EPA/AA/CTAB/PA/81-10
Brief Synopsis of EPA
Office of Research and Development
and the
Health Effects Institute Mobile Source Work
May, 1981
Control Technology Assessment and Characterization Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Office of Air, Noise and Radiation
U.S. Environmental Protection Agency
2565 Plymouth Road
Ann Arbor, Michigan 48105
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Summary
The EPA Office of Research and Development has many important mobile source
projects in progress as discussed in this paper while the Health Effects
Institute will begin work shortly. Some of the more important items that
can be noted at this point are given below.
1. ORD-ESRL has developed a preliminary method to collect gas phase hydro-
carbon samples from gasoline and Diesel vehicles for bioassay testing.
This method involves use of XAD-2 cartridge traps and is presently being
written up. After the method is available later this year, work can
start to make an assessment of the mutagenicity of the gas phase samples
relative to the particulates.
2. ORD-ESRL has done a number of tests to determine if N0£ in the
exhaust gas can cause artifact mutagen formation on the particulate
filter and thus an artificially high Ames test response. Preliminary
results indicate that no artifact will be formed provided that the N0£
levels in the diluted exhaust are below 5 ppm which is usually the case.
3. Significant work is being done to identify the compounds responsible for
the mutagenic activity in Diesel exhaust. Numerous oxygenated
polynuclear aromatic hydrocarbons and nitroaromatics have been
identified as being responsible for much of the mutagenic activity.
4. Additional light duty Diesel and gasoline vehicles have been tested.
Particulate emissions and Ames test response have been measured. Also,
several heavy duty Diesel engines have been tested. Much work will be
done on various synthetic fuels derived from coal and oil-shale in the
future.
5. ORD-EMSL has some short term monitoring work underway to measure
personal exposure to CO and correlate it to the readings taken at fixed
site NAAQS monitors. This work involves contractors measuring CO levels
along commuting routes and other places (e.g. central business district
and outlying areas).
6. A longer term CO monitoring project involving a large number of people
wearing CO monitors should be started soon. Their CO exposure will be
correlated to their personal activity and to readings obtained at the
fixed site NAAQS monitors.
7. Short term bioassay results have been obtained on a number of Diesel and
other samples including coke oven, cigarette smoke condensate, and
roofing tar emissions.
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7. Short term bioassay results have been obtained on a number of Diesel and
other samples including coke oven, cigarette smoke condensate, and
roofing tar emissions.
8. Skin tumorigenesis initiation data are available on Diesel particulate
samples and indicate these samples are less potent than coke oven
samples. Intraperitoneal injection results should be available shortly
but the intratracheal instillation results will not be available until
1983.
9. Results so far on whole animal inhalation work with Diesels have been
generally negative with the exception of some sister chromatid exchange
work with hamsters. The sister chromatid exchange work showed a linear
relationship between Diesel exposure and the sister chromatid exchange
response.
10. -ORD-HERL has started a clinical study to establish conclusively the
relationship between CO exposure and the decrease in time until onset of
chest pain for people with angina pectoris during exercise. Also,
animal work is starting to determine the effect of CO exposure on
fetuses. Results for the clinical and animal studies will be available
in 1982.
11. ORD-HERL is doing work to develop a tier bioassay test to be used for
mutagenic and carcinogenic substances for OMSAPC regulatory efforts
under Section 211 (fuel and fuel additives) and Section 202 (a)(4)
(assuring motor vehicle systems being certified do not cause or
contribute to an unreasonable risk to public health or welfare) of the
Clean Air Act. The tier test protocols are expected to be available in
late 1982.
12. A revised risk assessment estimating the potential carcinogenic impact
of Diesel exhaust emissions is being prepared by ORD and should be
available shortly. Meanwhile, ORD has concluded that the London Transit
Worker study is not adequately sensitive to show there would be no
excess cancer deaths resulting from the projected exposure to Diesel
exhaust.
13. The newly organized Health Effects Institute is an independent organi-
zation designed to conduct health research on motor vehicle pollutants.
The Institute is currently planning the programs they plan to conduct;
EPA and the motor vehicle industry will be submitting a list of
suggested program areas to the Institute.
Please call me if you have any questions or comments on this report.
Addressees: Flo Ryer Ron Bradow
Gerry Rausa Joellen Lewtas
Deran Pashan Judy Grahm
Lance Wallace Don Horstman
Gerry Akland Bill Pepelko
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8. Skin tumorigenesis initiation data are available on Diesel particulate
samples and indicate these samples are less potent than coke oven
samples. Intraperitoneal injection results should be available shortly
but the intratracheal instillation results will not be available until
1983.
9. Results so far on whole animal inhalation work with Diesels have been
generally negative with the exception of some sister chromatid exchange
work with hamsters. The sister chromatid exchange work showed a linear
relationship between Diesel exposure and the sister chromatid exchange
response.
10. ORD-HERL has started a clinical study to establish conclusively the
relationship between CO exposure and the decrease in time until onset of
chest pain for people with angina pectoris (a heart condition) during
exercise. Also, animal work is starting to determine the effect of CO
exposure on fetuses. Results for the clinical and animal studies will
be available in 1982.
11. ORD-HERL is doing work to develop a tier bioassay test to be used for
mutagenic and carcinogenic substances for OMSAPC regulatory efforts
under Section 211 (fuel and fuel additives) and Section 202 (a)(4)
(assuring motor vehicle systems being certified do not cause or
contribute to an unreasonable risk to public health or welfare) of the
Clean Air Act. The tier test protocols are expected to be available in
late 1982.
12. A revised risk assessment estimating the potential carcinogenic impact
of Diesel exhaust emissions is being prepared by ORD and should be
available shortly. Meanwhile, ORD has concluded that the London Transit
Worker study (a Diesel epidemiology study) is not adequately sensitive
to show there would be no excess cancer deaths resulting from the
projected exposure to Diesel exhaust.
13. The newly organized Health Effects Institute is an independent organi-
zation designed to conduct health research on motor vehicle pollutants.
The Institute is currently planning the programs they plan to conduct;
EPA and the motor vehicle industry will be submitting a list of
suggested program areas to the Institute.
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I. Introduction
For a number of years, the EPA Office of Research and Development (ORD) has
conducted a number of mobile source research programs. The initial programs
were characterization ones done by the Environmental Sciences Research
Laboratory (ESRL) which were followed in about 1975 by mobile source pro-
grams in both the Health Effects Research Laboratory (HERL) and the Environ-
mental Monitoring and Support Laboratory (EMSL).
