United States
Environmental Protection
Agency
Environmental Sciences Research^
Laboratory -
Research Triangle Park NC 2771 1
Research and Development
EPA-600/S3-81-032 July 1981
Project Summary
Atmospheric
Measurements of Selected
Hazardous Organic Chemicals
H. B. Singh, L. J. Salas, A. Smith, R. Stiles, and H. Shigeishi
Environmental Prcte.ro.u i-,^.; \
Region V, Library
230 South Dasrbora Staot
Chicago, Illinois
Methods ware developed for the
accurate analysis of an expanded list
of hazardous organic chemicals in the
ambient air. On-site analysis using an
instrumented mobile laboratory was
performed for a total of 44 organic
chemicals. Twenty of these are sus-
pected mutagens or carcinogens. Tox-
icity studies for several others are
currently pending. Six important mete-
orological parameters were also mea-
sured. Four field studies, each about
two-weeks duration, were conducted
in Houston, Texas; St. Louis, Missouri;
Denver, Colorado; and Riverside,
California. An around-the-clock mea-
surement schedule (24 hours per day,
seven days a week) was followed at all
sites, permitting extensive data col-
lection. Widely varying weather condi-
tions facilitated observations of pol-
lutant accumulation and wide variabil-
ities in concentrations of pollutants at
a given site. Concentrations, variabil-
ities, and human exposure (daily dos-
ages) were determined for all measured
pollutants. The diurnal behavior of
pollutants was studied. Average daily
outdoor exposure levels of all four
sites were determined to be 197
Aig/day for halomethanes (excluding
chlorofluorocarbons), 140 //g/day for
haloethanes and halopropanes, 89
//g/day for chloroalkenes, 32 fjg/day
for chloroaromatics, 1,394 //g/day
for aromatic hydrocarbons, and 479
/ug/day for secondary organics. Expo-
sure levels at Houston, Denver, and
Riverside were comparable, but levels
were significantly lower at St. Louis.
This Project Summary was devel-
oped by EPA's Environmental Sciences
Research Laboratory, Research Tri-
angle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
Because a vast number of potentially
harmful organic chemicals are released
into the environment, it is becoming
increasingly apparent that these chemi-
cals contribute to the growing rate of
cancer in industrialized countries. De-
spite recent and intense interest in toxic
chemicals, the atmospheric abundance
and fate of this important group of pollu-
tants remains poorly understood. The
purpose of this study is to characterize
the concentrations of a wide range of
toxic organic chemicals at several urban
and source-specific locations under
varying meteorological and source-
strength conditions. The overall program
of analytical methods development,
field measurements, data collection,
and analysis is expected to provide
information that will permit determina-
tion of the atmospheric abundance and
chemistry of this potentially harmful
group of chemicals.
-------
The research plan is primarily designed
to answer the following basic questions:
• What are the concentration levels
and variabilities of selected toxic
organic chemicals in typical urban
environments?
• What are the atmospheric fates of
these chemicals?
• What is the extent of human expo-
sure to selected toxic chemicals?
The answers to these questions will
be sought through a combination of
approaches:
4 A comprehensive program of field
measurements at several urban
locations and near several source-
specific locations.
• Analysis of data collected during
the field measurements and inte-
gration of this information with
data acquired from outside sources.
• Compilation of all available infor-
mation dealing with the sources,
sinks, chemistry, and effects (health
as well as environmental) of the
toxic chemicals of interest.
This report presents the results achieved
during the second year of a three-year
research effort. Analysis of data col-
lected during the second year is by no
means complete. Additional analysis
will be presented in forthcoming reports
and publications.
Procedures
The second-year research effort com-
prised a program of analytical methods
development, field-data collection, data
processing, and data interpretation for
an expanded set of hazardous organic
chemicals. All field measurements
were conducted in-situ with the help of
an instrumented mobile laboratory.
After completion of the program of
methods development, four field studies
of roughly two-week duration each
were conducted in Houston, Texas (Site
4); St. Louis, Missouri (Site 5); Denver,
Colorado (Site 6); and Riverside, Cali-
fornia (Site 7). These field studies were
completed between early May and late
July of 1980. The studies were designed
to complement the three field studies
conducted during the first year of this
project at Los Angeles, California (Site
1); Phoenix, Arizona (Site 2); and Oak-
land, California (Site 3). Continuing
practice of the first-year research, all
field work in the second year was per-
formed on a round-the-clock basis (24
hours per day, seven days a week),
permitting the efficient collection of a
large amount of data. A total of 44
organic chemicals and 5 meteorological
parameters were measured. Over 20 of
these chemicals are either mutagens or
suspected carcinogens; in many other
cases, toxicity studies are currently
incomplete.
