•  .     BRIDGEVILLE 


1 


Does  Not  Meet  Primary  Standards 

Cannot  Be  Classified  or  Better  Than 
National   Standards 


W  SACRAMENTO 


Figure  5.3-3 
Ukiah  District  CO  Classifications 


356 


ELK  VALLEY 


ARCATA 


.   SMITH  RIVER 


CRESCENT  CITY 
lllllllllllll 

DEL  NORTE 

llllllllllll 

KLAMATH 


ORICK 
llllllll 

HUMBOLDT 


HOOPA      . 

miiim 

BLUE  LAKE |  | 
.   KORBEL 
EUREKA  I  I 

KNEELAND 


^ 


Unclassified 

Primary  Standard  Violated 


Figure  5.3-4 
Ukiah  District  Ozone  Classifications 


W,  SACRAMENTO 


357 


50 


WOODLAND 

W  SACRAMENTO 


RIO  VISTA 


SAN  RAFAEL^ 

KENTFIELD 


Figure  5.3-5 

Annual  Geometric  Means  (  yg/m  ) 

For  Total  Suspended  Particulates  in  the  Ukiah  District 

NATIONAL  AMBIENT  AIR  QUALITY  STANDARD  FOR  TSP  =  75  uG/M3  ANNUAL  GEOMETRIC  MEAN 
CALIFORNIA  TSP  STANDARD  =  60  yG/M3  ANNUAL  GEOMETRIC  MEAN 


ARCATA 


SO 


2  Monitoring  Stations 


20 

L_ 


20 


40 

_l_ 


60 

-J 


MILES 


.   CH   - 

•  CALPELLA  -•  ^  #  WILLIAMS 

•  '         •UPPERLAKE  \ 

s  v.  \ 

V,     «LAKEPORT       >  1 

\        •  KELSEYVILLE  .  __  _-L 

^~  1  •      DUNNIGAN 

-- r ^  W  S 

•     CLOVERDALE  f       S  Vw* 


•     CLOVERDALE 

\  J  \ 

HEALDSBURG      J"*  \ 


\       DAVIS* 

£  SANTA  ROSA 

•  *SONOMA  \«  VACAVILLE 

^  \   £  NAPA 

NN     •    PETALUMA         |         *  FAIRFIELD 

Y  /     BEjfCIA 


a       WOODLAND 

W.SACRAMENTO 


RIO  VISTA 


SANRAFAE 

KENTFIELD 


Figure  5.3-6 

Annual  Average  S02  Concentrations  (pphm) 

in  the  Ukiah  District 


NATIONAL  AMBIENT  AIR  QUALITY  STANDARD  FOR  S02  =  0.03  ppm 
Source:  CARB,  1977  359 


Data  are  presented  as  contours  of  annual  average  values 
for  these  pollutants  based  upon  available  data  for  monitoring 
stations  at  locations  as  depicted  in  the  figures.  The  reader  is 
cautioned  in  the  use  of  these  and  subsequent  figures  that  con- 
tours have  been  provided  based  upon  a  limited  amount  of  available 
baseline  air  quality  data.  The  analysis  containing  the  figures 
can  be  used  with  most  confidence  at  locations  near  monitoring 
stations.  In  more  remote  areas,  additional  monitoring  data  would 
be  required  to  confidently  establish  baseline  levels.  Such  areas 
include  counties  which  have  not  been  classified  by  the  CARB  under 
the  requirements  of  the  Clean  Air  Act  Amendments  of  1977  due  to 
the  absence  of  sufficient  monitoring  data. 

Figure  5.3-5  presents  annual  geometric  means  for  total 
suspended  particulates  in  the  Ukiah  District.  The  figure  indi- 
cates that  particulate  levels  are  lowest  on  an  annual  basis  in 
Lake,  Napa,  Sonoma  and  Marin  Counties.  In  Lake  County,  values 
are  less  30  micrograms  per  cubic  meter  on  an  annual  basis. 
Highest  total  suspended  particulate  levels  in  the  Ukiah  District 
are  observed  in  Mendocino  County  and  in  the  Sacramento  Valley 
portion  of  the  District.  Fort  Bragg  recorded  the  highest  total 
suspended  particulate  value  on  an  annual  basis  in  1977  at  86.3 
micrograms  per  cubic  meter.  This  value  is  in  excess  of  both  the 
California  and  Federal  annual  standards.  In  the  Sacramento 
Valley,  values  are  in  excess  of  the  California  annual  standard  as 
well  as  the  Federal  secondary  standard  in  eastern  Colusa  and  Yolo 
Counties.  Higher  particulate  levels  in  this  area  are  not  unex- 
pected due  to  the  very  high  level  of  agricultural  activity  in 
this  region.  The  high  particulate  levels  in  the  Fort  Bragg  area 
are  well  correlated  with  observed  heavy  emissions  of  particu- 
lates. Particulate  levels  in  the  extreme  northwest  decrease  from 
the  elevated  values  observed  in  Mendocino  County  and  are  below 
applicable  standards  for  annual  values  of  total  suspended  partic- 
ul ates  . 

In  summary,  Figure  5.3-5  indicates  that  particulate 
levels  along  coastal  locations  are  lowest  in  the  extreme  southern 
portion  of  the  District  increasing  to  a  maximum  at  Fort  Bragg. 
Coastal  values  then  again  decrease  with  northward  progression 
through  Humboldt  and  Del  Norte  Counties.  In  the  inland  valleys, 
particulate  levels  reach  minimums  for  the  District  and  are  quite 
low  on  an  annual  basis.  Progression  further  eastward  into  the 
Sacramento  Valley  again  reveals  fairly  high  annual  values  of 
total  suspended  particulates  in  excess  of  the  California  and 
Federal  secondary  standards. 

Annual  average  sulfur  dioxide  concentrations  in  the 
Ukiah  District  are  presented  in  Figure  5.3-6.  Data  are  only 
available  for  Vallejo,  Benecia,  Napa  and  Santa  Rosa.  For  these 
stations,  only  Benecia  showed  a  non-zero  annual  average  SCU 
concentration.  Sulfur  dioxide  levels  tend  to  be  low  throughout 
California  and  particularly  in  fairly  rural  areas  such  as  the 
bulk  of  the  Ukiah  District.  No  values  in  excess  of  the  Federal 
annual  standard  have  been  noted  within  the  District. 


360 


The 
levels  in  the 
al  variations 
October  while 
January.  It 
due  to  mobile 
tion  of  ozone 
HC  during  which 


1977  (CARB,  1977)  data  indicate  that  pollutant 
Ukiah  District  are  subject  to  fairly  strong  season- 
Oxidant  readings  are  highest  between  April  and 
carbon  monoxide  reaches  peak  levels  from  October  to 
should  be  noted  that  ozone  formation  is  primarily 
source  emissions  (autos,  trucks,  etc.)*  The  forma- 
has  a  delay  time  from  initial  emissions  of  N0?  and 

and  0o 


time  these  pollutants  react  with  the  sun 


to  form  ozone 


Sulfur  dioxide,  unlike  ozone' 


steady  levels  throughout  the  year.   This 


i  n  d  i  - 
wh  i  1  e 


i  n  the  atmosphere 
rema  ins  at  f a  i  rl y 

cates  that  most  S  0  ?  is  attributable  to  stationary  sources 
other  pollutant  levels  are  affected  by  seasonal  changes  in  trans- 
portation patterns  as  they  are  related  to  the  combustion  of 
transportation  fuels. 

Frequency  of  Violations 

Figures  5.3-7  through  5.3-10  provide  the  frequency  of 
violations  of  key  standards  for  total  suspended  particulates, 
carbon  monoxide,  oxidant  and  lead.  A  specific  figure  for  sulfur 
dioxide,  nitrogen  dioxide  and  sulfates  has  not  been  provided  as 
violations  of  these  short-term  standards  were  not  were  not  re- 
corded . 

Figure  5.3-7  provides  the  frequency  of  violations  of  the 
California  twentyjfour  hour  standard  for  total  suspended  particu- 
lates (100  ug/m  ).  The  figure  indicates  that  the  short-term 
standard  is  violated  in  all  areas  with  the  exception  of  the 
extreme  southeast  which  includes  most  of  Sonoma,  Napa  and  Marin 
Counties.  The  highest  frequency  of  violations  occurred  at  Fort 
Bragg  where  the  short-term  was  violated  nearly  40  percent  of  the 
time.  Along  the  coastal  portions  of  the  Ukiah  District,  the 
frequency  of  violations  ranges  from  zero  in  the  extreme  southeast 
gradually  increasing  to  nearly  40  percent  at  Fort  Bragg,  decreas- 
ing again  with  northward  progression  into  Humboldt  and  Del  Norte 
Counties  where  the  frequency  of  violations  drops  off  to  5  to  10 
percent.  The  frequency  of  violations  is  also  quite  low  in  Napa 
and  Lake  Counties  which  is  in  good  agreement  with  the  trend  noted 
on  Figure  5.3-5  which  presented  the  annual  total  suspended  par- 
ticulate levels  throughout  the  region.  The  frequency  of  viola- 
tions of  the  short-term  standards  increases  with  progression  into 
the  Sacramento  Valley  portion  of  the  Ukiah  District.  Eastern 
Colusa,  Yolo  and  Solona  Counties  show  violations  of  the  short- 
term  standard  for  total  suspended  particulates  10  to  20  percent 
of  the  time.  Violations  in  this  area  are  largely  due  to  agricul- 
tural activity  while  the  violations  noted  along  the  north  coast 
are  due  largely  to  natural  sources  and  local  fugitive  dust  emis- 
sions. The  high  values  observed  in  Mendocino  County  correlate 
well  with  the  high  emission  densities  as  described  in  Section 
5.4. 

The  frequency  of  violations  of  the  Federal  eight-hour 
standard  for  carbon  monoxide  is  depicted  in  Figure  5.3-8  for  the 
Ukiah  District.   The  figure  shows  a  violation  only  at  Vallejo,  a 


361 


WOODLAND 

W  SACRAMENTO 


san  rafael! 

^     0 

KENTFIELD 

Figure  5.3-7 
Frequency   (%)  of  Violations  of  the  California 
24-Hour  Standard   (1)   for  Total   Suspended  Particulates 

(1)    CALIFORNIA  24-HOUR  STANDARD  FOR  TOTAL  SUSPENDED  PARTICULATES  =    100  uG/M' 
Source:      CARB,    1977  362 


ARCATA 


CO  Monitoring  Stations 


20 

_i_ 


MILES 


40 

_l_ 


60 

-J 


•      DUNNIGAN 


V, 


DAVIS  i 


WOODLAND 

W  SACRAMENTO 


•     SONOMA  X«   VACAVILLE 

NAPA 


FAIRFIELD 


RIO  VISTA 


SANRAFAEL* 

KENTFIELD 

Figure  5.3-8 

Frequency  (%)  of  Violations  of  the  Federal   8-Hour 

Standard   (1)   for  Carbon  Monoxide 

(1)   FEDERAL  8-HOUR  STANDARD  FOR  CARBON  MONOXIDE  =  9  ppm 
Source:      CARB,    1977  363 


ARCATA 


W  SACRAMENTO 


KENTFIELD 

0.1 


Figure  5.3-9  sanrafael* 

Frequency  [%)  of  Violations  of  the 

Federal    1-Hour  Standard   (1)   for  Oxidant 

(1)  FEDERAL  1-HOUR  STANDARD  FOR  OZONE  =  0.12  ppm* 

*  THE  FREQUENCY  OF  VIOLATIONS  WAS  DETERMINED  WITH  RESPECT  TO  THE  0.08  ppm 
STANDARD  WHICH  WAS  IN  EFFECT  IN  1977.   THE  CARB  DATA  SHOWS  FREQUENCIES  WITH 
RESPECT  TO  THE  OLD  STANDARD  AND  FREOUENCY  OF  VIOLATIONS  WITH  RESPECT  TO  THE 
0.12  STANDARD  CAN  NOT  BE  DETERMINED  FROM  THESE  DATA 
Source:   CARB,  1977 

■shQ. 


ARCATA 


WOODLAND 

W  SACRAMENTO 


Figure  5.3-10 
Frequency  of  Violations  of  the 
California  30-Day  Standard   (1)   for  Particulate  Lead 


(1)   NUMBER  OF  MONTHLY  AVERAGES  >   1.5  UG/M3 
Source:      CARB,    1977 


3fiB 


metropolitan  suburb  of  San  Francisco.  Carbon  monoxide  concen- 
trations in  more  rural  locations  can  be  expected  to  be  modest. 
As  indicated,  elevated  values  for  this  pollutant  are  generally 
due  to  large  emissions  associated  with  heavy  vehicular  usage. 

The  frequency  of  violations  of  the  Federal  one-hour 
standard  for  oxidant  is  presented  in  Figure  5.3-9.  Monitoring 
stations  for  oxidant  are  presently  only  available  in  Yolo, 
Solono,  Napa,  Sonoma  and  Marin  Counties,  the  metropolitan  suburbs 
of  the  Bay  Area.  Data  are  largely  unavailable  for  the  bulk  of 
the  remainder  of  the  District;  however  oxidant  levels  in  Mendo- 
cino, Humboldt  and  Del  Norte  Counties  are  expected  to  be  fairly 
modest.  The  available  data  indicate  that  the  one-hour  Federal 
standard  is  violated  with  the  highest  frequency  in  Yolo  County  at 
approximately  1  percent  of  the  annual  period.  The  data  show 
increasing  values  of  oxidant  with  eastward  progression  into  the 
Sacramento  Valley  portion  of  the  District.  Photochemical  oxidant 
emitted  in  the  metropolitan  Bay  Area  are  transported  into  the  San 
Joaquin  and  Sacramento  Valleys  during  the  summer  season  resulting 
in  photochemical  activity  in  this  inland  area.  Along  the  coastal 
portions  of  the  District,  the  onshore  transport  of  maritime  air 
generally  results  in  ozone  levels  that  are  near  or  well  below 
background  levels. 

Finally,  the  frequency  of  violations  of  the  California 
thirty-day  standard  for  lead  is  presented  in  Figure  5.3-10.  Once 
again,  violations  of  the  standard  for  lead  occur  most  frequently 
in  heavy  industrial  or  highly  developed  areas.  This  includes 
Marin,  Sonoma,  Napa  and  Solana  Counties.  The  frequency  of  viola- 
tion reaches  a  maximum  of  over  6  percent  of  the  annual  period  at 
San  Rafael.  Available  data  for  other  areas  of  the  District  are 
sparse  and  include  Santa  Rosa,  Lakeport  and  Fort  Bragg.  At  these 
latter  locations,  the  frequency  of  violations  were  zero  and  this 
trend  can  be  expected  to  continue  in  the  northern  portion  of  the 
District. 

Long-Term  Trends 

The  data  presented  in  Appendix  E  provide  an  indication 
of  pollutant  trends  in  the  Ukiah  District.  Oxidant  data  are  only 
available  for  select  station  within  the  District  and  only  Fair- 
field and  San  Rafael  provide  data  for  a  significant  period  of 
time.  These  two  stations  are  located  in  the  extreme  southern 
portion  of  the  District  and  do  provide  an  indication  of  trends  in 
the  San  Francisco  Bay  area.  At  San  Rafael,  mean  oxidant  values 
have  shown  a  definite  decrease  from  peak  values  observed  during 
the  mid  60' s.  Annual  means  have  dropped  from  around  5  pphm  to 
approximately  2  pphm  in  1975.  At  Fairfield,  the  decreasing  trend 
is  more  difficult  to  discern  from  the  mean  values.  However,  peak 
values  have  decreased  since  the  early  70's.  Other  data  available 
for  Petaluma,  Napa,  Eureka  and  Santa  Rosa  show  no  significant 
trends  . 


366 


Carbon  monoxide  data  are   only 
Napa,  San  Rafael  and  Santa  Rosa.    Nine 
sented  in  the  appendix  for  San  Rafael, 
monoxide  levels  have  been  fairly 
Peak  values  have  shown  a  modest 
16  ppm  in  1975.   Data  at  Santa 
have  also  shown  a  slight  decline 
and  Napa  are     not  available  for 


from  which  to  deduce  more  current  trends. 


available   for   Eureka, 

years  of  data  are  pre- 

At  this  station  carbon 

for  at  least  six  years . 

from  roughly  20  ppm  to 

the  period  1972  to  1975 

for  the  period.   Data  for  Eureka 

a  significant  period  of  record 


constant 
d  e  c  1  i  n  e  , 
Rosa  for 


Sufficient  data  for  sulfur  dioxide  are  not  available  in 
the  Ukiah  District  to  permit  a  long-term  trend  analysis.  A 
significant  period  of  nitrogen  dioxide  data  are  available  from 
San  Rafael.  These  data  show  little  difference  in  mean  NOo  values 
for  the  period  1969  through  1975,  although  values  during  this 
period  are  lower  than  peak  values  observed  in  1967  and  1968. 
Nitric  oxide  values  at  San  Rafael  have  shown  a  definite  increase 
from  the  low  values  observed  during  1969  and  1970.  Hydrocarbons 
at  San  Rafael  have  shown  a  definite  decrease  in  mean  values  since 
the  late  60's  with  very  low  values  being  observed  in  1979  when 
the  peak  value  was  6  ppm. 


Hi-volume  data  comprise  the  most  readily  available 
source  of  pollutant  data  in  the  Ukiah  District.  Discernible 
long-term  trends  are  generally  not.  evident  the  fairly  constant 
levels  observed  in  the  northern  part  of  the  District.  At  Napa, 
values  have  decreased  during  the  four  year  period  1972  through 
1975,  and  a  decrease  has  also  been  noted  at  San  Rafael. 


367 


5.4 


POINT  AND  AREA  SOURCES  OF  THE  UKIAH  DISTRICT 


The  Ukiah  District  encompasses  counties  in  four  air 
basins  -  the  North  Coastal,  the  North  Coastal  Mountain,  the 
Sacramento  Valley  and  the  San  Francisco  Bay  Area.  This  geograph- 
ical distribution  allows  a  diverse  range  of  agricultural  and  in- 
dustrial activities  and  settlement  patterns.  Industrial  activi- 
ties include  rock  aggregates,  oil  and  shipyards.  Timber  and  the 
associated  milling,  veneer,  plywood,  redwood,  pulp  and  paper 
industries  include  grain  warehouses  and  driers,  sugar  and  rice. 
These  industries  also  comprise  the  bulk  of  major  emitters  (100 
tons/yr  or  more)  for  the  district.  Other  sizable  emitters  in- 
clude West  Sacramento  and  open  burning  dumps. 

With  many  possible  types  of  emitters,  a  wide  range  of 
stack,  flow  and  emission  characteristics  occur.  Many  of  the 
lumber  and  timber  related  industries  do  not  have  stacks.  Equip- 
ment includes  bark  boilers,  crushers  and  kilns  (with  vents)  which 
emit  pollutants.  The  temperature  range  for  emissions  from  such 
equipment  is  wide  -  from  ambient  (77°F)  to  600°F.  Other  lumber 
products  are  made  more  generally  at  300-400°F.  Typical  emissions 
from  the  lumber  companies  are  particulates  and  carbon  monoxide. 
Particulate  emissions  fall  in  the  150-250  tons/yr  range,  with 
carbon  monoxide  output  reaching  as  high  as  1500  tons/yr.  Typical 
carbon  monoxide  emission  levels  are  250-350  tons/yr.  Table  5.4-1 
provides  a  summary  of  typical  source  exit  characteristics  for  a 
variety  of  source  types.  These  data  can  be  used  for  simplistic 
or  screening  level  modeling  as  discussed  in  more  detail  in  Sec- 
tion 4.9. 


There  are  a  few  large  lumber  industry  facilities  which 
do  not  have  stack  data.  Typically,  however,  there  are  6  stacks, 
80  feet  tall  (some  range  to  300  ft.)  with  diameters  from  5  to  12 
ft.  and  flow  rates  reaching  210,000  ACFM.  Typical  flow  rates, 
however,  are  30,000  to  65,000  ACFM.  Stack  temperatures  range 
from  77°F  to  465°F  usually  falling  around  400°F.   These  plants 


also  typically  emit  carbon  monoxide 
pollutants;  however,  emissions  of 
tons/yr . 


and  particulates  as  principal 
hydrocarbons  can  reach  150 


There  are  few  power  plants  in  the  district  which  are 
major  emitters.  In  the  district,  power  facilities  generally  have 
only  one  to  two  stacks  with  heights  at  about  120  feet  and  exit 
diameters  of  around  10  feet.  Typical  exit  temperatures  are  320  F 
with  flow  rates  around  200,000  ACFM.  Other  industrial  plants 
(sugar,  ports,  warehouses  and  so  on)  and  open  burning  dumps  do 
not  have  (or  do  not  list)  stack  exit  characteristics.  Pollutants 
commonly  are  TS P  and  NOx  with  some  hydrocarbons  and  carbon  monox- 
ide. Most  TSP  emissions  are  in  the  100-250  tons/yr  range. 
Figures  5.4-1  through  5.4-5  indicate  the  emission  densities  of 
the  criteria  pollutants  by  county  in  the  district. 

The  emission  densities  presented  in  Figures  5.4-1 
through  5.4-5  are  comprised  of  area  and  point  sources.  Area 
sources  comprise  three  principal   types:   solid  waste  disposal, 


368 


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ARCATA 


□ 

□ 


0  -  1,000 
1,000  -  2,500 
2,500  -  4,000 
4,000  -  6,500 
6,500  -  8,000 
8,000  -   12,000 


W.  SACRAMENTO 


Figure  5.4-1 
Total  Emissions  of  TSP  (Tons/Year) 
in  the  Ukiah  District 


370 


ELK  VALLEY 


s 


0  -  100 
100  -  350 
350  -  500 
500  -  750 
750  -  1,000 
1,000  -  5,000 
5,000  -  15,0C0 


W  SACRAMENTO 


Figure  5.4-2 

Total  Emissions  of  Sulfur  Dioxide  (Tons/Year) 

in  the  Ukiah  District 


371 


ELK  VALLEY 


ARCATA 


1,000  -   2,500 
PI      2,500  -   5,000 
5,000  -   10,000 
10,000  -   12,000 
12,000  -   18,000 


W.SACRAMENTO 


Figure  5.4-3 
Total  Emissions  of  Oxides  of  Nitrogen  (Tons/Year) 
in  the  Ukiah  District 


372 


; VALLEY 


ARCATA 


□ 


15,000  -  25,000 
25,000  -  40,000 
40,000  -  75,000 
75,000  -  100,000 
100,000  -  120,000 


Figure  5.4-4 
Total  Emissions  of  Carbon  Monoxide  (Tons/Year) 
in  the  Ukiah  District 


W.SACRAMENTO 


373 


ELK  VALLEY 


ARCATA 


1,000  -  5,000 
5,000  -  10,000 
10,000  -  20,000 


20,000  -  25,000 
>  25,000 


W  SACRAMENTO 


Figure  5.4-5 
Total  Emissions  of  Hydrocarbons  (Tons/Year) 
in  the  Ukiah  District 


374 


fuel  sources  other  than  factories  (such  as  residences,  institu- 
tions and  transportation)  and  evaporative  losses  from  solvents 
and  gases.  Major  emitters  in  the  Ukiah  District  are  transporta- 
tion, fuel,  solid  waste  disposal,  and  depending  on  the  county, 
forest  fires.  Sonoma  County  also  has  significant  solvent  evapor- 
ative hydrocarbon  emissions  -  6,476  tons/yr.  Lake,  Mendocino  and 
Sonoma  counties  have  the  greatest  area  emissions  from  total 
suspended  particulates  -  more  than  2,400  ton/yr  each.  Solano 
County  has  the  largest  emissions  of  sulfur  oxides  -  1,426  tons/yr 
with  Sonoma  and  Yolo  Counties  following  in  the  800  tons/yr  range. 
Marin,  Solano  and  Sonoma  Counties  have  the  highest  emissions  of 
NOx,  HC  and  CO.  On  an  overall  district  basis,  the  major  area 
pollutant  is  carbon  monoxide  at  613,226  tons/yr.  Hydrocarbons 
are  the  next  highest  with  127,945  tons/yr  followed  by  NOx  at 
64,006  tons/yr.  Point  sources  contribute  more  particulate  and 
more  sulfur  oxides  than  area  sources. 


Appendix  F  provides  a  summary  of  major  point  sources 
within  the  District  on  a  county  basis.  In  the  extreme  north,  in 
Del  Norte  County,  U.S.  Forest  Service  operations  at  Six  Rivers 
represent  the  major  point  source  in  the  region  for  all  pollut- 
ants. In  Humboldt  County,  Crown  Simpson  Facilities  at  Fairhaven 
are  major  emitters  of  suspended  particulates,  sulfur  oxides, 
nitrogen  oxides  and  carbon  monoxide.  Louisiana  Pacific  facili- 
ties at  Somoa  are  also  major  emitters  of  these  pollutants,  with 
the  exception  of  sulfur  dioxides.  Pacific  Gas  &  Electric's 
facility  at  Humboldt  Bay  in  Eureka,  is  a  major  emitter  of  nitro- 
gen oxides  while  Areata  Redwook  in  Orick  is  a  prime  contributor 
to  carbon  monoxide  levels.  In  Mendocino  County,  Georgia  Pacific 
at  Fort  Bragg  is  a  major  contributor  to  point  source  emissions  of 
carbon  monoxide,  hydrocarbons,  nitrogen  oxide,  and  particultes. 
There  are  no  major  emitters  of  sulfur  dioxide  in  the  county.  The 
appendix  indicates  that  no  major  emitters  are     located  in  Lake 


County.   Emissions  are     also  very  modest  in  Colusa  County  wi 


th 


only  three  point  sources  listed  which  barely  qualify  as  major 
emitters  of  suspended  particulates.  In  Yolo  County,  the  Rice 
Growers  Association  West  Sacramento  River  Plant  is  the  major 
emitter  of  total  suspended  particulates  in  the  county  on  a  point 
source  basis.  The  only  contributor  to  the  other  criteria  pollut- 
ants is  American  Star  Corporation's  Spreckels  Sugar  facility  at 
Woodland.  Napa  County  records  only  one  major  source  and  it 
barely  qualifies  as  a  major  emitter  for  particulates  and  sulfur 
oxides.  This  is  the  Bay  Salt  Rock  Company  in  Napa  on  the  Vallejo 
Highway.  In  the  southeast,  Sonoma  County  has  several  major 
emitters,  including  the  Masonite  Lumber  Company  in  Cloverdale 
which  is  the  major  emitter  of  the  criteria  pollutants.  Other 
large  sources  include  Cloverdale  Lumber,  Cloverdale  Plywood  and 
the  Louisiana  Pacific  Corporation  all  in  Cloverdale.  This  city 
is  the  home  of  many  of  the  major  point  sources  in  the  county. 
Finally,  there  are  no  major  point  sources  recorded  in  Marin 
County . 


375 


Marin, 
HC  and 
are  the 
concentrated 


through  5.4-5  indicate,  the  counties  of 

have  the  largest  emissions  of  CO,  N02, 

SOo.   However,  the  counties  with  the  highest  TSP  emissions 

northern 


As  Figures  5.4-1 
Solano  and  Sonoma 


count i es 
there  . 


due  to  the  lumber  industry  which  is 


The  Ukiah  District  is  also  the  site  of  a  special  type  of 
natural  and  manmade  air  pollutants.  The  Geyser's  Known  Geother- 
mal  Resource  Area  (KGRA)  is  a  major  geothermal  development  area. 
This  area,  depicted  in  Figure  5.4-6,  is  a  source  of  emissions 
associated  with  geothermal  development,  including  well  drilling, 
testing,  well  bleeds,  uncontrolled  wells,  stacking,  pipeline 
vents,  and  natural  fumaroles.  The  plant  emissions  are  the  larg- 
est source  of  hydrogen  sulfide  in  the  KGRA  with  natural  fumaroles 
accounting  for  only  0.3  percent  of  the  total  emissions  (Weres,  et 
al ,  1976).  Plant  emissions  at  Geysers  Units  1  through  10  during 
the  fall  of  1976  with  a  rated  power  of  396  megawatts.  Geothermal 
developments  are  also  sources  of  carbon  dioxide  and  sulfur  diox- 
ide. Other  pollutants  emitted  in  quantity  include  carbon  monox- 
ide, ammonia,  boron,  hydrogen,  nitrogen,  arsenic,  radon  and 
mercury.  The  impact  of  some  of  the  latter  heavy  metals  is  of 
critical  concern  to  biological  species  surrounding  the  large 
cooling  towers  which  must  be  used  to  dissipate  heat  at  most 
geothermal  developments  (Pacific  Gas  &    Electric,  1979). 

Figures  5.3-1  through  5.3-4  indicate  the  attainment 
status  of  the  various  counties  in  the  district.  It  is  evident 
that  most  of  the  district  is  subject  to  PSD  for  S02  and  NOp.  PSD 
would  also  apply  to  ozone  in  all  counties  except  for  the  Bay  Area 
counties,  for  CO  for  all  counties  except  Marin,  Napa,  the  Bay 
Area  portions  of  Sonoma  and  Solano,  and  Yolo,  and  for  TSP  for  all 
counties  except  Humboldt,  Mendocino  and  Yolo. 

The  Bay  Area  counties  will  be  subject  to  non-attainment 
rules  for  oxidant  and  CO.  Humboldt,  Mendocino  and  Yolo  will  be 
subject  to  non-attainment  rules  for  particulates. 


increments  (see  Section  6.4)  will  li 
struction  possible  in  the  area,  the 

facilities  and  control  equipment  to  be  used  tor  projected  emis- 
sions.   New  Source  Performance  Standards  will  have  to  be  con- 
idered  in  conjunction  with  PSD  and  NESHAPS  to  provide  a  balance 
etween  developmental   requests  to  utilize  BLM  lands  and  the 
ecreational  functions  now  substantially  governing  land  use. 


376 


5.5       ASSISTANCE  IN  AIR  POLLUTION  PROBLEMS 

REFERENCES 

Abstracts 

Air  Pollution  Control  Association  Abstracts 
Air  Pollution  Control  Association 
4400  Fifth  Avenue, 
Pittsburgh,  Pennsylvania 

Public  Health  Engineering  Abstracts 
Superintendent  of  Documents 
U.S.  Government  Printing  Office 
Washi  ngton ,  D. C. 

Periodicals 

Air  Engineering 

Business  News  Publishing  Company 
450  W.  Fort  Street 
Detroit,  Michigan 

Amer i  can  City 

The  American  City  Magazine  Corporation 
470  Fourth  Avenue , 
New  York ,  New  York 

American   Industrial   Hygiene   Association 
Journal 
14125  Prevost 
Det roi t ,  Michigan 

American  Journal  of  Public  Health  and  Nations' 
Health 

American  Public  Health  Association,  Inc. 
1790  Broadway 
New  York ,  New  York 

Archives  of  Environmental  Health 
American  Medical  Association 
535  N.  Dearborn  Street 
Chicago,  Illinois 

Atmospheric  Environment 
Pergamon  Press 
122  East  55th  Street 
New  York,  New  York 

Atmospheric  Pollution  Bulletin 
Warren  Spring  Laboratory 
Gunnels  Wood  Road 
Stevenage  ,  Engl  and 


377 


Chemical  Engineering 

McGraw-Hill  Publishing  Company,  Inc. 
330  W.  42nd  Street 
New  York,  New  York 

Chemical  Engineering  Progress 

American  Institute  of  Chemical  Engineers 
345  47th  Street 
New  York,  New  York 

Chemical  Reviews 

American  Chemical  Society 
20th  and  Northampton  Streets 
Easton,  Pennsylvania 

Environmental  Health  Series 

National  Centre  for  Air  Pollution  Control 
4676  Columbia  Parkway 
Cincinnati  ,  Ohio  45226 

Heating,  Piping  and  Air  Conditioning 
Keeney  Publishing  Company 
6  North  Michigan  Avenue 
Chi  cago ,  Illinois 

Industrial  and  Engineering  Chemistry 
American  Chemical  Society 
1155  Sixteenth  Street,  N.W. 
Washi  ngton  ,  D. C. 