In 1978, EPA started the Mobile Source Research Committee (MSRC) to help
assure that ORD mobile source work is responsive to the needs of the Office
of Mobile Source Air Pollution Control (OMSAPC). Since that time, a number
of problems have surfaced. OMSAPC feels that ORD will sometimes implement
work ORD feels is needed rather than work specifically requested by the
program office. ORD will frequently do some projects that OMSAPC
disapproves since OMSAPC feels these projects do not meet OMSAPC needs.
Also, there have been problems in transmitting results of ORD research to
OMSAPC. On the other hand, ORD frequently feels that some work requested by
OMSAPC is either not scientifically valid or too short term and of a
service-type function (e.g. run 300 samples for Ames test activity) rather
than longer term research. Even with these problems, there is considerable
ORD mobile source work that is useful to OMSAPC. Also, ORD and OMSAPC are
trying to resolve the problems experienced to date.
The purpose of this report is not to discuss any problem areas between
OMSAPC and ORD but instead to cover the ORD mobile source work itself. This
report will summarize the work in progress by ORD and give some of the
pertinent results. This report will also briefly mention future work
planned by ORD.
The results and work discussed in this paper are that available to OMSAPC as
of April 10, 1981.
II. Chemical Characterization Work
The chemical characterization work for unregulated mobile source emissions
is done by ESRL. This program involves developing methods to measure unreg-
ulated emissions and conducting extensive Diesel characterization work.
A. Development of Method to Collect
Gas-phase Hydrocarbons in Diesel Exhaust
One of the highest priorities expressed by OMSAPC was to develop a method to
collect artifact-free samples of gas phase hydrocarbons in motor vehicle
exhaust for bioassay testing. ESRL has evaluated both a filter cartridge
and a condensate method.
Preliminary tests have been done with a method involving filtering the
exhaust particulates and then condensing components in the gas stream. The
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condensate appears to have low Ames test activity. If the filter upstream
of the condenser is removed, the condensate will contain some Diesel par-
ticulate and has somewhat higher Ames test activity.
The filter cartridge method involves passing a gas stream sample after a
conventional particulate filter through a cartridge or bed of treated XAD-2
resin. After the gas stream is passed through the XAD-2, the hydrocarbons
absorbed onto the XAD-2 are removed from the resin by methylene chloride
extraction. The lower molecular weight hydrocarbons (e.g. below C-10) are
sufficiently volatile that they are probably lost during the extraction.
However, hydrocarbons above C-10 are retained and can then be subject to the
Ames test. Since the conventional particulate filter will generally retain
hydrocarbon compounds above C-15, the XAD-2 traps could provide a good
method to collect hydrocarbons in the C-10 to C-15 range.
A very preliminary result of Ames testing on the gas phase hydrocarbon col-
lected by this method for a VW Diesel Rabbit shows that the activity may be
low compared to that of the particulate.
The methods and results mentioned above are very preliminary and have not
yet been published by ORD. However, OMSAPC has requested that ORD publish
these results with a full description of the method as soon as possible.
In the past, ORD has expended great effort in identifying the hydrocarbon
compounds in the gas phase of Diesel and gasoline vehicle exhaust. This
work has been described by ORD in several publications and was recently sum-
marized in an OMSAPC report. ^
B. Potential Effect of N02 in
Mutagen Artifact Generation
EPA has been concerned that high levels of N02 in the dilution tunnel may
result in a reaction of N0£ with some of the hydrocarbons present either
in the gas stream or on the particulate filter. The reaction products
including various nitroaromatic compounds could result in an increased Ames
test response. Since these reaction products from the hydrocarbons and
M>2 would not be expected to form in the atmosphere where these compounds
would be greatly diluted, the Ames test response would be artifically high.
ORD has run some experiments where additional N0£ has been introduced into
the dilution tunnel. These experiments show that artifact is created in
Diesel particulates if the N02 levels are above 5 ppm. ORD plans to
publish these results shortly.
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A concern has also been raised that lower levels of N(>2 may result in
artifact formation although this artifact formation would probably be lower
than that which might be experienced at higher N(>2 levels. OMSAPC has run
some experiments with a single cylinder Diesel engine with artificial com-
bustion air containing no nitrogen and a nitrogen free fuel. In this
experiment, no NOx would be formed in the exhaust gas. By comparing the
results of these tests to tests with conventional air (80% N2, 20% 0£)
and regular Diesel fuel (which contains traces of nitrogen), one can deter-
mine if there were artifact formation due to the NC^. The results of
these tests have not yet bee: published. Also, investigators at Penn State
University and John Hopkins University plan to repeat these tests in the
coming year.
C. Study of Filter Efficiency
ORD has just completed a study^ examining various filters that can be used
for Diesel particulate collection. The filters investigated were Millipore,
Fluoropore FA, Dexiglas, Gelman A-E, Ghia Zefluor lu, Pallflex T60A20,
Pallflex TX40HI, and Pallflex 400HO.
A common back-up filter was used to measure any break-through from the test
filter. It was found that all of the filters collected greater than 95% of
the particulate on the primary filter as determined by the standard EPA
method^. However, it was noted that small differences in collection
efficiencies occurred in the cold start bag of the Federal Test Procedure
rather than the portions when the vehicle engines were warmed-up.
Even though all of these fiters may be acceptable for determining total par-
ticulate mass, it is not known if an interaction of the filter and the par-
ticulate such as can occur with glass fiber filters would affect the Ames
test results.
D. Identification of Types of Compounds
Responsible for Ames Test Activity in
Diesel Particulates.
ORD has spent effort in separating the methylene chloride extract of Diesel
particulates by high pressure liquid chromatography. Three major fractions
have been obtained: non-polar, moderately polar (transition), and highly
polar. Some of this work has been done in a cooperative scientific project
with Ford Motor Company.
The non-polar peak consists of aliphatic and polynuclear aromatic hydro-
carbons (many of them alkyl substituted) which are not responsible for a
major portion of the Ames test activity.
