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Geothermal Resources Council TRANSACTIONS, Vol. 14, Part II, August 1990
PM,
Source Apportionment Study i n P1easant Val 1ey, Nevada
R.T. Egami(')
(1)
(2)
J.C. Chow(')
J.G. Watson(')
and T. DeLong(2)
Desert Research I n s t i t u t e , P.O. Box 60220, Reno, NV 89506
Caithness Power, Inc., P.O. Box 18160, Reno, NV 89511
ABSTRACT
450 "C groundwater i n t h e Steamboat geothermal
f i e l d i n t o energy which supplies power t o 12,500
households i n n o r t h e r n Nevada.
A source apportionment study was conducted
between March 18 and A p r i l 4, 1988, a t Pleasant
Valley,
Nevada,
t o evaluate a i r p o l l u t a n t
concentrations t o which community r e s i d e n t s were
exposed and t h e source c o n t r i b u t i o n s t o those
pollutants.
D a i l y PM,
samples were taken f o r
chemical s p e c i a t i o n o f 40 t r a c e elements, ions, and
organic and elemental carbon.
Hourly hydrogen
s u l f i d e , wind speed and d i r e c t i o n , sigma theta,
temperature, and re1 a t i v e humidity data were a1 so
c o l l e c t e d . The o b j e c t i v e s o f t h i s case study are:
(1) t o determine t h e emissions source composition
o f t h e p o t e n t i a l upwind source, a geothermal p l a n t ;
(2)
to
measure
the
ambient
particulate
concentration and i t s chemical c h a r a c t e r i s t i c s i n
Pleasant Valley;
and (3) t o estimate t h e
c o n t r i b u t i o n s o f d i f f e r e n t emissions sources t o
PM,
Residents i n Pleasant V a l l e y have r e p o r t e d t h e
d e t e c t i o n o f odors i n t h e neighborhood since t h e
beginning o f 1988. These r e s i d e n t s have expressed
concern about p o t e n t i a l adverse h e a l t h e f f e c t s
which might be caused by gases and p a r t i c l e s which
accompany t h e odors. With t h e assistance o f Washoe
County D i s t r i c t Health Department o f f i c i a l s , an
ambient and source monitoring program was conducted
between March 18 and A p r i l 4, 1988. The study was
designed t o evaluate a i r p o l l u t i o n concentration
l e v e l s t o which t h e community r e s i d e n t s were
exposed.
Source emissions from t h e power-plant c o o l i n g tower and geological m a t e r i a l around t h e source and
receptor s i t e s were sampled and chemically
analyzed. Chemical mass bal ance receptor model ing
was performed t o determine t h e c o n t r i b u t i o n o f t h e
power-plant plume and o t h e r sources i n t h e area t o
PM,
concentrations. The study found t h a t :
(1)
p a r t i c u l a t e emissions from t h e geothermal c o o l i n g tower plume consisted p r i m a r i l y o f s u l f a t e ,
ammonia, c h l o r i d e , and t r a c e elements; (2) no
s i g n i f i c a n t q u a n t i t i e s o f t o x i c inorganic species .
were found i n t h e ambient a i r ; (3) ambient PM,
concentrations i n Pleasant V a l l e y were w i t h i n
Federal standards; and (4) source c o n t r i b u t i o n s t o
PM,
were approximately 60% geological materi a1 ;
20% motor v e h i c l e exhaust; and 10% cool ing-tower
p l ume.
The
PM,
1eve1 s , t h e chemical
concentrations, and t h e sum source c o n t r i b u t i o n
estimates are much lower than those l e v e l s found t o
be d e l e t e r i o u s t o pub1i c health.
INTRODUCTION
This paper addresses t h e p a r t i c u l a t e phase o f
t h e study. I t s o b j e c t i v e s are: 1) t o determine
t h e chemical c o n s t i t u e n t s o f emissions from t h e
geothermal power p l a n t ; 2) t o measure t h e ambient
concentrations o f p a r t i c u l a t e chemical species i n
t o estimate t h e
Pleasant Valley;
and 3 )
c o n t r i b u t i o n s o f d i f f e r e n t emissions sources t o
suspended p a r t i c u l a t e matter i n t h e r e s p i r a b l e s i z e
f r a c t i o n (PM,,
p a r t i c l e s l e s s than 10 pm i n
aerodynamic diameter).
I n order t o a t t a i n these
o b j e c t i v e s , f i l ter'samples o f suspended p a r t i c u l a t e
matter were taken both i n t h e cooling-tower plume
and on t h e ground.