Industrial  Hygiene  Foundation  of  America, 
Transactions  Bulletin 

Industrial    Hygiene    Foundation    of 
American,  Inc. 
4400  Fifth  Avenue 
Pittsburgh,  Pennsylvania 

Industrial  Medicine  and  Surgery 

Industrial  Medicine  Publishing  Company 

P.O.  Box  306 

Miami ,  FLorida  33144 

Industrial  Water  and  Wastes 

Scranton  Publishing  Company,  Inc. 
35  E.  Wacker  Drive 
Chicago ,  Illinois 

Journal   of   the   Air   Pollution   Control 
Associ  at i  on 

Air  Pollution  Control  Association 
4400  Fifth  Avenue 
Pittsburgh,  Pennsylvania 


378 


Journal  of  Colloid  Science 
Academic  Press,  Inc. 
Ill  Fifth  Avenue 
New  York ,  New  York 

Mechanical  Engineering 

American  Society  of  Mechanical  Engineers 
345  E.  47th  Street 
New  York ,  New  York 

The  Oil  and  Gas  Journal 

211  South  Cheyenne  Avenue 
Tul sa ,  Okl ahoma 

Publ ic  Heal th  Reports 

U.S.  Department  of  Health,  Education  and 

Wei  fare 

Public  Health  Service,  Superintendent  of 

Document  s 

U.S.  Government  Printing  Office 

Washington,  D.C.  20402 

Public  Works 

Public  Works  Journal  Corporation 
200  South  Broad  Street 
Ridgewood,  New  Jersey 

Smokeless  Air 

National  Society  for  Clean  Air 
Field  House,  Breams  Building 
London  E. C  .  ,  England 

Transaction   of   the   American   Society   of 
Mechanical  Engineers 

Journal  of  Engineering  for  Power  (Series 
A  of  the  Transactions  of  the  ASME) 
Journal   of   Engineering   for   Industry 
(Series  B) 

Journal  of  Heat  Transfer  (Series  C) 
Journal  of  Basic  Engineering  (Series  D) 
Journal  of  Applied  Mechanics  (Series  E) 
American  Society  of  Mechanical  Engineers 
345  East  47th  Street 
New  York  17,  New  York 


Transactions   of 
Engineers 

Institution  of  Chemical 
16  Belgrave  Square 
London  S. W. ,  Engl  and 


Institution   of   Chemical 
Engi  neers 


Environmental  Science  and  Technology 
American  Chemical  Society 
1155  Sixteenth  Street  N.W. 
Washington,  D.C.  20036 


379 


Books 

Encyclopedia  of  Instrumentation  for  Industrial 
Hygi  ene  ,  University  of  Michigan,  Ann 
Arbor,  1956. 

Frenkiel,  F.N.;  and  Sheppard,  P. A.  Editors, 
Atmospheric  Diffusion  and  Air  Pollution, 
Academi  c  Press  ,  London  ,  1959. 

Pub! ications 

Air  Pollution  Abatement  Manual  Manufacturing 
Chemists'  Association,  Inc. 
1625  Eye  Street,  N.W.  Washington,  D.C. 

The  Air  Pollution  Bibliography 

The   Library   of   Congress   Technical 
Information  Division  Washington,  D.C. 

Air  Pollution  Control  Association  Abstracts, 
Air  Pollution  Control  Association 
4400  Fifth  Avenue 
Pittsburgh,  Pennsylvania 

Applied  Science  and  Tehcnology  Index 
The  H.W.  Wilson  Company 
950  University  Avenue 
New  York,  New  York 

Battelle  Technical  Review 

Battelle  Memorial  Institute 
505  Ki  ng  Avenue 
Col umbus ,  Ohio 

Chemical  Abstracts 

American  Chemical  Society 
1155  Sixteenth   Street,  N.W. 
Washi  ngton ,  D.C. 

Engi  neer i  ng  Index 

Engineering  Index,  Inc. 
345  East  47th  Street 
New  York,  New  York 


on 


Materials   and 


Environmental   Effects 
Equi  pment 

Prevention  of  Deterioration  Center 
National  Academy  of  Sciences 
National  Research  Council 
2101  Constitution  Avenue,  N.W. 
Washi  ngton  ,  D.C. 


380 


Meteorological  and  Geoast rophysi cal  Abstracts 
American  Meteorological  Society 
45  Beacon  Street 
Boston,  Massachusetts 

Monthly  Catalog  of  United  States 
Government  Publications 
Superintendent  of  Documents 
U.S.  Government  Printing  Office 
Washi  ngton  ,  D. C. 

Public  Health  Engineering  Abstracts 
Superintendent  of  Documents 
U.S.  Government  Printing  Office 
Washi  ngton  ,  D. C. 

Quarterly  Cumulative  Index  Medicus 
American  Medical  Association 
535  N.  Dearborn  Street 
Chicago,  Illinois 

Readers'  Guide  to  Periodical  Literature 
The  H.W.  Wilson  Company 
950  University  Avenue 
New  York,  New  York 

Clearinghouse  Announcements  in  Science  and 
Technol ogy 

Category  68.  Environmental  Pollution  and 
Control  . 

CFSTI  U.S.  Dept.  Commerce 
Springfield,  Va.   22151 

Bibliographies 

Air  Pollution  Publications  -  A  Selected 
Bibliography  1955  -  1963.  Public  Health 
Service  Publication  No.  979. 

Air  Pollution  Publications  -  A  Selected 
Bibliography  1963-1966.  Public  Health 
Service  Publication  No.  979 

Environmental   Health   Series   Reports 

Referencees  and  Abstracts.  Public  Health 
Service,  National  Center  for  Air 
Pollution  Control,  1966. 

Reference  List  of  Publications.  Section  1  Air 
Pollution,  Public  Health  Service, 
National  Center  for  Air  POlltuion 
Control.   1964 


381 


Carbon  Monoxide  -  A  Bibliography  with 
Abstracts.  U.S.  Dept.  HEW,  Public  Health 
Service.      Publication    No.    1503.       1966. 

Sulfur  Oxides  and  other  Compounds  -  A 
Bibliography  with  Abstracts,  U.S.  Dept. 
HEW  Public  Health  Service,  Publicaiton 
No.     1093.     1965 

Nitrogen  Oxides:  An  Annotated  Bibliography 
NAPCA    Pub.    No.    AP-72,    August    1970. 

Hydrocarbons  and  Air  Pollution:  An  Annotated 
Bibliography.  NAPCA      PUb.      No.      AP-75 

(Parts    I ,    II ) ,    October    1970. 

Photochemical  Oxidants  and  Air  Pollution:  An 
Annotated  Bibliography.  Pub.  No  AP-88 
(Parts    1,    2),    March    1971. 

World      Meteorlogical       Organization-List      of 
Available    Publications 
WMO    Publications    Center 
UNIPUB    Inc. 
P.O.    Box   433 
New    York,    N.Y.    10016 

Professional  Meteorological  Consultants 

Professional  meteorologists  advertise  their  services  in 
the  Professional  Directory  section  of  the  Bulletin  of  the  Ameri- 
can Meteorological  Society.  In  the  May  1979  Bulletin,  83  such 
firms  and  individuals  were  listed.  The  American  Meteorological 
Society  has  in  the  last  several  years  instituted  a  program  of 
certifying  consulting  meteorologists.  Of  the  83  professional 
services  listings  in  the  Bulletin,  40  list  Certified  Consulting 
Meteorologists. 

Local  U.S.  National  Weather  Service  Office 

The  Air  Stagnation  Advisories  are  received  here  by 
teletype  from  the  National  Meteorological  Center.  Often  the 
public  telephones  the  Weather  Service  with  air  pollution  com- 
plaints which  the  meteorologists  may  have  traced  back  to  a  spec- 
ific source  by  examining  local  wind  circulations.  Through  per- 
sonal contact  with  the  meteorol ogi st- i n-charge  (MIC)  specific, 
localized  forecasts  may  be  arranged  to  support  a  short-term  air 
pollution  investigation  or  sampling  program. 

USEPA 

The  USEPA  provides  a  complete  information  service  to  all 
individuals,  groups,  companies,  etc.  This  includes  information 
on  regulations,  publications  as  well  as  expert  advice. 


382 


Contract  Work 

Many  universities  do  contract  work  for  private  organiza- 
tions and  for  government  agencies  on  meteorl og i cal  problems  and 
also  on  air  pollution  surveys. 


333 


5.6 


GLOSSARY  OF  TERMS 


Acetyl enes 
Acid 


Adhesi  on 
Aerosol 
Aff i  ni ty 


Al cohol 


Al dehyde 

Al  ert  Level s 


Al  gae 


Al kanes 


Al kenes 


Am  ides 


A  group  of  unsaturated  hydrocarbons  whose 
carbon  atoms  possess  a  triple  bond. 

A  compound  that  turns  blue  litmus  paper  red, 
generally  tastes  sour  and  most  often  is  corro- 
sive; in  solution  it  produces  hydrogen  ions  or 
protons  which  can  be  replaced  by  metal  to  form 
a  salt.  Acids  usually  contain  hydrogen, 
neutralized  alkalis  and  form  well  defined 
sal ts  . 


The  force  of  attraction  between  unlike 
cules,  causing  adjoining  or  attachment. 


mol  e- 


A  system  of  collodial  particles  dispersed  in  a 
gas  . 

A  natural  liking  or  reaction;  the  phylogenetic 
relationship  between  two  organisms  or  groups 
of  organisms  resulting  in  a  resemblence  in 
general  plan  or  structure;  the  force  by  which 
atoms  are    held  together  in  chemical  compounds. 

C?Hfi0  or  C^HrOH,  a  volatile,  colorless  pungent 
liquid;  often  used  as  a  generic  term  which 


met  hoi  al cohol  ,  amy  1 


includes  ethyl  alcohol, 
al cohol  and  gl ycer i  n  . 

Dehydrogenated  alcohol. 


A  concentration  of  pollution  which  dictates 
the  issuance  or  notification  by  State  Regula- 
tory Agencies  to  the  general  public  that  a 
threat  to  human  health  may  occur  due  to  ele- 
vated pollution  levels. 

Simple  aquatic  plants  without  leaves,  stems  or 
roots  sometimes  having  brown  or  reddish  pig- 
ments. 

The  group  of  hydrocarbons  in  the  methane 
series,  also  called  saturated  hydrocarbons  or 
parafins  (C-H). 

A  group  of  hydrocarbons  with  one  double  bond; 
also  called  olefins  or  unsaturated  hydrocar- 
bons (C=C ) . 


Organic   compounds  that   contain   the  CO 
radical  or  an  acid  radical  in  replacement 
one  hydrogen  atom  of  an  ammonia  molecule. 


NH2 
for 


384 


Am  i  n  e  s 


Amino  Acids 


Am  phi  bol e 


Anaerobic 

Anoxia 

Aortic 

Aqueous 
Aromat  i  cs 


Arteriosclerosis 

Asbestos 
Asphyxiant 

Bi  osphere 


Ammonia  bases,  that  is,  chemical  substances 
resulting  from  replacing  ammonia  hydrogen 
atoms  with  al kyl  groups  [(ChU)  -N-H  ];  amines 
are  products  of  animal  or  vegetable  decompo- 
sition. 

Fundamental  structural  units  of  proteins;  they 
are  fatty  acids  in  which  one  hydrogen  atom  has 
been  replaced  by  an  amino  group. 

Any  of  the  complex  group  of  the  hydrous  sili- 
cate materials  containing  chiefly  calcium, 
magnesium,  sodium,  iron  and  aluminum,  and 
including  hornblend,  asbestos,  etc. 

Living  in  the  absence  of  air  or  free  oxygen. 

Without  oxygen,  lack  of  oxygen  for  body  use. 

The  conveyance  of  blood  from  the  left  ven- 
trical of  the  heart  to  all  of  the  body  except 
the  1 ungs . 

Water  acting  as  a  solvent  in  a  solution;  a 
fluid  resembling  water. 

Any  unsaturated  hydrocarbon  with  cyclic  mole- 
cules resembling  benzene,  C^H^,  in  chemical 
behavior,  so  named  because  of  the  fragrant 
odor  of  many  in  the  class. 

An  arterial  disease  characterized  by  an  inel- 
asticity and  thickening  of  the  vessel  walls, 
with  lessened  blood  flow. 

A  fibrous  amphibole  used  for  making  fire-proof 
arti  cl es  . 

An  agent  or  substance  which  causes  death  or 
loss  of  consciousness  by  the  impairment  of 
normal  breathing. 

That  portion  of  the  world  and  its  atmosphere 
in  which  humans,  animals  and  plants  can  sur- 
vive. 


Broncho- 
constri  ctor 


Care  i  nogeni  c 


An  agent  that  causes  the  contraction  of  the 
muscles  which  control  the  pharynx. 

Refers  to  a  substance  that  is  known  to  induce 
cancer . 


385 


Catal ase 


Catal yst 


Catal yt ic 
Convertor 


Cation 
Cel 1 ul ose 


Chi orat  i  c 
Mottle 


Chi orosi  s 
Choi estrol 

Chrysot i  1  e 
Colloid 

Cy pri  nid 

Di  astase 

Def ormat i  on 

Di  scol orat  i  on 

Di  ssoc  i  at  i  on 


The  enzyme  responsible  for  the  decomposition 
and  oxidation  of  hydrogen  peroxide  into  water 
and  oxygen. 

A  substance  which  accelerates  or  promotes  a 
chemical  action  by  a  reagent  which  itself 
remai  ns  unchanged . 


A  device  attached  to  an  automobiles  internal 
combustion  engine  which  chemically  alters 
emissions  from  the  engine  prior  to  release 
through  the  exhaust  system.  The  catalytic 
convertor  was  introduced  on  modern-day  automo- 
biles in  the  mid-1970's  in  an  effort  to  reduce 
harmful  automobile  exhaust  emissions  and 
promote  a  cleaner  environment. 

Ions  of  positive  charge  deposited  on  the 
cathode . 

The  complex  carbohydrate  substance  that  forms 
the  material  of  cell  walls  of  plants. 


Brown  or  red  spots  on  the  surface  of  a  leaf 
caused  by  chemical  pollution. 

A  diseased  condition  in  green  plants  marked  by 
yellowing  or  blanching. 

A  sterol,  C-^H^cOH,  occurring  in  all  animal 
fat  and  oils,  biTe,  gall  stones,  nerve  tissue, 
bl ood  ,  etc  . 

A  fibrous  variety  of  serpentine;  asbestos. 

A  substnace  in  a  state  of  matter  characterized 
by  having  small  power  of  diffusion. 

Any  fish  belonging  to  the  minnow  family; 
carplike  in  form  or  structure. 

The  enzyme  responsible  for  starch  utilization. 


The  act  of  marring  the  natural  form  or  shape 
of  an  object;  distortion. 

The  act  or  fact  of  changing  or  spoiling  the 
color  of  an  object;  a  fade  or  a  stafn. 

The  breaking  up  of  a  compound  into  its  simpler 
constituents  by  means  of  heat  or  electricity. 


386 


Ecosystem 
Edema 

Emi  ssi  on  Density 
Endogenous 

Endotherm  ic 

Enzyme 


Ester 

Ether 
Fauna 
Fixation 

Fl  ora 

Fl ourescence 

Gl ucosidase 

Greenhouse 
Effect 


A  habitable  environment  existing  naturally  or 
created  artificially. 

Effusion  of  serous  fluid  into  the  interstices 
of  cells,  in  tissue  spaces  or  into  body  cavi- 
ties. 

Emissions  per  unit  area. 

Originating  or  developing  internally  or  with- 
in . 

Noting  or  pertaining  to  a  chemical  change  that 
is  accompanied  by  an  absorption  of  heat. 

A  protein  substance  secreted  in  animals  or  by 
plants  whose  function  is  catalytic,  promoting 
chemical  reactions  for  metabolic  or  physiolo- 
gical processes. 

A  compound  produced  by  the  reaction  between  an 
acid  and  an  alcohol  with  the  elimination  of  a 
mol ecul e  of  water . 

A  series  of  compounds  formed  by  dehydration  of 
al cohol s . 

Collective  animal  life  of  any  prticular  geo- 
graphical area  or  time. 

The  act  of  making  stable  in  consistence  or 
condition;  reduction  from  fluidity  or  vola- 
tility to  a  more  permanent  state. 

Collected  plant  life  of  any  particular  area  or 
t  ime . 

Emitting  radiation  (such  as  light)  as  a  result 
of,  and  only  during  the  time  of,  exposure  to 
radiation  from  another  source. 

The  enzyme  that  catalyzes  glucose. 


Most  of  the  infrared  radiation  emitted  by  the 
earth  is  absorbed  by  carbon  dioxide  and  water 
in  the  atmosphere.  Part  of  the  infrared 
radiaiton  absorbed  is  re-radiated  back  to 
earth.  This  trapping  and  recycling  of  terres- 
trial radiation,  which  makes  the  earth  warmer 
than  it  would  be  otherwise,  is  known  as  Green- 
house Effect,  because  it  was  once  thought  that 
greenhouses  remain  warm  by  the  same  process. 


387 


Heavy  Metal 
Hematocrit 
Hemogl obi  n 


Herbivorous 
Homol og 


Humus 


Hydrate 


Hydrol yze 

Hypertrophy 
Hyphai 

I nert i al 


I nsect i  vorous 

Intercostal  Leaf 
Area 

Irradiation 


A  metal  which  is  made  up  of  elements  having 
1 arge  atom  ic  wei  ghts  . 

A  centrifuge  for  separating  the  cells  of  the 
blood  from  the  plasma. 

The  protein  coloring  matter  of  the  red  blood 
corpuscles,  serving  to  convey  oxygen  to  the 
tissues  and  occurring  in  reduced  form  in 
venous  blood  and  in  conbination  with  oxygen  in 
arter i  al  bl ood  . 

Feeding  on  plants. 

An  object  corred spond i ng  in  structure  and  in 
origin,  but  not  necessarily  in  function,  to 
another  object;  chemicals  of  the  same  type, 
but  which  differ  by  a  fixed  increment  in 
certain  constituents. 

The  dark  organic  material  in  soil  produced  by 
the  decomposition  of  vegetable  or  animal 
matter . 

Compounds  with  large  amounts  of  water  as  part 
of  their  molecular  structure  and  without  re- 
arrangement of  the  atoms  of  the  H2O  group; 
hydration  is  the  chemical  union  of  water  and 
any  substance. 

To  subject  or  be  subjected  to  decomposition  in 
which  a  compound  is  split  into  other  compounds 
by  taking  up  the  elements  of  water. 

An  abnormal  enlargement  of  a  part  or  organ. 

One  of  the  thread-like  elements  of  the  vege- 
tative part  of  f ung i . 

Matter  having  the  property  by  which  it  retains 
its  state  of  rest  or  its  velocity  along  a 
straight  line  so  long  as  it  is  not  acted  upon 
by  an  external  force. 

Adapted  to  feeding  on  insects. 


Leaf  area  between  the  ribs. 

The  act  of  having  been  heated  with  radiant 
energy;  the  act  of  having  been  exposed  to 
rad  i  at  i  on  . 


388 


Irri  tant 


Ketones 


Leach 

Lichen 

Macrophage 

Marginal  Leaf 
Area 

Mercaptan 
Metabol i  sm 


Mi  crodecomposer 

Necrosi  s 
Ni tr i 1 es 

Nucleation 
Olefins 


A  biological,  chemical  or  physical  agent  that 
stimulates  a  characteristic  function  or  elic- 
its a  response,  especially  an  inflammatory 
response . 

A  group  of  organic  compounds  characterized  by 
a  carbonyl  radical  (  C  =  0  )  united  wih  two 
hydrocarbon  radicals;  usually  colorless, 
pungent  substances . 

A  process  by  which  a  liquid  filters  through 
another  substance. 

A  plant  composed  of  an  algae  and  fungi  growing 
together . 

A  large  cell  that  characteristically  engulfs  a 
foreign  material  and  consumes  debris  and 
foreign  bodies. 


Leaf  edges. 

Compound  analogous  to  alcohol  containing 
sulfur  in  place  of  oxygen  (R-S-H). 

The  chemical  activity  that  takes  place  in  the 
cells  of  living  organisms  involving  two  funda- 
mental procedures,  catabolism  and  anabolism, 
simultaneously  at  work;  the  former  refers  to 
the  breaking  up  of  substances  into  constituent 
parts,  the  latter,  building  up  of  the  sub- 
stances from  simpler  ones. 

Bacteria  which  breakdown  waste  material  in 
soil  and  in  water  as  a  prelude  to  the  initi- 
ation of  a  nutrient  recycling  process. 

Death  or  decay  of  tissue. 

Any  of  a  class  of  organic  compounds  with  the 
general  formula  RC  =  N. 

Any  process  by  which  a  phase  change 
(condensation,  sublimation,  freezing)  is 
initiated  at  certain  loci  (points). 

Members  of  a  hydrocarbon  group  characterized 
by  the  formula  C  Hpn  and  including  ethylene, 
propoylene  and  bu xylene;  they  are  highly 
reactive  and  can  be  formed  by  destructive 
distillation  of  coal  petroleum. 


389 


Organic  Acids 
Ox  id  i  zer 


Pathological 
Peroxidase 


Perox  ides 


Phenol 


Photochem  ical 
Photon 

Photopl ankton 

Photosynthes  i  s 


Phototox  i  cant 
Podsal 


Prec  ursor 


Acids  which  are  usually  derived  from  natural 
or  living  sources . 

A  substance  which  causes  the  conversion  of  an 
element  into  its  oxide  (which  is  accompanied 
by  an  increase  in  oxidation  number  as  opposed 
to  a  reducing  agent  which  promotes  a  decrease 
in  oxidation  number);  a  substance  which  pro- 
motes the  covering  of  an  element  with  a  coat- 
i  ng  of  oxide  or  rust . 

Caused  by  or  involving  disease. 

A  type  or  class  of  ox idored uctase  enzymes  that 
causes  the  oxidation  of  a  compound   by  the 


decomposition  of 
organ  i  c  perox  ide  . 


hydrogen  peroxide  or  an 


A  class  of  compounds  containing  oxygen  and 
other  elements,  with  the  Op  group  having  a 
valence  of  two  (-)  and  acting  like  a  radical. 

A  white  crystalline  solid  obtained  from  the 
distillation  of  tar;  it  is  poisonous  and 
corrosive  with  a  characteristically  pungent 
odor . 

Refers  to  the  effects  of  radiation,  visible  or 
ultraviolet,  upon  chemical  reactions. 

A  quantum  of  energy;  a  fundamental  bundle  of 
radiation  whose  energy  is  directly  propor- 
tional to  the  frequency  of  the  radiation. 


The  aggregate 
ing  organisms 
most  of  their 


of  passively  floating  or  drift- 
in  a  body  of  water  which  derive 
energy  from  1 i ght . 


The  process  by  which  green  plants,  containing 
chlorophyll,  with  the  aid  of  energy  from  the 
sun,  manufacture  carbohydrates  from  water  and 
carbon  dioxide. 

A  substance  that  is  poisonous  to  plants. 

An  infertile,  acidic  forest  soil  having  an 
ash-colored  upper  layer  depleted  of  colloids 
and  of  iron  and  aluminum  compounds,  and  a 
brownish  lower  layer  in  which  these  colloids 
and    compounds    have    accumulated.  fc 

A  person  or  object  that  goes  before  and  indi- 
cates   the    approach    or    something    else. 


390 


Primary 
Pol  1 ut ant 


Progen  i  tor 


Pulmonary 

Pu 1 monary 
Fi  brosi  s 


Rad  ical 


Reactant 


React i  vi ty 

Secondary 
Pol  1 utant 


Serpentine 


Serum  Lactate 
Dehydrogenase 


Si  nk 

Sorpt  i  on 

Source 
Spectroscopy 


A  pollutant  in  the  form  that  it  is  released 
from  its  source  is  considered  a  primary 
pollutant  as  opposed  to  a  secondary  pollutant 
which  has  undergone  chemical  change  after 
being  emitted  to  the  atmosphere. 

An  original  or  model  for  later  developments; 
predecessor;  precursor. 

Of  or  pertaining  to  the  lungs. 


A  condition  marked  by  an  increase  of  inter- 
stitial fibrous  tissue  in  the  lungs. 

A  combination  of  atoms  that  stay  together  and 
take  part  in  the  chemical  reaction  as  a  unit 
or  a  group  as  if  it  were  a  single  element. 

Any  substance  that  undergoes  a  chemical  change 
in  a  gi ven  react  ion. 

Pertaining  to  or  characterized  by  reaction. 


A  pollutant  is  considered  a  secondary  pollut- 
ant if  a  chemical  change  has  occurred  subse- 
quent to  its  release  from  its  source. 

A  common  mineral,  hydrous  magnesium  silicate, 
usually  oily  green  and  sometimes  spotted, 
occurring  in  many  varieties,  used  for  archi- 
tectural and  decorative  purposes. 


A  class  of  oxide  reductase  enzymes  that  cata- 
lyze the  removal  of  hydrogen  from  the  esters 
or  salts  of  lactic  acid. 

A  lower  state  or  condition. 

The  binding  of  one  substance  by  another  by  any 
mechanism,  such  as  absorption,  adsorption  or 
persorpt  i  on  . 

A  place  from  which  something  comes,  arises  or 
is  obtained. 

A  procedure  for  observing  the  spectrum  of 
light  or  radiation  from  any  source.  Spectro- 
scopy permits  the  examination  and  measurement 
of  the  spectrum  of  radiant  energy. 


391 


Stark-Einstein 
Law 


Stoi  ch  i  ometry 


Stunt  i  ng 
S  u 1  fate 


Sulfide 
Synerg  i  sm 


Terpene 
Thermodynamics 

Tox  i  c  i  ty 

Unci  ass  ifiable 


Vol atile 


A  law  of  chemistry  which  states  that  one 
proton  must  be  absorbed  by  a  substance  to 
initiate  chemical  decomposition. 

Branch  of  chemistry  dealing  with  weights  and 
proportions  of  elements  in  chemical  combina- 
tion and  the  methods  of  determining  them. 

Stopping  or  slowing  down  of  the  growth  or 
development  of  an  object. 

Chemical  compounds  (such  as  S03)  created  by 
the  photochemical  reaction  of  sulfur  dioxide. 
Sulfates  are  secondary  pollutants  with  import- 
ant health  and  visibility  effects. 

A  binary  compound  of  sulfur  with  the  valence 
of  two  (- ) ;  also  a  salt  of  hydrosul f ur i c  acid. 

The  principal  that  a  cooperative  action  be- 
tween two  agents  -  chemical  and  mechanical  for 
instance  -  results  in  an  effect  greater  than 
the  sum  of  the  two  effects  taken  independent- 
ly. 

A  series  of  hydrocarbons  of  the  general  for- 
mula CiqHi,-  found  in  resins. 

Deals  with  the  principals  of  conversion  of 
heat  into  other  forms  of  energy  and  vice 
versa  . 

The  quality,  relative  degree  or  specific 
degree  of  being  toxic  or  poisonous. 

With  respect  to  air  quality,  unclassifiable 
refers  to  those  areas  of  the  country  which 
cannot  be  a  designated  attainment  or  non- 
attainment  area  due  to  insufficient  baseline 
air  quality  information. 

Easily  vaporized;  tending  to  evaporate  at 
ordinary  temperatures  and  pressure  conditions. 


392 


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Amer.  Elsevier,  New  York,  New  York,  1971. 

Urone,  P.,  in  "Proceedings  of  International  Symposium  on  Air 
Pollution,"  pp.  505-520.  Union  of  Japanese  Scientists  and 
Engineers,  Tokyo,  Japan,  1972. 

U.S.  Environmental  Protection  Agency,  "Air  Quality  Criteria  for 
Carbon  Monoxide,"  No.  AP-62.  Research  Triangle  Park,, 
North  Carolina,  1970. 


398 


U.S.  Environmental  Protection  Agency,  "Air  Quality  Criteria  for 
Hydrocarbons,"  No.  AP-64.  Research  Triangle  Park,  North 
Carolina,  1970 . 

U.S.  Environmental  Protection  Agency,  "  Air  Quality  Criteria  for 
Nitrogen  Oxides,"  No.  AP-84.  Research  Triangle  Park,  North 
Carolina,  1971. 

U.S.  Environmental  Protection  Agency,  "Air  Quality  Criteria  for 
Photochemical  Oxidants,"  No.  AP-63.  Research  Triangle 
Park,  North  Carolina,  1970. 

U.S.  Environmental  Protection  Agency,  "Air  Quality  Criteria  for 
Sulfur  Oxides,"  No.  AP-50.  Research  Triangle  Park,  North 
Carol i  na  ,  1 969. 

U.S.  Environmental  Protection  Agency,  "Control  Techniques  for 
Sulfur  Oxide  Air  Pollutants,"  No.  AP-52.  Research  Triangle 
Park,  North  Carolina,  1969. 

U.S.  Environmental  Protection  Agency,  National  Emissions  Data 
System,  Monitoring  and  Data  Analysis  Division,  Office  of 
Air  Quality  Planning  and  Standards,  Research  Triangle  park, 
North  Carolina  27711 

U.S.  Environmental  Protection  Agency,  Region  IV.  Air  Pollution 
Control  Office,  Atlanta,  Georgia  (private  communication). 

U.S.  Environmental  Protection  Agency,  "Validation  of  Improved 
Chemical  Methods  for  Sulfur  Oxides  Measurements  from  Sta- 
tionary Sources,"  No  R2-72-105.  J.  N.  Driscoll,  Program 
Manager,  Walden  Research  Corp.,  Nat.  Tech.  Inform.  Serv., 
Springfield,  Virginia,  1972. 

Vandermeul en ,  J.H.  "Effects  of  Petroleum  Hydrocarbons  on  Algal 
Physiology:  Review  and  Progress  Report",  Society  for  Exper- 
imental Biology  Seminar  Series  2,  1976,  pp.  107-125. 

Weinstock,  B. ,  Science  176,  290  (1972). 

Weres,  0.,  et  al,  "Resource,  Technology  and  Environment  at  the 
Geysers",  Lawrence  Livermore  Laboratory,  Berkeley,  Calif., 
DOE/DUE,  Report  LBL-5231,  June,  1977. 

Williams,  W.T.,  et  al.  "Air  Pollution  Damage  to  the  Sierra 
Nevada  Mountains  of  California",  Journal  of  the  Air  Pollu- 
tion Control  Association,  3/77,  Vol.  27,  No.  3,  pp.  230- 
TTT. 

Yankel  ,  A.J.  et  al.  "The  Siver  Valley  Lead  Study:  The"  Relation- 
ship between  Childhood  Blood  Lead  Levels  and  Environmental 
Exposure",  Air  Pollution  Control  Association  Journal  28(8), 
August  1977,  pp.  763-767. 


399 


6.   AIR  QUALITY  REGULATIONS 

6.1       EXECUTIVE  SUMMARY 

6.1.1     Bac  kground 

The  Clean  Air  Act,  as  amended  in  1977,  is  the  primary 
legislative  tool  for  improving  and  monitoring  air  quality  in  the 
United  States.  Many  requirements  of  the  Act  apply  to  BLM  activi- 
ties, as  well  as  to  those  of  the  Fish  and  Wildlife  Service,  the 
National  Park  Service  and  the  National  Forest  Service. 

The  Clean  Air  Act  was  originally  passed  in  1955  and 
numerous  Amendments  have  been  initiated  over  the  past  25  years. 
Under  the  1970  Amendments,  for  example,  specific  limits  for 
pollutant  levels  were  established  including  dates  for  compliance. 
These  pollutant  levels,  called  the  National  Ambient  Air  Quality 
Standards  (NAAQS)  were  based  upon  air  "quality"  effects  on 
health.  The  1970  Act  mandated  the  States  to  formulate  plans  to 
achieve  compliance  with  the  ambient  standards.  These  plans, 
known  as  State  Implementation  Plans  (SIPs),  required  State  trans- 
portation control  plans,  emissions  limits  for  specific  categories 
of  sources,  and  permit  rules  for  new  or  modified  sources  of  air 
p  o  1 1  u  t  i  o  n  . 


Once  these  plans  were  adopted  by 
by  the  EPA,  they  were  binding  as  law. 
jurisdictional  authority  to  enforce  the 
plan.    If  a  State  was  found  by  the  EPA 
administration  of  the  plan,  the  EPA  was 
administer  the  plan  until  it  felt  that  the 


the  State,  and  approved 

The  State  then  had  the 

regulations  under  the 

to  be  deficient  in  its 

able  to  i  ntervene  and 

State  could  once  again 


resume  adequate  control  of  the  program(s).  It  should  be  noted 
that  this  concept  has  remained  in  the  latest  amendments  to  the 
Act . 