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Th e transition and polar fractions account for most of the Ames test
activity. About 50% by weight of the material in the transition fraction
consists of various oxygenated polynuclear aromatic hydrocarbons (including
hydroxy, ketone, carboxaldehyde, quinone, acid anhydride, and nitro
compounds). Three specific nitro compounds including 1-nitropyrene have
been identified. A total of about 80 other compounds have also been
identified. The remainder of the transition fraction is thought to be
contaminants introduced in the analysis procedure. The polar fraction con-
sists of carboxylic acid polynuclear aromatic hydrocarbons which also have
significant Ames test activity.^
It appears that a great number of compounds may be responsible for the Ames
test activity.
E. Particulate Emission Factors From Light and Heavy Duty Vehicles
OMSAPC expressed a need for additional particulate emission data from both
gasoline and Diesel vehicles.
Tests were run in-house at ESRL on a 1980 VW Diesel Rabbit and Oldsmobile
Diesel. Some tests were done with the VW under malfunction conditions. The
table below summarizes some of the most pertinent results.
Table 1
ESRL Tests on VW and Oldsmobile Diesel
Vehicle HC CO NOx Particulate Soluble Organics
g/mile g/mile g/mile g/mile %
VW normal 0.51 1.31 0.99 0.43 27
VW - a 0.68 1.69 1.23 0.54
VW - b 0.74 1.70 1.28 0.76
VW - c 0.51 1.31 0.99 0.43
Oldsmobile 0.25 1.24 1.54 0.54 15
a timing retarded/bad injector
b bad injector
c new injector
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These test results show that a bad injector increases the emissions; sim-
ilarly specific Ames test activity increased by over 50% on TA98 due to the
faulty injector. Tests of both vehicles over differenmt driving cycles
showed that Ames test specific activity was affected slightly by the driving
cycle: the cycles examined were the FTP, HFET, New York City cycle, and
Congested Freeway Driving Schedule^.
Additional studies" were done for EPA by the New York State Department of
Environmental Conservation on 19 in-use Diesels at different mileages.
These tests showed that various driving cycles> from the limited number of
tests run, do not affect Ames test specific activity other than emissions at
idle are somewhat less active. These tests show in-use particulate
emissions appear to be in the same range as obtained from tests of prototype
vehicles. However, the results to date may be too limited to make this a
firm conclusion in part since little data at high mileage are available.
ESRL has also conducted a contract study at Southwest Research Institute?
to measure unregulated emissions from four heavy duty engines (Caterpillar
3208, Mack ENDT 676, Cummins 290, and Detroit Diesel 8V-71) over the newly
developed EPA heavy-duty-engine transient cycle. A summary of some of the
emissions results is given below.
Table 2
Emissions Results From Heavy-Duty Engines*
Engine HC CO NOx Particulate
g/mile g/mile g/mile g/mile
1979 Caterpillar 3208 1.98 5.6 18.6 0.92
1979 Mack ENDT 676 1.61 9.6 29.1 1.95
1979 Cummins 290 2.37 11.2 25.4 1.64
1977 DD 8V-71 2.25 64.9 39.1 2.74
*results obtained over 1983 transient cycle
It was found that the Los Angeles Freeway segment of the transient cycle
contibuted most (40-50%) of the particulates collected. It was found that
sulfur compounds constituted about 10% of the particulate mass presumably
due to sulfate. Also, HCN and ^0 emissions were measured and found to be
below 80 mg/mile. Emissions were measured with different fuels; it was
found that HC was higher with the minimum quality DF-2 with the 4-stroke
engines and benzo(a)pyrene (BaP) emissions also increased with this fuel.
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F. Particulate Emissions from In-Use Gasoline Vehicles
ESRL started an in-house program to measure particulate emissions from 20
in-use gasoline vehicles. Of these cars, 16 are catalyst-equipped and thus
burn unleaded fuel. Ames tests will be run on the samples collected. Tests
have so far been run on 13 of the 20 cars but no results are available yet.
A final report on this is due later this year.
G. Synthetic Fuels Work
ESRL has obtained some shale-oil Diesel fuel samples and plans to test some
vehicles in-house with them. Both gaseous emissions including gas-phase
hydrocarbons and particulates will be analyzed. Some limited work was done
with a relatively high quality oil shale derived Diesel fuel showing the
Ames test reactivity of the particulates is roughly equivalent to that
obtained with conventional fuel.8 Future ESRL plans call for obtaining
H-coal, SRC-II and donor solvent fuels. This work complements work OMSAPC
has underway on coal and oil-shale fuels. Also, the ORD Industrial
Engineering Research Laboratory (IERL) plans to start a program here.
III. Carbon Monoxide and Other Monitoring Work
EMSL has a number of monitoring projects underway for CO and also does some
fuels and quality assurance work. Some of these are short term projects
while others are longer term.
A. Carbon Monoxide Work
In the past several years, several studies 9,10,11,12,13,14,15 have been
done indicating that CO levels that people are actually exposed to are
greater than predicted on the basis of the CO NAAQS fixed-site monitors. In
particular, work^ has shown that the fixed-site monitors underestimate CO
exposure for 1 hour periods for Boston commuters by about a factor of 2.
OMSAPC has placed very high priority on ORD work to define what actual
exposure is to CO. While it is recognized that the EPA NAAQS network for CO
is good for determining CO trends and levels at fixed sites, the fixed site
network is not as accurate as needed to determine actual exposure.
Another pollutant EPA needs actual exposure data on is Diesel particulates
so that more accurate carcinogenic risk assessments can be made. While it
is not currently possible to determine actual exposure to Diesel par-
ticulates by having people carry Diesel particulate monitors, CO can
possibly be used as a surrogate for Diesel particulate exposure. Thus, the
CO personal exposure work can possibly be used to refine the Diesel cancer
risk assessment.
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OMSAPC has requested that ORD implement CO exposure projects in two time
frames; a short term project can provide OMSAPC with preliminary data for
OMSAPC1 s more immediate needs while a longer term project can look at the
problem in more detail and meet longer term needs.
The short term CO monitoring project is being run in three cities, Stamford,
Connecticut, Denver, and Phoenix. ORD contractors are carrying a CO
personal monitor while driving over typical commuting routes determined by
local transportation data. The monitors are carried along these routes
during morning and evening rush hours. An average CO exposure value (e.g.
10 ppm 1 hour average) is determined for certain time periods. Then, during
the rest of the day, CO values are obtained by walking around the central
business district and driving in outlying suburban areas. Readings are
taken in various public buildings and stores.
These data are representative of what CO levels people are exposed to and
will be compared with values recorded at the NAAQS monitors. The data
should be collected by May 1981 and will be analyzed shortly thereafter.