The f i l t e r deposits were
characterized f o r a number o f chemical species.
The measurements i n t h e plume form a chemical
f i n g e r p r i n t which can be d i s t i n g u i s h e d from t h e
f i n g e r p r i n t s o f o t h e r p a r t i c u l a t e c o n t r i b u t o r s such
as geological m a t e r i a l , motor v e h i c l e exhaust, and
wood burning.
The Chemical Mass Balance (CMB)
receptor model (Watson e t al., 1990) was a p p l i e d t o
these data t o determine t h e c o n t r i b u t i o n o f t h e
power-plant plume and o t h e r sources t o t h e
i n h a l a b l e p a r t i c u l a t e concentrations measured by
t h e ground-based sampler.
Receptor models are
widely used i n t h e development o f State
Implementation Plans f o r meeting. ambient a i r
q u a l i t y standards (Watson e t a1 , 1989).
.
Pleasant V a l l e y i s a small r e s i d e n t i a l
community (population o f approximately 600) l o c a t e d
between Reno and Carson City, t h e two major urban
centers i n n o r t h e r n Nevada.
A 12.5-megawatt
geothermal power p l a n t operated by Cai thness Power,
Inc., i s l o c a t e d i n Pleasant V a l l e y approximately
20 km south o f Reno.
This power p l a n t converts
SAMPLING, ANALYSIS, AND MODELING
PM,
( p a r t i c u l a t e matter w i t h aerodynamic
diameter l e s s than 10 microns) samples were taken
d a i l y a t 20540 Eaton Road, Pleasant Valley, NV, f o r
24 hours per day from March 18 t o A p r i l 4, 1988.
1115
Egami e t a l .
Table 1
P1easant Val 1ey Source Apportionment Study
Ambient Measurements'
Sampl ing
Period
Measurement
Method/Instrument
D a i l y , 24
Hours/Day
D R I MEDIUM-VOLUME ( PM),
Sampler
D a i l y , 24
Hours/Day
Gravimetric Analysis on
Teflon-Membrane F i l t e r s w i t h
Cahn 31 Electro-Microbal ance
PM,
E l ement s
(from A1 t o Pb)
D a i l y , 24
Hours/Day
X-ray Fluorescence Analysis on
Central P o r t i o n o f T e f l o n Membrane F i 1t e r s w i t h Kevex
700/800 XRF Analyzer
PM,: Chloride,
N i t r a t e , and
S u l f a t e Ions
D a i l y , 24
Hours/Day
I o n Chromatographic Analysis
on f Quartz-Fiber F i l t e r
E x t r a c t s w i t h Dionex 4000i I o n
Chromatograph
Measurement
PMlO
PM,,
Mass
PM,
Ammonium I o n
Daily, 24
Hours/Day
Automated C o l o r i m e t r i c
Analysis on f Q u a r t z - F i b e r
F i l t e r E x t r a c t s w i t h TRAACS
800 Technicon System
PM,
Organic and
D a i l y , 24
Hours/Day
Thermal/Optical Reflectance
Carbon Analysis on 0.5 cm2
Punches from P r e - f ir e d Q u a r t z F i b e r F i l t e r s w i t h DRI/OGC
Thermal/Opti c a l Carbon
Analyzer
Elemental Carbon
resuspended road dust.
These samples were
d r i e d , sieved, and resuspended i n t o a s t i l l i n g
chamber using a forced a i r j e t .
PM,, and PM2.5
samplers were placed i n t h e chamber and t h e
resuspended d u s t was sampled j u s t as i t would be a t
a receptor s i t e .
The f i l t e r deposits were then
submitted t o t h e same chemical analyses performed
on r e c e p t o r sampl es
Cool ing- tower p l ume sampl es
were c o l l e c t e d u s i n g a suspended p l a t f o r m t o l o c a t e
t h e sampler i n t h e plume t o sample cooling-tower
emissions. Concurrent upwind background samples
were a l s o taken t o a l l o w t h e s u b t r a c t i o n o f
p a r t i c l e s from t h e ambient a i r which were entrained
i n t h e plume. The background sample was taken over
a longer p e r i o d than t h e plume sample t o acquire a
mass 1oadi ng s u f f i c i e n t f o r chemical analyses. The
changing meteorology over t h e sampling p e r i o d d i d
n o t guarantee t h a t t h e background sample was
uninfluenced by t h e plume b u t t h e winds d u r i n g t h e
sample p e r i o d g e n e r a l l y placed t h e background s i t e
upwind o f t h e power p l a n t .