On  August  7,  1977,  Congress  again  passed  amendments  to 
the  Clean  Air  Act'  (CAAA).  These  Amendments  significantly  altered 
approaches  to  maintaining  and  achieving  the  adopted  Air  Quality 
Standards.  The  three  most  substantial  alterations  to  the  Act  are 
considered  to  be  (1)  New  Source  Review  Requirement  (NSR)  (2)  Pre- 
vention of  Significant  Deterioration  (PSD),  and  (3)  the  require- 
ment that  States,  by  July  1979,  again  design  programs  (SIP)  for 
achieving  the  NAAQS.  Note  that  items  (1)  and  (2)  are  an  integral 
part  of  the  State  plan  (3). 

The  CAAA  also  extended  the  original  deadlines  for 
achieving  the  NAAQS  to  December  1982,  with  provisions  for  extend- 
ing compliance  to  1987  for  areas  with  severe  oxidant  and/or 
carbon  monoxide  problems.  Furthermore  Congress  empowered  EPA  to 
implement  sanctions  if  a  State  did  not  have  an  acceptable  SIP  by 
July  1979.  The  major  sanctions  that  the  EPA  is  able  to  impose 
are  to  ban  construction  of  major  sources  in  non-attainment  areas, 
and  to  withold  Federal  funding  for  projects  such  as  highway  and 
sewage  facilities.   As  part  of  an  acceptable  SIP,  a  State  which 


400 


requests  an  extension  of  the  ozone  and/or  carbon  monoxide  com- 
pliance date,  must  implement  a  statewide  motor  vehicle  inspection 
and  maintenance  (I/M)  program. 

A  number  of  areas  in  California  have  requested  an  exten- 
sion of  the  oxidant  and  CO  NAAQS  to  1987  (e.g.,  Los  Angeles,  San 
Diego,  etc.).  However,  due  to  the  reluctance  of  the  California 
Legislature  to  adopt  a  statewise  I/M  program,  the  California  SIP 
is  in  jeopardy  of  being  rejected.  As  of  July  1,  1979,  new  major 
sources  (and  certain  modifications  to  existing  major  sources)  are 
prohibited  from  locating  in  non- atta i nment  areas  of  the  state. 
Additionally,  if  the  Legislature  does  not  adopt  an  I/M  program 
prior  to  the  time(s)  EPA's  conditional  approval(s)  expire,  then 
Federal  Highway  &  Sewage  funding  will  also  be  withheld. 

6.1.2    Permit  Rules  for  New  or  Modified  Sources 

Since  1970,  the  Clean  Air  Act  has  required  that  any  new, 
or  modified  source(s)  of  air  pollution  undergo  a  preconst ruct  i  on 
rev  i  ew.  The  purpose  of  this  review  is  to  ensure  that  such 
sources  would  not  violate  any  ambient  standard  or  contribute  to 
any  existing  violations  of  these  standards.  This  review  is  known 
as  New  Source  Review,  and  has  been  expanded  by  the  Amendments  of 
1977. 

6.1.2.1  Nonatta i nment  Areas 

In  nonatta i nment  areas  (areas  that  do  not  meet  the 
NAAQS),  States  are  required  to  develop  permit  rules  which  meet 
the  requirements  of  the  CAAA.  Specifically,  these  permit  rules 
must  require  the  following:  (1)  new  or  modified  source  locating 
in  a  non-attainment  area  must  obtain  a  high  degree  of  emission 
control  (called  Lowest  Achievable  Emission  Rate  or  LAER)  for  the 
problem  pol 1 ut ant ( s ) ,  and  (2)  obtain  emission  reductions  of  that 
pollutant,  commonly  called  emission  offsets  or  tradeoffs.  Trade- 
offs are  generally  obtained  by  retrofitting  existing  sources  with 
air  pollution  control  equipment,  or  by  "retiring"  older  units. 
Because  of  the  permit  moratorium  for  nonattai nment  areas,  sources 
wishing  to  locate  in  such  areas  may  not  receive  permits  until  the 
nonatta i nment  portion  of  the  SIP  has  been  approved  by  the  EPA. 

The  State  of  California  has  numerous  non-attainment 
areas  and  as  such,  a  majority  of  the  State  Implementation  Plan 
consists  of  "plans"  or  "tactics"  to  bring  the  affected  regions 
(air  basins)  into  compliance  with  the  NAAQS. 

6.1.2.2  Attainment  Areas  and  Prevention  of  Significant  Deteri- 
oration Review 

In  attainment  areas  (areas  in  which  the  air  quality  is 
better  than  the  NAAQS),  the  Clean  Air  Act  amendments  require  SIPs 
to  contain  a  special  permit  program  for  new  or  modified  sources. 
This  permit  program  is  called  Prevention  of  Significant  Deteri- 
oration of  air  quality.   As  a  result  of  this  requirement,  the 


401 


EPA,  on  June  19,  1978,  promulgated  the  Prevention  of  Significant 
Deterioration  (PSD)  regulations.  The  basic  intent  of  these 
regulations  is  to  keep  "clean  air  clean."   This  is  accomplished 


by  placing  ambient  air  quality  limitations  for 
late  matter  in  addition  to  the  NAAQS  which  have 
for  these  pollutants.   The  increase  in  ambient 
these  two  pollutants  from  a  given  baseline 
limited  by  what  are    called  "increments."   These 
depending  on  the  class  designation  of  the  area 
or  modified  source  is  attempting  to  locate  (see 


S0?  and 
been 


part l c  u- 

established 

concentration  of 

concentration  is 

increments  differ 

in  wh  i  ch  the  new 

Fi  gure  6.1-1). 


three 


The  Clean  Air  Act  and  the 
"classes"  of  clean  air  areas. 


PSD  regulations  established 
Each  class  has  been  assigned 


numerical   increments  for  particulate  matter 
concentrations;  increments  will  be  set  in  the 
other  criteria  pollutants.   These  increments 
to  the  ambient  concentration  increase  above 
tion  which  will  be  allowed  in  each  particular 


and  sulfur  dioxide 

near  future  for  all 

indicate  the  limit 

basel i  ne  concent ra- 

" class"  area. 


Class  I  increments  allow  only  minor  air  quality  in- 
creases; Class  II  increments  allow  a  moderate  amount  of  deteri- 
oration; Class  III  increments  allow  the  most  air  quality  deter- 
ioration, although  violations  of  the  NAAQS  are  never  permitted. 
Class  I  areas  include  national  memorials  and  national  wilderness 
areas  exceeding  6,000  acres  in  size. 

Sources  subject  to  PSD  must  use  Best  Available  Control 
Technology  (BACT)  on  the  proposed  new  sources  or  modified 
sources,  and  furthermore,  must  demonstrate  that  the  emissions 
will  not  result  in  concentrations  in  excess  of  the  PSD  increments 
for  SOp  and  particulate  matter.  The  most  important  aspect  of 
these  regulations  is  that  increment  consumption  is  viewed  from  a 
cumulative  viewpoint.  That  is,  if  a  source  consumes  part  of  the 
increment,  then  the  next  source  to  apply  for  a  permit(s)  must 
work  within  the  remaining  portion  of  the  increment.  Thus,  it  is 
possible  for  the  increment  to  be  "used  up"  in  a  particular  area. 
Increment  consumption  is  granted  on  a  first-come,  first-serve 
basis. 


6.1.2.3 


Role  of 
Process 


the  Federal  Land  Manager  in  the  Permit  Review 


Federal  Land  Managers  (FLM)  have  input  to 
mitting  process  if  a  project  will  have  an  impact 
area.   Once  a  source  makes  an  application  to  the 
must  make  a  determination  as  to  the  probable  impact 
will  have.   As  early  as  possible,  the  EPA  must  conta 
priate  FLM  if  it  is  thought  that  the  project  will  h 
on  a  Class  I  area.   The  FLM  may  then  review  all 
studies  performed  in  conjunction  with  the  EPA  permi 
within  the  60  day  review  period.    If  the  FLM  fi 
facility  would  have  an  adverse  impact  on  the  "air  qu 
values"  of  the  land  area,  a  permit  cannot  be  issued 
must  then  demonstrate  that  no  adverse  impact  would  o 


the  PSD  per- 
on  a  Class  I 

EPA,  the  EPA 
s  the  project 
ct  the  appro- 
ave  an  impact 
air  quality 
t  eppl i  cat  i  on 
nds  that  the 
al i  ty  related 
The  source 
ccur.   Denial 


402 


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24-Hour  Maximum 


Figure  6.1-1 
Prevention  of  Significant  Deterioration 
Maximum  Allowable  Increments  as  a  Function  of  Class  Designation 

(  yg/m3  ) 

403 


by  the  FLM  may  be  made 
Class  I  increments  will 


even  if  it  has  been  demonstrated  that  the 
not  to  be  exceeded  by  the  project. 


It  is  also  important  to  note  that  if  the  FLM  proposes 
activities  on  land  within  his  jurisdiction,  the  available  incre- 
ment must  not  be  exceeded.  This  may  inhibit  future  land  manage- 
ment decisions,  and  should  be  considered  in  the  early  part  of  the 
decision  process. 


6.1.2.4 


Rol  e  of  the 
Proced  ure  s 


Federal  Land  Manager  in  Class  Redes i gnat i on 


The  FLM  also  has  a  minor  role  in  the  process  of  redesig- 
nating a  particular  class  area  (for  example,  a  Class  II  area  to 
be  redesignated  to  a  Class  I  area).  Redes  i  gnat  i  ons  may  only  be 
proposed  by  the  state  or  by  an  Indian  Governing  Body.  If  the 
area  to  be  redesignated  contains  Federal  lands,  the  FLM  is  to  be 
notified  of  the  proposal.  The  FLM  will  be  allowed  to  comment  on 
the  proposal,  and  if  he  is  opposed  to  it  but  the  State  wishes  to 
continue  to  pursue  it,  he  must  be  provided  with  an  explanation  of 
the  reasons  why  the  State  feels  it  should  be  redesignated.  The 
FLM  may  also  provide  input  at  the  public  hearing  which  is  re- 
quired for  all  redes  i  gnat  i  ons ;  however,  the  State  has  the  ulti- 
mate authority. 


6.1.3 


Visibility  Protection 


The  1977  Amendments  added  to  the  Clean  Air  Act  a  section 
entitled  "Visibility  Protection  for  Federal  Class  I  Areas".  This 
section  declares  as  a  national  goal  "the  prevention  of  any  fu- 
ture, and  the  remedying  of  any  existing,  impairment  of  visibility 
in  mandatory  Class  I  Federal  areas"  where  impairment  results  from 
man-made  air  pollution.  Such  a  list  of  Mandatory  Class  I  federal 
areas  was  first  published  in  the  November  3,  1977  Federal  Regis- 
ter and  was  revised  on  Nov.  30,1979.  Those  areas  so  designated 
are  presented  in  Table  6.4-2  and  Figure  6.4-1,  respectively.  The 
Amendments  also  required  that  by  February  1978,  the  Secretary  of 
Interior,  in  consultation  with  the  States  and  the  FLM's,  identify 
any  mandatory  Class  I  areas  where  visibility  contributes  signifi- 
cant value  to  that  particular  area.  These  areas  were  published 
in  the  February  24,  1978  Federal  Register.  As  such,  all  Class  I 
areas  are  areas  in  which  visibility  is  an  important  value.  The 
EPA,  by  February  1979,  was  to  have  completed  a  study  and  report 
to  Congress  on  available  methods  for  implementing  this  national 
goal.  This  document  was  not  available  in  time  to  be  addressed  in 
this  report.  Additionally,  the  EPA  was  authorized  to  promulgate 
regulations  requiring  retrofits  on  specified  pieces  of  equipment 
so  that  visibility  would  be  maintained,  or  enhanced.  The  FLM 
must  be  consulted  with  regard  to  these  regulations. 


6.1.4 


Emission  Standards 


The  Clean  Air  Act  gave  the  EPA  the  authority  to  promul- 
gate emission  standards  for  specific  categories  of  equipment.   It 


404 


also  gave  EPA  the  authority  to  designate  certain  pollutants  as 
"hazardous",  and  to  set  emission  standards  for  such  hazardous 
pollutants  for  specific  categories  of  equipment. 

The  EPA  has  promulgated  New  Source  Performance  Standards 
(NSPS)  and  National  Emission  Standards  for  Hazardous  Air  Pollut- 
ants (NESHAPS).  The  NSPS  standards  presently  consist  of  emission 
limits  of  pollutants  for  28  sources  categories.  The  NESHAPS  have 
been  established  for  mercury,  beryllium,  asbestos,  vinyl  and 
chloride  (a  NESHAPS  for  benzene  has  been  proposed). 


6.1.5 


State  Regul at i  ons 


6.1.5.1   Perm  it  Rules 

As  previously  discussed,  a  major  intent  of  the  Clean  Air 
Act  was  to  establish  procedures  for  permit  rules,  and  require 
States  to  adopt  such  rules  as  part  of  their  SIP.  Until  such  time 
as  these  rules  are  approved  by  the  EPA,  and  incorporated  in  the 
SIP,  the  EPA  still  retains  permitting  authority  over  affected 
sources  . 

The  lead  State  agency  in  California  is  the  Air  Resources 
Board  (ARB).  ARB  is  responsible  for  coordinating  the  SIP  and  has 
exclusive  authority  over  mobil  sources.  Additionally,  it  moni- 
tors local  agencies  (County  Air  Pollution  Control  Districts) 
activities  over  stationary  sources,  and  also  conducts  compliance 
tests  . 

ARB  also  adopts  modal  rules  governing  all  sources,  and 
encourages  the  local  districts  to  adopt  similar  rules,  so  that 
there  is  a  degree  of  uniformity  throughout  the  State.  Note, 
however,  as  discussed  in  Section  6.5,  local  districts  tend  to 
adopt  rules  which  reflect  the  nature  of  the  area  (i.e.,  indus- 
trial vs .  rural  )  . 


405 


6.2 


THE  ROLE  OF  THE  FEDERAL  LAND  MANAGER 


As  defined  in  the  Clean  Air  Act  Amendments  of  1977,  the 
Federal  Land  Manager  (FLM)  for  the  BLM  has  the  responsibility  to 
protect  the  air  quality  related  values  of  lands  within  his  juris- 
diction. This  responsibility  must  be  addressed  in  a  number  of 
programs  including  protection  of  visibility,  fire  management,  oil 
and  gas  leasing,  land  use  planning  of  Federal  lands,  issuance  of 
right-of-way  permits,  and  the  preparation  of  Environmental  Impact 
Statements  (EIS's)  attendant  to  such  permits.  Land  management  by 
the  BLM  is  primarily  concerned  with  recreational  areas  (  e.g., 
wilderness  areas)  but  the  concerns  of  the  Land  Manager  are  cer- 
tainly not  limited  to  these  aspects.  For  example,  oil  wells,  or 
gas  pipelines  which  are  on  Federal  lands,  come  under  the  juris- 
diction of  the  FLM.  In  order  for  the  Manager  to  issue  a  BLM 
permit  for  such  activities,  he  must  ascertain  that  the  owner  or 
operator  of  the  project  has  obtained  all  necessary  State,  local 
and  Federal  permits.  These  include  environmental  permits  in  many 
cases.  Thus,  it  is  imperative  for  the  FLM  to  be  familiar  with 
the  legislative  and  regulatory  aspects  of  air  quality  in  addition 
to  the  baseline  meteorology  and  air  quality  with  which  the  permit 
is  concerned.  An  understanding  of  the  rudiments  of  the  air 
quality  review  processes  in  California  can  be  helpful  in  the 
preparation  of  future  EIS's,  since  many  applicants  are  required 
by  law  to  prepare  air  quality  assessments  to  obtain  project 
approval.  Such  assessments  could  be  used  by  the  FLM  in  prep- 
aration of  an  EIS  and  in  making  a  final  decision. 

In  recent  years,  the  role  of  the  FLM  in  the  protection 
of  air  quality  has  increased.  Recent  federal  legislation  has 
provided  increasingly  stringent  restrictions  to  protect  the  clean 
air  resource  from  further  deterioration  by  new  or  modified 
sources.  The  1977  Amendments  require  the  FLM  to  take  an  active 
role  in  the  EPA's  PSD  permit  process.  Specifically,  the  Clean 
Air  Act  has  given  the  FLM  the  authority  to  comment  on  projects 
which  impact  the  air  quality  in  areas  designated  as  Class  I 
(i.e.,  national  parks,  monuments  or  wilderness  areas  in  excess  of 
6,000  acres,  or  any  other  area  designated  by  the  State  as  a  Class 
I  Area).  In  the  words  of  the  Act,  the  FLM  must  actively  protect 
the  "air  quality  related  values,  including  visibility"  of  such 
lands  and  may  oppose  programs  felt  to  be  deleterious  to  Class  I 
areas.  The  Act  also  authorizes  the  FLM  to  take  an  affirmative 
role  in  visibility  protection  in  these  areas,  as  well  as  taking 
part  in  altering  the  Class  designation  of  any  area  incorporating 
federal  lands. 

Because  "air  quality  related  values"  are  one  of  the 
concerns  of  the  FLM,  it  is  necessary  that  the  Managers  be  fam- 
iliar with  the  implications  of  clean  air  legislation  as  it  af- 
fects Federal  lands.  Section  6.3  discusses  the  Federal  legis- 
lative history  concerning  air  pollution  provisions  of  the  1977 
Amendments  pertinent  to  Federal  land  areas  and  visibility  pro- 
tection, and  also  indicates  where  the  FLM  may  participate  in  the 
implementation  of  such  provisions. 


406 


6.3 


HISTORY  OF  AIR  QUALITY  LEGISLATION 


Public  concern  for  the  nations  air  quality  and  for  the 
effect  that  polluted  air  has  on  human  health  and  welfare  led  to 
the  passage  of  National  Air  Pollution  Legislation  in  1955. 
Amendments  to  this  legislation  were  passed  in  1963,  1965,  1967, 
1970  and  1977  (Table  6.3-1  is  a  list  of  clean  air  legislation 
enacted  by  the  Federal  Government).  Prior  to  the  1970  amend- 
ments, the  responsibility  for  air  quality  was  held  by  the  States 
with  the  Federal  Government  providing  little  more  than  financial 
and  technical  assistance.  Some  progress  toward  cleaner  air  was 
achieved;  however,  in  the  opinion  of  a  significant  portion  of  the 
population,  it  was  insufficient.  As  a  result,  the  1970  Amend- 
ments introduced  the  Federal  Government  as  a  regulatory  force. 
The  States  remained  responsible  for  developing  air  quality  Imple- 
mentation Plans  but,  under  the  1970  Amendments,  specific  limits 
were  set  and  certain  pollutant  concentration  levels  had  to  be 
achieved  by  stipulated  dates.  The  specific  concentration  levels 
are    called  the  National  Ambient  Air  Quality  Standards  (NAAQS). 

Two  types  of  NAAQS  were  mandated  by  the  Amendments  of 
1970.  Primary  standards  set  levels  which  allow  an  adequate 
margin  of  safety  for  public  health  while  Secondary  standards 
specify  levels  which  protect  the  public  welfare  from  any  known  or 
anticipated  adverse  effects  associated  with  a  pollutant's  pres- 
ence in  the  ambient  air.  Secondary  effects  on  public  welfare 
refer  to  impacts  on  soils,  water,  crops,  visibility,  as  well  as 
effects  on  economic  values  and  on  personal  comfort  and  well 
being.  Table  6.3-2  shows  the  standards  at  current  levels.  As 
can  be  seen,  the  secondary  standards  are,  in  most  cases,  more 
stringent,  due  primarily  to  the  wide  range  of  items  included 
under  'public  welfare'  which  the  secondary  standards  must  pro- 
tect . 

The  1977  Amendments  attempted  to  deal  with  controversies 
that  had  developed  concerning  achievement  of  the  regulations  and 
the  overall  achievement  of  the  goals  of  the  Clear  Air  Act.  The 
energy  shortage  and  the  cost  and  development  of  air  quality 
control  equipment  on  both  stationary  and  mobile  sources  caused 
industry  to  seek  delays  in  achieving  mandatory  standards.  Envir- 
onmental organizations,  through  the  use  of  the  judicial  system, 
had  forced  the  EPA  to  promulgate  legislation  to  prevent  the 
significant  deterioration  of  air  quality  in  regions  of  the  coun- 
try where  the  air  was  cleaner  than  the  established  standards. 
Promulgation  of  the  original  PSD  regulations  brought  opposition 
from  persons  concerned  about  such  issues  as  industrial  growth, 
employment,  the  economy  and  EPA  authority.  These  and  other 
concerns  influenced  the  Congress  to  consider  amending  the  Clean 
Air  Act  to  establish  new  deadlines  for  achieving  certain  stan- 
dards and  to  resolve  the  PSD  issue.  s- 


407 


Table  6,3-1 
Clean  Air  Legislation  Enacted  by  the  Federal  Government 


Date 


Public  Law 


Purpose  of  Law 


6/55 

9/59 

6/60 

12/63 

10/65 


10/66 


11/67 


12/69 


12/70 


6/74 


8/77 


84-159 
86-365 
86-493 
88-206 
89-272 


89-675 


90-148 


91-190 


91-604 


93-319 


95-95 


Provide  research  and  technical  assistance 
relating  to  air  pollution  control. 

Extend  the  Federal  Air  Pollution  Control  Law 
PL  84-159. 

Direct  the  Surgeon  General  to  study  and  report 
on  health  effects  of  automobile  emissions. 

Improve,  strengthen  and  accelerate  programs  for 
the  prevention  and  abatement  of  air  pollution. 

(Title:  Motor  Vehicle  Air  Pollution  Control  Act) 
Require  standards  for  automobile  emissions  and 
authorize  research  in  solid  waste  disposal 
programs . 

(Title:  Clean  Air  Act  Amendments  of  1966). 
Authorize  grants  to  air  pollution  control 
agencies  for  maintenance  of  control  programs. 

(Title:  Air  Quality  Act  of  1967).   Authorize 
planning  grants,  expand  research  relating  to 
fuels,  and  authorize  air  quality  standards. 

(Title:  National  Environmental  Policy  Act). 
Establish  the  Council  on  Environmental  Quality, 
direct  Federal  agencies  to  consider  environ- 
mental quality  regulations. 

(Title:  Clean  Air  Act  Amendments  of  1970). 
Provide  a  more  effective  program  to  improve 
the  quality  of  air. 

(Title:  Energy  Supply  and  Environmental 
Coordination  Act).   Provide  means  of  dealing 
with  the  energy  shortage. 

(Title:  Clean  Air  Act  Amendments  of  1977). 
Requires  BACT  review  on  a  much  expanded  basis. 
Established  PSD  requirements.   Required 
v i  s  i  b i 1 i  ty  be  considered. 


408 


Table  6.3-2 
National  Primary  and  Secondary  Ambient  Air  Quality  Standards 


Air  Contaminant 


Averaging  Time 


Federal  Primary 
Standard 


Federal  Secondary 
Standard 


Nitrogen  Dioxidel/ 


Sulfur  Dioxide 


Suspended 
Particulate 


Hydrocarbons 
(corrected  for 
Methane ) 

Photochemical 
Ozone  (oxidant) 

Carbon  Monoxide 


Lead 


Annual  Average 


Annual  Average 


24-Hour 


3-Hour 


Annual 
Geometric  Mean 

24-Hour 

3-Hour 
6-9  a.m. 


1-Hour 

8-Hour 

1-Hour 
30-Day 


100  ug/m"3 
(0.05  ppm) 

80  yg/m3 
(0.03  ppm) 

365  yg/m3 
(0.14  ppm) 


75  yg/nr 

260  ug/m3 

160  yg/m3 
(0.24  ppm)2_/ 

240  yg/m3 
(0.12  ppm) 

10  mg/m3 
(9  ppm) 

40  mg/m3 
(35  ppm) 
1 . 5  yg/m3 


100  yg/m3 
(0.05  ppm) 


1300  yg/m3 
(0.5  ppm) 

60  yg/m3 

150  yg/m3 

160  yg/m3 
(0.24  ppm) 


240  yg/mJ 
(0.12  ppm) 

10  mg/m3 
(9  ppm) 

40  mg/m3 
(35  ppm) 


Source:   38  Code  of  Federal  Regulations  25678,  September  14,  1973 

NOTE:   ppm  =  parts  per  million 

ug/m3  =  micrograms  per  cubic  meter 
mg/m3  =  milligrams  per  cubic  meter 

j_/   Nitrogen  dioxide  is  the  only  one  of  the  nitrogen  oxides 
considered  in  the  ambient  standards. 

2/   Maximum  3-hour  concentration  between  6-9  a.m. 


409 


6.4 


SUMMARY  OF  THE  CLEAN 
RELATED  REGULATIONS 


AIR  ACT  AMENDMENTS  OF   1977 


AND 


1977 
to  th 
i  cant 
ment . 
p  r  o  v  i 
attai 
schem 
n  a  t  i  o 
regul 
regul 
cusse 
compr 
1974. 


Pres  i  dent  Carter 
(PL  95-95)  into  law 
e  Clean  Air  Act  Part 
Deterioration  (PSD) 


signed  the  Clean  Air  Act  Amendments  of 

on  August  7,  1977.   The  Amendments  add 

C,  concerning  the  Prevention  of  Signif- 

of  air  quality  and  visibility  enhance- 


Part  B  adds  a  section  on  ozone  protection.   Part  D  adds 
sions  for  State  Implementation  Plan  requirements  for  non- 

the  PSD  section  establishes  a 

air  quality  cleaner  than  minimum 

the  EPA  to  promulgate  a  permit 

sources  in  such  areas.    Such 

June  19,  1978  and  will  be  dis- 

regulations  are  generally  more 

in 


nment  areas.    In  general, 

e  for  protecting  areas  with 

nal  standards  and  requires 

ation  for  new  or  modified 

ations  were  promulgated  on 

d  more  fully  below.   These 

ehensive  than  those  originally  promulgated  by  the  EPA 


The  amendments  continue  the  use  of  two  major  control 
schemes  designed  by  the  1970  amendments:  National  Ambient  Air 
Quality  Standards  (NAAQS)  and  New  Source  Performance  Standards 
(NSPS).  In  the  five  year  period  from  January  1971  through  Jan- 
uary 1976,  the  EPA  promulgated  emission  limits,  or  NSPS,  for  19 
source  categories.  The  Amendments  of  1977  increased  the  19 
source  categories  to  28.  Additionally,  the  1977  Amendments 
require  EPA  to  update  NSPS  every  four  years. 


6.4.1 


National  Ambient  Air  Quality  Standards  (NAAQS) 


As  mentioned  above,  the  Clean  Air  Act  amendments  of  1970 
mandated  the  EPA  to  promulgate  primary  and  secondary  NAAQS.  The 
1977  Amendments  require  that  the  EPA  complete,  by  December  31, 
1980,  and  at  five-year  intervals  thereafter,  a  thorough  review  of 
air  quality  criteria,  and  that,  if  appropriate,  the  National 
Ambient  Air  Quality  Standards  be  revised.  The  EPA  is  also  manda- 
ted to  promulgate  a  NAAQS  for  N0?  concentrations  over  a  measure- 
ment period  of  not  more  than  three  hours.  This  was  originally 
due  by  August,  1978,  but  the  EPA  has  not  as  yet  issued  such  a 
regulation.  If  the  EPA  finds  that  there  is  no  significant  evi- 
dence that  such  a  standard  is  needed  to  protect  public  health, 
such  a  standard  will  not  be  required  to  be  promulgated  (the  Nov. 
30,  1979  Federal  Register  indicated  this  decision  would  be  made 
by  May  1,  1980). 


6.4.2 


Designation  of  Attainment  Status 


The  Clean  Air  Act  Amendments  of  1977  required  that  by 
December  6,  1977,  every  State  submit  to  the  EPA  a  listing  of  the 
attainment  status  of  its  Air  Quality  Control  Regions  (AQCR's)  for 
each  of  the  six  pollutants  for  which  a  NAAQS  has  l>een  estab- 
lished. In  the  March  19,  1979  and  Sept  11th  and  12th,  1979 
issues  of  the  Federal  Register,  a  re-listing  of  all  nonatta i nment 
areas,  by  state,  were  published.  If  an  area  has  air  quality 
better  than  the  NAAQS  for  S09  and  TSP,  it  will  be  designated  as 


410 


an  attainment  area;  if  air  quality  is  worse  than  the  NAAQS,  it 
will  be  designated  as  a  nonatta  i  nment  area.  AQCR's  may  be  sub- 
divided with  areas  designated  as  "attainment",  as  well  as  areas 
being  designated  as  "nonatta i nment " .  Areas  for  which  there  is 
insufficient  information  to  determine  whether  the  standards  have 
been  met  will  be  designated  as  "unable  to  classify."  Attain- 
ment/ nonatta  i  nment  designations  will  be  made  on  a  pollutant- 
specific  basis.  Thus,  an  area  may  be  an  attainment  area  for  one 
pollutant,  and  a  nonatta i nment  area  for  another  pollutant. 


6.4.3 


State  Implementation  Plans 


The  1977  Amendments  retained  the  use  of  the  State  Imple- 
mentation Plan  (SIP)  which  was  originally  introduced  in  the  1970 
Amendments.  All  SIPs  will  have  to  be  revised  to  implement  the 
standards  and  regulations  mandated  by  the  Amendments.  The  SIPs 
as  originally  devised  in  the  1970  Amendments  required  transpor- 
tation control  plans,  emission  limits  for  specific  categories  of 
sources,  and  permit  rules  for  new  or  modified  sources  of  pollu- 
tion. The  goal  of  these  plans,  as  stated  above,  was  to  ensure 
that  the  NAAQS  would  be  met  in  all  areas  of  the  country. 

As  stated  previously,  the  1977  Amendments  expand  upon 
the  SIP  requirements,  and  differentiate  between  two  different 
pi  an  types  : 

•    Areas   in  which  the  NAAQS  are  being  met   (attainment 
areas ) 

t    Areas  in  which  one  or  more  of  the  NAAQS  are    being  vio- 
lated (nonatta i nment  areas) 

Thus,  a  State  may  have  to  address  both  concepts  in  developing  its 
State  Implementation  Plan. 

6.4.3.1   Nonatta i nment  Areas 

Under  the  new  Amendments,  States  containing  nonattain- 
ment  areas  must  have  submitted  to  the  EPA  by  July  1,  1979,  an 
approvable  implementation  plan  which  provides  for  attainment  of 
primary  standards  by  December  31,  1979.  The  plan  must  provide 
for  the  implementation  of  "reasonably  available  control  measures" 
on  existing  stationary  sources  to  be  determined  by  the  State. 
If,  despite  these  "reasonable  available  control  measures",  a 
State  cannot  attain  primary  standards  for  carbon  monoxide  or 
photochemical  oxidant  before  the  1982  deadline,  it  may  request  an 
extension  to  1987.  To  be  eligible  for  an  extension,  a  vehicle 
inspection  and  maintenance  program  must  be  adopted  by  that  State. 

The  Amendments  also  made  specific  requirements  regarding 
permit  rules.  Since  1970,  the  Clean  Air  Act  has  required  that 
any  new  or  modified  source  of  air  pollution  must  undergo  a  pre- 
construction  review.   The  purpose  of  this  review  is  to  ensure 


411 


that  such  sources  would  not  violate  any  ambient  standard  or 
contribute  to  any  existing  violations  of  these  standards.  This 
review  is  known  as  New  Source  Review. 


The  Amendments  require  that  in  nonatt a i nment  areas,  the 
SIP  must  also  contain  permit  requirements  for  the  review  of  new 

the  requirement  for  such 


or  modified  sources  which  would  include 
sources  to  achieve  a  "Lowest  Achievable 
that  particular  source  and  pollutant, 
offsets  for  that  particular  pollutant 
proj  ect . 


Emission  Rate"  (LAER)  for 
and  to  secure  emission 
in  the  locality  of  the 


Most  importantly,  the  Amendments  impose  a  permit  mora- 
torium. No  permits  may  be  issued  in  a  nonatta  i  nment  area  (nei- 
ther by  the  State  nor  the  EPA)  after  July  1,  1979  unless  a  SIP 
for  that  area  has  been  approved  by  the  EPA.  Thus,  sources  wish- 
ing to  locate  in  such  areas  may  not  receive  permits  until  the 
nonatta i nment  portion  of  the  SIP  for  that  area  has  been  approved 
by  the  EPA.  Numerous  States  did  not  comply  with  the  SIP  time 
frames  established  by  the  Clean  Air  Act  Amendments  and  on 
November  23,  1979,  EPA  announced  that  conditional  approvals  for 
SIP's  would  not  be  extended  past  the  time  the  States  were  ori- 
ginally given  to  correct  any  SIP  deficiencies.  No  second  condi- 
tional approvals  would  be  given,  and  in  those  cases  where  a  State 
has  failed  to  meet  a  scheduled  commitment  date  -  the  SIP  would  be 
rejected,  and  the  sanctions  authorized  under  the  Act  would  be 
imposed. 