A total of 44 trace chemicals were
targeted and are categorized in Table 1.
The categories include chlorofluorocar-
bons, halomethanes, haloethanes, halo-
propanes, chloroalkenes, chloroaromat-
ics, aromatic hydrocarbons, and oxy-
genated and nitrogenated species. The
chlorofluorocarbons are considered to
be nontoxic but are excellent tracers of
polluted air masses. Formaldehyde was
the only aldehyde measured, although
work is in progress to develop measure-
ment methods utilizing liquid chroma-
tographic techniques for other aliphatic
and aromatic aldehydes. A number of
important meteorological parameters
(wind speed, wind direction, tempera-
ture, pressure, relative humidity, and
solar flux) were also measured.
For all halogenated species and or-
ganic nitrogen compounds shown in
Table 1, electron-capture detector (ECD)
gas chromatography (GC) was the pri-
mary means of analysis. The aromatic
hydrocarbons were measured using
flame-ionization detector (FID) gas
chromatography. Formaldehyde was
the only species measured by the wet
chemical analysis technique utilizing
the chromotropic acid procedure (U.S.
Public Health Science, 1965).
The identity of trace constituents was
established by using the following
criteria:
• Retention times on multiple GC
columns (minimum of two columns)
• EC thermal response
• EC ionization efficiency
• Limited GC/MS analysis.
Details of these comparisons for halo-
carbon species, organic nitrogen com-
pounds, and aromatic hydrocarbons
have already been published. The use of
secondary standards nearly three times
a day clearly demonstrated the excellent
precision that was obtainable during
field studies. The precision of reported
field measurements is estimated to be
±5 percent. The measurements pre-
sented here have an overall estimated
accuracy of better than ±15 percent.
The four selected sites in Houston,
Texas; St. Louis, Missouri; Denver,
Colorado; and Riverside, California, in
all cases, represented an open urban
atmosphere. There were no nearby
sources or topographical features that I
could directly affect the representative-
ness of the measurements. Despite the
logistical difficulty, a 24-hour measure-
ment schedule offers the most efficient
means of collecting the maximum amount
of data to characterize the burden of
toxic organic chemicals in the ambient
air. In addition, night abundances of
trace chemicals are likely to provide
crucial information about the sources
and sinks of measured species. There-
fore, during all field programs a 24-
hour-per-day, seven-days-a-week mea-
surement schedule was followed.
During the sampling programs, gen-
eral weather conditions were not un-
usually severe. In Houston, rainfall and
passage of fronts did not allow for
severe pollution episodes. St. Louis
weather produced relatively clean en-
vironmental conditions. Weather in
Denver was moderately hot and stag-
nant. At Riverside, the first half of the
study period exhibited relatively clean
conditions; the second half was more
representative of hot and somewhat
stagnant conditions.
Results
Experiments at all sites were per-4
formed satisfactorily, and no breakdowns i
were encountered. The entire data base
was collected, validated, and compiled
on our master data file. This file also
contains the data that were collected in
the first year of this research effort. All
of the meteorological information is
currently on chart papers and is easily
accessible. The master data file will be
updated as additional studies are con-
ducted. While the collected data have
been compiled, validated, and statisti-
cally treated, no detailed meteorological
analyses have been conducted. The
interpretation of data is therefore by no
means complete, and further analysis
and interpretations will continue.
Table 2 summarizes data on all of the
organic chemicals measured during the
four field studies; maximum, minimum,
and average concentrations are pre-
sented for each of the measured species.
The averages and the standard devia-
tions associated with the concentration
data are calculated from the actual data
acquired and involve no interpolations.