Samples were taken on f i l t e r s w i t h a D R I
MEDIUM-VOLUME PM, (DRI-10) sampler. The DRI-10 i s
a special sampler designed t o c o l l e c t PM, samples
onto Teflon-membrane and p r e - f i r e d q u a r t z - f i b e r
f i l t e r s a t a f l o w r a t e o f 30 l i t e r s per minute.
I n a d d i t i o n t o t h e PM, measurements, a Meloy
Model
285
hydrogen
sulfide
analyzer
and
meteorological monitors were i n s t a l l e d a t t h e
sampl i n g s i t e t o continuously monitor hydrogen
s u l f i d e (H,S), wind speed, wind d i r e c t i o n , sigma
theta, temperature, and re1a t i v e humidity. These
continuous measurements were averaged over s i x minute and one-hour i n t e r v a l s .
.
Table 1 summarizes t h e ambient measurements.
Chow (1987) describes t h e a n a l y s i s methods which
were a p p l i e d i n t h i s study.
Source samples f o r
soil,
paved-road dust,
storage p i l e s ,
and
geothermal cool ing- tower p l umes were a1so c o l 1ected
i n both PM,
and PM,
( p a r t i c u l a t e matter w i t h
aerodynamic diameter 'less than 2.5 microns) s i z e
fractions.
Other source chemical f i n g e r p r i n t s included
t h e Denver Brown C1 oud wood-burni ng source p r o f i1e
(Watson e t al., 1988b), t h e S t a t e o f Nevada A i r
P o l l u t i o n Study (SNAPS) mobile source p r o f i l e f o r
automobile emissions (Watson e t al., 1988a), t h e
South Coast A i r Q u a l i t y Management D i s t r i c t ' s
Geological samples were taken from vacant
areas and storage p i l e s i n t h e v i c i n i t y o f
t h e s a m p l i n g , s i t e and geothermal p l a n t .
Samples
were
also
swept from roadways t o represent
1116
Egami e t a l .
Table 1 (continued)
Pleasant V a l l e y Source Apportionment Study
Ambient Measurements"
Sampl ing
Period
Measurement
Met hod/ Instrument
PMlO
D a i l y , 24
Hours/Day
D R I MEDIUM-VOLUME ( PM,),
Sampler
Hydrogen Sul f i d e
Hourly, 24
Hour s/Day
F1ame Photometric/Mel oy 285
Wind Speed
Hourly, 24
Hour s/Day
Cup Anemometer/Met One
Wind D i r e c t i o n
Hourly, 24
Hours/Day
Vane/Met One
Sigma Theta
Hourly, 24
Hours/Day
Computed/Campbell 21X
Temperature
Hourly, 24
Hours/Day
Thermistor/Met One
Re1a t ive Humid i t y
Hourly, 24
Hours/Day
Resistance/Met One
Measurement
"Chow (1987) describes t h e measurement processes, data processing, and q u a l i t y
assurance procedures.
The EPA/DRI Chemical Mass Bal ance receptor
model (Watson e t a1 , 1990) was applied t o t h e PM,
chemical composition measurements f o l l o w i n g t h e
appl ic a t i on and Val id a t ion protocol s o f Pace and
Watson (1987). A f t e r several i n i t i a l t e s t s , t h e
e i g h t source p r o f i l e s which were chosen f o r
a p p l i c a t i o n t o t h e d a t a sets were: primary s o i l
d u s t (COMP1, COMPE), primary c o n s t r u c t i o n dust
(CDLIME) , primary motor v e h i c l e exhaust (MVRENOI),
primary r e s i d u a l o i l combustion (ROILSD), primary
plume emissions (PLUMEl),
secondary ammonium
n i t r a t e (NH4N03),
secondary ammonium s u l f a t e
(NH4S04, NH4HS04), and secondary organic carbon
(ORGANICS).
The v e g e t a t i v e burning source
c o n t r i b u t i o n was small and t h e omission o f t h i s
source-type d i d n o t change t h e o v e r a l l modeling
results.
1ime/gypsum and r e s i d u a l o i l combustion source
p r o f i l e s (Cooper e t al.,
1987), and s i n g l e c o n s t i t u e n t source p r o f i l e s (Watson, 1979) f o r
secondary ammonium s u l f a t e , secondary ammonium
n i t r a t e , and secondary organic carbon.
.