The  lead  state  agency  in  California  is  the  Air  Resources 
Board  (ARB).  ARB  is  responsible  for  coordinating  the  SIP  and  has 
exclusive  authority  over  mobile  sources.  Additionally,  it  moni- 
tors local   agencies   (County  Air  Pollution  Control   Districts) 


activities 
tests  . 


over  stationary  sources,  and  also  conducts  compliance 


sources  ,  and 
rules,  so  that 
Note, 
tend  to 
i  nd  us- 


ARB  also  adopts  modal  rules  governing  all 
encourages  the  local  districts  to  adopt  similar 
there  is  a  degree  of  uniformity  throughout  the  State, 
however,  as  discussed  in  Section  6.5,  local  districts 
adopt  rules  which  reflect  the  nature  of  the  area  (i.e. 
trial  vs.  rural). 

6.4.3.2   Attainment  Areas 

•    Prevention  of  Significant  Deterioration  (PSD) 

The  1977  Amendments  kept  active  the  concept  of  PSD. 
This  is  a  permit  rule  which  must  be  incorporated  into 
SIPs  for  attainment  areas.  It  applies  to  specific 
sources  which  are  named  in  the  Clean  Air  Act  and  the 
EPA's  subsequent  regulation.  It  is  essentially  a  New 
Source  Review  rule  for  those  sources  in  attainment 
areas,  or  in  those  areas  which  have  been  designated  as 
"unable  to  be  classified",  according  to  Section  107  of 
the  Clean  Air  Act  as  amended. 


412 


Unlike  the  nonatta i nment  areas,  there  is  no  permit 
moratorium  imposed.  The  failure  of  a  State  to  adopt 
into  their  SIP  a  permit  rule  incorporating  the  PSD 
requirements  of  the  Clean  Air  Act,  does  not  impose  a 
moratorium  on  permits.  Thus,  if  a  SIP  is  not  approved 
by  the  EPA  in  an  attainment  area ,  sources  will  be  re- 
quired to  obtain  such  permits  from  the  EPA,  as  well  as 
obtaining  any  permits  required  by  the  State.  When  the 
State  adopts  a  PSD-type  rule  which  is  approved  by  the 
EPA,  then  the  State  has  the  jurisdictional  authority  to 
administer  it,  and  a  source  need  only  obtain  the  State 
permit . 

The  basic  intent  of  the  PSD  regulations  is  to  keep 
"clean  air  clean".  This  is  accomplished  by  placing 
limitations  on  the  amount  that  pollutant  concentrations 
can  be  increased  above  what  is  termed  "baseline  concen- 
tration". This  will  be  discussed  in  further  detail 
bel ow. 

Classification  of  Attainment  Areas  under  PSD 

The  Clean  Air  Act,  and  subsequent  PSD  regulations  desig- 
nate all  attainment  areas  as  either  Class  I,  II  or  III, 
depending  on  the  degree  of  deterioration  that  is  to  be 
allowed.  Limits  are  assigned  to  increases  in  pollution 
concentrations  for  S0~  and  particulate  matter  for  each 
classification  (See  Table  6.4-1).  Class  I  increments 
allow  only  minor  pollutant  concentration  increases  while 
Class  III  increments  allow  the  most  concentration  in- 
creases. However,  in  no  instance  may  the  NAAQS  be 
exceeded . 

Congress  specified  that  certain  areas  were  to  be  auto- 
matically designated  Class  I.  These  areas  include 
national  memorials,  parks  and  wilderness  areas  exceeding 
6,000  acres  in  size,  already  in  existence  by  the  date  of 
enactment.  A  list  of  the  Class  I  areas  for  California 
are  presented  in  Table  6.4-2  and  illustrated  in  Figure 
6.4-1  (this  may  be  viewed  in  conjunction  with  overlay 
G).   These  areas  may  not  be  redesignated. 

Under  PSD  regulations,   the   remaining   areas  are      all 

These  areas  may  be  redesignated  by 
Class  I  or  Class  III,  following  the 
in  the  regulations,  and  which  will 
FLM's  role  in  the  Redesi gnat i on  of 
All  new  Wilderness  Areas  must  be 
CI  ass  I  or  II. 


presently  Class  II. 
the  states  to  either 
procedures  outl i  ned 
be  discussed  in  the 
Area  Classifications 
designated  as  either 


Applicability  and  Review  Requirements 

On  June  19,  1978,  the  EPA  promulgated  the  requirements 
for  PSD  as  required  in  the  Clean  Air  Act  Amendments  of 


413 


Table  6.4-1 

Prevention  of  Significant  Deterioration 
Maximum  Allowable  Increments 
(In  Micrograms  Per  Cubic  Meter) 


Pol  1 utant 


Class  I 


Class  II 


Class  III 


Particulate  Matter 
Annual  Geometric  Mean 
24-Hour  Maximum* 


5 
10 


19 
37 


37 
75 


Sulfur  Dioxide 
Annual  Arithmetric  Mean 
24-Hour  Maximum* 
3-Hour  Maximum* 


2 

5 

25 


20 

91 

512 


40 
182 
700 


*May  be  exceeded  once  per  year 


414 


Table  6.4-2 
Mandatory  Class  I  Areas  Under  1977 
Clean  Air  Act  Amendments  for  California 

National  Parks 
Kings  Canyon 
Lassen  Volcanic 
Redwood 
Sequoi  a 
Y  o  s  e  m  i  t  e 

National  Wilderness  Areas  Over  6,000  Acres 
A  g  u  a  Tibia 
Caribou 
Cucamonga 
Death  Valley 
Desol ation 
Dome  Land 
Emigrant 
Hoover 
Joshua  Tree 
John  Mui  r 
Kai  ser 
Lava  Beds 
Marble  Mountain 
Mi  n a  rets 
Mokel umne 
Pinnacles 
Point  Reyes 
Salmon  Trinity  Alps 
San  Gabriel 
San  Jacinto 
San  Rafael 
South  Warmer 
Thousand  Lakes 
Ventana 
Yolla-Bolly  Middle  Eel 


415 


ELK  VALLEY 


Redwood  National  Park 


ARCATA 


ONLY  THE  WILDERNESS 
PORTIONS  ARE  DESIGNATED 
CLASS  I 


W  SACRAMENTO 


Point  Reyes  National  Seashore* 


Figure  6.4-1 
Mandatory  Class  I  Areas  Under  1977  Clean  Air  Act  Amendments 


416 


1977.  The  following  discussion  is  based  on  the  PSD 
requirements  as  contained  therein.  Appendix  H  contains 
a  summary  analysis  of  the  June  18,  1979  decision  by  the 


United  States  Court  of  Appeals, 

Alabama  Power  Co.  versus  USEPA. 

cantly  impact  PSD 

dix.   It  should 

Court  i  ssued  its 

lations;  however, 

that  decision  is 


D.C.  Circuit  regarding 
This  case  will  signifi- 
indicated  in  the  Appen- 
in  December,  1979,  the 
regarding  the  PSD  regu- 
due  to  time  constraints  an  analysis  of 
not  incorporated  in  this  report. 


regulations  as 
be  noted  that 
final  decision 


The  CAAA  of  1977  gave  detailed  requirements  to  assist 
states  in  the  modification  of  their  SIP's  to  conform 
with  the  Amendments.  Twenty-eight  source  categories 
have  been  specified  as  subject  to  the  PSD  regulations 
and  are  listed  in  Table  6.4-3.  A  source  included  in  the 
28  source  categories  having  potential  emissions  (uncon- 
trolled) greater  than  100  tons/yr  for  a  pollutant  i  s  a 
major  PSD  source  for  that  pollutant,  (provided  the  area 
in  which  the  source  is  locating  has  been  classified  as 
attainment  for  that  pollutant;  otherwise,  it  is  subject 
to  nonattainment  rules). 

In  addition  to  the  28  categories  specified,  there  is 
also  a  "catch-all"  category.  Sources  having  potential 
(uncontrolled)  emissions  greater  than  250  tons/yr  are 
major  PSD  sources  for  that  pollutant  (provided,  once 
more,  that  the  area  in  which  the  source  is  locating  is 
an  attainment  area    for  that  pollutant). 

Major  PSD  sources  must  apply  Best  Available  Control 
Technology  (BACT)  for  each  applicable  pollutant  and 
undergo  an  air  quality  analysis.  BACT  means  an  emission 
limit  or  control  technology  representing  the  maximum 
degree  of  reduction  with  respect  to  a  particular  source 
and  pollutant,  taking  into  account  energy,  environmental 
and  economic  impacts,  and  technical  feasibility.  This 
determination  is  made  by  the  EPA,  but  demonstration  made 
by  the  Applicant  will  be  considered. 

If,  after  application  of  BACT,  the  pollutant  levels  are 
greater  than  50  tons/yr,  1,000  lbs/day  or  100  Ibs/hr 
(whichever  is  the  most  stringent),  an  air  quality  analy- 
sis must  be  performed.  The  PSD  regulations  require  that 
a  source  demonstrate  that  no  violations  of  NAAQS  for 
NOp,  CO  and  HC  will  occur  (assumed  that  the  area  under 
consideration  is  in  attainment  for  these  pollutants). 
While  NO-,  CO  and  HC  concentrations  can,  in  effect,  be 
increased  to  the  respective  NAAQS,  SO^  and  particulate 
matter  increases  are  limited  by  "  increments-  above  the 
"baseline  concentration".  The  "increments"  are  defined 
by  the  PSD  Class  designation  for  the  area  in  which  the 
source  is  located. 


417 


Table  6.4-3 
PSD  Major  Stationary  Sources 
Potential  Emission  of  Any  Pollutant  Greater  than  100  tons/yr 

Fossil-Fuel  Fired  Steam  Electric  Plants 
(More  than  250  MMBTU/Hr  Input) 

Coal  Cleaning  Plants  (with  Thermal  Dryers) 

Kraft  Pulp  Mills 

Portland  Cement  Plants 

Primary  Zinc  Smelters 

Iron  and  Steel  Mill  Plants 

Primary  Aluminum  Ore  Reduction  Plants 

Primary  Copper  Smelters 

Municipal  Incinerators 

(Capable  of  Charging  More  than  250  Tons  Refuse/Day) 

Hydrofluoric,  Sulfur  and  Nitric  Acid  Plants 

Petroleum  Refineries 

Lime  Plants 

Phosphate  Rock  Processing  Plants 

Coke  Oven  Batteries 

Sulfur  Recovery  Plants 

Carbon  Black  Plants  (Furnace  Process) 

Primary  Lead  Smelters 

Fuel  Conversion  Plants 

Sintering  Plants 

Secondary  Metal  Production  Plants 

Chemical  Process  Plants 

Fossil  Fuel  Boilers  (or  Combinations  Thereof) 

(With  Total  Storage  Capacity  Exceeding  300  Thousand  BBLS) 

Taconite  Ore  Processing  Plants 

Glass  Fiber  Processing  Plants 

Charcoal  Products  Plants 

and 

Notwithstanding  the  sources  above,  any  source  which  emits 
or  has  potential  to  emit  250  tons/yr  or  more  of  any 
pollutant  regulated  under  the  act. 


418 


Baseline  concentration  is  essentially  the  air  quality, 
or  concentration  level  of  SO.?  and  particulate  matter 
that  "existed"  on  August  7,  1<T77.  Thus,  the  emissions 
from  a  proposed  source  are  "modeled"  via  computer  simu- 
lation, and  a  concentration  prediction  is  obtained.  The 
S0?  and/or  particulate  matter  concentration  obtained 
must  not  exceed  the  incremental  PSD  limit  for  the  area 
in  which  the  source  is  locating;  furthermore  the  concen- 
tration obtained  (or  "used")  is  applied  against  the 
i  ncrement .  This  means  increment  consumption  is  cumula- 
tive. That  is,  if  emissions  from  the  source  result  in 
S0?  and  particulate  concentrations  which  consume  part  of 
the  increment  allowed  from  the  "baseline  concentration", 
then  the  next  source(s)  to  apply  for  PSD  permits  must 
work  within  the  remaining  increment  (See  Figure  6.4-2). 

It  should  be  noted  that  SOo  and  particulate  concentra- 
tions are  prohibited  from  exceeding  the  NAAQS.  Thus,  if 
a  "baseline  concentration"  is  close  to  the  NAAQS,  and 
the  additional  "increment"  defined  by  the  values  in 
Table  6.4-1  would  exceed  the  NAAQS,  then  NAAQS  becomes 
the  upper  limit,  and  the  increment  is  "reduced" 
accordingly. 

Federal  Land  Manager's  Role  in  Class  I  Area  Reviews 

•    Denial;  impact  on  air  quality  related  values 

FLM's  have  input  to  the  PSD  permitting  process  if  a 
project  is  believed  to  have  an  impact  on  a  Class  I  area. 
Once  a  PSD  application  is  submitted,  the  EPA  must  con- 
tact the  appropriate  FLM  if  it  is  believed  that  the 
project  will  have  any  air  quality  impact  on  a  Class  I 
area  . 

If  the  FLM  finds  that  emissions  from  a  proposed  facility 
would  have  an  adverse  impact  on  "air  quality  related 
values"  (which  include  visibility)  of  the  land  area 
(even  though  allowable  Class  I  increments  would  not  be 
exceeded),  he  can  recommend  to  the  EPA  that  the  permit 


be  denied.   If 
t i  on ,  a  perm  it 


the  EPA  concurs  with 
wi 1 1  not  be  i  ssued  . 


the  FLM  s  demonstra- 


Class  I  variances 

Conversely,  in  a  situation  where  Class  I  increments  are 
predicted  to  be  exceeded,  the  applicant  may  appeal  to 
the  FLM.  The  applicant  must  demonstrate  to  the  FLM  that 
the  emissions  from  the  facility  will  not  adversely 
impact  air  quality  related  values.  If  the  FLM  concurs 
with  this  demonstration,  he  must  certify  this  concur- 
rence, and  the  state  may  then  authorize  the  EPA  to  issue 
a  permit  which  would  allow  the  facility  to  comply  with 
less  stringent  air  quality  increments.   In  such  cases, 


419 


NAAQS 


A/Q  8/7/77 


NAAQS 


Maximum  AT  low- 
able  Limit 


A/Q  8/7/77 


Baseline  Concentration 
is  the  Air  Ouality  of 
Pollutant  as  of  8/7/77 


PSD  Increment  for  SO2  or 
Particulate  Added  to  Base 
line  Establishes  Upper 
Limit  Under  PSD.  The 
NAAQS  is  the  Upper  Limit 
in  All  Cases  and  Cannot 
be  Exceeded 


NAAQS 


NAAQS 


Maximum  Al low- 
able  Limit 


As  Sources  Are  Permitted 
Under  PSD,  Their  Concen- 
trations of  SO2  or  Parti- 
culate Consume  Increment 


Each  Succeeding  PSD  Source 
to  Apply  for  Permit  has 
Increasingly  Less  Incre- 
ment Within  Which  to  Work 


Figure  6.4-2 
Determination  of  Maximum  Allowable  Ambient 
Limit  Under  PSD  Increment 


420 


the  maximum  increments  imposed  are    the  same  as 
II  values,  except  for  the  three-hour  SOo 
which  is  not  to  exceed  325   q/m   (The  Class 
hour  S09  increment  is  512   g/m  .) 


the  Class 

increment  limit 

II  three- 


SOp  var i  ance 


by  Governor  with  FLM's  concurrence. 


In  situations  where  the  Class  I  increments  are  predicted 
to  be  exceeded,  and  the  source  would  exceed  the  relaxed 
SO2  increments  as  described  above,  the  applicant  may 
appeal  to  the  Governor  to  receive  a  variance  for  sul fur 
dioxide  only.  Particulate  matter  variances  cannot  be 
obtained.  In  making  this  appeal,  the  applicant  must 
demonstrate  that  neither  the  24-hour  nor  the  3-hour  S0o 


increment  limits  can  be  achieved.  The 
ment  of  20  g/m  must  be  met,  however, 
applicant  must  also  demonstrate  that 
not  adversely  affect  the  air  quality 


annual  S0?  i  ncre- 

Additional ly  the 

the  proj  ect  will 

related  values  of 


the  area.  The  FLM,  again,  has  input  in  this  process  and 
is  required  to  make  a  recommendation  to  the  Governor  who 
can  agree  or  disagree  with  the  FLM  recommendation.  In 
addition,  a  public  hearing  must  be  held.  After  consi- 
dering the  public  input,  the  Governor,  may  grant  a 
variance.  The  EPA  can  then  issue  a  permit,  and  the 
source  would  then  be  permitted  to  exceed  the  SOo  incre- 
ments presented 
per  year  . 


in  Table  6.4-4  for  no  more  than  18  days 


Variance  by  the  Governor  with  the  President's 
cone  urrence 


If,  in  the  above  process,  the  FLM  does  not  concur,  the 
permit  can  not  be  approved,  unless  the  Governor  over- 
rides the  FLM's  veto.  The  Governor  has  the  authoriza- 
tion to  override  this  veto  and  recommend  a  variance.  In 
such  a  situation,  the  recommendations  of  both  the  FLM 
and  the  Governor  are  sent  to  the  President.  The  Presi- 
dent may  approve  the  Governor's  recommendation  if  he 
finds  the  variance  to  be  in  the  national  interest.  If 
the  variance  is  approved,  the  EPA  may  issue  a  permit, 
and  the  source  would  then  be  permitted  to  exceed  the  SOo 
increments  presented  in  Table  6.4-4  for  no  more  than  18 
days  per  year. 


The  procedure  discussed  above  is  outlined 
6.4-3. 


in  Fig  ure 


421 


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422 


Table  6.4-4 

3 
Maximum  Allowable  Increase  (  gm/  ) 

Under  Class  I  S0~  Variances 


Peri  od  of  Exposure 

24-hour  max  i  mum 

3- hour  maximum 


Terrain   Areas 


Low 


36 
130 


High 

62 
221 


•    Air  Quality  Related  Values 

The  only  "air  quality  related  value"  specifically  cited 
in  the  1977  Amendments  is  visibility.  Other  values  may 
include  fish  and  wildlife  resources,  vegetation,  archae- 
logic  sites  and  soil  impacts.  The  EPA  has  yet  to  pro- 
vide general  guidelines  regarding  the  evaluation  of 
impacts  of  proposed  emitting  sources  on  "air  quality 
related  values"  and  until  such  guidance  is  available, 
determinations  are  to  be  made  on  a  case- by -case  basis. 
The  FLM  reviewing  the  permit  can  recommend  conditions 
which  would  ensure  protection  of  air  quality  related 
values.  For  example,  a  condition  that  the  facility 
monitor  the  impacts  of  its  emissions,  and  reduce  their 
level  if  adverse  effects  begin  to  occur  may  be 
recommended  . 

FLM  role  in  Redes i gnat  ion  of  Area  Classifications 

A  state  may  redesignate  any  area  to  Class  I.  States  are 
also  permitted  to  redesignate  certain  areas  to  Class  III  except 
the  following  areas  greater  than  10,000  acres  in  size:  present 
national  monuments,  primitive  areas,  recreation  areas,  wild  and 
scenic  rivers,  wildlife  refuges,  lakeshores,  seashores,  and 
future  national  parks  and  wilderness  areas.  Redes i gnat i on  of  an 
area  to  Class  III  is  a  complicated  process  requiring  approval  by 
the  governor,  public  notices  and  hearings,  consultation  with  the 
state  legislature,  and  approval  by  a  majority  of  potentially 
affected  local  residents. 

Detailed  analyses  are  required  prior  to  public  hearing 
including  health,  environmental,  economic,  social  and  energy 
impacts  of  the  proposal.  Redes i gnat i on  of  areas  within  Indian 
reservations  may  only  be  done  by  the  applicable  Indian  governing 
body. 

The  EPA  Administrator  may  disapprove  a  proposed  redesig- 
nation  only  if  the  redes  i  gnat  ion  does  not  meet  the  procedural 
requirements  of  Part  C  of  the  Act.  If  federal  lands  are  included 
in  the  proposed  redes i gnat i on  area,  the  FLM  is  to  submit  recom- 


423 


mendations  on  the  proposal,  but  the  state's  decision,  if  it 
differs,  is  binding.  The  EPA  may  be  requested  to  resolve  dis- 
putes between  states  and  Indian  tribes  on  proposed  redesigna- 
tions.   The  redesi gnat i on  process  is  summarized  in  Figure  6.4-4. 


6.4.4 


Visibility  Protection 


The  1977  Amendments  added  to  the  Clean  Air  Act  a  section 
entitled  "Visibility  Protection  for  Federal  Class  I  Areas".  This 
section  declares  as  a  National  goal  "the  prevention  of  any  fu- 
ture, and  the  remedying  of  any  existing,  impairment  of  visibility 
in  mandatory  Class  I  Federal  areas"  where  impairment  results  from 
man-made  air  pollution.  The  Amendments  also  required  that  by 
February  1978,  the  Secretary  of  Interior,  in  consultation  with 
the  states  and  the  FLM's,  are  to  identify  any  mandatory  Class  I 
areas  where  visibility  contributes  significant  values  to  the 
area.  These  areas  were  published  in  the  February  24,  1978  Feder- 
al Register.  As  such,  all  Class  I  areas  in  California  are  areas 
in  which  visibility  is  considered  to  be  an  "important"  value.  As 
stated  previously,  the  EPA  was  to  have  conducted  a  study  on 
visibilty  (by  Feb  1979),  and  promulgate  regulations  on  visibility 
by  August ,  1979. 

These  regulations,  in  essence,  are  to  provide  guidelines 
to  the  states  on  the  various  techniques  and  methods  to  be  used  to 
achieve  the  National  goal  for  visibility.  Such  a  goal  would  be 
stated,  in  all  probability,  as  a  "visibility  standard". 

The  regulations  would  identify  "impaired  visibility 
areas"  and  would  require  each  SIP  in  such  areas  to  adopt  emission 
limits  on  sources  of  pollution,  compliance  schedules  and  other 
measures  necessary  to  achieve  the  visibility  standard.  These 
measures  will  include  what  the  Clean  Air  Act  terms  "Best  Availa- 
ble Retrofit  Technology"  (BART).  Thus,  SIPs  must  impose  BART  on 
specific  sources  named  in  the  Clean  Air  Act.  These  sources 
consist  of  the  sources  in  the  28  PSD  categories,  which  have 
potential  (uncontrolled)  emissions  greater  than  250  tons/yr  of 
any  pollutant.  In  addition  to  these  measures,  the  SIPs  must 
develop  long-term  strategies  for  achieving  the  visibility  stan- 
dard . 

The  EPA  is  allowed  to  exempt  sources  from  BART;  such 
exemptions  can  be  made  if  the  EPA  feels  that  such  sources  will 
not  contribute  to  visibility  impairment.  The  EPA  may  not  how- 
ever, give  this  source-wide  exemption  to  fossil-fuel  fired  power 
plants  greater  than  750  MW.  These  units  would  be  included  in  the 
states'  regulations  and  BART  must  apply.  Exemptions  for  these 
units  may  only  be  made  on  a  case-by-case  basis,  where  the  owner 
of  such  units  demonstrates  to  the  EPA  that  the  unit  of  concern 
would  not  contribute  to  impairment  of  visibility. 

Any  exemption  that  the  EPA  makes  regarding  these  sources 
and  their  inclusion  in  the  SIP,  must  go  through  the  FLM.  The 
Clean  Air  Act  mandates  that  the  FLM's  concurrence  must  be  ob- 


424 


Figure  6.4-4 
Redes i gnat ion  Procedure 


Yes 


Does  Area  To  Be 
Redesignated  Contain  Federal  Land? 


No 


Written  Notice  by  State  or 
Indian  Governing  Body  to  FLM 


Allow  Up  to  60  Days  for  Con- 

ferring or  Submitting  Written 

Comments  of  FLM  to  State  or 

IGB*. 

State  (or  IGB*)  Must  Prepare 

Lists  of  Inconsistencies 

Between  FLM's  Comment  and  the 

State's  (or  IGB*)  Recommenda- 

tions for  Redesignation,  Plus 

Reasons  for  Making  the  Redesig- 

nation Against  the  Recommenda- 

tion of  the  FLM. 

Detailed  Analysis  of  Reasons 
for  Redesignation,  Including 
Health,  Environmental,  Social 
and  Energy  Impacts  of  Proposal , 
Should  be  Prepared  30  Days 
Prior  to  Public  Hearing. 


Other  States  -  IGB's  and  Federal 
Land  Mgrs.  Whose  Lands  are 
Affected  by  the  Redesignation 
Must  be  Notified  30  Days  Prior 
to  Public  Hearing 


Submit  Final  Proposal  to  EPA,  EPA 
can  Disapprove  Only  on  Grounds  of 
Procedural  Requirements,  or  Class 
I  Areas  Specified  on  PSD  Regula- 
tions Which  May  Not  be 
Reclassified. 


*  Indian  Governing  Body 


425 


tained  in  order  for  any  exemption  of  this  type 
(Section  169A(c)(3)  of  the  Clean  Air  Act). 


to  be  effective. 


The  Clean  Air  Act  requires  that  a  public  hearing  be  held 
on  the  proposed  revision  of  any  SIP  relating  to  the  E PA ' s  visi- 
bility requirements.  The  State  is  also  required  to  consult  with 
the  FLM  on  the  proposed  revision.  Any  recommendations  and  con- 
clusions made  by  the  FLM  on  this  revision  are  required  to  be 
included  in  the  public  notice  announcing  the  hearing. 


6.4.5 


Ozone  Protection 


The  1977  Amendments  also  added  a  section  on  ozone  pro- 
tection to  the  Clean  Air  Act  (Part  B).  The  purpose  of  this 
section  is  to  provide  for  (1)  better  understanding  of  the  effects 
of  human  actions  on  the  stratosphere;  (2)  better  understanding  of 
the  effects  of  changes  in  the  stratosphere;  (3)  information  on 
progress  made  in  regulating  activities  which  may  affect  the  ozone 
in  the  stratosphere  in  such  a  way  as  to  cause  or  contribute  to 
endangerment  of  the  public  health  and  welfare;  and  (4)  informa- 
tion on  the  need  for  additional  legislation  in  this  area. 

The  Act  authorizes  the  EPA  to  conduct  a  study  of  the 
effect  of  all  substances,  as  well  as  practices  and  activities, 
which  may  affect  the  stratosphere  (particularly  ozone).  The  EPA 
may  use  any  university  or  contractor  to  perform  the  studies 
required  by  the  Clean  Air  Act.  In  addition  to  the  EPA  study,  the 
Act  mandates  that  further  research  and  monitoring  be  done  by  the 
following  agencies: 

1.  National  Oceanic  and  Atmospheric  Administration 

2.  National  Aeronautics  and  Space  Administration 

3.  National  Science  Foundation 

4.  United  States  Department  of  Agriculture 

5.  United  States  Department  of  Health,  Education  and 
Wei  fare 


Authorization  is  given  to  the 
any  substance  which  the  EPA 


EPA  to  write  regulations  to  control 


believes,  based 


their  studies 


on 

would  affect  the  stratosphere,  particularly  in  the  formation  of 
ozone.  This  would  include  chl  orof  1  uorocarbon  emissions  from 
aerosol  cans  and  emissions  from  airplanes,  cars,  etc.  These 
regulations  must  take  into  account  the  feasibility  and  the  costs 
of  achieving  these  controls.  However,  such  regulations  may 
exempt  medical  use  products  for  which  the  EPA. determi nes  there  is 
no  suitable  substitute. 


426 


6.  5 


STATE  AND  COUNTY  REGULATIONS 


6.5.1 


State  Ambient  Air  Quality  Standards 


California  began  setting  Air  Quality  Standards  in  1969 
under  the  provisions  of  the  Mulford-Carrell  Act.  With  the  pas- 
sage of  the  Clean  Air  Act  Amendments  in  1970,  the  Federal  Govern- 
ment began  adopting  such  standards  for  the  entire  country. 
Wherever  there  is  some  variation  between  state  and  federal  Air 
Quality  Standards,  the  most  stringent  or  limiting  standard 
applies.  Table  6.5-1  compares  the  Federal  and  California  stan- 
dards.  It  should  be  noted  that  the  1977  Amendments  were  recently 

passed  and  may  eventually  have  a  significant  effect  on  state 
standards  and  county  reg ul at i on s- part i c ul arl y  in  those  regions 
containing  Class  I  areas. 


6.  5.  2 


County  Regul at  i  ons 


The  Bureau  of  Land  Managements  Ukiah  District  (District 
4)  consists  of  10  counties  situated  in  four  air  basins.  A  list- 
ing of  the  counties  by  basin  is  as  follows: 

North  Coast  Basin 

Al 1  of  Del  Norte  County 
All  of  Humboldt  County 
All  of  Mendocino  County 
Part  of  Sonoma  County 

San  Francisco  Bay  Area  Basin 

Part  of  Sonoma  County 
Al  1  of  Napa  County 
Part  of  Sol ano  Co  unty 
All  of  Marin  County 

Sacramento  Valley  Basin 

Al 1  of  Col usa  Co  unty 
All  of  Yolo  County 
Part  of  Solano  County 

La  ke  County  Air  Basin 

Al 1  of  La  ke  County 


The  counties  of  the  San  Francisco  Bay  Area  Basin  al 
the  Bay  Area  Air  Quality  Management  District  (AQMD). 
vidual  county  Air  Pollution  Control  Districts  in  the 
Air  Basin  have  adopted  common  rules  and  regulations, 
ties  of  Yolo  and  Solano  have  formed  the  Yolo-Solano 
counties  of  Lake  and  Colusa  are  individual  APCD's. 


so  com  prise 
The  i  n  d  i  - 


North 
^  The 
APCD. 


Coast 

cou  n- 

The 


427 


Table  6.5-1 
Ambient  Air  Quality  Standards 


Aver  aging  Time 

California  Standard*                                                               National  Standards2 

Pollutant 

Concentration 

Method4                 Primary3,  $ 

Secondary  3-  ■ 

Method7 

O«i0»nt 
(Ozone) 

1  hour 

0.10  ppm 
1.200  ug/m3) 

Ultraviolet                |  240    ug/m3 
Photometry            |(o.l2   ppm) 

Same  as 
Primary  Std. 

Chemiiuminescent 
Method 

Carbon  Monoxide 

12  hour 

10  ppm 

(1  1  mg/m3) 

Non-Dispersive 
Infrared 
Spectroscopy 

_ 

Same  as 
Primary 
Standards 

Non-Olspersive 
Infrared 
Spectroscopy 

•  hour 

- 

10  mg/m3 
(9  ppm) 

1  hour 

40  ppm 
(46  mg/m3) 

40  mg/m3 
(35  ppm) 

Nitrogen  Oiomds 

Annual  Average 

- 

Salt  smart 
Method 

100  ug/m3 
(0.05  ppm) 

Same  as 
Primary 
Standards 

Proposed: 
Modified  j-m 
Saltzman  (escort.) 
Chemiiuminescent 

1  hour 

0.2S  ppm 
(470  ug/m3) 

— 

Sulfur  Otoxide 

Annual  Average 

- 

Conductimetrlc 
Method 

•0  ug/m3 
(0.03  ppm) 

- 

24  hour 

0.0S  ppm 
(131  ug/m3)9 

365  ug/m3 
(0.14  ppm) 

- 

Pararouniline 
Method 

3  hour 

- 

- 

1300  ug/m3 
(0.5  ppm) 

1  hour 

0.5  ppm 
(1310  ug/m3) 

- 

- 

Suspended 
Particulate 

Annual  Geometric 
Mean 

60  ug/m3 

High  Volume 
Sampling 

75  ug/m3 

60  ug/m3 

Hign  Volume 

24  hour 

100  ug/m3 

260  ug/m3 

150  ug/m3 

Sampling 

Sulfates 

24  hour 

25  ug/m3 

AIHL  Metnod 
No.  61 

- 

- 

- 

La  ad 

30  Day 
Average 

1.5  ug/m3 

AIHL  Method 
No.  54 

1.5  ug/m3 

- 

High  Volume 
Sampling 

Hydrogen  Sulflda 

1  hour 

0.03  ppm 
(42  ug/m3) 

Cadmium 
Hydroxide 
Stracten 
Method 

- 

- 

- 

Hydrocarbons 
(Corrected  for 

Met  nana) 

3  hour 
(6-9  a.m.) 