In addition. Table 2 presents an average
daily outdoor exposure for each of the
species and the standard deviations
associated with this average daily expo-
sure. The value is determined based on*
an average daily air intake of 23 m3 aim
-------
Table 1. Target Chemicals for Second-Year Research
Chemical Name* Chemical Formula
Toxicitrf
Chloro-Fluorocarbons
Trichloromonofluoromethane (F11)
Dichlorodifluoromethane (F12)
Trichlorotrifluoroethane (F113)
Dichlorotetrafluoroethane (F114)
Halomethanes
Methyl chloride
Methyl bromide
Methyl iodide
Methylene chloride
Chloroform
Carbon tetrachlorlde
Haloethanes and halopropanes
Ethyl chloride
1.1 Dichloroethane
1,2 Dichloroethane
1,2 Dibromoethane
1,1,1 Trichloroethane
1.1,2 Trichloroethane
1,1,1,2 Tetrachloroethane
1,1,2,2 Tetrachloroethane
1,2 Dichloropropane
Chloroalkenes
Vinyl/dene chloride
(cis) 1,2 Dichloroethylene
Trichloroethylene
Tetrachloroethylene
Ally/ chloride
Hexachloro-1,3 butadiene
Chloroaromatics
Monochlorobenzene
a-Chlorotoluene
o-Dichlorobenzene
m-Dichlorobenzene
p-Dichlorobenzene
1,2,4 Trichlorobenzene
Aromatic hydrocarbons
Benzene
Toluene
Ethyl benzene
m/p-Xylene
o-Xylene
4-Ethyl toluene
1,2,4 Trimethyl benzene
1,3,5 Trimethyl benzene
Oxygenated and nitrogenated species
Formaldehyde
Phosgene
Peroxyacetyl nitrate (PAN)
Peroxypropionyl nitrate (PPN)
Acrylonitrile$
CCIaF
CCIzFz
CCIzFCCIFz
CCIFzCCIFz
CHaCI
CHaBr
CHal
CHzClz
CHCIa
ecu
CzHsCI
CHCIzCHa
CHzCICHzCI
CHzBrCHzBr
CHaCCIa
CHzCICHCIz
CHCICCIa
CHCIzCHCIz
CHzCICHCICHa
CHz=CCIz
CHCI=CHCI
CHCf=CCI2
CCIfCCIz
CICHzCH=CHz
ClzC=CCI-CCI=CCIz
CeHsCHzCI
1,2,4
CeM.
1,2,4 CtHa(CHa)a
1,3.5 CeHafCHah
HCHO
COCIz
CHaCOOONOz
CHaCHtCOOONOz
CH^CN
These chlorofluorocarbons
are nontoxic but have
excellent properties as tracers
of urban air masses
BM*
BM
SC^.BM
BM
SC.BM
SC.NBM}
NBM
SC.BM
SC
Weak BM
SC.NBM
NBM
SC.BM
BM
SC.BM
NBM
SC.BM
SC
SC
BM
BM
SC
SC.BM
Phytotoxic
Phytotoxic
SC
*ln addition to chemical species, meteorological parameters were measured. These were: wind speed, wind direction, temperature,
pressure, relative humidity and solar flux
^BM: Positive mutagenic activity based on Ames salmonella mutagenicity test (Bacterial Mutagens)
NBM: Not found to be mutagens in the Ames salmonella test (Not Bacterial Mutagens)
SC: Suspected Carcinogens
'atisfactory measurement method for ambient analysis is not available
-------
Table 2. Concentrations and Daily Outdoor "Exposures of Measured Chemical Species
Houston - Site 4
(14-25 May 1980)
St. Louis • Site 5
(29 May - 6 Jun 1980)
Concentration
(ppt)
Chemical Group and Species
Chlorofluorocarbons
Trichlorofluoromethane (F1 1)
Dichlorofluoromethane IF 12)
Trichlorotrifluoroethane (Ft 13)
Dichlorotetrafluoroethane (F1 14)
Helomethanes
Methyl chloride
Methyl bromide
Methyl iodide
Methylene chloride
Chloroform
Carbon tetrachloride
Haloethanes and halopropanes
Ethyl chloride
1.1 Dichloroethane
1,2 Dichloroethane
1,2 Dibromoethane
1,1.1 Trichloroethane
1, 1.2 Trichloroethane
1,1.1.2 Tetrachloroethane
1. 1.2.2 Tetrachloroethane
1,2 Dichloropropane
Chloroalkenes
Vinylidene chloride
Ids) 1.2 Dichloroethylene
Trichloroethylene
Tetrachloroethylene
Allyl chloride
Hexachloro-1 ,3 butadiene
Chloroaromatics
Monochlorobenzene
a-Chlorotoluene
o-Dichlorobenzene
m-Dichlorobenzene
p-Dichlorobenzene
1.2.4 Trichlorobenzene
Aromatic hydrocarbons
Benzene
Toluene
Ethyl benzene
m/p Xylene
o-Xylene
4-Ethyl toluene
1,2,4 Trimethyl benzene
1,3.5 Trimethyl benzene
Oxygenated species
Formaldehyde
Phosgene
Peroxyacetyinitrate (PAN)
Peroxyproponlynitrate (PPN)
Mean
474
897
199
28
955
100
3.6
574
423
404
227
63
1512
59
353
32
12
11
81
25
71
144
401
<5
11
309
<5
7
7
—
2
5780
10330
1380
3840
1307
870
1150
460
—
<20
438
110
S.D.t
178
474
190
10
403
58
2.2
553
749
449
273
20
1863
72
263
24
15
9
37
36
59
195
598
—
20
517
—
9
8
—
2
5880
1085O
1400
4270
1460
1030
1470
800
—
—
836
140
Max.