Figure 1 shows t h e chemical f i n g e r p r i n t s o f
t h e d i f f e r e n t emissions sources which are expected
t o c o n t r i b u t e t o PM,
concentrations i n Pleasant
Valley.
The power-plant c o o l i n g tower contains
mostly s o l u b l e species such as ammonium, potassium,
nitrate,
sulfate,
and c h l o r i d e ions.
These
probably o r i g i n a t e from s a l t s d i s s o l v e d i n t h e
water. Copper, zinc, arsenic, bromine, palladium,
s i l v e r , cadmium, and l e a d are a l s o found i n t h e
plume, b u t a t l e v e l s which are much l e s s than
0.01%. The m e t a l l i c species may have o r i g i n a t e d i n
t h e power-pl ant plumbing Others may be dissolved
i n t h e water. Arsenic, f o r example, i s o f t e n found
i n Nevada well-water.
Some o f these species may
a l s o have been e n t r a i n e d i n t h e plume from d i l u t i o n
w i t h t h e ambient a i r and are n o t e n t i r e l y
e l i m i n a t e d by t h e background s u b t r a c t i o n . None o f
these species i s present a t l e v e l s which would be
considered d e l e t e r i o u s t o health. The power-pl ant
plume f i n g e r p r i n t i s s u b s t a n t i a l l y d i f f e r e n t from
t h e chemical f i n g e r p r i n t s o f o t h e r sources.
.
RESULTS AND DISCUSSION
PM, concentrations were e n e r a l l y low, w i t h an
average o f 13.8 f 7.4 pg/m9; over t h e sampling
period. The highest PM, concentration o f 40.9 f
2.1 pg/m3 occurred on 3/22/88 and i s much lower than
t h e National Ambient Q u a l i t y Standard (NAAQS) 24hour PM,
standard o f 150 pg/m3.
Among t h e 41
chemical species which were sought, o n l y those
common t o geological c r u s t a l m a t e r i a l (such as
1117
Egami et a7.
Geological Source Profile
Geological Source Profile
(From COMPO
(From COMPP)
Percent of Mass Emissions
100
101
11
10
1
1
0.1
0.1
0.0 1
0.0 1
0.001
........................................
0.001
NKNSOEASPSCKCTVCMFCNCZQASBRSYZMPACl8SBLHP
H*OOCCLl
4 34
Percent of M a s s Emissions
NKNSOEASPSCKCTVCMFCNCZQASBR3YZMPACl3SBLHP
L A I RNEOIUNASERBR RODQDNNBAAQB
H*OOCCLI
4 34
Chemical Species
Plume With Background Substracted
(From PLUME11
!Percent of Mass Emissions
Chemical Species
,
Motor Vehicle Profile
(From MVRENOS)
Percent of M a s s Emiasiona
100 9
10
10
1
1
0.1
0.1
0.0 1
0.0 1
0.001
.........................................
0.00 1
NKNSOEASPSCKCTVCMFCNCZQASBRSYZMPACI8SBLHP
H*OOCCLI
4 34
NKNSOEASPSCKCTVCMFCNCZQASBR3YZMPAClSSBLHP
L A I RNEOIUNASERBR RODQDNNBAAQB
H*OOCCLI
4 34
Chemical Species
Figure 1.
L A I RNEOIUNASERBR RODODNNBAAQB
L A I RNEOIUNASERBR RODQDNNBAAQB
Chemical Species
Chemical Source P r o f i1es Appl i e d i n the P1easant Val 1ey Source Apportionment
Study. The p r o f i l e s are: a) Composite Geological Source P r o f i l e around the
Sampling S i t e (COMPl), b) Composite Geological Source P r o f i l e from t h e Geothermal
P l a n t (COMP2), c) Cool ing-Tower Plume Source P r o f i l e (PLUME1) w i t h Background
Subtraction, and d) SNAPS Motor Vehicle Source P r o f i l e (MVREN04).
contribution
estimates.
