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.

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  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

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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

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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

—
—

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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

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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

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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

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Environmental Protection
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Information
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