1105
2817
1664
58
2284
278
11.2
3404
5112
2934
1248
126
7300
368
1499
129
80
77
253
136
429
960
3215
<5
154
2785
58
67
47
—
13
37700
65650
7280
23780
9790
7470
9260
5350
—
<20
4350
630
Min.
305
482
37
12
531
45
0.6
49
38
126
10
9
50
10
134
<5
2
2
22
<4
21
5
34
<5
1
9
<5
1
1
—
1
840
1040
50
270
80
60
50
70
—
—
-------
1 Table 2. (continued)
Denver - Site 6
(15-28 Jun 19801
Riverside • Site 7
(1-13 July 1980)
Chemical Group and Species
Chlorofluorocarbons
Trichlorofluoromethane (F1 1)
Dichlorofluoromethane (F12)
Trichlorotrifluoroethane (F113)
Dichlorotetrafluoroethane (F114I
Halomethanes
Methyl chloride
Methyl bromide
Methyl iodide
Methylene chloride
Chloroform
Carbon tetrachloride
Haloethanes and halopropanes
Ethyl chloride
1,1 Dichloroethane
1,2 Dichloroethane
1.2 Dibromoethane
1.1,1 Trichloroethane
1.1.2 Trichloroethane
1. 1, 1,2 Tetrachloroethane
1, 1,2,2 Tetrachloroethane
1,2 Dichloropropane
Chloroalkenes
Vinylidene chloride
(cis/ 1,2 Dichloroethylene
Trichloroethylene
Tetrachloroethylene
Ally! chloride
Hexachloro-1 ,3 butadiene
Chloroaromatics
Monochlorobenzene
a-Chlorotoluene
o-Dichlorobenzene
m-Dichlorobemene
p-Dichlorobenzene
1.2.4 Trichlorobenzene
Aromatic hydrocarbons
Benzene
Toluene
Ethyl benzene
m/p Xylene
o-Xylene
4-Ethyl toluene
1,2.4 Trimethyl benzene
1,3,5 Trimethyl benzene
Oxygenated species
Formaldehyde
Phosgene
Peroxyacetylnitrate (PAN}
Petroxyproponylnitrate (PPN)
Mean
637
1005
221
34
763
124
1.8
967
18S
174
41
65
241
31
713
27
W
10
48
31
76
196
394
<5
2
290
<5
26
8
—
6
4390
6240
2220
2860
1280
900
1410
340
12300
<20
443
46
S.D.
255
565
235
9
132
SI
1,0
926
206
19
24
31
297
IS
553
10
12
3
14
49
61
313
158
—
1
217
—
34
7
—
4
3940
5280
3130
3320
1210
760
2310
240
5900
—
1246
47
Max.
1246
3178
1608
60
1157
227
4.8
4874
1636
274
125
142
2089
78
2699
56
89
17
99
224
605
2483
1130
<5
7
1114
111
227
36
—
35
23910
24600
18520
20850
6000
4380
154SO
1290
28700
<20
11647
318
Min.
289
471
28
17
519
23
0.6
108
19
116
10
11
54
10
171
7
5
3
20
<4
25
7
99
<5
0.4
33
-------
25°C and 1 atmosphere for a 70-kg
male. The daily exposures were calculated
by estimating hourly values by linear
interpolations between measured data.
Much of the information presented in
table 2 is self-explanatory, so only
salient observations will be made below.
Table 3 summarizes the total average
exposure for the four sites to each
chemical category as defined in Table 2.