Primary
geological
m a t e r i a l was t h e major source c o n t r i b u t o r and
accounts f o r 58% o r 8.0 f 1.4 pg/m3 o f t h e average
PM.,
Primary motor v e h i c l e exhaust was t h e second
l a r g e s t source c o n t r i b u t o r a t 17% o r 2.3 f 0.2 pg/m3
o f t h e average PM.,
The geothermal cool ing-tower
plume was detectable and c o n t r i b u t e d an average o f
9% o r 1.3 f 0.3 pg/m3 o f t h e average PM.,
Primary
c o n s t r u c t i o n dust, secondary organics, secondary
ammonium n i t r a t e , and secondary ammonium s u l f a t e
source c o n t r i b u t i o n s were small, ranging from 0.3
f 0.03 t o 0.8 f 0.2 pg/m3 o f t h e average PM.,
aluminum, s i l i c o n , potassium, calcium, and i r o n ) ,
secondary ammonium, n i t r a t e , s u l f a t e , and organic
and elemental carbon were found. Most o f t h e o t h e r
elemental concentrations i n c l u d i n g t o x i c species
such as mercury, cadmium, arsenic, and selenium,
were a t o r near instrument d e t e c t i o n l i m i t s . These
d e t e c t i o n l i m i t s are orders o f magnitude lower than
hazardous 1eve1s
.
The Chemical Mass Balance receptor model was
a p p l i e d t o each 24-hour sample. With t h e selected
was
source p r o f i l e s , n e a r l y 100% o f t h e PM,
accounted f o r w i t h i n measurement and modeling
u n c e r t a i n t i e s , i n over 90% o f t h e cases.
The
values o f a l l CMB performance measures are w e l l
w i t h i n t h e c r i t e r i a range s p e c i f i e d i n EPA model
a p p l i c a t i o n and Val i d a t i o n p r o t o c o l s (Pace and
Watson, 1987).
The highest PM,
c o n c e n t r a t i o n o f 40.9 f 2.1
pg/m3 was measured on 3/22/88. T h i s value i s three
times h i g h e r than t h e average PM, concentration o f
13.8 pg/m3 over t h e sampling period. The 24-hour
average wind speed on 3/22/88 was 4.8 m/s and t h e
highest h o u r l y average was 10.4 m/s. Over 72% o r
2.9 k 2.5 pg/m3 o f t h e PM, mass on 3/22/88 was
c o n t r i buted by geological m a t e r i a1 No detectable
plume c o n t r i b u t i o n was found on t h i s h i g h PM, day.
Figure 2 d i s p l a y s t h e i n d i v i d u a l 24-hour
source apportionment r e s u l t s f o r t h e study p e r i o d
and Figure 3 r e p o r t s t h e average source
.
1118
Geothermal cool ing-tower plume c o n t r i b u t i o n s
ranged from 0.34 f 0.49 pg/m3 on 3/19/88 t o 3.8 f
0.93 on 3/28/88. The plume c o n t r i b u t i o n s were
about t h r e e times h i g h e r than t h e average 1.3 f 0.3
pg/m3 on 3/27/08, 3/28/88, and 3/29(88, rang ing from
3.0 f 0.7 t o 3.8 2 0.9 pg/m.
The h o u r l y
meteorological
data
indicate
predominantly
n o r t h e r l y and n o r t h w e s t e r l y winds on these days
w i t h an average wind speed o f 2 t o 4 m/s. Hourly
average HS, concentrations i n excess o f 0.1 ppb were
detected 10% o f t h e time on these days, which
confirms t h e plume impact.
Egami e t a l .
Average and maximum PM,
concentrations
measured i n Pleasant Valley are much lower
than Federal standards.
No s i g n i f i c a n t
q u a n t i t i e s of t o x i c inorganic species were
found i n ambient a i r .
0
Resuspended dust c o n t r i b u t e d over 60%, motor
v e h i c l e exhaust c o n t r i b u t e d approximately 20%,
and t h e geothermal cooling-tower
plume
c o n t r i b u t e d l e s s than 10% o f t h e average PM,
i n ambient a i r . The absolute concentrations
c o n t r i b u t e d by any source are much lower than
those l e v e l s which have been found t o be
d e l e t e r i o u s t o pub1 i c health.
0
The c o n t r i b u t i o n s from each o f these sources
are f a r below l e v e l s which have been found t o cause
adverse h e a l t h e f f e c t s .
CONCLUSIONS
REFERENCES
The conclusions t o be derived from t h i s study
are the f o l l o w i n g :
0
Chow, J.C., 1987. Q u a l i t y Assurance P r o j e c t Plan
f o r t h e Determination o f P a r t i c l e Size
D i s t r i b u t i o n and Chemical Composition o f
P a r t i c u l a t e Matter from Selected Sources i n
C a l i f o r n i a P a r t 11:
Laboratory Operations.
Prepared f o r t h e
Document No. 8069.1Fl.
Cal i f o r n i a A i r Resource Board, Sacramento, CA,
by t h e Desert Research I n s t i t u t e , Reno, NV.