Some results should be available later this summer from this analysis.
Other EMSL short term work being done on CO monitoring include a contract
with Sciences Application Inc. who has outfitted nine people in the Los
Angeles area with CO monitors and recorded their CO exposure as they went
about their normal activities. Data from this study should be available
later this year.
EMSL is also planning a longer term CO monitoring study which will include
an assessment of people's activities as well as their CO exposure. A diary
type log will be kept by the people carrying the monitors to record their
activities. Thus, a relationship can be developed between personal activity
and CO exposure. It is tentatively expected that about 100 people will
carry the monitors for certain time periods. This project will give OMSAPC
a more definitive assessment of actual CO exposure as compared to that pre-
dicted from the fixed site NAAQS monitors. This work is starting in FY81
and will continue into FY82.
Some limited FY81 work is underway to improve CO personal monitors and to
incorporate integrators in them so that both instantaneous CO and time
integrated CO measurements can be taken.
B. Fuel Registration and Analysis
EMSL has the responsibility for operation of the fuel registration program
required by Section 211(b) of the Clean Air Act Amendments. This program
involves registration of all fuel and fuel additives listing their
components, concentration levels, and purpose of using the additives. Much
of the information (especially on fuel additive composition) can be held
"confidential" by the provisions of these regulations. EMSL plans to issue
a report on the fuels and fuel additives registered in late 1981.
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Other provisions of Section 211 require EPA to promulgate regulations
requiring needed health or emission-control-device testing of fuels and fuel
additives. Initially, ORD was developing these regulations but in early
1980 the responsibility for proposing these regulations was shifted to
OMSAPC. OMSAPC is still counting on ORD to develop a tier bioassay test for
mutagenic compounds; this work is discussed later in Section IVC. OMSAPC
will use these tier bioassay tests as one element in the fuel and fuel
additive protocols.
EMSL also provided analysis support to the Office of Enforcement on trace
contaminants in unleaded fuel such as lead, manganese and phosphorus. EMSL
also analyzed some fuel samples for OMSAPC, performed benzo(a)pyrene
analyses on Diesel particulate samples, and ran sample extractions prior to
Ames test analysis. However, EMSL management decided the priority for this
work was low and recently discontinued these analyses.
IV Health Work
The ORD-HERL Laboratories in Cincinnati and Research Triangle Park provide
OMSAPC with research support in the mobile source health area. The current
work is on Diesels and development of a tier biossay test.
A. Diesel Work
The largest amount of HERL FY81 mobile source resources are being spent on
Diesel health work. The work includes short term bioassay tests, skin
tumorigenesis, intratracheal instillation, and whole animal inhalation.
This work is being used to determine a carcinogenic potency for Diesel
exhaust particulate to use in a carcinogenic risk assessment. The end
product of all of the Diesel health work will be a cancer risk assessment
predicting the carcinogenic risk associated with exposure to light and heavy
duty Diesel exhaust. The health work on Diesels is discussed below but the
Diesel risk assessment is covered in Section V as a separate entity.
1. Bioassay Tests
For several years HERL-RTP has been running a variety of short term
bioassay tests including the Ames test, sister chromatid exchange,
L-5178Y mouse lymphoma, and Balb tests. Two short term carcinogenesis
tests (viral enhancement and Balb) have also been run.
These tests have been run on a variety of light and heavy duty Diesel
particulate extracts. The light duty Diesels tested include an Olds-
mobile, VW Rabbit, and Nissan. The Nissan Diesel had a poorly designed
injector (which has been redesigned on newer Nissan Diesels) that
resulted in considerable "after injection" (i.e. late injection) of
Diesel fuel. EPA understands that Ames test results with the new
injection system are considerably lower. The samples from the
Caterpillar heavy duty Diesel were stored for an extended period which
may have resulted in sample deterioration. OMSAPC has requested that
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ORD run new heavy duty Diesel samples. Bioassay tests have also been
run on particulate extract from a limited number of gasoline vehicles.
The gasoline car tested was a 1977 Mustang catalyst equipped vehicle
that apparently was running somewhat richer than manufacturers' speci-
fications.
To date, very few if any bioassay tests have been run on gas phase
samples from either gasoline or Diesel vehicles mainly due to lack of a
method to collect samples for bioassay tests. However, as mentioned in
Section II A, work is proceeding by ESRL to develop such a method and
one is expected shortly.
The bioassay test response of the motor vehicle samples have been
compared to other samples. The other samples collected are from coke
ovens, roofing tar, and cigarette smoke condensate. The coke oven
samples collected by ORD were taken from a coke oven owned by U.S. Steel
in Gadsen, Alabama. The samples were collected in a location that was
upwind of the coke ovens a large fraction of the time. However, it is
thought that much of the sample mass was collected when the coke ovens
were discharging and presumably the wind was in the right direction even
though this may have occurred only a small fraction of the time. In
other words, OMSAPC is not currently sure how much of the coke oven
samples are actual coke oven emissions.^ OMSAPC hopes that this
point is clarified in the ORD report to be issued on this work. ORD is
currently obtaining additional coke oven samples for bioassay and other
tests. The additional samples are being obtained in the coke oven main
itself and may give different results from the earlier samples. It is
not known yet how the new samples would be representative of actual coke
oven emissions to which people are exposed. The cigarette smoke
condensate samples were obtained by a standard laboratory apparatus
designed to duplicate cigarette smoking. The roofing tar emissions were
obtained by collecting a particulate sample above a hot pot of roofing
tar.
The reason that the coke oven, cigarette smoke, and roofing tar samples
were investigated is that extensive epidemiology data exist for these
substances while almost no good epidemiology data exist for Diesel
emissions.
The results from the bioassay tests have been calculated as the response
per unit mass of particulate extract. The responses were rated on a
relative basis with the Nissan arbitrarily assigned a ranking of 100. A
known carcinogen (benzo(a)pyrene) was used for comparison. The results
from this work are summarized in Table 3 below and are discussed in
detail in several references.^7,18,19,20 They were also covered in an
ORD sponsored workshop held February 1981 on Diesel risk
assessment.16,21
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Table 3
COMPARATIVE POTENCY RANKINGS
MUTAGENESIS TESTS
CARCINOGENESIS TESTS
AMES
SCE
L-5178Ya BALE3
VIRAL
ENHANCE BAL8
TUMOR
INITIATION
DIESEL: CATERPILLAR
NISSAN
OLDS
VW RABBIT
GASOLINE:
MUSTANG
COMPARATIVE
SOURCES :
CIGARETTE
COKE
ROO? TAR
STANDARDS :
B(a)P
4.3
100
23
22
25
7
18
7
1112
0
100
0
50
1
0
44
291
1750
1C
100
64
50
38
21
339
850
189
0
100
750
NTd
750
300
15
750
25000
0
100
25
50
50
200
800
2016
52000
0
100
0
NT
200
200
500
500
16700
0
100
28
6
16
0
355
120
16500
aln the presence of an Aroclor-1254 induced rat hepatic S-9.