- 

- 

160  ug/m3 
(0.24  ppm) 

Same  as 
Primary 
Standards 

Flame  Ionization 
Oetection  Using 
Gas  Chromatography 

ethylene 

•  hour 

0.1  ppm 

- 

- 

- 

1  hour 

0.5  ppm 

Visibility 
Reducing 
"Articles 

1  observation 

In  sufficient  amount  to             (•) 
reduce  the  prevailing  visibility 
to  leu  than  10  miles  when  the 
relative  humidity  Is  less  than  70% 

- 

- 

- 

APPLICABLE  ONLY  IN  THE  LAKE  TAHOE  AIR  BASIN: 

Carbon  Monoxide 

•  hour 

6  ppm 
(7  mg/m3) 

NOIR 

- 

— 

- 

visibility 
Reducing 
Particles 

1  observation 

In  sufficient  amount  to           <•) 
reduce  the  prevailing  visibility 
to  less  than  30  miles  when  the 
relative  humidity  Is  leu  than  70% 

- 

- 

- 

428 


Table  6.5-1  (Cont.) 


NOTES: 


California  standards  are  values  that  are  not  to  be 
equaled  or  exceeded. 

National  standards,  other  than  those  based  on  annual 
averages  or  annual  geometric  means,  are  not  to  be 
exceeded  more  than  once  per  year. 

Concentration  expressed  first  in  units  in  which  it  was 
promulgated.  Equivalent  units  given  in  parentheses 
are  based  upon  a  reference  temperature  of  25°C  and 
a  reference  pressure  of  760  mm  of  mercury.  All  mea- 
surements of  air  quality  are  to  be  corrected  to  a  ref- 
erence temperature  of  25°C  and  a  reference  pressure 
of  760  mm  of  Hg  (1,013.2  millibar);  ppm  in  this  table 
refers  to  ppm  by  volume,  or  micromoles  of  pollutant 
per  mole  of  gas. 

Any  equivalent  procedure  which  can  be  shown  to  the 
satisfaction  of  the  Air  Resources  Board  to  give  equi- 
valent results  at  or  near  the  level  of  the  air  quality 
standard  may  be  used. 

National  Primary  Standards:  The  levels  of  air  quality 
necessary,   with    an    adequate    margin    of   safety,   to 


protect  the  public  health.  Each  state  must  attain  the 
primary  standards  no  later  than  three  years  after  that 
state's  implementation  plan  is  approved  by  the  En- 
vironmental Protection  Agency  (EPA). 

National  Secondary  Standards:  The  levels  of  air 
quality  necessary  to  protect  the  public  welfare  from 
any  known  or  anticipated  adverse  effects  of  a  pollutant. 
Each  state  must  attain  the  secondary  standards  within 
a  "reasonable  time"  after  implementation  plan  is 
approved  by  the  EPA. 

Reference  method  as  described  by  the  EPA.  An  "equi- 
valent method"  of  measurement  may  be  used  but  must 
have  a  "consistent  relationship  to  the  reference  method" 
and  must  be  approved  by  the  EPA. 

Prevailing  visibility  is  defined  as  the  greatest  visibility 
which  is  attained  or  surpassed  around  at  least  half  of 
the  horizon  circle,  but  not  necessarily  in  continuous 
sectors. 

At  locations  where  the  state  standards  for  oxidant 
and/or  suspended  particulate  matter  are  violated. 
Federal  standards  apply  elsewhere. 


429 


6.5.3 


Perm  it  Rules 


As  mentioned  previously,  the  intent  of  the  Clean  Air  Act 
in  establishing  procedures  for  permit  rules  is  to  require  the 
states  to  write  and  adopt  such  permit  rules  into  their  individual 
SIPs.  Until  such  time  as  these  rules  are  approved  by  the  EPA  and 
incorporated  in  the  SIP,  the  EPA  still  remains  the  permitting 
authority.  Thus,  in  California,  many  Applicants  who  are  required 
to  obtain  a  PSD  permit  from  the  EPA,  are  also  required  to  obtain 
a  New  Source  Review  permit  from  the  County. 

In  nonatta i nment  areas,  however,  no  permits  may  be 
issued  until  the  SIP  for  these  areas  is  approved  by  the  EPA. 
Thus,  in  California,  no  permits  can  be  issued  in  these  areas.  At 
the  present  time,  many  counties  have  rewritten  their  permit  rules 
to  conform  with  a  model  or  guideline  rule  which  was  drafted  by 
the  CARB. 

The  permit  rules  have  in  the  last  year  been  rewritten  by 
the  local  districts  to  conform  to  the  CARB  Model  Rule.  Although 
there  are  individual  differences  between  the  various  districts' 
rules  regarding  cut-off  limits  for  review,  control  technology, 
etc.,  the  basic  content  of  the  rules  follows  the  CARB  Model  Rule. 
Thus  a  description  of  the  provisions  of  the  Model  Rule  will 
suffice  to  describe  the  general  district  requirements. 


At  the  present  time,  these  rewritten 
submitted  to  the  CARB  by  the  local  districts. 
process  of  reviewing  these  rules  to  see  if  they 
Model  Rule.  After  CARB  reviews  the  local  rule, 
it,  it  then  submits  it  to  the  EPA  for  review  and 
SIP.  A  local  District  may  not  submit  directly 
the  State  may  submit  individual  rules  to  the  EPA 
the  SIP.  At  this  point,  no  rules  have  been  submitted  to  the  EPA; 
they  are  presently  either  being  adopted  by  the  local  District  for 
submission  to  the  CARB,  or  have  already  been  submitted  to  CARB 
and  are    waiting  for  their  review. 

6.5.3.1   Description  of  Model  Rule/Districts'  Rules 


rules  have  been 
CARB  is  in  the 
conform  with  the 
and  cone  ur s  with 
inclusion  in  the 
to  the  EPA;  only 
for  inclusion  in 


The  CARB  Model  Rule  was  written  to  ensure  compliance 
with  the  requirements  of  the  Clean  Air  Act,  and  to  provide  the 
individual  APCD's  with  guidance  in  writing  their  rules.  By  and 
large,  most  of  the  Districts  in  California  have  adopted  the  rule, 
with  some  minor  changes  between  Districts.  Thus,  a  description 
of  CARB's  Model  Rule  will  suffice  to  describe  the  indivudual 
Districts'  rules  in  California. 

The  Model  Rule/District  Rules  currently  apply  in  both 
attainment  and  nonattai nment  areas  (A  state  PSD  rule  will  even- 
tually control  sources  in  attainment  areas).  All  sources,  re- 
gardless of  emission  levels,  must  first  demonstrate  compliance 
with  all  District  rules  and  regulations  (emission  limits,  etc.). 
It  must  also  demonstrate  that  all  company-owned  sources  in  the 
State  are  in  compliance  with  all  emission  limitations  and  stan- 
dards which  are  part  of  the  SIP  approved  by  the  EPA. 


430 


If  the  emissions  from  the  source  are  greater  than  250 
lbs/day  (per  the  Model  Rule;  this  may  differ  from  District  to 
District),  for  any  pollutant,  BACT  is  required  for  all  pollu- 
tants . 

If,  after  application  of  BACT,  emissions  of  any  pollu- 
tant are  greater  than  250  lbs/day,  the  source  must  meet  specific 
requirements  which  differ  according  to  two  different  scenarios  as 
i 1 1 ust rated  bel ow  : 

t    Sources  Locating  in  Nonattainment  Areas 

Offsets  must  be  obtained  for  pollutants,  in  ratios 
greater  than  1.2:1. 

t     Sources  Locating  in  Areas  which  are  Attainment  or  Show 
Infrequent  Violations 

Offsets  are  required  only  as  much  as  is  needed  to  pre- 
vent a  new  violation  or  to  prevent  the  worsening  of  an 
existing  one. 

6.5.3.2   California's  Air  Conservation  Program  (ACP) 

In  1976,  the  CARB  began  writing  a  proposed  guideline 
permit  rule  affecting  new  or  modified  sources  locating  in  attain- 
ment areas  of  the  State.  It  was  the  state's  version  of  the  EPA's 
PSD  program,  and  was  called  the  California  Air  Conservation 
Program  (ACP).  The  CARB  had  drafted  a  rule  incorporating  a 
four-level  classification  system  of  lands,  as  opposed  to  the 
EPA's  three-class  increment  system. 

However,  since  the  Clean  Air  Act  Amendments  of  1977 
drastically  changed  the  PSD  requirements  for  states,  and  with  the 
rush  of  activity  associated  with  nonattainment  planning,  the  ACP 
for  the  State  was  temporarily  dropped. 

Activity  resumed  recently  on  drafting  the  California 
version  of  PSD.  However,  at  this  time,  the  rule  is  being  written 
to  be  equivalent  to  the  EPA's  present  PSD  regulations,  and  will 
not  contain  extensive  additions,  or  differences,  as  in  the  origi- 
nal version.  The  CARB's  purpose  in  their  actions  is  to  draft  a 
rule  that  the  local  Districts  can  easily  adopt  and  which  would  be 
easily  approvable  by  the  EPA.  The  rule  would  then  be  part  of  the 
SIP,  and  could  be  enforced  by  the  local  Districts. 

Subsequent  to  inclusion  in  the  SIP,  the  CARB  will  then 
commence  work  on  a  new  version  of  the  ACP  which  would  eventually 
replace  their  PSD  regulation.  Thus,  their  PSD  regulation  serves 
only  as  an  interim  measure  in  order  to  obtain  full  State  juris- 
dictional authority  to  administer  permit  programs  i n  _attai nment 
areas.  The  ACP  will,  in  essence,  be  a  more  detailed  PSD  regula- 
tion which  is  tailored  to  the  air  quality  concerns  and  needs  of 
California.  It  is  not  known  at  this  time  whether  the  ACP  will 
include  the  utilization  of  the  national  Class  I,  II,  and  III 
increment  or  another  suitable  increment  standard. 


131 


The  CARB  wishes  to  have  their  interim  PSD  regulation 
(Model  Rule)  drafted  by  October.  They  wish  to  have  the  Districts 
adopt  this  regulation  by  the  end  of  1979. 

6.5.3.3   Emission  Regulations 

The  remainder  of  this  section  is  categorized  by  the 
pollutant  causing  event  or  by  the  pollutant.  Each  category  is 
followed  by  a  discussion  that  describes  either  the  typical  regu- 
lation as  adopted  by  all  or  a  vast  majority  of  the  APCD's,  or  the 
regulations  as  adopted  by  an  individual  or  group  of  APCD's.  The 
discussions  are  not  intended  to  be  all-inclusive;  for  more  de- 
tailed information  and  for  special  incidences,  refer  to  the 
county  rules  and  regulations  directly. 

Visible  Emissions 

This  regulation  prohibits  the  discharge  of  air  pollu- 
tants for  more  than  three  minutes  in  any  hour  which  is  as  dark  or 
darker  than  No.  1  or  No.  2  on  the  Ringelmann  Chart  (as  published 
by  the  U.S.  Bureau  of  Mines)  depending  on  the  APCD.  Some  APCDs 
allowexceptions. 

The  Bay  Area  APCD  and  Mendocino  County  APCD  use  Ringel- 
mann No.  1.  The  Lake  County  APCD,  Yolo-Solano  APCD,  and  all  of 
the  APCDs  in  the  North  Coast  Air  Basin  with  the  exception  of 
Mendocino  County  use  Ringelmann  No.  2.  The  following  exceptions 
general  1 y  appl y : 

1.    Smoke  from  fires  for  prevention  of  a  fire  or  health 
hazard  which  cannot  be  abated  by  any  other  means. 


2.    Smoke  from  fires  for  instruction  of  public  and 
trial  employees  in  methods  of  fighting  fire. 


i  nd  us- 


3.  Agricultural  operations  used  in  the  growing  of  crops  or 
raising  of  fowl,  animals,  or  bees. 

4.  The  use  of  an  orchard  or  citrus  grove  heater  which  does 
not  produce  unconsumed  solid  carbonaceous  matter  at  a 
rate  in  excess  of  one  (1)  gram  per  minute. 

5.  Emissions  which  fail  to  meet  the  requirement  solely 
because  of  the  presence  of  uncombined  water. 

The  Ringelmann  Chart  is  actually  a  series  of  charts, 
numbered  from  0  to  5,  that  simulate  various  smoke  densities  by 
presenting  different  percentages  of  black.  The  charts  are  com- 
monly referred  to  by  number,  thus  a  Ringelmann  No.  1  is  equiva- 
lent to  20  percent  black;  a  Ringelmann  No.  5  is  equivalent  to  100 
percent  black.  They  are  used  for  measuring  the  opacity  of  smoke 
generated  from  stacks  and  other  sources  by  matching  with  the 


432 


actual  effluent  the  various  numbers,  or  densities,  indicated  by 
the  charts.  Persons  can  be  trained  and  certified  to  use  the 
Ringelmann  method  using  visual  judgment  without  the  use  of  the 
charts  . 

Incinerator  Burning 

The  burning  of  combustible  refuse  in  any  incinerator  is 
prohibited  except  in  multiple-chamber  incinerators  or  other 
equipment  found  in  advance  by  the  Air  Pollution  Control  Officer 
to  be  equally  effective  for  controlling  air  pollution.  This  rule 
generally  does  not  apply  to  incinerators  used  to  burn  only  house- 
hold rubbish  and  yard  trimmings  from  single  or  two- family  dwell- 
ing on  its  premises.  However,  in  some  counties,  burning  in  non- 
approved  equipment  may  be  done  only  on  "burn-days". 

A  multiple  chamber  incinerator  is  any  article,  machine, 
equipment,  contrivance,  structure  or  part  of  a  structure  used  to 
dispose  of  combustible  refused  by  burning,  consisting  of  three  or 
more  refactory  lined  combustion  furnaces  in  series,  physically 
separated  by  refractory  walls,  interconnected  by  gas  passage 
ports  or  ducts  and  employing  adequate  design  parameters  necessary 
for  maximum  combustion  of  the  material  to  be  burned. 

Particulate  Matter 

These  regulations  limit  the  amount  of  particulate  matter 
that  can  be  discharged  from  a  source.  A  limit  is  also  estab- 
lished on  the  allowable  rate  of  particulate  emission  based  on 
process  weight.   The  rate  varies  for  the  APCDs. 

Yolo  and  Solano  County  APCDs  prohibit  the  discharge  of 
particulate  matter  in  excess  of  0.3  gr/SCF  of  exhaust  volume  as 
calculated  for  standard  conditions. 

The  Bay  Area  AQMD  limits  the  weight  of  particulates  in 
an  exhaust  gas  stream  to  0.15  gr/SCF.  For  any  incineration 
operation  or  salvage  operation  capable  of  burning  100  tons  of 
waste  per  day,  the  limit  is  0.05  gr/SCF.  In  addition,  an  allow- 
able rate  of  emission  is  established  based  on  a  process  weight 
table  contained  in  the  regulations.  Maximum  emissions  allowed 
under  this  table  are  40  lbs/hr. 

Lake  County  limits  combustion  contaminants  from  sources 
other  than  combustion  sources  to  0.2  gr/SCF  or  the  emission  limit 
as  established  by  the  process  weight  table  contained  in  the 
regulations.  Maximum  emissions  allowed  under  this  table  are  40 
lbs/hr. 

Combustion  sources  must  meet  the  following  p-articulate 
matter  limitations  in  Lake  County: 

1.    0.2  gr/SCF  calculated  at  12%  C  0  2  for  equipment  in  use 
prior  to  December  20,  1971; 


433 


2.    0.1  gr/SCF  of  gas  calculated  at  12%  COo  for  equipment 
beginning  operation  after  December  20,  1571. 

The  above  particulate  emission  limits  also  apply  to  geothermal 
operations  although  an  exemption  can  be  made  during  the  air 
drilling  phase  of  the  operation,  during  which  time  the  particu- 
late emission  rate  may  reach  a  level  of  100  lbs/hr  for  a  time 
period  not  to  exceed  16  days. 

The  North  Coast  Air  Basin  has  the  following  particulate 
matter  rules: 


1. 
2. 

3. 

4. 


The  discharge  from  any  combustion  source  in  excess  of 
0.2  gr/SCF  (0.46  grams  per  standard  cubic  meter  (g/SCM) 
of  exhaust  gas),  calculated  at  12%  of  C02  is  prohibited. 

Steam  generating  units,  installed  or  modified  after  July 
1,  1976  may  not  discharge  in  excess  of  0.1  gr/SCF  (0.23 
g/SCM)  of  exhaust  gas  calculated  at  12%  C02» 

Kraft  recovery  furnaces  may  not  discharge  in  excess  of 
0.1  gr/SCF  of  exhaust  gas. 

Non-combustion  sources  may  not  discharge  in  excess  of 
0.2  gr/SCF  of  exhaust  gas. 

The  above  emission  limits  are  summarized  in  the  table 


bel  ow 


Table  6. 5-2 
Limits  for  Particulate  Matter 


County/D  i  stri  ct 
Yolo/Solano  APCD 
Bay  Area  AQMD 


Stack  Gas 
Concent  rat  i  on 
Limit 

0.3  gr/SCF 


(1)  Incinerator  operation    0.5  gr/SCF 
or 
Sal vage  operat i  on 


(2 )  All  other  sources 

Lake  County 

( 1 )  All  sources  other 
than  combust i  on 
sources 


0.15  gr/SCF 


0.2  gr/SCF 


434 


Emission 
Limit 


Process  weight  table 
used  to  determine 
al 1 owabl e  emi  ss  i  on 
rate.   Maximum  limit 
allowed  is  40  lbs/hr. 


Process  weight  table 
used  to  determine 
al 1 owabl e  emi  ss  i on 
rate.   Maximum  1 imi t 
allowed  is  40  lbs/hr. 


(2)  Combustion  sources 
in  use  prior  to 
December  20,  1971 


(3)  Combustion  sources 
in  use  after 
December  20,  1971 


North  Coast  Air  Basin 


(1)  Combustion  sources 


0.2  gr/SCF 


0.1  gr/SCF 


0.2  gr/SCF 


0.1  gr/SCF 


Process  weight  table 
used  to  determine 
al 1 owabl e  emi  ss  i  on 
rate.   Maximum  limit 
allowed  is  40  Ibs/hr 

Process  wei  ght  table 
used  to  determine 
al 1 owabl e  emi  ssi  on 
rate .   Max  imum  limit 
allowed  is  40  lbs/hr 


Process  wei  g  ht  table 
used  to  determine 
al 1 owabl e  em  i  ss  i  on 
rate .   Max  i  mum  limit 
allowed  is  40  lbs/hr 

Process  weight  table 
used  to  determine 
al 1 owabl e  emi  ssi  on 
rate .   Max  imum  limit 
alio wed  is  40  lbs/hr 

Process  weight  table 
used  to  determine 
al 1 owabl e  emi  ssi  on 
rate.   Maximum  limit 
alio wed  is  40  lbs/hr 

Process  we  i  ght  table 
used  to  determine 
al 1 owabl e  emi  ssi  on 
rate  .   Max  imum  limit 
alio wed  is  40  lbs/hr 

Sulfur  Compounds 

These  regulations  limit  either  the  emission  of  sulfur 
compounds  at  the  point  of  discharge  or  the  atmospheric  concen- 
tration of  sulfur  compounds. 

In  the  Bay  Area  AQMD,  sources  of  sulfur  dioxide  must 
either  meet  a  300  ppm  limit  at  the  emission  point  or  a  much  more 
restrictive  limit  at  ground  level  -  0.5  ppm  for  three  consecutive 
minutes  or  0.5  ppm  averaged  over  60  minutes  or  0.04  averaged  over 
24  hours.  Further,  the  limits  specified  below  are  also-  not  to  be 
exceeded : 


(2)  Steam  generating 
units  installed 
or  modified  after 
July  1,  1976 


(3)  Kraft  recovery 
furnaces 


0.1    gr/SCF 


(4 )    Non-combu  st  io  n 
so  urces 


0.2    gr/SCF 


435 


Tabl e  6.5-3 

Bay  Area  AQMD 
Maximum  Allowable  SCU  Ground  Level  Limits 


SCK  Concent  rat i  on 
ppm  ( vol  ) 


Averaging  Time 
(hrs) 


1.5 
0.  5 
0.3 
0.  1 
0.04 


0.05 
1.0 
3.2 
9.6 
24.0 


The  Bay  Area  AQMD  has  established  the  following  limita- 
tions for  sulfur  recovery  plants,  sulfuric  acid  plants  and  re- 
finery equipment  in  refineries: 

Table  6. 5-4 


Bay  Area  AQMD 
Emission  Limitations  for  Sulfur  Recovery  Plants 
and  Refinery  Equipment 


Source 


S  0  0  Limitation 


Existing  Controlled 
PI  ants 


Existing  Uncontrolled 
PI  ants 


The  more  restrictive  of  1500 
ppm  (vol)  or  120  lbs  per  short 
ton  of  sulfur  products 

By  1984,  such  plants  must  meet 
the  more  restrictive  of:  250 
ppm  (vol)  or  4  lb  per  short 
ton  of  sulfur  produced. 

3000  ppm  (vol ) 

By  1981  the  limit  shall  be: 
The  more  restrictive  of  250 
ppm  (vol)  or  4  lbs  per  short 
ton  of  sulfur  produced. 


New  Sulfur  Recovery  Plants 


The  more  restrictive 
ppm  ( vol )  or  4  lbs 
sul fur  prod  uced . 


of:  250 
SOp/ton 


436 


Existing  Sulfuric  Acid 
PI  ants 

Acid  plants  constructed 
prior  to  1955 

Acid  plants  constructed 

after  1955 


Fluid  Catalytic  Cracking 
Units,  Fluid  Co  ker  s 

Coke  Calcining  Kilns 
(vol )  or  250  lbs/hr. 


6000  ppm  through  1981 


3000  ppm  through  1981 

By  1981  the  limit  shall  be: 
More  restrictive  of  300  ppm 
( vol )  or  7  lbs  S02/ton  H2S04 
produced 


New  Sulfuric  Acid  Plants 

( vol )  or  4  lbs  S02/ton  H?  S04 
prod  uct 


More  restrictive  of  30  ppm 


1000  ppm  (vol ) 

More  restrictive  of  400  ppm 


Lake  County  prohibits  the  discharge  from  any  sulfur 
recovery  unit  producing  elemental  sulfur  of  effluent  process  gas 
containing  more  than:  (1)  300  ppm  by  volume  of  sulfur  compound 
calculated  as  S0o,  (2)  10  ppm  by  volume  of  hydrogen  sulfide,  and 


(3)  100  pounds  per  hour  of  sulfur  compounds  calculated 
d  i ox  ide  . 


as  sulfur 


For  geothermal  wells  and  power  plants,  Lake  County  has 
recently  adopted  rules  for  the  control  of  FUS  emissions.  FUS  is 
limited  to  150  ppm  from  geothermal  wells,  unless  there  is  an  FUS 
control  system  capable  of  achieving  a  75%  or  greater  reduction  in 
emissions.  In  all  cases,  the  FU  S  emissions  must  be  demonstrated 
not  to  exceed  the  1-hour  ambient  state  standard  for 


H  o  S . 


the 


control 


FUS 
ambient  monitor- 


Exemptions  to  the  150  ppm  limit  and 
system  may  be  made  if  the  developer  installs  an 
i ng  system  in  the  downwind  direction  of  the  geothermal  well,  and 
the  ambient  air  standard  for  FUS  is  not  exceeded.  However,  an 
upper  limit  of  1000  ppm  is  imposed. 


Geothermal   power  plans  must 
schedule  of  FUS  emissions: 


meet  the  following  time 


437 


Table  6. 5-5 


Emission  Limits  of  H?S  from 
Geothermal  Power  Plants 
in  Lake  County 


Source 


Emission  Limit 


Plants  which  have  received 
Authority  to  Construct  (A/C) 
prior  to  January  1,  1979 

Plants  receiving  A/C  on  or 
after  January  1,  1979 

Plants  receiving  A/C  on  or 
after  January  1,  1983 

All  plants  by  1990 


175  g/MW-hr  until  1990 


100  g/MW-hr  until  1990 


50  g/MW-hr  until  1990 


50  g/MW-hr 


In  Northern  Sonoma  County,  the  emission  limitations  for 
H2S  from  geothermal  power  plants  are  the  same  as  those  listed 
aDove  for  Lake  County.  However,  geothermal  wells  are  limited  to 
2.  5  kg  H2S/hr. 

The  North  Coast  Air  Basin  has  the  following  regulations 
for  emissions  of  total  reduced  sulfur  (TRS): 

1.  Kraft  recovery  furnaces:  (a)  10  ppm  or  0.30  pounds  of 
TRS  per  ton  of  kraft  pulp  mill  production  as  a  monthly 
arithmetic  average,  whichever  is  more  restrictive;  (b) 
15  ppm  of  TRS  as  a  daily  arithmetic  average;  (c)  40  ppm 
of  TRS  for  more  than  60  cumulative  minutes  in  any  one 
day. 

2.  Lime  kilns:  shall  not  exceed  40  ppm  of  TRS  or  0.20 
pounds  of  TRS  per  ton  of  kraft  pulp  mill  production  as  a 
daily  arithmetic  average,  whichever  is  more  restrictive. 

3.  Other  kraft  mill  sources:  shall  not  exceed  20  ppm  of 
TRS  or  a  cumulative  value  of  0.20  pounds  of  TRS  per  ton 
of  kraft  pulp  mill  production  as  a  daily  arithmetic 
average,  whichever  is  more  restrictive. 

N  i  t rogen  Ox  i  des 

The  Bay  Area  APCD  limits  nitrogen  oxide  emissions  from 
stationary  sources.   The  limits  are    as  follows: 

1.  Sources  with  heat  input  equal  to  or  greater  than  250 
million  Btu/hr.  -  125  ppm  when  burning  natural  gas  and 
225  ppm  when  burning  oil. 


438 


2 .  Sources  with  heat  input  equal  to  or  greater  than  1,750 
million  Btu/hr.  -  175  ppm  when  burning  natural  gas  and 
300  ppm  when  burning  oil. 


Area  AQMD  prohibits  any  source  from  emitting 
.  of  lead  per  day  resulting  in  a  ground  level 
1.0  micrograms  per  cubic  meter  in  excess  of  the 


Lead  Emissions 

The  Bay 
more  than  13  lbs 
concentration  of 
bac  kgro  und  1 evel  . 

Odors 

Two  methods  have  been  used  by  counties  to  regulate  odors 
in  the  atmosphere.  In  most  counties,  odors  are  covered  under 
regulations  for  nuisances  (see  separate  section).  The  Bay  Area 
APCD  Regulations  call  for  district  personnel  to  take  a  sample  of 
a  suspected  odor  if  ten  citizen  complaints  are  received  within  90 
days.  The  sample  is  then  diluted  with  four  parts  of  odor  free 
air.  If  it  remains  odorous  after  dilution,  the  source  is  in 
violation  of  the  regulation. 

Nu  i  sances 


This  regulation  generally  prohibits  any  source  from 
emitting  air  contaminants  or  other  material  which  cause  injury, 
detriment,  nuisance  or  annoyance  to  any  considerable  number  of 
persons  or  to  the  public  or  which  endanger  the  comfort,  repose, 
health  or  safety  of  any  persons  or  the  public  or  which  cause  or 
have  a  tendency  to  cause  injury  or  damage  to  business  or  prop- 
erty. The  working  of  this  regulation  varies  with  the  overall 
detail  of  the  county  or  district  regulations.  In  some  cases, 
nuisances  such  as  odors  are  separated  out  and  dealt  with  di- 
rect! y . 


Sulfur  Content  of  Fuels 

The  Bay  Area  AQMD  limits  the  sulfur  in  fuels 
percent  or  the  emissions  from  fuel  burning  to  300  ppm  (as 

Reduction  of  Animal  Matter 


to 
SO 


0.5 
2). 


This  prohibits  the  reduction  of  animal  matter  in  a 
source  unless  all  generated  emissions  are  incinerated  at  temper- 
atures of  not  less  than  1200  degrees  Fahrenheit  for  a  period  of 
not  less  than  0.3  seconds  or  processed  in  a  manner  determined  by 
the  Air  Pollution  Control  Officer  to  be  equally  or  more  effective 
for  the  purpose  of  air  pollution  control. 

Miscellaneous  Regulations 

Other  common  regulations  usually,  but  not  always  in- 
cluded by  counties  and  districts,  include  prohibitions  on  emis- 
sions from  organic  solvents,  new  source  performance  standards, 


439 


emission  standards  for  hazardous  air  pollutants,  regulations  on 
organic  liquid  loading,  regulations  on  loading  gasoline  into 
stat  i  onary  tanks  . 

6.5.3.4   Burning  Regulations 

The  CARB  has  promulgated  regulations  governing  the  use 
of  open  outdoor  fires  for  agricultural  operations  and  forest 
management.  Agricultural  burning  guidelines  and  meteorological 
criteria  for  the  regulation  of  agricultural  burning  were  promul- 
gated for  each  air  basin  on  March  17,  1971.  The  purpose  of  the 
regulation  was  to  permit  burning  on  days  with  good  meteorology 
based  upon  established  meteorol og iccal  criteria.  Regulations 
were  adopted  on  March  17,  1971  and  revised  on  June  21,  1972, 
February  20,  1975,  with  a  proposed  revision  April  27,  1978. 

The  regulations  require  that  burning  permits  be  obtained 
prior  to  the  use  of  open  outdoor  fires.  These  permits  are  to  be 
prepared  by  the  designated  agency  and/or  the  appropriate  APCD. 
In  most  instances,  the  California  Department  of  Forestry  (CDF) 
serves  as  the  designated  agency  for  burning  in  forested  areas 
throughout  the  state  and,  therefore,  is  responsible  for  the 
issuance  of  permits. 

While  the  CDF  serves  as  the  designated  agency  for  the 
issuance  of  burning  permits  in  California,  this  responsibility 
can  be  further  delegated  to  other  agencies.  In  some  instances, 
the  BLM  has  been  given  authority  by  the  CDF  to  issue  permits  for 
land  areas  managed  by  the  Department  of  Interior.  These  include 
the  Susanville  and  Bodie  Planning  Units.  In  these  instances,  BLM 
area  managers  are  directly  responsible  for  the  issuance  of per- 
mits and  for  coordination  with  other  agencies.  However,  unless 
this  authority  has  been  properly  delegated,  BLM  area  managers  are 
not  responsible  for  permitting  for  open  outdoor  burning. 

BLM  area  managers  responsible  for  the  administration  of 
Department  of  Interior  lands  in  California  must  be  cognizant  of 
the  procedures  necessary  prior  to  any  burning  activities  in  these 
areas.  The  principal  points  of  contact  for  the  BLM  area  managers 
include  the  local  APCD,  the  CARB,  the  National  Weather  Service 
(NWS)  and  the  CDF.  The  latter  agency  should  serve  as  an  initial 
point  of  contact  for  area  managers  faced  with  the  problem  of 
burning  on  federal  lands  for  the  first  time.  CDF  personnel  can 
explain  permit  issuance  procedures  to  BLM  personnel  and  it  is 
good  practice  for  BLM  land  managers  to  become  very  familiar  with 
this  process.  Table  6.5-6  provides  a  list  of  all  CDF  contacts 
within  California  suitable  for  use  by  BLM  land  managers. 