Chlorofluorocarbons (CFCs)
Four CFCs (fluorocarbon 11, 12,113,
and 114) were measured. As indicated
earlier, CFCs are not expected to be toxic
to the human body. They do, however,
act as useful indicators of urban trans-
port, and were, therefore, routinely
measured throughout the sampling pro-
gram.
Halomethanes
Six halomethanes were measured.
As can be seen from Table 1, all six of
these chemicals are either mutagens or
suspected carcinogens. Chloroform
levels are significantly elevated in the
urban environments. Concentrations
approaching 5 ppb were encountered at
more than one site. The average daily
intake of chloroform was as low as 9
/Kg/day in St. Louis and was close to 80
/jg/day in Riverside (Table 2). While the
sources of chloroform are still largely
unknown, automobiles, chlorination of
water, and direct emissions probably all
contribute significantly. The variability
of chloroform at Riverside is nearly
identical to methylene chloride, further
confirming its urban source.
Haloethanes and Halopropanes
Nine important chemicals in the
haloethane and halopropane category
were measured (Table 2). Since this is
the first measurement of ethyl chloride,
no comparative data are available. It is
estimated that 0.01 million tons of ethyl
chloride is released into the atmosphere
every year in the United States. Mea-
surements in this study suggested high
levels of this chemical in Houston,
where concentrations as high as 1.3
ppb were encountered. The average
concentration (0.23 ppb) and the daily
average exposure (14/ug/day) were also
highest in Houston.
Chloroalkenes
Six chloroalkenes were sought. Of
these, ally! chloride (a suspected car-
cinogen) was found to be present at
concentrations of less than 5 parts per
Table 3. Summary of Exposure to Hazardous Organic Chemical Groups
Total A verage Daily Exposure (fig/day)
Chemical Category*
Chlorofluorocarbons^
Halomethanes
Haloethanes and
halopropanes
Chloroalkenes
Chloroaromatics
Aromatic hydrocarbons
Oxygenated species
Houston
Site 4
205
203
210
88
37
2130
—
St. Louis
Site 5
141
97
59
78
25
430
344
Denver
Site 6
241
168
137
92
34
1616
396
Riverside
Site 7
262
319
153
98
—
1401
696
Average
of Sites
212
197
140
89
32
1394
479
*As defined in Table 2
t/VOT" suspected to be directly toxic
trillion at all sites. Vinylidene chloride (a
bacterial mutagen and a suspected car-
cinogen) was measured at an average
concentration of 10 to 30 parts per
trillion at all sites.
There are two dominant chloroethyl-
enes in the atmosphere: trichloroethyl-
ene and tetrachloroethylene. Trichloro-
ethylene is a large-volume chemical
(annual U.S. emissions = 0.15 million
tons) that is also a suspected carcino-
gen. The highest concentration of 2.5
ppb was measured at Denver (Table 2).
Typically the average concentrations
were between 0.1 to 0.2 ppb.
The second large-volume chloroethyl-
ene that is also a suspected carcinogen
is tetrachloroethylene. Its annual U.S.
emissions are estimated to be about 0.3
million tons. At all sites, the tetrachloro-
ethylene atmospheric abundance was 2
to 4 times that of trichloroethylene. This
is due to larger emissions as well as its
much longer lifetime when compared to
trichloroethylene. The highest concen-
tration of tetrachloroethylene was 7.6
ppb. The daily average exposure was
determined to be between 60 and 80
pig/day at all sites.
Chloroaromatics
Six Chloroaromatics were sought. No
data are being reported of p-dichloro-
benzene because of unknown inter-
ferences. Monochlorobenzene was the
most dominant of the chlorobenzenes
and its average concentration appeared
to be close to 0.3 ppb. The highest
concentration was 2.8 ppb in Houston.
This is not inconsistent with its large
source (0.1 to 0.15 million tons/year in
the United States) and its moderately
long lifetime.
Aromatic Hydrocarbons
Eight aromatic hydrocarbons were
sought. The two most dominant aromatic
hydrocarbons were benzene and toluene.
The average abundance of toluene ex-
ceeded that of benzene at all sites:
Average toluene/benzene concentra-
tion ratios at Sites 4, 5, 6, and 7 were
respectively 1.8, 1.1, 1.4, and 1.5. As
the air masses aged (or in cleaner j
environments) the toluene/benzene •
ratio decreases, largely because of the '
longer lifetime of benzene compared to
toluene (8 days versus 2 days). Highest
benzene and toluene concentrations of
38 ppb and 66 ppb were measured in
Houston.