The chemical composition o f t h e geothermal
cool ing-tower plume c o n s i s t s mostly o f
s u l f a t e , ammonium, c h l o r i d e , and some t r a c e
elements. The t r a c e elements are m e t a l l i c i n
nature and probably d e r i v e from t h e metals
used i n t h e power-plant plumbing.
Concentration (ug/m3)
50
10
0
-10
I
I
I
3/18
1
I
I
I
3/21
I
I
I
3/24
I
I
3/27
I
I
Set,
Sec. Sulfate
Sec. Nitrate
Pri. Cons.
I
4/02
Organics(
Pri. Mob.
I
I
3/30
Pri. Geol.
Figure 2.
I
I
I
I
Pri. plumes
Unexplained
Twenty-four-hour Source C o n t r i b u t i o n Estimates t o PM,
f o r t h e Pleasant
V a l l e y Source Apportionment Study. When t h e unexplained c o n t r i b u t i o n i s
p o s i t i v e , t h e CMB apportionment has n o t accounted f o r a1 1 c o n t r i b u t o r s t o
measured mass. When t h e unexplained c o n t r i b u t i o n i s negative, the sum of
a l l c o n t r i b u t i o n s exceeds t h e measured mass. A l l negative c o n t r i b u t i o n s
are w i t h i n c a l c u l ated and measured u n c e r t a i n t y i n t e r v a l s
.
1119
Egami e t a l .
Primary Cooling-Tower Plume
Secondary Organics 0.8+-0.2
1.3+-0.3
Primary Geological
8.0+-1.4
Source Contributions to 13.8 pg/m3 Average PM,, Mass
Figure 3 .
Calculated Source Contributions (pg/m3) t o Average Measured
PM,
a t Pleasant V a l l e y Sampling S i t e between 3/18/88 and
4/4/88.
Cooper, J.A., D.C. Redline, J.R. Sherman, L.M.
Valdovinos, W.L. Pollard, L.C. Scavone, and C.
Badgett-West, 1987.
PM,
Source Composition
L i b r a r y f o r the South Coast A i r Basin. F i n a l
Report.
South Coast A i r Qualit y Management
D i s t r i c t , E l Monte, CA.
Watson, J.G., J.C. Chow, and C.V. Mathai, 1989.
Receptor Model s i n A i r Resources Management:
A Summary o f t h e APCA I n t e r n a t i o n a l S p e c i a l t y
Conference, JAPCA, 39, 419.
Watson, J.G., N.F. Robinson, J.C. Chow, R.C. Henry,
B.M. Kim, T.G. Pace, E.L. Meyer, Q. Nguyen
(1990). "The USEPA/DRI Chemical Mass Balance
Receptor Model, Version 7. ''
Accepted f o r
pub1i c a t i o n i n €nviron. Software.
Pace, T.G., and J.G. Watson, 1987. Protocol f o r
Applying and V a l i d a t i n g t h e CMB Model.
EPA
450/4-87 - 010, U S Env ironment a1 P r o t e c t ion
Agency, Research T r i a n g l e Park, NC.
..
It
na ~
.
1 P
U. ,
1979.
Chemi c a i i i eiirleni B a i ance
Receptor Model Methodology f o r Assessing t h e
Sources o f Fine and T o t a l P a r t i c u l a t e Matter.
Ph.D. D i s s e r t a t i o n , Oregon Graduate Center,
Beaverton,
OR.
University
Microfilms
I n t e r n a t i o n a l , Ann Arbor, MI.
+en...
~ U I I u
,
Watson, J.G., J.C. Chow, R.T. Egami, C.A. Frazier,
A. Goodrich, and C. Ralph, 1988a. PM, Source
Apportionment i n Reno and Sparks, Nevada f o r
State Implementation P1 an Development, Volume
I: Modeling Methods and Results. Document
8086.2Fl.
Prepared as p a r t o f t h e State o f
Nevada A i r P o l l u t i o n Study (SNAPS) by Desert
Research I n s t i t u t e , Reno, NV.
Watson, J.G.,
J.C. Chow, L.W. Richards, S.R.
Anderson, J.E. Houck, and D.L. D i e t r i c h ,
1988b. The 1987-88 Metro Denver Brown Cloud
A i r P o l l u t i o n Study Volume 111:
Data
Interpretation.
DRI Document No. 8810.1F3.
Prepared f o r the Greater Denver Chamber o f
Commerce, Denver, CO, by Desert Research
I n s t i t u t e , Reno, NV.
1120