The  requirements  for  a  burning  permit  apply  to  all  land 
areas  in  the  state  with  a  few  exceptions.  Open  burning  for 
agricultural  operations  in  the  growing  of  crops  or  the  raising  of 
fowl  or  animals,  as  well  as  disease  or  pest  prevention  are  exempt 
from  permitting  requirements  above  an  elevation  of  3,000  feet 
MSL.   This  exception  does  not  apply  in  the  Tahoe  Air  Basin.   Land 


440 


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areas  located  at  an  elevation  above  6,000  feet  MSL,  except  in  the 
Tahoe  Air  Basin,  are  exempt  from  permitting  requirements  for  all 
agricultural  burning  which  includes  outdoor  fires  for  agricul- 
ture, pest  control,  forest  management,  range  improvement,  im- 
provement of  land  for  wildlife  and  game  habitat,  as  well  as  in 
the  raising  of  fowl  or  animals.  Most  burning  on  BLM  lands  will 
be  for  forest  management  or  range  improvement  activity  and  there- 
fore would  be  exempt  to  permitting  requirements  above  6,000  feet 
MSL.  Below  this  level,  a  permit  will  probably  be  required  for 
burning  on  BLM  lands.  Other  special  aspects  of  permitting  re- 
quirements include  the  permission  to  burn  between  the  period  of 
January  through  May  for  range  management,  even  on  no-burn  days  if 
50%  of  the  land  area  has  been  chemically  treated.  In  addition, 
BLM  land  planners  can  notify  the  CARB  seven  days  in  advance  for  a 
major  burn  at  an  altitude  below  6,000  feet  MSL.  The  agency  will 
then  provide  a  special  forecast  48-hours  prior  to  the  burn  and 
daily  thereafter  as  a  special  service. 

Once  again,  the  CDF  will  serve  as  the  designated  agency 
for  permitting  for  most  BLM  lands  in  California.  Other  points  of 
contact  for  BLM  land  managers  include  the  CARB  for  burn/no-burn 
decisions  for  land  areas  at  altitudes  below  6,000  feet  MSL.  In 
addition,  close  contact  must  also  be  maintainted  with  the  NWS 
relative  to  fire  weather  forecasts  such  that  all  burning  can  be 
strictly  controlled  during  dangerously  dry  periods.  These  are 
the  key  contacts.  It  is  important  to  proceed  with  an  attitude  of 
cooperation  with  all  agencies  to  insure  safe  outdoor  burning  as 
well  as  to  limit  the  possible  impacts  on  ambient  air  quality  by 
the  resultant  smoke.  BLM  land  managers  will  be  required  to  keep 
a  record  of  the  amount  of  acreage  and  the  tonnage  of  material 
burned  daily  as  the  APCD's  will  request  this  information  in 
preparing  their  required  quarterly  reports  to  the  CARB  regarding 
burning  permi  ts . 

Individual  counties  will  prohibit  such  burning  unless 
the  appropriate  permit  from  CDF  or  other  designated  agency  has 
been  obtained.  In  addition,  the  individual  APCD's  or  county  air 
pollution  control  officer  may  designate  a  particular  day  as  a 
"burn  day"  or  "no-burn  day"  dependent  upon  the  meteorological 
conditions  within  his  jurisdiction  and  time  of  year.  Persons 
with  the  appropriate  permits  may  commence  their  outdoor  burning 
subject  to  the  conditions  of  their  permits  on  days  designated 
"burn  days".  Individual  county  burning  requirements  are  dis- 
cussed bel ow . 

Open  Burning* 

Prohibits  the  maintenance  of  an  open  fire  (i.e.,  outdoor 
burning  unless  specifically  allowed  by  regulation.  The  language 
of  the  regulation  and  the  exceptions  which  apply  vary  by  APCD. 


*  Including  provisions  for 
range  improvement  burning. 


agricultural,  forest  management  and 


442 


On  permissive  burn  days,  the  Yolo-Solano  APCD  exempt  the 
following  fires: 

1.  A  fire  set  or  permitted  by  any  public  officer  for  the 
purpose  of  preventing  a  health  hazard  which  cannot  be 
abated  by  any  other  means,  or  for  the  instruction  of 
industrial  employees  in  the  method  of  fighting  fires. 

2.  For  right  of  way  clearing  by  a  public  entity  or  utility, 
or  for  levee,  reservoir,  and  ditch  maintenance  when  the 
material  has  been  prepared  by  stacking,  drying,  or  other 
methods  to  promote  combustion  as  specified  by  the  Air 
Pollution  Control  Officer  (APCO). 

3.  Agricultural  burning  permitted  by  law. 

On  all  days  this  rule  does  not  apply  to  the  following 
fires  in  the  Yolo-Solano  APCD: 

1.  A  fire  set  or  permitted  by  any  public  officer  for  the 
instruction  of  a  public  or  industrial  employees  in  the 
methods  of  fighting  fire  where  a  permit  has  been  issued 
by  the  APCO,  or  backfires  necessary  to  save  life  or 
v al uabl e  property . 

2.  Fires  for  recreational  use  and  cooking  of  foods. 

3.  To  abate  fires  pursuant  to  Chapter  2  of  Part  1  of  Divi- 
sion 12  of  the  California  Health  and  Safety  Code. 

4.  Fires  not  used  for  disposal  of  materials  and  which  the 
APCO  determines  necessary  and  not  to  have  significant 
air  pollution  effects. 

5.  Fires  to  burn  empty  sacks  or  containers  which  contain 
pesticides  or  other  toxic  substances. 

The  Yolo-Solano  APCD  further  prohibit  the  use  of  open  outdoor 
fires  for  the  disposal  of  petroleum  waste,  demolition  debris, 
construction  debris,  tires  or  other  rubber  materials,  materials 
containing  tar,  or  for  metal  salvage  or  burning  of  vehicle 
bodies. 

The  Bay  Area  APCD  allows  the  following  exceptions  to  the 
general  prohibition  of  open  fires. 

1.  Cooking  and  recreational  fires. 

2.  Fires  burning  as  safety  flares  or  for  the  combustion  of 
waste  gases . 


443 


3.  The  use  of  flame  cultivation  which  uses  LPG  or  natural 
gas-fired  burners  designed  and  used  to  kill  seedling 
grass  and  weeds  in  orchards,  vineyards  and  field  crops 
and  the  growth  is  such  that  the  combusion  will  not 
continue  without  the  burner. 

4.  Any  fire  demonstrated  to  emit  under  all  operating  condi- 
tions nothing  but  carbon  dioxide,  nitrogen  oxides,  or 
water  vapor. 

5.  Agricultural  fires  allowed  by  the  County  Agricultural 
Commissioner  for  disease  and  pest  prevention. 

6.  Fires  allowed  by  public  officials  for  prevention  of  fire 
hazards  including  the  disposal  of  dangerous  materials. 

7.  Fires  for  the  instruction  of  public  and  industrial 
employees  in  fire  fighting  methods.  (Each  fire  fighting 
agency  may  set  one  fire  for  the  purpose  of  training 
volunteer  fire  fighters  per  quarter  year  on  other  than  a 
permissive  burn-day  if  the  APCO  is  notified  at  least  two 
weeks  i  n  advance . ) 

8.  Agricultural  fires  permitted  by  the  proper  officer 
necessary  to  establish  an  agricultural  crop  in  a  loca- 
tion which  formerly  contained  another  type  of  agricul- 
tural crop  or  natural  growth,  during  a  period  between 
October  1  and  April  30. 

9.  Agricultural  fires  permitted  by  the  proper  officer 
necessary  to  maintain  and  continue  the  growing  fruit  and 
nut  trees,  vineyards  and  cane  fruits,  as  a  gainful 
occupation;  and  for  the  purpose  of  disposal  of  periodic 
prunings  and  attrition  losses  from  fruit  and  nut  trees, 
vineyards  and  cane  fruits,  during  a  period  beginning 
December  1  and  ending  April  30. 

10.  Agricultural  fires  permitted  by  the  proper  officer  for 
disposal  of  grain  stubble  from  agricultural  operations 
on  which  both  grain  and  vegetable  crops  are  harvested 
during  the  same  calendar  year  and  on  which  it  is  neces- 
sary to  remove  the  grain  stubble  and  straw  before  plant- 
ing a  field  vegetable  crop,  during  a  period  beginning 
June  1  and  ending  August  31. 

11.  Agricultural  fires  permitted  by  the  proper  officer 
necessary  to  maintain  and  continue  growing  of  field 
crops  as  a  gainful  occupation  and  for  the  purpose  of 
disposal  of  stubble  and  straw,  during  a  period  beginning 
September  1  and  ending  December  31. 

12.  Fires  necessary  to  control  the  growth  of  vegetation  in 
irrigation  ditches  and  canals. 


444 


13.  Fires  for  preventing  or  eliminating  a  flood. 

14.  Fires  certified  by  the  Department  of  Fish  and  Game  and 
necessary  for  the  improvement  of  lowland  and  marsh  for 
wildlife  and  game  habitat,  during  a  period  beginning 
February  1  and  ending  March  31,  and  a  period  beginning 
October  1  and  ending  October  31. 

15.  Fires  necessary  to  remove  wood  and  vegetation  debris 
deposited  by  flood  waters,  for  continuing  or  maintaining 
agriculture  as  a  gainful  occupation  during  a  period 
between  October  1  and  May  31. 

16.  Range  management  fires  permitted  by  the  State  Forester 
necessary  to  maintain  and  continue  the  grazing  of  ani- 
mals as  a  gainful  occupation  and  for  range  improvement 
and  grazing,  during  a  period  between  July  1  and  April 
30.  Brush  to  be  burned  shall  be  treated  at  least  six 
months  prior  to  burn  if  determined  to  be  technically 
feasible.  Unwanted  trees  over  six  inches  in  diameter 
are  to  be  felled  and  dried  for  a  minimum  of  six  months. 

17.  Forest  management  fires  to  remove  debris  and  for  forest 
management  purposes  during  a  period  between  November  1 
and  April  30. 

All  burning  in  the  Bay  Area  APCD  must  be  conducted  only  on  per- 
missive burn-days  or  with  the  permission  of  the  APCO.  Other 
conditions  are:  (1)  no  material  or  fuel  is  to  be  ignited  nor  any 
material  or  fuel  added  to  any  fire  when  the  wind  velocity  is  less 
than  5  miles  per  hour,  or  when  the  wind  direction  at  the  site 
causes  the  smoke  to  drift  toward  populated  areas;  (2)  all  piled 
material  is  to  be  dried  a  minimum  of  60  days  prior  to  ignition  or 
demonstrated  to  contain  less  than  23  percent  moisture  on  a  dry 
basis;  (3)  material  to  be  burned  is  not  to  contain  more  than  5 
percent  native  soil  on  a  weight  basis;  and  (4)  piled  material  in 
most  cases  is  limited  to  a  base  area  not  to  exceed  25  square 
yards  and  the  height  is  to  be  at  least  2/3  of  the  average  width 
of  the  pile. 

The  North  Coast  Air  Basin  prohibits  open  fires  for  the 
disposal  of  rubber  petroleum  or  plastic  wastes,  demolition  de- 
bris, tires,  tarpaper,  wood  waste,  asphalt  shingles,  linoleum, 
cloth,  household  garbage  or  burning  of  automobile  bodies,  except 
for  the  fol 1 owi  ng : 


1. 
2. 


Cooking  and  recreational  fires. 


Fires  for: 
safety  hazard 
(  b )  training 
( c)  backf i  res 
ty. 


(a)  the  prevention  of  a  fire,  health  or 
which  cannot  be  abated  by  any  other  means; 

personnel  in  the  methods  of  fire  fighting; 
necessary  to  save  life  or  valuable  proper- 


,445 


3.  Fires  used  in  the  operation  of  a  solid  waste  dump  for 
which  a  limited  time  extension  has  been  granted  by  the 
California  Air  Resources  Board. 

The  following  open  outdoor  fires  are  permitted  in  the 
basin  on  permissive  burn-days: 

1.  Agricultural  operations  for  the  growing  of  crops  or 
raising  of  fowl  or  animals. 

2.  Range  improvement  to  remove  unwanted  vegetation  or 
establish  an  agricultural  practice. 

3.  Forest  management  to  remove  forest  debris. 

4.  Wildlife  improvement  to  enhance  wildlife  or  game  habi- 
tat . 

5.  Disposal  of  approved  combustibles  from  single  or  two- 
family  dwellings  on  their  premises.  (Such  burning  is 
exempt  from  permissive  burn-day  notification  except  in 
the  Humboldt  Bay  Air  Basin  and  the  Ukiah-Little  Lake  Air 
Basin.) 

6.  Right-of-way  clearing  by  a  public  entity  or  utility. 

7.  Ditch,  levee  and  reservoir  maintenance. 

Lake  County  prohibits  outdoor  fires  for  the  purpose  of 
disposal  of  burning  of  petroleum  wastes,  demolition  debris, 
fires,  trees,  wood  waste,  or  other  combustible  or  flammable  solid 
or  liquid  waste;  or  for  metal  salvage  or  burning  of  motor  vehicle 
bodies.   Open  fires  may  be  conducted  for  the  following  purposes: 

1.  Prevention  of  a  fire  hazard  which  cannot  be  abated  by 
any  other  means  on  permissive  burn-days. 

2.  The  instruction  of  public  and  industrial  employees  in 
methods  of  fighting  fire. 

3.  Backfires  necessary  to  save  life  or  valuable  property. 

4.  Disposal  of  solid  waste  from  single  or  two -family  dwell- 
ings on  its  premises  on  burn-days. 

5.  Cooking  and  recreational  fires. 

6.  Right-of-way  clearing  by  a  public  entity  or  utility  or 
for  levee,  reservoir,  and  ditch  maintenance  on  burn- 
days  . 

7.  For  disposal  of  Russian  thistle. 


446 


Agricultural  burning,  range  improvement  burning,  and 
forest  management  burning  require  a  permit  from  the  U.S.  Forest 
Service,  the  California  Division  of  Forestry,  or  a  County  Fire 
Protection  District.  Range  improvement  and  forest  management 
burning  may  be  conducted  on  no-burn  days  between  January  1  to  May 
31. 

The  APCO  in  Lake  County  and  the  North  Coast  Air  Basin 
may  authorize  by  permit  open  fires  for  the  purpose  of  disposing 
of  agricultural  wastes,  or  wood  waste  from  trees,  vines,  bushes, 
or  other  wood  debris  free  of  non-wood  materials  in  a  mechanized 
burner  such  that  no  air  contaminant  is  discharged  into  the  atmos- 
phere for  a  period  of  more  than  30  minutes  in  any  8  hour  period 
which  is  as  dark  or  darker  than  No.  1  on  the  Ringelmann  Chart,  as 
published  by  the  U.S.  Bureau  of  Mines. 

A  permissive  burn-day  is  any  day  on  which  a  designated 
person  or  agency  (i.e.,  California  Air  Resources  Board,  APCD) 
determines  that  certain  specified  burning  is  permitted.  The 
primary  criteria  for  determining  a  burn-day  are  meteorological 
conditions. 


447 


6.6 


GLOSSARY  OF  TERMS 


Air  Pol  1 ut  i  on 
Control  District 


Air  Quality 
Rel ated  Val ues 


Attainment  Areas 


Basel i  ne 
Concent  ration 


Best  Avai 1 abl e 
Control 
Technology  (BACT) 


Best  Ava  i 1 abl e 
Retrofit 
Technology  (BART) 

Burn  Day 


CI  ass 
Designation 


In  California,  the  county  regulatory  body 
responsible  for  the  administration  of  air 
pollution  regulations. 

Under  the  Prevention  of  Significant  Deteriora- 
tion Regulations  for  Class  I  areas,  the  effect 
of  potential  pollutant  emissions  on  such 
variables  of  soils,  vegetation  and,  most 
importantly,  visibility  must  be  reviewed. 

The  term  attainment  area  means  for  any  air 
pollutant  an  area  which  is  shown  by  monitored 
data  or  which  is  calculated  by  air  quality 
modeling  to  comply  with  any  National  Ambient 
Air  Quality  Standard  for  such  a  pollutant. 

The  ambient  concentration  level  reflecting 
actual  air  quality  as  of  August  7,  1977  minus 
any  contribution  from  major  stationary  sources 
and  major  modifications  on  which  construction 
commenced  on  or  after  January  6,  1975. 

An  emission  limitation  (including  a  visible 
emissions  standard)  based  on  the  maximum 
degree  of  reduction  for  each  pollutant  subject 
to  regulation  under  the  Act  which  would  be 
emitted  from  any  proposed  major  stationary 
source  or  major  modification  which  the  Admin- 
istrator, on  a  case  by  case  basis,  taking  into 
account  energy,  environmental  and  economic 
impacts  and  other  costs  determined  to  be 
achievable  for  such  source  or  modification 
through  application  of  production  processes  or 
available  methods,  systems  and  techniques 
including  fuel  cleaning  or  treatment  or  inno- 
vative fuel  combustion  techniques  for  control 
of  such  pollutant.  BACT  must  always  be  at 
least  as  stringent  as  the  Applicable  New 
Source  Performance  Standard. 

Same  as  Best  Available  Control  Technology  with 
specific  application  to  existing  sources. 


A  burn  day  is  any  day  on  which  a  designated 
person  or  agency  determines  that  certain 
specified  burning  is  allowed. 

The  designation  of  the  country  as  either  Class 
I,  II  or  III  under  the  rules  for  the  Preven- 
tion of  Significant  Deterioration.  Class  I 
areas  reflect  the  most  stringent  requirements 
while  Class  III  areas  are    the  most  lenient. 


"448' 


CI  ean 
(CAA) 


Air  Act 


CI ean  Air  Act 
Amendment  s 
of  1977 


The  body  of  air  quality  legislation  promul- 
gated 1955  in  with  Amendments  in  1963,  1965, 
1967,  1970,  and  1977,  and  codified  in 
42USC740/et  seq.,  which  are  designed  to  regu- 
late the  nations  air  quality  for  the  purpose 
of  protecting  human  health  and  welfare. 

They  represent  the  latest  in  a  series  of 
expanding  regulatory  requirements  designed  to 
protect  the  air  quality  resource  in  the  United 
States.  The  Amendments  of  1977  ( PL  95-1 90 ) 
introduced  key  concepts  including  the  Preven- 
tion of  Significant  Deterioration,  the  use  of 
Best  Available  Control  Technology  and  the 
protection  of  ambient  visibility  levels. 


Criteria 
Pol  1 ut  ants 


Designated 
Agency 

Federal  Land 
Manager 


That  group  of  pollutants  for  which  National 
Ambient  Air  Quality  Standards  have  been  prom- 
ulgated based  upon  an  analysis  of  the  effects 
of  such  pollutants  upon  human  health  and 
welfare.  Currently,  S02,  NO  ,  CO,  HC ,  TSP, 
lead  and  photochemical  oxidaifts  are  criteria 
pol 1 ut ant s  . 

The  governmental  agency  with  final  authority 
relative  to  air  quality  regulations. 

Federal  Land  Manager  means  with  respect  to  any 
lands  in  the  United  States,  the  Secretary  of 
the  Department  with  authority  over  such  lands. 


I ncrements 


The  maximum  allowable  increase  in  a  specific 
pollutant  concentration  over  and  above  exis- 
ting "baseline  concentrations"  as  specified  in 
Section  163  of  the  CAA  or  as  limited  by  the 
difference  between  Air  Quality  Standards  and 
baseline  concentrations  for  that  pollutant. 


I nd  i  an 
Governing  Body 


Lowest  Achievable 
Emi  ss  i  on  Rate 
(LAER) 


The  term  means  the  governing  body  of  any 
tribe,  band  or  group  of  Indians  subject  to  the 
jurisdiction  of  the  United  States  and  recog- 
nized by  the  United  States  as  possessing  power 
of  self  government . 

The  emission  control  technology  applicable  to 
source  located  in  a  nonattainment  area  is 
established  based  upon  the  term  Lowest  Achiev- 
able Emission  Rate.  This  term  means  that 
level  of  emissions  which  reflects  the  most 
stringent  emission  limitation  that  is  con- 
tained in  the  Implementation  Plan  of  any  state 
or  the  most  stringent  emission  limitation 
which  is  achieved  in  practice  on  such  class  or 
category  of  source  which  ever  is  more  stringent. 


449 


Mandatory  CI  ass 
I  Area 


Mod  i  f i  cat i on 


Nat  i  onal  Ambi  ent 
Air  Quality 
Standards  (NAAQS) 


National 

Emissions  Stand- 
ards for 
Ha  zardous  Ai  r 
Pol  1 utants 
(NESHAPS) 


New  Source 


New  Source 
Performance 
Standards  (NSPS) 


New  Source 
Review 


The  term  means  Federal  areas  which  may  not  be 
designated  as  other  than  Class  I  areas  under 
the  Clean  Air  Act  Amendments  of  1977.  These 
areas  are  specified  in  Section  162(a)  of  the 
Act . 

Any  physical  change  in  the  method  of  operation 
or  an  addition  to  a  stationary  source,  which 
increases  the  potential  emission  rate  of  any 
pollutant  regulated  under  the  Act  by  either 
100  tons/year  or  more  for  any  source  category 
identified  by  the  New  Source  Performance 
Standards  or  by  250  tons/year  or  more  for  any 
stat  i  onary  source . 

The  Clean  Air  Act  Amendments  of  1970  required 
that  specific  pollutant  concentration  levels 
be  identified  for  the  protection  of  human 
health  (i.e.,  Primary  Standard)  and  welfare 
(i.e.,  Secondary  Standards)  for  each  of  the 
criteria  pollutants.  These  specific  pollutant 
levels  comprise  the  National  Ambient  Air 
Qual i  ty  Standa  rds . 

Standards  promulgated  for  air  pollutants  for 
which  no  ambient  air  quality  standard  is 
applicable  and  which  in  the  judgement  of  the 
Administrator  cause  or  contribute  to  air 
pollution  which  may  reasonably  be  anticipated 
to  result  in  an  increase  in  mortality  or  an 
increase  in  serious  irreversible  or  incapaci- 
tating reversible  illness. 

Any  new  structure,  building,  facility,  equip- 
ment, installation  or  opera i ton  which  is 
located  on  one  or  more  continuous  or  adjacent 
properties  and  which  is  owned  or  operated  by 
the  same  person. 

National  Standards  promulgated  by  the  USEPA 
which  set  emissions  limitations  for  standards 
of  performance  for  each  of  28  separate  cate- 
gories of  stationary  sources. 

No  major  emitting  facility  on  which  construc- 
tion is  commenced  after  the  date  of  the  enact- 
ment of  the  Clean  Air  Act  Amendments  of  1977 
may  be  constructed  in  any  area  unless  the 
formal  permit  application  process^  has  been 
completed  in  accordance  with  regulations 
required  by  Section  165  of  the  Clean  Air  Act 
Amendments  of  1977. 


450 


No  Burn  Day 


Nonattainment 
Areas 


A  no  burn  day  is  any  day  on  which  a  designated 
person  or  agency  determines  that  certain 
specified  burning  is  not  permitted. 

The  term  nonattainment  area  means,  for  any  air 
pollutant,  an  area  which  is  showed  by  moni- 
tored data  or,  which  is  calculated  by  air 
quality  modeling,  to  exceed  any  National 
Ambient  Air  Quality  Standard  for  such  pollut- 
ant . 


Offsets 


Soruces  locating  in  nonattainment  areas,  must 
obtain  emission  reductions  form  other  existing 
sources  in  the  region  that  more  than  offset 
the  increase  in  emissions  from  the  new  source. 
Such  offsets  must  produce  a  positive  net  air 
quality  benefit  resulting  in  reasonable  fur- 
ther progress  toward  attainment  of  the  appli- 
cable standard . 


Perm  it 
Mora  tori  urn 


Potential 
Emissions 


Pre-Construction 
Review 


The  cessation  of  the  air  quality  permitting 
process  pending  the  resolultion  of  mandatory 
regulatory  activity. 

Potential  Emissions  refer  to  the  maximum 
emission  of  pollutants  in  the  absence  of  air 
pollutant  control  equipment. 

No  major  emitting  facility  on  which  construc- 
tion is  commenced  after  the  date  of  the  enact- 
ment of  the  Clean  Air  Act  Amendments  of  1977 
may  be  constructed  in  any  area  unless  the 
formal  permit  application  process  has  been 
completed  in  accordance  with  regulations 
required  by  Section  165  of  the  Clean  Air  Act 
Amendments  of  1977. 


Prevent  ion  of 
Si  gn  i  f i  cant 
Deterioration 


Pri  mary 
Standards 


Reasonably 
Available  Control 
Technology  (RACT) 


Specific  requirements  contained  in  the  Clean 
Air  Act  Amendments  of  1977  (i.e.  Part  C, 
Sections  160  through  169)  designed  to  protect 
the  air  quality  resource  in  regions  of  the 
country  where  present  baseline  pollutant 
levels  are  below  the  National  Ambient  Air 
Qual i ty  Standard  s  . 

Standards  promulgated  as  part  of  the  National 
Ambient  Air  Quality  Standards  which  set  pollu- 
tant levels  which  provide  an  adequate  margin 
of  safety  for  public  health. 

The  least  stringent  in  the  control  technology 
heirarchy  applicable  to  existing  sources  which 
require  a  level  of  control  necessary  to  insure 
compliance  with  existing  emissions  regula- 
tions. 


451 


Retrofitting 


Secondary 
Standards 


The  installation  of  additional  control  tech- 
nology on  existing  sources  of  air  pollutants. 

Standards  promulgated  as  part  of  the  National 
Ambient  Air  Quality  Standards  which  specify 
levels  which  protect  the  human  welfare  from 
known  or  anticipated  adverse  effects  associ- 
ated with  a  pollutants  presence  in  the  ambient 
air. 


State 

Impl ementat  i  on 

Plan  (SIP) 


The  concept  of  State  Implementation  Plans  was 
introduced  in  the  1970  Clean  Air  Act  Amend- 
ments. There  purpose  is  to  insure  that  the 
NAAQS  are  met  in  all  areas  of  the  country  and 
require  a  transportation  control  plan,  emis- 
sions limits  for  specific  categories  for 
sources  and  permit  rules  for  new  or  modified 
sources  of  pollutants. 


45; 


BIBLIOGRAPHY 


Bay  Area  Air  Pollution  Control  District,  Air  Pollution  and  the 
San  Francisco  Bay  Area,  Eleventh  Edition  ,  San  Francisco, 
California,  June  1977,  pp.  51. 

Bay  Area  Air  Pollution  Control  District,  Regulation  1  (January, 
1978;  Regulation  2  (June,  1977);  Regulation  3  (November, 
1977);  Regulation  5  (April  20,  1977);  Regulation  7  (December, 
1975);  Regulation  8  (December  1976),  San  Francisco,  Cali- 
f orni  a  . 

Lake  County  Air  Pollution  Control  District,  Rules  and  Regula- 
tions, Lakeport,  California,  April  3,  1978. 


North  Coast  Air  Basin,  Air  Pollution  Control  Plan  and  Regulations 
3  and  4,  May  13,  1976,  and  October  15,  1977. 

Yolo-Solano  Air  Pollution  Control  District,  Rules  and  Regula- 
tions, Woodland,  California,  September  28,  1977. 

Ninety-Fifth  Congress,  "Clean  Air  Act  Amendments  of  1977"  (Public 
Law  95-95;  91  STAT.  685),  August  7,  1977. 

The  Clean  Air  Act  (42  U.S.C.  1857  et  seq.) 

Easton,  E.B.  and  F.J.  O'Donnel,  "The  Clear  Air  Act  Amendments  of 
1977."  Journal  of  Air  PollutionControl  Association,  Vol. 
27,  No.  10,  October  1977,  p.  943-947. 

Goldsmith,  B.J.  and  R.J.  Mahoney,  "Implications  of  the  1977  Clean 
Air  Act  Amendments  for  Stationary  Sources",  Environmental 
Science  and  Technol ogy ,  Vol.  12,  No.  2,  Feb.  1976,  p.  144- 
149. 

High,  M.D.  "Status  Report  on  Federal  Regulations  For  New  Source 
Performance  Standards".  Journal  of  Air  Pollution  Control 
Association,  Vol.  26,  No.  5,  May  1976,  p.  471--479. 

Stern,  A.C.  "Prevention  of  Significant  Deterioration  -  A  Criti- 
cal Review",  Journal  of  Air  Pollution  Control  Association, 
Vol.  27,  No.  5,  May  1977,  p.  440-453. 


453 


7.  1 


7.   MONITORING  RECOMMENDATIONS 
GENERAL  REQUIREMENTS 


Possible  alternatives  for  future  land  development  of  BLM 
lands  within  the  Ukiah  District  may  require  the  preparation  of 
extensive  environmental  research  reports  and  impact  analyses.  In 
light  of  this  fact,  it  is  important  to  isolate  areas  currently 
under  BLM  administration  that  lack  substantial  onsite  data  nec- 
essary for  the  preparation  of  air  quality  and  meteorological 
analyses.  Additionally,  areas  within  the  Ukiah  District  that 
require  enhancement  of  the  current  existing  data  base  must  be 
identified  so  that  transport  and  diffusion  analyses  can  be  accu- 
rately performed. 

The  ultimate  objective  is  to  be  able  to  define  air 
transport  and  dispersion  characteristics  and  associated  baseline 
ambient  air  quality  levels  within  the  Ukiah  District.  An  accu- 
rate and  current  data  base  provides  the  means  to  achieve  this 
objective  and  enhances  credibility  of  regional  environmental 
impact  statements.  It  is  of  vital  importance  to  all  organiza- 
tions concerned  with  future  land  development  within  the  Ukiah 
District,  that  the  most  accurate  and  complete  environmental 
impact  statements  be  developed. 

A  review  of  the  previous  sections  describing  regional 
air  quality,  dispersion  meteorology  and  baseline  climatology  for 
the  Ukiah  District  indicates  that  certain  areas  lack  the  satis- 
factory historical  data  base  necessary  to  provide  a  definitive 
characterization  of  these  topical  items  which  are  essential  in 
environmental  analyses.  Climatological  data  are  generally  ade- 
quate for  all  portions  of  the  Ukiah  District.  Ambient  air  quali- 
ty data  are  readily  available  for  most  areas  of  the  district 
where  there  exist  substantial  population  centers.  These  cities 
and  communities  are  well  distributed  along  the  Pacific  Coast. 
Detailed  dispersion  meteorological  data  are  available  at  a  few 
select  locations  throughout  the  district  and  represent  the  least 
resolved  data  base  of  all  the  major  air  quality  components.  Data 
are  available  to  provide  an  assessment  of  regional  dispersion  for 
most  of  the  Ukiah  District;  however,  the  extent  of  the  current 
data  base  available  for  site- specific  dispersion  analyses  on 
lands  under  BLM  administration  is  generally  not  satisfactory. 

Lands  within  the  Ukiah  District  currently  under  BLM 
jurisdiction  entail  three  basic  geographical  areas.  As  depicted 
in  Figure  7.1-1,  a  majority  of  the  BLM  lands  in  the  Ukiah  Dis- 
trict are  located  in  the  mountainous  areas.  A  small  portion  of 
the  BLM  lands  are  located  along  the  coast. 

Alternative  future  land  uses  for  these  areas  may  include 
construction  or  expansion  of  energy  related  facilities,  other 
commerical  industrialization,  recreation,  agriculture,  forestry 
and  many  others.   The  development  of  BLM  administered  lands  for 


454 


Coastal 

Coastal  Mountains-Northern  Area 

Coastal  Mountains-Southern  Area 


Figure  7.1-1 
Categories  of  BLM  Lands  in  the  Ukiah  District 


455 


these  alternatives  may  require  extensive  and  elaborate  environ- 
mental impact  assessments  including  air  quality,  dispersion 
meteorology  and  climatology.  The  most  accurate  environmental 
impact  assessment  is  derived  from  a  highly  detailed  site-specific 
data  base.  Hence,  the  adequacy  of  the  air  quality  data  base  for 
specific  areas  of  concern  must  be  identified. 

The  Clean  Air  Act  Amendments  of  1977  required  continuous 
monitoring  data  after  August  7,  1978  in  support  of  permit  appli- 
cations for  new  major  sources  of  air  contaminants.  The  monitor- 
ing is  required  for  a  period  of  one  year  unless  (1)  the  analysis 
could  be  accomplished  sati  sfactori 1y  in  a  shorter  period  or  (2) 
available  offsite  data  exists  which  satisfactorily  describes 
onsite  conditions. 