^Mouse skin tumor initiation in male and female sencar mice after 24 weeks of treatment.
cTesting incomplete at this time.
dNot tested.
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Th e skin tumor initiation work is discussed later in this paper.
It was determined that the Balb test is not suitable for a complex
mixture^ so that the Balb data cannot be used for any comparisons. Also,
there is some concern that the Ames test may overreact to nitrogen
containing compounds such as are present in Diesel particulates. There is
also concern about whether bioassay test results in general can be extra-
polated to human health effects.22
Nevertheless, the data in Table 3 (especially the skin tumor initiation
data) can be used as an input for a Diesel risk assessment.
HERL has also done some work to evaluate whether mutagens adsorbed on Diesel
particulates are released in the presence of physiological fluids. This
work showed that substantial mutagenic activity is released from Diesel
particles upon incubation with serum and lung cytosol.23 This work is
continuing and is important in determining if physiological fluids present
in the body alter the mutagenic activity of the particulate.
2. Skin Tumorigenesis and Intratracheal Instillation
HERL has started long term projects for skin tumorigenesis and intratracheal
instillation.
The skin tumorigenesis work was done with motor vehicle and other samples as
discussed in Section IVA1. Both C-57A and Sencar mice were used. Recent
results with the C-57 black mice (a relatively non-sensitive breed) were
negative (i.e. no carcinogenic response) with the exception of one dose of
the roofing tar samples.24 Work with the more sensitive Sencar mouse does
show a positive response after 24 weeks of treatment.25,26 These results
are given in Table 3 above. These results are preliminary ones; the results
from the full scale study should be available within a year. OMSAPC feels
that additional work is needed for heavy duty Diesel samples. Also, the
cigarette smoke condensate showed no result probably due to the fact that
the active components are too dilute in the condensate sample. This work
should be repeated with a more active fraction of the condensate.
It is generally thought^ that the skin tumorigenesis results are more
significant from a human health viewpoint than bioassay tests since the
whole animal is involved.
The intratracheal instillation work with Syrian golden hamsters involves
placing specific quantities of the samples listed in Table 3 on the
trachea. The doses are repeated at certain intervals. The advantage of
intratracheal instillation versus inhalation testing is that larger doses
can be administered to the animals in a very controlled fashion. The
animals are then followed over their lifetime (about 2 years) to see if
cancerous tumors develop.
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This work is being done under an EPA Cooperative Agreement with IITRI in
Chicago. Unfortunately, there is probably no way to get any meaningful
results until the animals die since this is a lifetime study. A report on
the work is scheduled for early 1983.
3. Whole Animal Inhalation
HERL-Cincinnati has done extensive work on whole animal inhalation for
Diesel exhaust. This work was described in detail in the recent proceedings
of the EPA Diesel symposium held in 1979.
A study2°>29 wag recently completed which examined the effect of Diesel
particulate exposure on the ability of A/Jax mice to dispose of radioactive
labelled BaP that were deposited by intratracheal instillation. While it
was seen that mice exposed to Diesel exhaust had less capacity to dispose of
the BaP, the significance of this finding is not clear to OMSAPC.
Another animal inhalation program involved the liver foci; test were run on
rats that had most of their livers surgically removed and were fed a special
choline-devoid or supplemented diet for 3-6 months. The rats were exposed
to either clean air or Diesel exhaust. This test showed no changes in the
rats exposed to Diesel exhaust.30
An initial study was done with Strain A mice which did seem to show a slight
effect due to Diesel particulates but there were some questions about the
significance of the results.^7,31 This study was repeated with more
animals and the results are just being compiled now.
Another study32 was performed with hamsters. A sample of Diesel
particulate extract was intratracheally instilled in the animals. Lung
tissues from these animals were later analyzed for chromatid exchange.
Recent analysis-^ shows the response from this test is linearly related to
Diesel particulate concentration. Thus, this test could be regarded as a
useful in-vivo test. Future work could involve using other samples includ-
ing more Diesels and possibly coke oven, cigarette smoke, and roofing tar
samples.
Another project that is currently underway is intraperitoneal injection of
Diesel particulate, coke oven, cigarette smoke condensate and roofing tar
samples into the lung cavities of laboratory animals. This work will be a
supplement to the other work on these samples discussed in Table 3.
Another project-^ involved determining if Strain A mice exposed to Diesel
exhaust had abnormal sperm. No sperm abnormalities were noted in the Strain
A mice. Also, the urine of Swiss mice exposed to Diesel exhaust was
analyzed to see if it were positive on the Ames test due to excretion of
mutagenic substances.35 No difference was found in the urine of mice
exposed to Diesel exhaust compared to the control group.
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Finally, HERL has run a study^6 with male Chinese hamsters exposed to
Diesel exhaust for six months. An increase in sperm abnormality was noted
although no increase in chromosomal abnormalities in bone marrow cells were
found in animals exposed to Diesel exhaust. Also, no increase in sister
chromatid exchange was noted in bone marrow cells of these animals.
Other Diesel whole animal inhalation work is underway with cats,
rabbits^?, rats^° and hamsters. The project with cats is directed more
towards non-carcinogenic lung effects.
OMSAPC has requested an evaluation from ORD on the general usefulness of
inhalation studies to detect increased incidence of Diesel cancer in
laboratory animals. EPA wants to be certain that a negative result on a
whole animal inhalation test is in fact significant.
B. Carbon Monoxide Health Work
EPA has compiled a detailed summary of health effects work on carbon
monoxide in the recent Criteria Document.3' of particular interest to EPA
are the numerous studies^0*^ >42,43,44,45,46,47 which show a relationship
between carbon monoxide and the onset of heart pain in persons with angina
pectoris. This work has been criticized since the onset of heart pain can
be regarded as a subjective measure that may not be indicative of further
heart damage. Also, OMSAPC has expressed interest in some studies^°>^'
that have related CO levels in the ambient air to an increase in hospital
admissions due to cardiorespiratory complaints. These studies have been
criticized for several reasons (basically a lack of showing that the CO
exposure itself was responsible for the health problems requiring hospital
admission) and OMSAPC has expressed an interest in having them repeated.