A common source of all measured
aromatic hydrocarbons was indicated,
as the diurnal variation of all the aromatic
hydrocarbons at a given site was nearly
identical.
As a whole! the aromatic hydrocarbon
group is the most dominant, and daily
intake of this group was the highest at
all sites (Table 3).
Oxygenated Species
Four oxygenated species were sought:
formaldehyde, phosgene, peroxyacetyl
nitrate (PAN), and peroxypropionyl
nitrate (PPN). Liquid chromatographic
analysis of other aldehydes that are also
toxic is currently underway. Formalde-
hyde was measured at relatively high
concentrations that varied from 6 to 41
ppb. The abundance of formaldehyde
compared to most other suspected
carcinogens that were measured in
urban atmospheres is significant. It is
also found to be a bacteria mutagen and
a suspected carcinogen (Table 1). Phos- m
-------
gene data are limited because of instru-
mental and meteorological parameters.
As is clear from Table 2, PAN and PPN
levels were quite low at all sites. This
was largely attributable to the prevailing
weather. Maximum PAN levels at sites
4,5,6, and 7were4.4ppb,0.9ppb, 11.5
ppb, and 5.6 ppb. The PPN levels were
roughly lower by a factor of 5 when
compared to those of PAN.
Conclusions and
Recommendations
Table 2 summarizes the average
concentrations measured at each of the
sites antf the daily average exposure
based on a total air intake of 23 mVday
for a 70 kg male. The corresponding
standard deviations associated with
these parameters are shown in Table 2.
The mutagenicity and toxicity informa-
tion for individual species is also sum-
marized in Table 1. Table 3 summarizes
average exposure (jug/day) to individual
categories of chemical groups at each of
the sites. Overall, the total exposure to
measured toxic chemicals at Houston,
Denver, and Riverside was comparable
(it was significantly lower at St. Louis).
As a category, exposure to aromatic
hydrocarbons is the highest, and to
chloroaromatics the lowest, at all sites.
Hot-spots for specific toxic chemicals
are found at different locations. As is
clear from Table 2, the ambient levels of
1,2-dichloroethane (a suspected car-
cinogen) were significantly elevated at
the Houston site despite meteorological
conditions that were unfavorable to
pollutant accumulation. Hot-spots of
methylene chloride (a weak mutagen)
and chloroform (a suspected carcinogen)
were observed at Riverside. The high
concentrations of chloroform at River-
side are surprising. (No large sources
are known.) Special tests were con-
ducted to ensure the reliability of these
data: Chloroform data were found to be
accurate to within ± 10 percent. For-
maldehyde, another suspected carcino-
gen, was measured at high concentra-
tions at all sites.
In the third (final) year of this project, a
significant emphasis will be placed on
field measurements and on analysis
and interpretation of the data set col-
lected during this study. The major
effort in the third year will be devoted to:
• Expanding the list of toxic chem-
icals to be measured
• Conducting additional field studies
in selected p.S. cities
• Analyzing and interpreting all col-
lected field data
• Preparing a final report.
During the und of the second year,
and the early part of the third year of re-
search, efforts will be directed to devel-
oping measurement methods for ambient
aldehydes and ketones (as well as
formaldehyde, which was measured in
the second year). A high-pressure liquid
chromatograpti. (HPLC) has been ac-
quired and wil be utilized. Attempts to
identify currertly unidentified species
found to be nearly ubiquitously present
will continue, cind further efforts will be
made to improve the separation of
chlorinated aromatics (especially p-
CeH4CI2).
-,
H. B. Singh, L J. Salas, A. Smith, R. Stiles, andH. Shigeishiare with SRI Inter-
nationa I, Wen/o Park, CA 94025.
Larry Cupitt is the EPA Project Officer (see below).
The complete report, entitled "Atmospheric Measurements of Selected Haz-
ardous Organic Chemicals, " (Order No. PB81 -200 628; Cost:£&£& subject to
change) will be available only from:
Na\ ional Technical Information Service
52115 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Sciences Research Laboratory
U.Sf. Environmental Protection Agency
Research Triangle Park, NC27711
« US. GOVERNMENT PRINTING OfFKE 1W1 -757-01Z/7Z33
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
CHICAGO 1L 60604
------- |