As  discussed  in  Section  6,  the  need  for  monitoring  in 
support  of  Prevention  of  Significant  Deterioration  (PSD)  permit 
applications  is  based  upon  a  potential  to  emit  100  tons  or  more 
per  year  of  any  pollutant  regulated  under  the  Clean  Air  Act  for 
one  of  28  major  emitting  facilities  identified  by  the  Act. 
other  classes  of  industry,  monitoring  requirements  are  based 
potential  emission  rate  of  250  tons  per  year.  Monitoring  is 
required  for  TSP  (total  suspended  particulates),  S0?,  CO,  0o 


any 

For 

on  a 

then 

and 

the 


NO 


unless  it  can  be  established 


emission  requirement  for 


that  a  source  will  exceed 
only  one  pollutant,  then  only  that 
pollutant  need  be  monitored.  Meteorological  monitoring  in  sup- 
port of  the  program  must  include  (1)  hourly  average  wind  speed 
and  direction,  (2)  hourly  averaged  atmospheric  stability,  (3) 
hourly  surface  temperature,  and  (4)  hourly  precipitation  amounts. 
Monitoring  at  multiple  sites  for  both  air  quality  and  meteorology 
is  usually  required  in  areas  of  rugged  terrain.  In  most  cases, 
monitoring  will  be  required  for  a  period  of  one  year.  This  may 
be  shortened,  however,  if  the  EPA  agrees  that  worst  case  condi- 
tions will  be  established  during  a  reduced  time  period.  In  the 
case  that  baseline  conditions  have  been  adequately  established, 
this  monitoring  requirement  may  be  waived.  Further  guidance 
relative  to  monitoring  requirements  is  contained  in  the  EPA 
Guideline  Series  OAQPS  No  1.2-096,  "Ambient  Monitoring  Guidelines 
for  Prevention  of  Significant  Deterioration  (PSD)." 


456 


7.2 


INSTRUMENTATION 


This  section  provides  a  brief  review  of  instrumentation 
that  is  commonly  used  to  monitor  the  various  air  quality  and 


meteorological  parameters.  A 
the  management  and  operation 
provided . 


summary  of  costs  associated  with 
of  monitoring   programs   is   also 


7.2.1 


General  Requirements 


The  purchase  of  an  instrument 
of  two  classes  of  requirements: 

1.  General  Instrumentation 

2.  Specific  Objectives 


requires  the  consideration 


There  are  many  instrumentation  requirements  that  will  obviously 
depend  on  the  specific  objectives  of  the  study  for  which  the 
instrument  is  needed.  There  are,  however,  a  number  of  instrument 
requirements  that  should  be  considered  before  the  purchase  of  any 
instrument.  The  purpose  of  this  section  is  to  describe  these 
general  requirements  so  that  a  buyer  will  be  able  to  distinguish 
between  the  instrumentation  attributes  that  are  important,  and 
those  that  are  only  "window  dressing".  The  EPA  may  be  contacted 
for  futher  guidance  on  instrumentation  and  methods  of  procedure. 

Re! i a  b  i 1 i  t  y 

Reliability  is  possibly  the  most  important  criterion  for 
an  instrument  in  continous  use.  Regardless  of  how  accurately  an 
instrument  is  calibrated  and  read,  it  must  be  reliable  to  give 
reproducible  results. 

Quality  Control 

Quality  control  are  those  activities  performed  to  insure 
that  equipment  is  maintained  and  calibrated  within  specifica- 
tions. 

Quality  Assurance 

Quality  assurance  is  the  method  which  verifies  that 
quality  control  activities  are  performed,  e.g.,  adherence  to 
schedule,  documentation,  double  checks,  etc. 

Accuracy 

Accuracy  is  defined  as  the  closeness  of  the  instrument 
output  reading  to  the  true  value  of  the  parameter.  The  qualifi- 
cations of  an  accurate  instrument  are    as  follows: 

1.  It  is  properly  calibrated  under  known  conditions 

2.  It  has  characteristics  that  are    unchanging  with  time 


457 


3.  The  reactions  of  the  instrument  (dynamic  response)  to 
changes  in  the  measured  parameter  are  known  to  within 
the  limits  of  error  requirements. 

Precision 

Precision  is  generally  defined  as  the  degree  of  close- 
ness of  a  series  of  readings  of  an  unchanging  parameter.  There 
often  is  confusion  between  the  terms  accuracy  and  precision.  One 
way  of  clarifying  their  meanings  is  through  the  use  of  the  "bulls 
eye"  analogy.   Figure  7.2-1  depicts  this  analogy. 

Sens  i  t  i  v  i  ty 

Sensitivity  is  defined  as  the  smallest  change  in  the 
measured  variable  that  causes  a  detectable  change  in  the  output 
of  the  instrument. 

Simp! i  c  i  ty 

The  lack  of  instrumentation  experience  among  most  obser- 
vers makes  this  attribute  a  must  for  most  meteorological  and  air 
quality  instrumentation.  The  qualifications  of  a  simple  instru- 
ment are    as  f ol 1 ows : 


1. 


Operational 
simpl e 


adjustments   of  the   instrument   should   be 


2. 


A  simply  written  Standard  Operating  Procedures   (SOP) 
manual  should  accompany  the  instrument 


Adjustments  that  are  not 
purchaser  should  require  a 


intended  to  be 
special  tool. 


made  by  the 


Durabi 1 i  ty 


Obviously,  an  instrument  should  be  durable  enough  to 
survive  vibrations  and  shock  encountered  in  transportation,  rough 

handling,  etc.   A  meteorological  or  air  quality  instrument,  in 

addition,  should  be  able  to  perform  reliably  in  all  seasons  of 
the  year ,  and  in  a  smoggy  and  corrosive  atmosphere. 

Conveni  ence 

Convenience  of  operation  is  definitely  a  must  for  an 

operational  instrument.   As  a  general  rule,  an  instrument  that  is 
simple  to  operate  is  also  convenient  to  operate. 


Other  requirements  such  as 
ratio,  etc.  are  objective  oriented, 
1 ater  sect  i  on  . 


time  constants,  damping 
and  will   be  covered  in  a 


458 


Neither  accurate 
nor  precise 


Accurate  but 
not  precise 


Precise  but 
not  accurate 


BOTH  accurate 
and  precise 


Figure  7.2-1 
The  Relationship  Between 
Instrument  Accuracy  and  Precision 


459 


7.2.2 


Meteorological  Instruments 


Measurement  of  atmospheric  variables  that  affect  the 
diffusion  and  transport  of  air  pollutants  is  a  necessity  in 
nearly  every  air  pollution  investigation.  Suitable  measurements 
may  be  available  from  existing  instrumentation  at  Weather  Service 
city  offices,  airport  stations,  or  from  universities  or  indus- 
tries with  meteorological  installations.  Frequently,  however, 
existing  instrumentation  does  not  give  detailed  enough  measure- 
ments, is  not  representative  of  the  area  in  question,  or  does  not 
measure  the  variables  desired  (such  as  turbulence)  and  additional 
instruments  must  be  operated. 

Of  primary  importance  in  air  pollution  meteorology  is 
the  measurement  of  wind,  including  both  velocity  (direction  and 
speed)  and  the  turbulence.  The  stability  of  the  lower  layers  of 
the  atmosphere  in  which  the  pollution  diffuses  is  important  and 
may  be  determined  from  an  analysis  of  the  turbulence  character- 
istics of  the  atmosphere  or  the  temperature  lapse  rate. 

Of  secondary  importance  is  the  measurement  of  humidity 
(which  may  affect  atmospheric  reactions),  temperature,  precipi- 
tation (of  importance  in  washout  of  pollutants),  and  solar  radi- 
ation (which  affects  photochemical  reactions  in  the  atmosphere). 
Particularly  for  research  studies,  it  may  also  be  desirable  to 
measure  meteorological  elements  affected  by  pollutants,  such  as 
visibility,  solar  radiation,  and  illumination  (radiation  in  the 
visible  range). 


Wind  Measurements 


Surface  Instrumentation 


t    Wind  Speed 

Generally,  wind  speed  sensors  are  broken  down  into  the 
following  categories: 

a.  Rotational  Anemometers 

1)  Vertical  Shaft 

2)  Horizontal  Shaft 

b.  Pressure  Anemometers 

1)  Flat  Plate  Type  Anemometer 

2)  Tube  Type  Anemometer 

c.  Bridled  Cup  Anemometer 

d.  Special  Types 

1)    Hot  Wire  Anemometer 

2  )    Sonic  Anemometer 

3  )    B  i  v  a  n  e 

4)         Vert i cal /Hori zontal     (UVW)    Anemometer 


460 


Pressure  anemometers,  hot  wire  and  sonic  anemometers 
have  enjoyed  extensive  use  in  research  type  operations,  but  they 
all  have  disadvantages  which  have  prohibited  their  use  in  opera- 
tional type  situations,  such  as  air  pollution  surveys.  The 
rotational  type  anemometers  are  the  most  common  type  of  wind 
speed  sensor  in  use  today  mainly  because  they  are  the  only  types 
that  satisfy  all  of  the  following  desirable  operational  features: 

a.  Essentially  linear  relationship  between  the  sensor 
output  and  the  wind  speed; 

b.  Calibration  unaffected  by  changes  in  atmospheric  temper- 
ature, pressure  or  humidity; 

c.  Able  to  measure  a  wide  range  of  wind  speeds  (<2  to  200 
mph  [.9  to   90  m/s]) . 

d.  Long  term  calibration  stability,  or  calibrations  that 
remain  unchanged  after  10  years  continuous  operation; 

e.  Output  of  the  sensor  easily  adapted  to  remote   indi- 
cation; 

f.  Recording  of  the  wind  speed  data  easily  adaptable  to 
either  analog  or  digital  form;  and 

g.  Generally  an  extremely  small  maintenance  requirement. 
Figure   7.2-2   provides   a   visual   review  of   routinely 

available  anemometers. 

•     Wind  Direction 

Wind  direction  sensors  are  visually  presented  in  Figure 
7.2-3  (a-p).  They  include;  (1)  flat  plate  vanes  (a,  b, 
c,  d,  g,  i,  k,  1),  (2)  splayed  vanes  (e,  f,  h,  p)  and 
(3)  aerodynamic  shaped  vanes  (j,  m,  n,  o) . 


The  splayed  vane  of  Figure  7.2-3  has,  mainly  because  of 
its  durability  and  reliability,  found  widespread  use  in 


its  role  as  the  main  wind 
National  Weather  Service.   It 
direction  data  obtained  from 
vice  should  be  used  only  as 
wind  direction. 


direction  sensor  for  the 
should  be  noted  that  wind 

the  National  Weather  Ser- 
an  indication  of  average 


A  bi-directional  vane  is  designed  to  rotate  around  a 
vertical  axis  to  measure  the  azimuth  angle  of  the  wind, 
as  does  a  conventional  wind  vane.  It  also  can  move  in 
the  vertical  to  measure  the  elevation  angle  of  the  wind. 
Because  the  vertical  motions  of  the  atmos-phere  are 
frequently  of  a  different  character  than  the  horizontal 
motions  (anisotropic  turbulence),  measurement  of  both 
the  horizontal  and  vertical  motions  are  desirable.  This 
is  particularly  true  under  stable  conditions  when  the 


461 


p      «L 

|s^#i 

ft    •—        4 

^K.                          * 

JT    .               JN;X-    ,,j 

"■4 

■SteHto^^^ 

J^^^^^^j^^^ 

pi—a.nw     - 


Climet  Inst.  Co.   (a) 


R.M.   Young  Co.    (b] 


Belfort  Inst.   Co.   (c! 


Henry  J.  Green  Co.   (d)  Electric  Speed  Indicator  Co.   (e)       Science  Associates  Inc.   (f) 


Teledyne-Geotech  (Bkmn  &  Whtly)   (g) 


Teledyne-Geotech  (Bkmn  &  Whtly)  (h) 


Figure  7.2-2 
Cup  Anemometers 


462 


Climet  Inst.  Co.  (a) 


R.H.  Young  Co.  (b) 


Belfort  Inst.  Co.  (c) 


t    !    A 


Science  Associates  Inc.   (g)  Epic  Co.   (h) 


Epic  Co.    (i) 


e 


Bendix  Co.    (m) 


Belfort  Inst.  Co.   (n) 


Teledyne-Geotech  (1) 


Figure  7.2-3 
Wind  Vanes 


463 


L 


Wong  Lab.  (d) 


Electric  Speed  Indicator  Co.  (e)   Science  Associates  Inc.  (f) 


S' 


& 


(1 


Teledyne-Geotech  (j) 


Teledyne-Geotech  (k) 


■  .  ».  £2&i    B  i 


Raim  Inst.  Co.   (o) 


■«»».»  r  ■^.•~-  r  *» 


rVi«rfrni«i  ufcww   iHtUi'  i    ij>» 


Epic  Co.  (p) 


Figure  7.2-3  (Cont.) 
Wind  Vanes 


464 


vertical  motion  is  almost  absent,  but  horizontal  changes 
in  wind  direction  may  be  appreciable.  Micro-potentio- 
meters are  usually  used  to  produce  an  analog  record  of 
both  angles.  The  total  wind  speed  can  be  measured  by 
replacing  the  counterweight  with  a  propeller  anemometer. 
Figure  7.2-4  shows  two  typical  anemometer  bivanes. 

Wind  Measurements  -  Airborne  (Winds  Aloft) 

Fixed  location  wind  velocity  sensors  measure  the  wind  at 
a  fixed  height  as  it  varies  with  time.  Most  airborne  sensors  are 
used  to  average  wind  velocity  through  a  given  depth  of  the  atmos- 
phere at  a  particular  time. 

•    Pilot  Balloon  (pibal) 

This  method  of  measuring  wind  velocity  uses  a  gas-filled 
free  balloon  (Figure  7.2-5)  which  is  tracked  visually 
through  a  theodolite.  The  theodolite  is  an  optical 
system  used  to  measure  the  azimuth  and  elevation  angle 
of  the  bal 1 oon . 
a.    Single  Theodolite  Pibal  s 

When  only  one  theodolite  is  used,  the  balloon  is 
inflated  to  have  a  given  amount  of  free  lift.  The 
elevation  and  azimuth  angles  are  used  with  the 
assumed  ascent  rate  to  compute  wind  directions  and 
speeds  aloft.  A  theodolite  is  shown  in  Figure 
7.2-6. 


b. 


Double  Theodolite  Pibals 


By  this  method,  the  ascent  rate  of  the  balloon  is 
not  assumed,  but  calculated  from  the  elevation  and 
azimuth  angles  of  the  two  theodolite  observations 
taken  simultaneously.  The  two  theodolites  are  set 
a  known  distance  apart  (the  baseline).  Two  types 
of  pilot  balloons  frequently  used  reach  3000  ft. 
within  5  minutes  and  8  minutes,  respectively,  after 
release.  If  detailed  structure  of  winds  with 
height  is  to  be  determined,  readings  of  azimuth  and 
elevation  angle  must  be  read  every  15  or  30  sec- 
onds . 

Rawi  nsonde 

This  method  of  measuring  wind  velocity  aloft  also  uses  a 
gas-filled  free  balloon,  but  it  is  tracked  either  by 
radio  direction  finding  apparatus,  or  by  radar.  The 
former  method  is  that  most  frequently  used  in  the  U.S. 
The  radio  transmitter  carried  by  the  free  balloon  is 
usually  used  to  transmit  pressure,  temperature  and 
humidity  information  to  the  ground  (radiosonde).    The 


465 


"  'ii  iii  ram  a. 


Figure  7,2-4  Anemometer  Bi vanes 


Figure  7.2-5  Meteorological  Balloons  (L  to 
R  -  Tetroon,  Pilot  Balloon, 
Kytoon) 


Figure  7.2-6  Theodolite 


466 


radio  direction  finding  equipment  determines  the  eleva- 
tion angles  and  azimuth  angles  of  the  transmitter.  The 
height  is  determined  by  evaluation  of  the  temperature 
pressure  sounding.  Using  radar,  the  slant  range  is 
available  for  determining  height.  Soundings  taken  with 
this  type  of  equipment  are  made  on  a  routine  basis  for 
supporting  forecasting  and  aviation  activities.  The 
ascent  rate  of  these  balloons  is  on  the  order  of  1000 
feet/minute,  so  they  do  not  yield  as  much  detailed 
information  on  winds  in  the  lowest  part  of  the  atmos- 
phere as  is  desired  for  many  air  pollution  meteorolo- 
gical purposes. 

•  Rocket  Smoke  Plumes 

A  system  using  a  cold  propellant,  recoverable  rocket  to 
emit  a  vertical  smoke  trail  to  an  altitude  of  1200  feet 
has  been  developed.  This  smoke  trail  is  photographed 
simultaneously  at  short  time  intervals  by  two  cameras 
2000  feet  from  the  launch  site,  at  right  angles  to  each 
other.  The  difference  in  position  of  the  smoke  trail 
from  two  successive  photographs  is  a  measure  of  one 
component  (north-south  for  example)  of  the  wind  and  can 
be  determined  at  any  number  of  heights  from  ground  level 
to  1200  feet.  Another  similar  system  has  been  reported 
by  Cooke  (1962). 

•  Constant  Level  Balloons 

Unlike  the  previous  airborne  sensors  for  wind  velocity 
which  obtain  average  measurements  through  a  vertical 
layer,  constant  level  balloons  are  used  to  determine  the 
trajectory  or  path  of  an  air  parcel  during  a  given  time 
interval.  In  order  to  maintain  a  constant  altitude 
(more  accurately  to  fly  along  a  constant  air  density 
surface)  the  balloon  must  maintain  a  constant  volume.  A 
tetrahedron  shaped  balloon  (tetroon)  of  mylar  has  been 
used  for  this  purpose  (Figure  7.2-5).  These  have  been 
tracked  visually  and  by  radar    (Angell  and  Pack,  1960). 

Temperature  Lapse  Rate 

The  vertical  structure  of  temperature  gives  an  indica- 
tion of  the  stability  and  turbulence  of  the  atmosphere. 

•  Temperature  Difference  Measurements 

One  method  of  estimating  the  vertical  structure  of 
temperature  is  by  measuring  the  difference  in  tempera- 
ture between  sensors  mounted  at  different  heights. 
This,  of  course,  gives  an  average  condition  between  any 
two  particular  sensors. 


467 


Balloon-borne  Sensors 

Temperature  sensors  may  be  lifted  by  either  free  or 
captive  balloons.  By  these  methods,  temperature,  not 
temperature  difference,  is  measured. 


1. 


Radiosonde 


The  method  of  radiosonde  ( rad i o- sound i ng s )  observa- 
tions is  used  routinely  for  temperature,  pressure 
and  humidity  soundings  of  the  upper  air.  A  free 
balloon  carries  the  sensors  and  a  radio  transmitter 
aloft.  Cycling  from  sensor  to  sensor  is  accom- 
plished by  means  of  an  aneroid  barometer,  and 
consequently,  is  a  function  of  pressure.  Observa- 
tions are  normally  made  twice  daily  at  0000  GMT  and 
1200  GMT  at  approximately  70  stations  in  the  con- 
tiguous U.S.  The  ascent  rate  of  the  balloon  is 
about  1000  ft/minute.  Generally  only  4  to  6  temp- 
erature readings  are  recorded  within  the  lower  3000 
feet,  so  the  vertical  temperature  information  is 
not  too  detailed,  but  it  is  still  of  considerable 
use  when  more  detailed  information  is  not  avail- 
able. 

T-Sonde 

This  system  consists  of  a  temperature  sensor  and 
radio  transmitter  which  is  carried  aloft  by  a  free 
rising  balloon.  The  main  difference  between  this 
system  and  the  radiosonde  system  is  that  only 
temperature  is  measured.  Ten  to  twelve  measure- 
ments are  taken  within  the  lower  3000  feet  of  the 
atmosphere,  thus  giving  a  more  detailed  structure 
of  temperature  with  height. 

Tethered  Kite  Balloon 

Using  a  captive  balloon  system  to  make  vertical 
temperature  measurements  has  the  advantages  of  both 
a  complete  recovery  of  all  components  of  the  sys- 
tem, and  as  detailed  a  temperature  sounding  as  is 
be  made  by  controlling  the  level  of  the 
balloon  having  fins  is  much  easier  to 
gives  greater  lift  in  slight  winds  than 
balloon  (see  Figure  7.2-5).  Most  kite 
be  used  in  winds  less  than  15  knots 


des  i  red  may 
sensor.  A 
control  and 
a  spheri  cal 
bal 1 oons  can 


and  for  air  pollution  meteorology  purposes,  these 
light  wind  periods  are  of  greatest  interest. 
Because  of  hazards  to  aircraft,  prior  permission 
from  the  FAA  is  required  for  flights  exceeding  500 
feet  above  ground  and  several  methods  of  relaying 
the  observation  to  the  ground  have  been  used. 


468 


•  Aircraft  Borne  Sensors 

In  some  cases,  light  aircraft  or  helicopters  have  been 
used  for  obtaining  temperature  lapse  rate  measurements. 
Although  there  are  complete  systems  commercially  avail- 
able for  this  metod  of  temperature  lapse  rate  measure- 
ment, one  can  use  standard  temperature  sensors  (therm- 
isters,  resistence  thermometers,  etc.)  and  recorders,  as 
long  as  exposure  guidelines  are    followed. 

Precipitation 

Because  large  particles  and  water  soluble  gases  may  be 
removed  from  the  atmosphere  by  falling  precipitation,  measure- 
ments of  this  element  may  be  needed.  Chemical  or  radioactive 
analysis  of  rainwater  may  also  be  desired. 

•  Standard  Rain  Gauge 

The  standard  rain  gauge  consists  of  a  metal  funnel  8 
inches  in  diameter,  a  measuring  tube  having  1/10  the 
cross-  sect  i  onal  area  of  the  funnel,  and  a  large  con- 
tainer 8  inches  in  diameter  (Figure  7.2-7).  Normally, 
precipitation  is  tunneled  into  the  measuring  tube  and 
the  depth  of  water  in  the  tube  is  measured  using  a  dip 
stick  having  a  special  scale  (because  of  the  reduction 
in  area).  Measurements  with  this  instrument,  because 
they  are  made  manually,  yield  only  accumulated  amount 
since  the  last  measurement. 

H  umi  d  i ty 

Because  of  its  influence  upon  certain  chemical  reactions 
in  the  atmosphere  and  its  influence  upon  visibility,  it  may  be 
desirable  to  measure  humidity  in  connection  with  an  air  pollution 
investigation.  Also,  some  air  pollutants  affect  receptors  dif- 
ferently with  different  humidities,  so  measurement  may  be  im- 
portant in  this  respect. 

•  Hy grot hermograph 

This  instrument  measures  both  temperature  and  humidity 
by  activating  pen  arms  to  give  a  continuous  record  of 
each  element  on  a  strip  chart.  The  chart  generally  can 
be  used  for  7  days.  The  humidity  sensor  generally  uses 
human  hairs  which  lengthen  as  relative  humidity  in- 
creases and  shorten  with  humidity  decreases.  Tempera- 
ture measurements  are  usually  made  with  a  bourdon  tube 
which  is  a  curved  metal  tube  containing  an  organic 
liquid.  The  system  changes  curvature  with  .changes  in 
temperature,  activating  the  pen  arm.  A  hygrot hermograph 
is  shown  in  Figure  7.2-8. 


469 


Figure  7.2-9 
"Black  and  White"  Pvranometer 


470 


•  Psychrometers 

Humidity  measurement  by  a  psychrometer  involves  obtain- 
ing a  dry  bulb  temperature  and  a  wet  bulb  temperature 
from  a  matched  set  of  thermometers.  One  thermometer 
bulb  (wet  bulb)  is  covered  with  a  muslin  wick  moistened 
with  distilled  water.  There  must  be  enough  air  motion 
to  cause  cooling  of  the  wet  bulb  due  to  evaporation  of 
the  water  on  the  wick.  To  obtain  this  a  motor  driven 
fan  may  be  used  to  draw  air  at  a  steady  rate  past  the 
moistened  wick  while  a  reading  is  taken.  A  sling  psy- 
chrometer has  both  thermometers  mounted  on  a  frame  which 
is  whirled  through  the  air  to  cause  cooling  by  evapora- 
tion. Relative  humidity  is  then  determined  from  the  dry 
and  wet  bulb  readings  through  the  use  of  tables.  Con- 
tinuous measurements  of  humidity,  however,  can  not  be 
obtained  using  psychrometers. 

Radiation 

The  influence  of  the  sun's  radiation  upon  the  turbulence 
of  the  atmosphere  and  upon  certain  photochemical  reactions  is 
sufficient  to  make  measurements  of  radiation  quite  important.  In 
addition,  radiation  may  be  reduced  due  to  particulate  pollution 
in  the  atmosphere.  Particularly  for  research  purposes,  it  may  be 
desirable  to  measure  this  effect  by  comparisons  between  urban  and 
non-urban  stations  with  similar  instruments. 

0    Total  Radiation 

The  direct  radiation  from  the  sun  plus  the  diffuse 
radiation  from  the  sky  may  be  measured  by  pyranometers. 
These  instruments  are  mounted  so  that  the  sensor  is 
horizontal  and  can  receive  the  radiation  throughout  the 
hemisphere  defined  by  the  horizon.  The  instrument 
illustrated  in  Figure  7.2-9  is  of  this  type. 

•  Direct  Solar  Radiation 

The  direct  solar  radiation  may  be  measured  continuously 
by  using  the  pyrhel i ometer  shown  in  Figure  7.2-10  moun- 
ted upon  an  equatorial  mount  (Figure  7.2-11)  to  keep  it 
pointed  toward  the  sun.  By  using  filters,  different 
spectral  regions  of  radiation  may  be  determined. 

•  Net  Radiation 

The  difference  between  the  total  incoming  (solar  plus 
sky)  radiation  and  the  outgoing  terrestial  radiation  may 
be  useful  in  determining  the  stability,  and  -nence,  the 
turbulent  character  of  the  lowest  portion  of  the  atmos- 
phere. A  net  radiometer  serves  this  purpose  and  is 
shown  in  Figure  7.2-12. 


471 


L 


Figure  7.2-12 
Net  Radiometer 


Figure  7.2-13 
Transmissometer  Detector 


/il  A  v 

II 

■-     »*V*    V"     a  ^*"      '-„•.    ■    .-*"*>£**         *'.'..! 

■■-■•.'  ','-  "•.  ♦   :.:•»• ".:. ■-■      ■ 

r 

.-.,  ±,4  #    ;  ,  ,~,|->;  ^j-  '•"-,>.•;/.<    !~, . 

*'■* 

;:  ;j:\.  v  -r.f.--.-._  5  .<- -.  :*  ...*■.   • 

Figure  7.2-14 
Transmissometer  Receiver 


i 


Figure  7.2-15 
Integrating  Nephelometer 


472 


Visibility 


Visibility,  in  addition  to  being  affected  by  precipita- 
tion, is  affected  by  humidity  and  air  pollution.  Frequently, 
visibility  is  estimated  by  a  human  observer.  An  instrument  to 
measure  visibility,  called  a  transmissometer,  measures  the  trans- 
mission of  light  over  a  fixed  baseline,  usually  on  the  order  of 
500  to  700  feet.  An  intense  light  source  from  the  projector  is 
focused  on  a  photocell  in  the  detector, 
reaching  the  photocell  over  the  constant 
assumed  to  be  proportional  to  visibility, 
restricted  to  estimating  visibility  in  one 


The  amount  of  light 
baseline  distance  is 

The  transmissometer  is 

direction  only. 


A  transmissometer  is  also  limited  in  that  the  light 
transmission  it  detects  is  affected  mainly  by  liquid  droplets  in 
the  air.  It  does  not  detect,  to  any  great  efficiency,  the  par- 
ticulate matter  in  the  atmosphere.  The  projector  is  shown  in 
Figure  7.2-13  and  the  detector  in  Figure  7.2-14.  A  relatively 
new  instrument,  called  a  nephel ometer ,  has  been  developed  which 
measures  the  amount  of  light  scattered  by  impurities,  (mainly 
dust)  and  thus  indicates  visibility  as  it  is  affected  by  particu- 
late matter  in  the  atmosphere.  It  provides  for  continuous  out- 
put, operating  day  or  night,  rain  or  shine  and  is  relatively  easy 
to  calibrate.  It  is  limited,  however,  in  that  measurements  may 
be  taken  only  at  the  instrument  location.  An  integrating  nephel- 
ometer  is  shown  in  Figure  7.2-15. 

Another  instrument  used  to  determine  visibility  is  the 
Vista  Ranger  (telephot ometer),  which  provides  radiance  values  of 
a  target  and  the  sky,  contrast  transmittance  and  data  regarding 
target  chromat i ci ty .  In  other  words,  it  is  a  telescope  type 
instrument  which  looks  at  the  sky  and  a  target  (such  as  a  moun- 
tain peak)  and  measures  the  brightness  contrast  between  the  two 
and  transmits  information  on  the  true  color  of  what  is  seen. 
Measurements  can  be  made  over  long  path  lengths  (tens  of  Km)  and 
provide  quantitative  and  continuous  output.  The  Vista  Ranger, 
however,  can  be  used  only  during  daytime  and  readings  are  more 
accurate  during  times  of  higher  sun  angle  and  relatively  clear 
skies. 


7.2.3 


Air  Quality  Instruments 

The  following  paragraphs  discuss  sampling  techniques  for 


NO 


CO,  0 


the  measurement  of  the  criteria  pollutants  TSP,  SOo 
and  non-methane  (unreactive)  hydrocarbons  (NMHC).  Sampling  for 
more  sophisticated  pollutant  species  (e.g.,  sulfates,  organic 
compounds,  etc.)  is  beyond  the  realm  of  the  discussion  and  refer- 
ence is  made  to  the  bibliography  for  a  more  detailed  discussion. 

7.2.3.1Particulates 

Particulate  pollutants  are  divided  generally  into  dust 
that  settles  in  air  and  dust  that  remains  suspended  as  an  aero- 
sol. The  physical  consideration  determining  the  class  into  which 
a  particle  falls  is  the  particle  diameter. 


473 


As  a  matter  of  working  definition,  particles  larger  than 
10  inch  diameter  are  usually  thought  of  as  "settleable"  while 
those  of  a  smaller  diameter  are  referred  to  as  "suspended". 

Instruments  designed  to  collect  either  class  of  partic- 
ulates are  ordinarily  chemically  passive  physical  collectors 
whose  function  is  merely  to  permit  measurement  of  the  collected 
material  without  regard  to  the  composition.  Generally,  the 
particulates  encountered  include  various  mineral  dusts  (i.e. 
metallic  oxides,  sand,  carbon  particles,  flyash  fibers  and  pol- 
len). These  particulates  can  be  collected  using  equipment  based 
on  one  or  more  of  the  following  principles. 

Dust  Sampling  by  Gravity  Settling  (Dustfall) 

Particles  generally  larger  than  10  in  diameter,  which 
are  known  to  settle  from  air  and  collect  on  horizontal  surfaces, 
can  be  sampled  merely  by  placing  an  open  container  in  an  outdoor 
area  that  is  free  from  overhead  obstructions.  These  collectors 
are  ordinarily  constructed  of  polyethylene,  glass,  or  stainless 
steel,  since  the  inside  walls  must  be  inert  to  atmospheric  oxi- 
dative flaking,  which  would  contribute  to  sample  weight.  In 
addition,  identical  dustfall  containers  should  be  employed  in  the 
same  sampling  network  or  where  a  comparison  of  results  will  be 
made.   Figure  7.2-16  presents  a  simple  dustfall  collector. 

In  sampling  rather  large  areas,  such  as  entire  communi- 
ties, it  is  common  to  employ  at  least  one  dustfall  container  for 
every  10  square  miles.  On  the  other  hand,  when  dustfall  sampling 
is  intended  to  measure  the  effect  of  a  given  industry  or  indus- 
trial complex,  containers  may  be  placed  as  close  as  a  few  hundred 
feet  apart . 


atmo 

Ther 

foJJ 

Mg 

el  ec 

meas 

ul  at 

eval 

eros 

emi  s 

depo 

will 

fish 


This  basic  working  principal  is 
spheric  deposition  station  located 
e  are  40  to  60  sinrUar 
owing  elements: 
,  and  pH 


stations  ?  nationwide 

N03",  P04'\  CO,  NH4, 

including  total  and  free  acidity  and 


SO 


the  foundation  for  the 

in  the  Ukiah  District. 

rn^e  a  s  u  r+i  n  g  |  h_  e 

K  ,  Na  ,  Ca   , 

al  kal  i  ni  ty  and 

trical  conductivity.  The  objectives  of  this  program  are  to 
ure  atmospheric  deposition,  through  precipitation  and  partic- 
e  settling,  identifying  spatial  and  temporal  trends,  to 
uate  the  importance  of  natural 
ion,  etc.)  and  human  activities 
sions,  etc.)  as  they  contribute 
sition  and  finally,  to  research 

have  on  activities  such  as 
eries  and  wildlife  management. 


phenomena   (volcanos,  soil 

(power  plants,  industrial 

to  the  total   atmospheric 

the  effect  these  elements 

agricultural,  forest,  range, 


Dust  Sampling  by  High-Volume  Filtration  (The  High  Volume  Sampler) 

The  high-volume  (hi-vol)  sampler  (see  Figure  7.2-17) 
employs  the  sloping  roof  of  the  shelter  as  a  means  for  causing 
air  entering  the  sampler  under  the  eaves  of  the  roof  to  change 


474 


Figure  7.2-16 
Simple  Dustfall  Collector 


475 


Figure  7.2-17 
High  Volume  (hi-vol)  Air  Sampler 


476 


direction  at  least  90  before  entering  the  horizontal  filter. 
Particles  that  remain  entrained  in  the  air  sample  prior  to  hori- 
zontal filtration  have,  in  so  doing,  satisfied  the  definition  of 
truly  suspended  dust  or  dust  that  is  not  subject  to  settling 
under  the  influence  of  gravitational  force. 