These and other health studies have been summarized in a recent review
article.50
Both OMSAPC and the Office of Air Quality Planning and Standards (OAQPS)
have expressed a need for additional CO health work. ORD is implementing
FY81 programs to meet these needs.
The first program is a replication of the CO clinical studies relating CO
exposure to actual changes in heart parameters during exercise for people
with angina pectoris. This work will be done with a radionuclide gamma
camera designed to determine changes in heart parameters (e.g. chamber
discharge volume and rates). While this work is to be completed by
December, 1982, OMSAPC has requested a written progress report in 1981.-^
Other CO work being done by HERL includes some clinical work to examine the
Coburn equation which predicts the blood carboxyhemoglobin level as a
function of CO exposure. This work will be completed in September 1982.
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OMSAPC and OAQPS feel that work on the effect of CO on susceptible subgroups
such as fetuses is needed. HERL has started some work on pregnant rats to
determine if exposure to CO affects the newly born rat neonate. An interim
report on this work which is now underway is to be prepared later this
year. The study will be completed in 1982. HERL also plans some animal
studies to determine the effect of CO alone and in combination with 03 and
M>2 on xenobiotic metabolism in animals. Additional work is being
considered to correlate CO exposure and fetal carboxyhemoglobin levels with
cardiovascular and central nervous system maldevelopment in the animal fetus
and neonate. These two projects would be complete in 1983.
HERL has proposed some epidemiology feasibility studies on CO but these
studies have not been currently approved by the Mobile Source Research Com-
mittee. The one study would determine cardiovascular effects of CO exposure
at high altitude while the second study would determine the effect of
ambient carbon monoxide exposure on pregnancy outcome.
C. Tier Bioassay Development
OMSAPC has need for a tier bioassay test for both the Section 211 fuel and
fuel additive regulations and the Section 202 (a)(4) regulations designed to
assure that unregulated emissions from motor vehicles do not cause or con-
tribute to an unreasonable risk to public health, welfare or safety. These
two sets of regulations are being currently developed by OMSAPC. The tier
bioassay test would be designed to minimize the cost and complexity of
determining the potential carcinogenicity of these emissions. The test is
designed in a tier fashion so that if a mixture passes the first test (a
test that should result in few false negatives), no further testing is
needed. If it fails, successive tests of increasing complexity are needed
until the mixture passes a test (again a test designed for few false
negatives). If a mixture fails the tier bioassay process, either the
fuel/fuel additive for Section 211 or the vehicle for Section 202 (a)(4) may
have to be altered until the emission products do pass the tier tests.
A problem with developing a tier test is to specify suitable pass/fail
criteria for each successive test of the tier. HERL feels that they may not
be in a position to specify these cut points. Yet, OMSAPC feels that HERL1 s
specifying such cutpoints is an inherent part in developing this tier
approach.
The following tests are being used by HERL:
1. microbial mutagenesis
2. cellular toxicity
3. gene mutations in mammalian cells
4. mitotic recombination in yeast
5. sister chromatid exchanges in mammalian cells
6. oncogenic transformation in mammalian cells
7. in vivo/in vitro confirmatory assays employed as
required.
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Endpoints include:
gene mutations, DNA damage, chromosomal effects, oncogenic
transformation (carcinogenesis, vn vitro), and cellular
toxicity.
A report on the short-term bioassay results and a report on correlation of
short-term bioassay test results is due October 1981. A revised tier will
be constructed and investigated with a final tier and guidelines being
available for OMSAPC in late 1982. It is not known yet how toxic (i.e. non-
cancer) emissions will be handled for Section 211 but it is possible that
the approach that would be used for Section 202 (a)(4) could be used here as
well. In addition to developing the tier biossay, HERL is running limited
bioassay tests to support ESRL for the work described in Section II. HERL
is also advising OMSAPC on the use of the Ames test for OMSAPC programs.
While OMSAPC now has contractor capability to run the Ames test, HERL is
still working on data analysis for the Ames test. This capability is in the
process of being transferred to OMSAPC.
V. Diesel Carcinogenic Risk Assessment
The major output of the massive ORD Diesel research program is to be a
revised carcinogenic risk assessment projecting the potential number of
cancer cases that could be associated with exposure to light and heavy duty
Diesel exhaust.
An initial risk assessment^ was based on assuming the potency of Diesel
exhaust extract is equivalent to that of the benzene-soluble organics from
coke oven emissions. The best estimate number of projected cancer cases in
1990 would be about 350 and 670 for light and heavy duty Diesels
respectively. Since this risk assessment was released, a number of
criticisms of it have been made by various people including the National
Academy of Sciences.
It is agreed that a new risk assessment is needed. ORD is scheduled to
release a new risk assessment shortly. The biggest change that could be
expected in the new risk assessment is that a lower potency would be assumed
for Diesel exhaust compared to coke oven emissions based on the recent skin
tumorigenesis results.25,26,54
ORD did release a report recently of great value to OMSAPC on the London
Transit Worker study.54 This epidemiology study of London transit workers
exposed to Diesel bus emissions has been cited by many people as a strong
indication that Diesel emissions result in no excess cancer risk. ORD
analyzed the study parameters statisically looking at the particle level
exposure time, and number of people involved. It was their conclusion that
thousands of excess cancer deaths could result in the United States
population as a whole and still be consistent with the results of the London
Transit Worker study. The ORD analysis has been reviewed both inside and
outside EPA by various experts.
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VI Health Effects Institute
In late 1980, the Health Effects Institute was formed to conduct health
research for mobile source emissions. While the Institute is jointly funded
by the industry and EPA, it is set up as an independent entity so that the
research done will be purely scientific and free of any bias.
At this point, the Health Effects Institute is formulating plans for the
type of research they would implement. EPA and the industry will be
specifying the type of work that is important from their perspectives.
Specific projects should be started later this year.
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REFERENCES
1. Penny Carey and Janet Cohen, EPA, "Comparison of Gas Phase Hydrocarbon
Emissions from Light Duty Gasoline Vehicles and Light-Duty Vehicles
Equipped with Diesel Engines", EPA-OMSAPC Report (CTAB/PA/80-5),
September 1980.