The  hi -vol  is  a  vacuum  cleaner- type  motor  that  is  used 
to  draw  sample  air  through  a  filter  area.  The  filter  most  fre- 
quently employed  is  the  8  X  10  inch  mat,  which  allows  collection 
of  an  air  sample  at  a  rate  from  40  to  60  cubic  feet  per  minute 
(cfm)  over  a  normal  sampling  period  of  2  4  hours.  Ihese  condi- 
tions permit  the  sampling  of  from  58,000  to  86,000  ft  of  ambient 
air,  with  consequent  extraction  of  about  1/2  gram  of  suspended 
particulate  (aerosol).  This  provides  quite  a  substantial  weight 
of  sample,  which  greatly  simplifies  subsequent  chemical  or  physi- 
cal analysis. 


The  motor  is  usually  started  and  stopped  by  a  simple 
clock  timer,  and  the  duration  of  sampling  is  measured  by  an 
elapsed  time  meter  that  is  placed  in  series  with  the  Hi -Vol 
motor.  Starting  and  finishing  times  are  at  the  discretion  of  the 
operator,  although  the  EPA  recommends  starting  and  finishing  from 
midnight  to  midnight--24  hours  every  sixth  day.  The  National  Air 
Sampling  Network  operates  such  samplers  over  the  entire  country. 
On  the  other  hand,  short-term  studies  to  determine  day-to-day 
variation  in  particulate  levels  may  require  continuous  daily  24- 
hour  sampling. 

7.2.3.2   Continuous  Gas  Analyzers 

In  general,  these  instruments  are  based  on  one  of  the 
following  principles  of  operation:  color i met ry,  atomic  or  mo- 
lecular absorption,  chemi 1 umi nescence  ,  conductivity,  coulometry, 
or  c  omb  u  st  i  on  . 


In  the  past,  colorimetric  instructions  have  been  used 


with  varying  degrees  of  success  to  monitor  air  by 
sical  col  or- form i ng  reactions  to  such  plumbing  and 
were  required  to  produce  continuous  recorded  data, 
ly,  however,  the  realm  of  solid-state  physics  has 
sensing  equipment  that  respond  to  physical  rather 
properties  at  even  the  lowest  levels  of  gaseous  air 


adapting  cl a  s- 
electronics  as 
More  recent- 
produced  gas- 
t  han  chemi  ca 1 
contaminants . 


Therefore,  emphasis  is  placed  on  the  more  recent  physi- 
cal instrumentation  for  the  individual  air  contaminants.  Future 
development  in  continuous  air  monitoring  systems  will  probably  be 
along  the  lines  of  physics  rather  than  solution  or  chemical 
meas  urement . 

Carbon  Monoxide  ^ 

Automated  continuous  methods  for  CO  include  applications 
of  gas  chromatography,  nondispersive  infrared  absorption,  cataly- 
tic oxidation,  and  displacement  of  Hg  from  HgO  to  produce  mercury 
vapor . 


477 


The  most  commonly  used  instruments  for  CO  measurement 
are  those  which  use  the  principle  of  nondi s pers i ve  infrared, 
employing  either  a  long  path  (40  in)  or,  more  recently,  a  10  cm 
(0.39  in)  path  of  infrared  radiation. 

These  analyzers  depend  on  the  characteristic  energy  of 
absorption  of  the  CO  molecule  at  not  only  its  absorption  wave- 
length maximum  of  4.6  but  also  at  a  number  of  equally  specific 
lines  ranging  from  2  to  15    ,  which  together  differentiate  CO 


from  such  interferences  as  C09,  H90,  S09  and  NO 


2* 


As  shown  in  Figure  7.2-18,  these  instruments  employ  a 
heated  filament  as  the  source  of  radiation,  a  chopper  to  alter- 
nate radiation  between  the  sample  and  reference  cells,  a  sample 
cell  (usually  copper  or  brass),  a  reference  cell  of  the  same 
material,  and  a  detector. 


Sulfur  Dioxide  ( S 0 2 ) 


Among  the  earliest  applications  of  continuous  analyzers 
to  ambient  air  monitoring  were  those  involving  measurement  of 
SO2.  Both  continuous  and  intermittent  (sequential)  sampling 
methods  have  been  employed.  These  often  made  use  of  the  colori- 
metric  method  of  West  and  Gaeke.  The  West-Gaeke  method  was  first 
adopted  as  the  approved  reference  method  by  the  National  Air 
Pollution  Control  Association  (NAPCA,  1969),  before  being  re- 
placed by  the  EPA  colorimetric  method. 

For  the  past  several  years,  the  monitoring  of  sources 
such  as  kraft  paper  mills  and  oil  refineries,  whose  emissions 
require  a  continuous  total  sulfur  analyzer,  has  been  accomplished 
by  means  of  a  total  combi ned- sul f ur  flame  photometer. 

In  this  analyzer,  sample  air  is  admitted  into  a  hydro- 
gen-rich air  flame.  Specificity  to  sulfur  arises  from  the  use  of 
a  narrowband  interference  filter  that  shields  the  photomul t i pi i er 
tube  detector  from  all  but  the  394  m  emission  energy  of  flame- 
excited  sulfur  atoms. 

Nitrogen  Dioxide  ( N 0 9 ) 

Traditionally,  continuous  analyzers  for  NO2  have  em- 
ployed the  Gri es s-Sal t zman  modified  colorimetric  method.  Recent- 
ly, several  continuous  NOo-measur i ng  instruments  operating  on  the 
principle  of  chemi  1  urn i nescence  have  been  marketed.  Here,  a 
photomultiplier  detector  is  used  to  measure  the  luminescence 
produced  in  the  gas  phase  reaction  between  ozone  and  NO. 

This  method  directly  measures  NO  rather  than  N02«  It  is 
mentioned  here  because  it  forms  the  basis  for  a  reliable  differ- 

a  reducing  medium 
N02  to  NO.  Subse- 
quent reaction  of  NO,  thus  formed,  with  ozone  produces  chemilumi- 
nescence  equivalent  to  NO  ,  where  NO-  =  NO  -  NO.  The  sensitivi- 
ty of  this  method  is  reported  as  0.1)1  ppm.   To  date,  sufficient 


ential  measurement  of  NOo  through  the  use  of 
such  as  stainless  steel  at  230°C,  to  convert 


478 


Out 


Dehumidifier 


IR  source 


Detector 


Sample  cell  Interference 

Mil 


Chopper  Comparison  cell 


Amplifier 


Recorder 


nzc 


Control  section 


Figure  7.2-18 
Diagram  of  Nondispersive  Infrared  Analyzer 


479 


field  experience  has  been  obtained  to  indicate  the  overall  relia- 
bility of  the  instrument  over  long  periods  of  operation. 

Ozone 

The  first  chemiluminescence  approach  to  a  specific  ozone 
determination  probably  was  developed  by  Regener  (1960)  Regener 
found  that,  when  air  containing  ozone  contacts  the  surface  of  a 
plate  prepared  by  absorbing  rhodamine  B  on  silica  gel,  a  lumi- 
nescence is  produced  from  the  chemical  reaction.  The  intensity 
of  the  luminescence  is  proporat i onal  to  the  concentration  of 
ozone  present  to  concentrations  as  low  as  0.001  ppm. 


Regener's  detector  was  found  to 
of  interferences,  such  as  NO?*    It  was 
Nederbracht  (1965)  detector,  wnich  employs 
of  the  ethylene  reaction  with  ozone. 


be  subject  to  a  number 

soon  f o 1 1  owed  by  the 

the  chemiluminescence 


A  number  of  commercially  available  analyzers  have  now 
been  marketed.  It  appears  that  the  ozone-ethyl ene  chemi 1 umi ne s- 
cent  reaction,  having  been  adopted  by  the  EPA  as  a  standard 
method  for  ozone,  will  soon  become  the  basis  for  the  common 
continuous  ozone  field  analyzer.  Figure  7.2-19  presents  a  schem- 
atic of  a  continuous  chemiluminescence  ozone  meter. 

Hydrocarbons 

Commercial  instruments  that  automatically  measure 
hydrocarbons  fall  into  two  main  categories: 

1.  The  total  hydrocarbon  continuous  monitor,  and 

2.  The  semi cont i nuous  nonmethane  hydrocarbon  monitor. 

Briefly,  automatic  monitoring  of  hydrocarbon  levels 
depends  on  the  fact  that  most  organic  compounds  easily  pyrolyze 
when  introduced  into  an  air- hydrogen  flame.  This  pyrolysis 
produces  ions  that  are  collected  either  by  the  metal  of  the  flame 
jet  itself  (charged  negative)  or  by  a  cylindrical  collecting  grid 
(positively  charged)  that  surrounds  the  flame.  The  sensitivity 
to  organic  materials  varies  slightly  depending  on  the  number  and 
kind  of  ions.  As  a  general  rule,  however,  detector  response  is 
in  proportion  to  the  number  of  carbon  atoms  in  the  chain  of  the 
organic  molecule.  Thus,  propane  (three  carbon  atoms)  gives 
roughly  three  times  the  intensity  of  response  as  does  methane, 
and  so  on . 

This  "nonselectivity"  is  both  an  advantage  and  a  dis- 
advantage, depending  on  the  information  expected  from  the  air 
analysis.  Nonselectivity  toward  hydrocarbons,  but  selectivity 
in  the  sense  that  other  compounds  do  not  cause  response,  provides 
this  continuous  instrument  with  the  capability  of  measuring  the 
whole  general  class  of  organic  compounds  without  concern  for 
interference.   When  the  instrument  response  is  calibrated  using 


480 


so*.  ( i :  : 
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Figure  7.2-19 
Diagram  of  Air-Ethylene  System  for 
Continuous  Chemi luminescent  Ozone  Meter 


401 


methane,  the  continuous  strip  chart  readout  is  then  a  record  of 
the  real-time  variation  in  ambient  hydrocarbons  as  though  they 
were  100%  methane . 

The  Federal  ambient  air  quality  standard  of  0.24  ppm 
(6:00  to  9:00  a.m.)  average  for  nonmethane  hydrocarbons  necessi- 
tates the  selective  measurement  of  this  class  of  compounds  in 
preference  to  total  hydrocarbons,  especially  when  elevated  levels 
of  ozone  are  either  known  or  suspected. 

This  analysis  is  accomplished  by  a  differential  meas- 
urement using  the  following  procedure.  First,  small  measured 
volumes  of  air  are  delivered  intermittently  (4  to  12  times/hr)  to 
a  flame  ionization  detector  to  measure  total  hydrocarbons. 
Following  this  measurement,  another  similar  sample  volume  is 
admitted  into  a  stripper  column,  which  removes  the  relatively 
heavy  non-methane  hydrocarbons  and  water.  The  effluent  from  this 
column,  consisting  of  methane  and  CO,  then  enters  a  gas  chromato- 
graph  for  separation.  The  methane,  which  exits  first,  passes 
unchanged  through  a  catalytic  reduction  tube  and  into  the  detec- 
tor, where  it  is  recognized  as  methane.  Carbon  monoxide,  which 
exits  next,  passes  through  a  pi  at i num- hydrogen  reducing  atmos- 
phere, and  emerges  as  methane.  It  is  thus  detectable  by  the  ion- 
izing flame  where  it  is  electronically  recognized  as  CO. 

Nonmethane  levels  for  these  sequential  samples  results 
from  subtracting  the  signal  of  the  methane  hydrocarbons  from  the 
total  hydrocarbons  where  nonmethane  HC  =  total  HC  -  methane  HC. 


7.2.4 


Monitoring  Program  Operation 


Monitoring  programs  require  a  diversity  of  skills  for 
the  successful  management  of  a  complete  program.  Key  components 
of  a  monitoring  program  include: 

Si  te  Sel ect i  on 

System  Desi  gn 

Equipment  Selection  and  Purchase 

Initial  Calibration  and  Installation 

Onsite  Surveillance,  Maintenance  and  Repair 

Quarterly  Calibration 

Data  Handling,  Reduction,  Summarization  and  Analysis 

Qual i  ty  Assurance 

Report  Preparation 

The  costs  associated  with  air  quality  and  meteorological 
monitoring  programs  can  be  enormous.  Therefore,  it  is  important 
to  isolate  the  specific  data  requirements  necessary  for  a  partic- 
ul ar  study  area . 

Tables  7.2-1  and  7.2-2  recommend  various  types  of  air 
monitoring  and  meteorological  instrumentation  that  can  provide 
reliable  data  necessary  for  air  quality/meteorological  analyses. 


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tion as  presented  in  the  tables  include  the  purchase  price  only. 
Table  7.2-3  provides  a  review  of  total  program  costs  as  a  func- 
tion of  the  various  components  as  detailed  above.  The  range  of 
cost  varies  from  a  simplistic  approach  (e.g.,  particulate  sam- 
pling) to  the  sophisticated  (e.g.,  full  PSD  permit  support  moni- 
toring of  gaseous,  particulate  and  meteorological  parameters). 
The  prices  vary  from  approximately  $10,000  to  $200,000  for  a  year 
of  monitoring.  A  sophisticated,  multiple  site  program  can  easily 
cost  over  one  million  dollars. 

Figure  7.2-20  presents  a  schedule  for  the  completion  of 
a  one-year  monitoring  program  which  indicates  a  16  month  period 
from  project  inception  to  completion.  This  schedule  assumes  that 
no  problems  arise.  Realistically,  it  often  takes  two  years  to 
obtain  one  year  of  data. 


489 


Table  7.2-3 
Summary  of  Monitoring  Program  Costs 

Site  Selection  -$1000 

System  Design  ~$  500  -  $3000 

Equipment  Selection  and  Purchase  -$2000  -  $100,000 

Installation  and  Initial  Calibration  ~$  500  -  $5000 

Onsite  Surveillance,  Maintenance  and  Repair  -$5000  -  $50,000 

Quarterly  Calibrations  ~$  500  -  $5000 

Data  Handling,  Reduction,  Summarization  and  -$1000  -  $10,000 
Analysis 

Quality  Assurance  ~$  500  -  $5000 

Report  Preparation  -$1000  -  $10,000 


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7.3 


UK  I  AH  DISTRICT  MONITORING  REQUIREMENTS 


Specific  regions  within  the  Ukiah  District  lack  sub- 
stantial air  quality,  dispersion  meteorology  and  climatological 
data  necessary  for  Environmental  Impact  Statement  (EIS)  devel- 
opment and  would  require  ons  i  te  air  quality  and/or  meteorological 
monitoring  programs  to  supply  supportive  data  for  future  analy- 
ses. Table  7.3-1  provides  an  evaluation  of  the  adequacy  of  the 
current  data  base  for  air  quality  impact  analyses  for  lands 
currently  under  BLM  jurisdiction.  A  satisfactory  rating  indi- 
cates that  sufficient  data  exists  within  the  particular  area  to 
provide  s  i t e- s  pec  i  f i  c  information  necessary  to  accurately  de- 
scribe the  air  quality/meteorological  baseline.  An  unsatisfac- 
tory rating  indicates  that  insufficient  site-specific  data  are 
available  for  use  in  future  EIS  level  analyses. 

As  outlined  in  Table  7.3-1,  climatological  data  are 
readily  available  for  all  BLM  lands  in  the  Ukiah  District.  These 
data  are  generally  adequate  for  accurate  si t e- spec i f i c  assess- 
ments. On  the  other  hand,  considerable  data  resolution  would  be 
necessary  for  s i t e- speci f i c  dispersion  meteorology  and  air  quali- 
ty assessments  for  the  various  BLM  land  areas  in  the  Ukiah  Dis- 
trict. 

Coastal  Region 

For  BLM  lands  located  in  the  coastal  region,  climatolo- 
gical data  are  generally  satisfactory  for  any  analysis  that  would 
be  required  for  BLM  lands.  Dispersion  meteorological  data  are 
generally  acceptable  in  terms  of  the  basic  parameters  wind  speed, 
wind  direction  and  atmospheric  stability.  More  sophisticated 
data  on  winds  aloft  and  mixing  height  are  generally  not  satisfac- 
tory in  any  portion  of  the  Ukiah  District.  Air  quality  data  are 
only  satisfactory  along  the  coastal  area  in  terms  of  total  sus- 
pended particulates.  Onsite  monitoring  would  be  recommended  for 
the  remainder  of  the  criteria  pollutants  as  well  as  visibility. 

Coastal  Mountains  -  Northern  Area 

Climatological  data  are  once  again  satisfactory  for  the 
preparation  of  climatological  analysis  for  this  portion  of  the 
Ukiah  District.  Dispersion  meteorological  data,  however,  are 
almost  completely  lacking  and  are  unsatisfactory  for  an  analysis 
of  the  ventilation  potential  of  this  region.  The  Geysers  KGRA  is 
one  exception  to  the  unsatisfactory  nature  of  the  data  base  in 
the  northern  portion  of  the  coastal  mountains.  In  this  region, 
considerable  meteorological,  air  quality  and  gaseous  tracer 
studies  have  been  conducted  around  the  Geysers  thermal  area. 

Air  quality  data  in  this  portion  of  the  District  are 
generally  unsatisfactory  with  the  exception  of  total  suspended 
particulates.  Monitoring  for  the  criteria  pollutants  is  general- 
ly only  conducted  in  the  metropolitan  portion  of  the  Distict  in 
the  extreme  south  and  visibility  data  tend  to  be  lacking  through- 
out the  District. 


492 


Table  7.3-1 
Summary  of  the  Adequacy  of  CI imatological ,   Dispersion 
Meteorological   and  Air  Quality  Data  for  BLM  Lands  in  the  Ukiah  District 


BLM  Land  Areas 

A 

B 

C 

Parameters 

Coastal 

Coastal   Mountains 
Northern  Area 

Coastal  Mountains 
Southern  Area 

Climatology 

Temperature 

Precipitation 

Others 

Dispersion 
Meteorology 

Wind  Speed 
Wind  Direction 
Stabil ity 
Winds  Aloft 
Mixing  Height 

Air  Quality 
TSP 

so9 

NOx 
03X 

CO 

Visibility 

Satisfactory 
Satisfactory 
Satisfactory 

Satisfactory/  A 
Satisfactory^    ' 
Satisfactory 
Unsatisfactory 
Unsatisfactory 

Satisfactory 

Unsatisfactory 

Unsatisfactory 

Unsatisfactory 

Unsatisfactory 

Unsatisfactory 

Satisfactory 
Satisfactory 
Satisfactory 

Unsatisfactory),^ 
Unsatisfactory,,,; 
Unsatisfactory^    ' 
Unsatisfactory 
Unsatisfactory 

Satisfactory 

Unsatisfactory 

Unsatisfactory 

Unsatisfactory 

Unsatisfactory 

Unsatisfactory 

Satisfactory 
Satisfactory 
Satisfactory 

Satisfactory/,  I 
Satisfactory^    ' 
Satisfactory 
Unsatisfactory 
Unsatisfactory 

(3) 
Unsatisfactory),^ 

Unsatisfactory/.^ 

Unsatisfactory^    ' 

Satisfactory     ,** 

Unsatisfactory^    ' 

Unsatisfactory 

Satisfactory      -  Sufficient  site-specific  data  to  accurately  describe  a  particular 

parameter  for  future  EIS  analyses. 

Unsatisfactory  -   Insufficient  site-specific  data  to  accurately  describe  a  particular 

parameter  for  future  EIS  analyses. 

Local   terrain  features  will   result  in  dispersion  characteristics  not  well   defined 
by  the  available  data. 

2 
Primarily  for  BLM  Lands   in  northern  Mendocino  and  eastern  Humboldt  Counties. 

3 
Unsatisfactory  in  Colusa  County. 

4 
Satisfactory  in  Napa  County. 


49.3 


Coastal  Mountains  -  Southern  Area 

As  described  for  the  other  two  portions  of  the  Ukiah 
District,  climatological  data  are  once  again  satisfactory. 
Dispersion  meteorological  data  are  satisfactory  in  terms  of  the 
basic  parameters  wind  speed,  wind  direction  and  atmospheric 
stability  but  are  unsatisfactory  for  the  more  sophisticated 
parameters  winds  aloft  and  mixing  height.  These  latter  parame- 
ters are  generally  only  available  at  major  National  Weather 
Service  stations  and  as  a  result  of  site  specific  studies  con- 
ducted by  applicants  for  major  power  development  projects.  Air 
quality  data  in  this  region  are  again  largely  unsatisfactory  with 
the  exception  of  ozone  for  which  sufficient  data  exists. 

Future  Monitoring 

The  monitoring  requirements  required  in  support  of  air 
quality  permit  applications  are  an  oblibligation  of  the  Appli- 
cant. The  data  have  been  presented  to  inform  the  Federal  Land 
Manager  (FLM)  of  monitoring  requirements,  as  the  role  of  the  FLM 
in  the  protection  of  air  quality  has  increased  in  recent  years. 
The  1977  Amendments  require  the  FLM  To  take  an  active  role  in 
E PA ' s  PSD  permit  process.  In  addition,  the  FLM  must  actively 
protect  the  "air  quality  related  values",  primarily  visibility, 
of  Class  I  Areas  (i.e.,  national  parks,  monuments  and  wilderness 
areas  [See  Section  6.4]). 


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be  esta  bl i  shed 

Agreement  wi  t h 

i  es  for  Class  I 


charged  with  ensuring  "reasonable  progress" 
national  goal  of  remedying  impairment  to 
I  Areas.  To  do  this,  a  visibility  baseline 
BLM  is  presently  entering  into  a  Coopera- 
the  EPA  which  will  begin  visibility  baseline 
areas  in  California.  This  program  will  be  an 
nsion  of  the  EPA's  Western  Fine  Particulate  Network  which 
udes  forty  stations  uniformly  distributed  throughout  Montana, 
h  Dakota,  Wyoming,  South  Dakota,  Utah,  Colorado,  Arizona  and 
Mexico.  The  purpose  of  this  study  is  to  determine  the  im- 
s  of  western  energy  resource  development.  Particulate  sam- 
are  taken  twice  weekly  and  undergo  mass  concentration  and 
e  element  analysis. 


The  visibility  monitoring  program  will  include  two 
initial  site  locations.  One  site  will  be  located  in  the  Susan- 
ville  District  and  one  within  a  desert  area  of  the  Riverside 
District  as  mandated  by  the  EPA.  The  objective  of  the  program  is 
to  measure  visibility,  aerosal  characteristics  and  climatology  in 
remote  areas  influenced  by  industrial  expansion  and  population 
growth.  The  program  is  also  to  differentiate  between  natural  and 
man-made  contributions  to  visibility  degradation. 

In  addition  to  sophisticated  visibility  measurements  by 
telephotometers,  nephelometers  and  color  photography,  size  segre- 
gated particulate  sampling  will   be  conducted  with   subsequent 


494 


trace  element  analysis.  The  measurement  program  will  be  sup- 
ported by  basic  meteorological  monitoring  including  wind  speed 
and  direction,  temperature  and  relative  humidity. 

Baseline  visibility  is  poorly  defined  in  the  Ukiah 
District.  However,  monitoring  programs  should  emphasize  those 
areas  that  incorporate  or  are  adjacent  to  Class  I  areas.  There- 
fore, visibility  monitoring  would  be  recommended  near  either  the 
Point  Reyes  National  Seashore  or  the  Redwood  National  Park. 


495 


7.4 


GLOSSARY  OF  TERMS 


Ace  uracy 


Anisotropic 
Turbul 1 ence 

B  i  -  V  a  n  e 


Chemil uminescence 


Chromatograph 


Col  on"  met  ry 


Conductivity 


Constant  Level 
Bal 1 oons 


Cou 1 ometry 


Durab  i 1 ty 


The  closeness  of  the  instrument  output  to  the 
true  value  of  the  parameter. 

Turbulence  which  is  directionally  dependent. 


A  wind  direction  instrument  designed  to  rotate 
around  a  vertical  axis  to  measure  the  azimuth 
and  elevation  angle  of  the  wind. 

The  use  of  a  phot om u 1 t i pi i er  detector  to 
measure  the  luminescence  produced  in  a  gas 
phase  reaction  between  two  species. 

Analyzers  used  for  the  separation  and  measure- 
ment of  volatile  compounds  and  of  compounds 
that  can  be  quantitatively  converted  into 
volatile  derivatives. 

The  measurement  or  analysis  of  shade,  tint, 
value,  brightness  and  purity  of  a  color. 

The  property  or  power  of  conducting  or  trans- 
mitting heat,  electricity,  etc. 

Constant  level  balloons  are  used  to  determine 
the  trajectory  of  an  air  parcel  at  a  desired 
pressure  level  during  a  given  time  interval. 

A  method  used  in  microanalysis  to  determine 
quantities  in  solutions  by  measuring  the 
amount  of  electricity  required  to  effect  a 
chemical  change. 

The  ability  of  an  instrument  to  survive  vi- 
brations and  shock  encountered  in  transporta- 
tion, rough  handling  and  normal  operating 
cond  i  t  i  ons . 


Dustfal  1 

Dynamic  Response 
Fl ame  Ioni  zat  i  on 


The  simple  collection  of  dust  due  to  gravita- 
tional settling. 

The  real  time  reaction  of  an  instrument. 

The  ionization  of  gas  samples  through  their 
introduction  into  an  air  hydrogyn  flame. 
Species  specific  ions  are  then  measured  by  a 
detector  which  measures  ion  intensity  result- 
ing from  the  flame  ionization  of  any  organic 
compound . 


496 


Fl ame  Photometry 


Gri  ess-Sal t  zman 
Method 

Hi  gh- Vol ume 


Hydrot hermograph 


Nephel ometer 


Net  Rad  i  at i  on 


Net  Radiometer 


Nond  i  spers  i  ve 

Infrared 

Ab  sorpt  i  on 


Pilot    Balloon 

Precision 
Psychrometer 

Pyranometer 
Pyrhel i  ometer 
Rad  i  osonde 


The  use  of  a  hydrogen  rich  air  flame  to  induce 
the  emission  of  excited  atoms  specific  to  the 
pollutant  being  measured. 

A  continuous  colorimetric  method  for  NU? 
detection. 

The  collection  of  particulate  matter  on  a 
filter  medium  through  the  collection  of  an  air 
sample  at  a  continuous  standard  rate. 

An  instrument  for  the  measurement  of  tempera- 
ture and  humidity  through  the  use  of  human 
hairs  which  increase  or  shorten  as  a  function 
of  atmospheric  moisture  content. 

An  instrument  which  indicates  visibility 
impairment  due  to  the  presence  of  particulate 
matter  in  the  atmosphere. 

The  difference  between  the  total  incoming 
radiation  and  the  outgoing  terrestrial  radia- 
tion. 

An  instrument  for  the  measurement  of  net 
radiation. 

The  use  of  the  principal  whereby  gaseous 
compounds  absorb  infrared  radiation  at  specif- 
ic wave  lengths.  In  nond i spers i ve  absorption, 
a  detector  is  exposed  to  a  wide  wave  length 
band  of  rad  i  at  i  on  . 

A  method  for  the  measurement  of  wind  velocity 
and  wind  direction  as  a  function  of  height 
using  a  gas  filled  free  balloon. 

The  degree  of  closeness  of  a  series  of  read- 
ings of  an  unchanging  parameter. 

An  instrument  which  combines  a  dry  bulb  and 
wet  bulb  thermometer  for  the  subsequent  calcu- 
lation of  humidity. 

An  instrument  used  to  measure  direct  radia- 
tion. 

An  instrument  used  for  the  continuous  measure- 
ment of  direct  solar  radiation. 

The  use  of  a  free  balloon  to  carry  meteoro- 
logical sensors  and  a  radio  transmitter  aloft. 


497 


Rawi  nsonde 

Rel i  abi 1 i  ty 

Sensiti  vity 

Sim  pi  i  c  i  ty 

T-Sonde 
Theodol i  te 
Total  Radiation 
Transm  issometer 


UVW  Anemometer 


A  method  of  measuring  winds  aloft  using  a  gas 
filled  free  balloon  and  radio  direction  find- 
ing apparatus,  usually  radar. 

The  ability  of  an  air  quality  or  meteorologi- 
cal instrument  to  provide  reprod uceabl e  re- 
sults. 

The  smallest  change  in  the  measured  variable 
that  causes  a  detectable  change  in  the  output 
of  the  inst  rument . 

Describes  an  instrument  that  can  be  operated 
by  an  individual  through  the  use  of  Standard 
Operating  Procedures. 

The  use  of  a  free  balloon  to  carry  a  tempera- 
ture sensor  and  radio  transmitter  aloft. 

An  optical  system  used  to  measure  the  azimuth 
and  elevation  angle  of  a  pilot  balloon. 

The  direct  radiation  from  the  sun  plus  the 
diffuse  radiation  from  the  sky. 

An  instrument  used  for  the  measurement  of 
visibility  through  the  measurement  of  the 
transmission  of  light  over  a  fixed  baseline. 
Usually  on  the  order  of  500  -  700  feet. 

An  anemometer  designed  to  measure  wind  speed 
in  the  horizontal  (x  and  y  directions)  and 
vert  i  cal . 


498 


BIBLIOGRAPHY 


Angell  ,  J.K.  and  Pack,  H.J.,  "Analysis  of  Some  Preliminary  Low 
Level  Constant  Level  Balloon,  (Tetroon)  Flights."  Monthly 
Weather  Review,  88,  pages  235-248,  1960. 

Cooke,  T.H.  "A  Smoke  Trail  Technique  for  Measuring  Wind"  -  Quar- 
terly Journal  of  the  Royal  Meteorological  Society,  8_8,  pages 
83-88,  1962. 

U.S.  Department  of  Health,  Education  and  Welfare,  "Air  Qual i  ty 
Criteria  for  Sulfur  Oxides"  Chapter  2,  page  21,  Washington, 
D.C.  ,  January,  1969. 

U.S.  Environmental  Protection  Agency,  Ambient  Monitoring  Guide- 
lines  for  Prevention  of  Significant  Deterioration  (PSD)",  EPA 
450/Q-78-019,  May,  1978  (OAQPS  No  1.2-096). 


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OVERLAY  A 
BLM  LANDS  UKIAH  DISTRICT 


20 

_L_ 


40 

I 


MILES 


BUREAU  OF  LAND 
MANAGEMENT  DOMAIN 


60 

_J 


OVERLAY  B 
UKIAH  DISTRICT  TOPOGRAPHY 


ELEVATIONS 

DUUU 

3000 

1500 

500 

0 

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W     SAC  RAMI.NTl] 


OVERLAY  C 
CLIMATIC  ZONES  FOR  UKIAH  DISTRICT 


COASTAL  MOUNTAIN 


SACRAMENTO 


OVERLAY  D 
MEAN  ANNUAL  TEMPERATURE  CONTOURS  (°F) 


60 


OVERLAY  E 
MEAN  ANNUAL  PRECIPITATION  (INCHES) 


SAN  RAFAEL   • 


OVERLAY  F 
CALIFORNIA  AIR  BASINS  IN  THE  UKIAH  DISTRICT 


j   NORTH  COASTAL  MOUNTAINS 


OVERLAY  G 
MANDATORY  CLASS  I  AREAS  UNDER  1977  CLEAN  AIR  ACT  AMENDMENTS 


ELK  VALLEY 


Redwood  National  Park 


ONLY  THE  WILDERNESS 
PORTIONS  ARE  DESIGNATED 
CLASS  I 


W.  SACRAMENTO 


Point  Reyes  National  Seashore* 


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