2. Frank Black and Lisa Doberstein, EPA, "Filter Media for Collecting
Diesel Particulate Matter", ESRL Internal Report to be submitted to the
Society of Automotive Engineers for publication, March 1981.
3. Federal Register, "Standard for Emission of Particulate for
Diesel-Fueled Light-Duty Vehicles and Light-Duty Trucks", Vol. 45, No.
45, 14496-14525, March 5, 1980.
4. Dennis Schuetzle, Frank S. C. Lee, and Thomas J. Prater, Ford Motor Co.,
and Silvester B. Tejada, EPA, "The Identification of Polynuclear
Aromatic Hydrocarbon Derivatives in Mutagenic Fractions of Diesel
Particulate Extracts", presented at the 10th Annual Symposium on the
Analytical Chemistry of Pollutants, Dortmund, Germany, May 28-30, 1980
and to be published in the International Journal of Environmental
Analytical Chemistry.
5. Peter A. Gabele, Frank M. Black, Foy G. King, Roy B. Zweidinger, and Rex
A. Brittain, EPA, "Exhaust Emission Patterns from Two Light-Duty Diesel
Automobiles", Society of Automotive Engineers Paper 810081, February
1981.
6. Richard E. Gibbs, James D. Hyde, Stanley M. Byer, New York State
Department of Environmental Conservation, "Characterization of Par-
ticulate Emissions from In-use Diesel Vehicles", Society of Automotive
Engineers Paper 801372, October 1980.
7. Harry E. Dietzmann, Mary Ann Parness, Southwest Research Institute, and
Ronald L. Bradow, EPA, "Emissions from Trucks by Chassis Version of 1983
Transient Procedure", Society of Automotive Engineers Paper 801371,
October 1980.
8. J. Lewtas Huisingh, David L. Coffin, Ronald L. Bradow, Larry Claxton,
Ann Austin, Roy Zweidinger, Robert Walter, Joe Sturm, and Robert H.
Jungers, "Comparative Mutagenicity of Combustion Emissions of a High
Quality No. 2 Diesel Fuel Derived from Shale Oil and a Petroleum Derived
No. 2 Diesel Fuel", Interagency Symposium on the Health Effects Invest-
igation of Oil Shale Development, Gatlinburg, Tennessee, June 1980.
9. James L. Repace, Wayne R. Ott, and Lance A. Wallace, EPA, "Total Human
Exposure to Air Pollution", Air Pollution Control Association Paper
80-61.6, June 1980.
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10. Mark Wolcott, EPA, "Summary Report of Several Ambient Carbon Monoxide
Studies", EPA-OMSAPC Report (TEB-81-9), November 1980.
11. William F. Biller, Thomas B. Feagans, Ted R. Johnson, George M. Duggan,
and James E. Capel, "Estimated Exposure to Ambient Carbon Monoxide Con-
centrations Under Alternative Air Quality Standards", EPA-OAQPS
Strategies and Air Standards Division Draft Report, RTP, N.C. 27711,
August 1980.
12. Lance Wallace, EPA, "Personal Air Quality Monitors: Past Uses and
Present Prospects", ACS Proceedings, 4th Joint Conference on Sensing of
Environmental Pollutants, 1978.
13. A. C. Gullon, Environment Canada "Motor Vehicle Pollutants in Canadian
Cities", Air Pollution Control Association Paper 80-2.1, June 1980.
14. Anthony D. Cortese and John D. Spengler, "Ability of Fixed Monitoring
Stations to Represent Personal Carbon Monoxide Exposure", Journal of the
Air Pollution Control Association 26, 1144, 1976.
15. James W. Jabara and Thomas J. Keefe, "Carbon Monoxide: Dosimetry in
Occupational Exposures in Denver Colorado", Archives of Environmental
Health, _35, 198, 1980.
16. Joseph H. Somers, EPA, "Trip Report on EPA-ORD Diesel Risk Assessment
Meeting", OMSAPC memo, March 4, 1981.
17. Larry Claxton and Joellen L. Huisingh, EPA, "Comparative Mutagenic
Activity of Organics from Combustion Sources", Proceedings of the
Symposium on Pulmonary Toxicology of Respirable Particles, March 1980.
18. J. L. Huisingh, R. L. Bradow, R. H. Jungers, B. D. Harris, R. B.
Zweidinger, K. M. Gushing, B. E. Gill, and R. E. Albert, "Mutagenic and
Carcinogenic Potency of Extracts of Diesel and Related Environmental
Emissions: Study Design, Sample Generation, Collection, and
Preparation", EPA-HERL Report, February 1981.
19. J. Lewtas Huisingh, EPA, "Short-term Carcinogenesis and Mutagenesis
Bioassays of Unregulated Automotive Emissions", Bulletin of the New York
Academy of Medicine, in press 1981.
20. Bruce C. Casto, George G. Hatch, Shiu L. Huang, Joellen L. Huisingh,
Stephen Nesnow, Michael D. Waters, "Mutagenic and Carcinogenic Potency
of Extracts of Diesel and Related Environmental Emissions; In Vitro
Mutagenesis and Oncogenic Transformation", EPA-HERL Report, February
1981.
21. Jeff Alson, EPA, "Trip Report on the Diesel Health Effects Workshop Held
in RTP on February 24-25, 1981", OMSAPC memo, March 1981.
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22. "Health Effects of Exposure to Diesel Exhaust", the report of the Health
Effects Panel of the Diesel Impacts Study Committee, National Research
Council, National Academy of Sciences, 1980.
23. Leon C. King, Mike J. Kohan, Ann C. Austin, Larry D. Claxton, and J.
Lewtas Huisingh, EPA, "Evaluation of the Release of Mutagens from Diesel
Particles in the Presence of Physiological Fluids", Environmental Muta-
genesis, in press 1981.
24. Stephen Nesnow, EPA, "Report on Skin Tumorigenesis Studies of Diesel
Emissions and Related Samples on C57 Black Mice", ORD-HERL memo, January
12, 1981.
25. Stephen Nesnow, EPA, "Report on Skin Tumorigenesis Studies of Volkswagen
Turbo Rabbit and Home Heater Samples on Sencar Mice", ORD-HERL memo,
January 24, 1981.
26. Stephen Nesnow, Larry L. Triplett, and Thomas J. Slaga, "Tumorigenesis
of Diesel Exhaust, Gasoline Exhaust, and Related Emission Extracts on
Sencar Mouse Skin", ORD-HERL Report, 1981.
27. "Health Effects of Diesel Engine Emissions: Proceedings of an Internat-
ional Symposium", EPA Report 600/9-80-057ab, Volumes 1 and 2, November
1980.
28. E. T. Cantrell, H. W. Tyner, W. B. Peirano, and R. M. Danner, "Benzo(a)
pyrene Metabolism in Mice Exposed to Diesel Exhaust: Metabolism and
Excretion", Environment International, in press 1981.
29. H. W. Tyner, E. T. Cantrell, R. Homes, I. P. Lee, W. B. Peirano, and R.
M. Danner, "Benzo(a) pyrene Metabolism in Mice Exposed to Diesel
Exhaust: Uptake and Distribution", Environment International, in press
1981.
30. M.A. Pereira, H. Shinozuka, and B. Lombardi, "Test of Diesel Exhaust
Emissions in the Rat Liver Foci Test", ORD-HERL Report, 1980.
31. John G. Orthoefer, Wellington Moore, Dale Kraemer, Freda Truman, Walden
Crocker, You Yen Yang, EPA, "Carcinogenicity of Diesel Exhaust as Tested
in Strain A Mice", ORD-HERL Report, 1980.
32. Donald E. Rounds, "Mutagenicity of Diesel Exhaust to Hamster Lung
Tissue", ORD-HERL Report, 1980.
33. William E. Pepelko, EPA, Letter to Gerald Rausa on Sister Chromatid
Exchange, March 10, 1981.
34. M. A. Pereira, P. S. Sabharwal, L. Gordon, and A. J. Wyrobek, "The
Effect of Diesel Exhaust on Sperm-shape Abnormalities in Mice", ORD-HERL
Report, 1980.
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35. M. A. Pereira, T. H. Connor, J. Meyne, and M. S. Legator, "Metaphase
Analysis, Micronuclei Assay and Urinary Mutagenicity Assay of Mice
Exposed to Diesel Emissions", ORD-HERL Report, 1980.
36. M. A. Pereira, P. S. Sabharwal, P. Kaur, C. B. Ross, A. Choi, and T.
Dixon, "In-vivo Detection of Mutagenic Effects of Diesel Exhaust by
Short Term Mammalian Bioassay", ORD-HERL Report, 1980.
37. "Study of the Teratologic Effects of Long-term Exposure to Diesel
Exhaust (Rabbits)", Final Report by Wil Research Laboratories,
Cincinnati, Ohio for EPA Contract 68-03-2652, 1980.
38. "Study of the Teratologic Effects of Long-Term Exposure to Diesel
Exhaust Emissions (Rats)", Draft Final Report by Wil Research
Laboratories, Cincinnati, Ohio for EPA Contract 68-03-2652, 1980.
39. "Air Quality Criteria for Carbon Monoxide (Preprint)", EPA Report -
600/8-79-022, CO Criteria Document, Office of Research and Development,
October 1979.
40. E. W. Anderson, R. J. Andelman, J. M. Strauch, N. J. Fortuim, and J. H.
Knelson, "Effects of Low-Level Carbon Monoxide on Onset and Duration of
Angina Pectoris: A Study on 10 Patients with Ischemic Heart Disease",
Ann. Intern. Med. _7£, 46-50, 1973.
41. W. S. Arnow, "Effect of Passive Smoking on Angina Pectoris", N. Engl. J.
Med. 299. 21-24, 1978.
42. W. S. Aronow and J. Cassidy, "Effect of Carbon Monoxide on Maximal
Treadmill Exercise: A Study in Normal Persons", Ann. Intern. Med. 83,
496-499, 1975.
43. W. S. Aronow, J. Ferlinz, and F. Glauser, "Effect of Carbon Monoxide on
Exercise Performance in Chronic Obstructive Pulmonary Disease", Am. J.
Med. j>3, 904-908, 1977.
44. W. S. Aronow and M.W. Isbell, "Carbon Monoxide Effect on Exercise-
Induced Angina Pectoris", Ann. Intern. Med. 79, 392-395, 1973.
45. W. S. Aronow, C. N. Harris, M. W. Isbell, S. N. Rokaw, and B. Imparato,
"Effect of Freeway Travel on Angina Pectoris", Ann. Intern. Med. 77,
669-676, 1972.
46. W. S. Aronow, J. Cassidy, J. S. Vangrow, H. March, J. C. Kern, J. R.
Goldsmith, M. Khemka, J. Pagano, and M. Vawter, "Effect of Cigarette
Smoking and Breathing Carbon Monoxide on Cardiovascular Hemodynamics on
Anginal Patients", Circulation 50, 340-347, 1974.
47. W. S. Aronow, "Effect of 2% Venous Carboxyhemoglobin on Exercise-Induced
Angina Pectoris", 1980.
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48. T. L. Kurt, R. P. Mogielnicki, and J. E. Chandler, "Association of the
Frequency of Acute Cardiorespiratory Complaints with Ambient Levels of
Carbon Monoxide", Chest J4, 10-14, 1978.
49. T. L. Kurt, R. P. Mogielnicki, J. E. Chandler, and K. Hirst, "Ambient
Carbon Monoxide Levels and Acute Cardiorespiratory Complaints: An
Exploratory Study", Am. J. Health 69_, 360-363, 1979.
50. Gerard M. Turino, "Effect of Carbon Monoxide on the Cardiorespiratory
System", Journal of the Air Pollution Control Association, 63, 253A,
1981.
51. Mathew L. Petrovick, EPA, "Biomedical Instrumentation and Techniques for
Cardiovascular Carbon Monoxide Exposure Studies", ORD-HERL Report,
August 27, 1980.
52. Roy E. Albert, EPA, "Initial Review of the Potential Carcinogenic Impact
of Diesel Exhaust", EPA Memo, June 11, 1979.
53. Todd W. Thorslund, EPA, "A Suggested Approach for the Calculation of the
Respiratory Cancer Risk Due to Diesel Engine Exhaust", EPA-ORD Report,
February 1981.
54. Todd Thorslund, EPA, "Answer to the Posed Question 'Are the results
obtained in the London Transit Worker Study sufficient to dismiss any
concern regarding the potential cancer hazard for the U. S, population
in the future, due to Diesel engine exhaust?"1, EPA-ORD memo, January
29, 1981.
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