INTEGRATED AIR CANCER PROJECT
Research to Improve Risk Assessment of Area Sources:
Wood Stoves and Mobile Sources: Boise, Idaho
SUMMARY REPORT
PART I: RESEARCH RESULTS
Air and Energy Engineering Research Laboratory
Atmospheric Research and Exposure Assessment Laboratory
Health Effects Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
-------
IACP BOISE DELIVERABLE COMPONENTS
Summary Report
Appendices
Peer-Reviewed Journal Articles Appendix 1
Proceedings Manuscripts Appendix 2
Reports Appendix 3
Centralized Database Appendix 4
US EPA REGION 4 LIBRARY
AFC-TOWER 9th FLOOR
61 FORSYTH STREET SW
ATLANTA, GA. 30363
-------
Editor
Debra Walsh
IACP Technical Information Coordinator
EHRT, Inc.
Primary Authors
Joe lien Lewtas
Larry Cupitt
Robert Stevens
Chuck Lewis
Roy Zweidinger
Dempsey Ray
Robert McCrillis
HERL, Chairman Steering Committee
AREAL, Steering Committee
AREAL, Steering Committee
AREAL, Source Apportionment Team Leader
AREAL, Identification Team Leader
AREAL, Data Management
AEERL, Wood Stove Emissions Team Leader
Primary Contributors
Ross Highsmith
Bert Eskridge
Randall Watts
Larry Claxton
Debra Walsh
Sarah Warren
Marsha Nishioka
Tadeusz Kleindienst
Graham Glen
Daniel Thompson
Jonathan Simonson
George Klouda
Ray Steiber
Jim Dorsey
AREAL
AREAL
HERL
HERL
EHRT
EHRT
Battelle
Mantech
Mantech
Mantech
Mantech
NIST
AEERL
AEERL (Retired)
Other Contributors See Attached Publications
-------
TABLE OF CONTENTS
EXECUTIVE SUMMARY 1
INTRODUCTION 3
Pilot Studies 4
Selection of Boise 4
Overview of Boise Field Study 4
STUDY DESIGN AND GOALS 6
First Goal: Identification of Carcinogens 6
Second Goal: Source Apportionment of Carcinogens 6
Third Goal: Improvement of Human Exposure and Comparative Cancer
Risk Assessment 7
IDENTIFICATION OF CARCINOGENS 8
Mutagenicity . 8
Carcinogenicity 9
Bioassay-Directed Fractionation (BDF) 9
Chemical Characterization and Quantitation of Carcinogens 9
Hazard Identification Summary 9
SOURCES OF RISK 10
Source Apportionment 10
Characterization of Wood Combustion Emissions 13
Characterization of Mobile Source Emissions 14
Atmospheric Transformation: A Potential Source of Risk 14
HUMAN EXPOSURE 16
Exposure Concentrations 16
Particles 17
Extractable Organic Matter (EOM) 17
Semivolatile Organic Compounds (SVOCs) 17
Aldehydes 18
Volatile Organic Compounds (VOCs) 18
Inorganic Species 18
Human Time-Activity Profiles in Boise 19
Apportionment and Estimation of Human Dose to EOM 20
COMPARATIVE CARCINOGENICITY 21
Mutagenicity and Carcinogenicity Relationships 21
Characterization in Related Airsheds 26
-------
TECHNICAL HIGHLIGHTS 27
Characterization of the Air Toxics and Sources in Outdoor Air 27
Characterization of the Air Toxics and Sources in Indoor Air 28
Characterization of the Mutagenic and Carcinogenic Activity 29
Source Apportionment 30
Source Characterization 30
Atmospheric Transformation 30
CENTRALIZED DATABASE 31
CONCLUSIONS 32
Identification of Carcinogens * 32
Source Apportionment of Carcinogens 32
Human Exposure and Comparative Carcinogenicity 32
REFERENCES FOR SUMMARY REPORT 34
COMPLETE LISTING OF IACP BOISE PUBLICATIONS 40
-------
EXECUTIVE SUMMARY
This report summarizes the major findings of the first comprehensive Integrated
Air Cancer Project (IACP) field study. This study was conducted in Boise, Idaho, where
residential wood combustion (RWC) and mobile sources (MS) have been identified as
the major contributors to air pollution. The IACP initially focused on products of
incomplete combustion (PICs). Incomplete combustion products include polycyclic
organic matter (POM) primarily adsorbed to respirable particles. PICs were identified as
a major source of carcinogenic risk in urban areas. Therefore, the research strategy
focused on PICs, especially those from residential home heating and motor vehicles that
are major, ubiquitous emission sources in populated areas. The PICs constitute a large
fraction of the atmospheric burden of pollutants on a national basis.
The component of PICs estimated to make the largest contribution to human
cancer risk is the POM associated with airborne particles. The extractable organic
matter (EOM) adsorbed to airborne particles contains most of the carcinogenic POM.
Under some ambient conditions, the semivolatile organic compounds (SVOCs) may also
contain polycyclic aromatic compounds. The carcinogenicity of SVOCs has not yet been
studied. This project, for the first time, both apportions and characterizes the
carcinogenicity of ambient POM from particles using in vivo animal tumor data, receptor
modeling and human exposure data developed in this field study. The ambient POM
sample containing 33% contribution of motor vehicle emissions was more than twice as
tumorigenic as the ambient sample with only 11% motor vehicle emissions.
More than 185 different chemical species, including volatile organic compounds
(VOCs), aldehydes, SVOCs, polycyclic aromatic hydrocarbons (PAHs), nitroarenes, and
inorganic elements were monitored both outdoors and indoors. The residential
component of the study included matched pairs of homes, one with and one without a
wood stove. Resources limited the design of the study to homes without other unvented
combustion sources (e.g., tobacco smoke or kerosene heaters). Human exposure
estimates and indoor.outdoor relationships were determined for many of these species.
The concentrations of fine particle mass measured indoors were nearly always lower than
outdoor concentrations, but generally highly correlated, indicating that infiltration of
outdoor particles had a significant influence on indoor concentrations. When wood
burning stoves were operated properly, they did not directly contribute particulate
matter, most organic pollutants, or mutagenicity to the homeowners' indoor air. Wood
burning did contribute substantial particulate matter and organics to the outdoor air and
indirectly increased these pollutants in all homes in the neighborhood, regardless of the
presence or absence of a wood stove, by infiltration of these pollutants from outside air.
In all of the monitored homes, the indoor concentrations of one or more VOCs were
highly correlated with, and equivalent to, the outdoor concentrations of the same VOCs.
This means that for many VOCs, outdoor sources establish the lower limit of exposure
concentrations. All of the monitored homes had some indoor source of VOCs and
1
-------
SVOCs. The indoor to outdoor ratio of total nonmethane organic compounds (NMOC)
had a median value of 2. The high indoor concentrations of total NMOC were often the
result of only one or two specific chemicals, the identity of which varied from house to
house. In addition, the total SVOC measurements were consistently 3-5 times higher
indoors than outdoors.
Atmospheric transformations in this airshed are contributing to the presence of air
toxics and may account for a component of the increased tumorigenicity associated with
the POM from mobile sources. Nitrogen oxides appear critical in the formation of
mutagenic transformation products. The gas-phase mutagenic products are also persis-
tent, and may remain in the air for hours after they are produced. Exposures to the
transformation products may occur over large population areas and for long periods of
time. For these reasons, new studies are focusing on the mammalian dosimetry and
genotoxic effects of atmospheric transformation products in the lung. The major goal of
these studies will be to determine the potential human cancer risk of transformation
products.
2
-------
INTRODUCTION
The IACP is a long-term EPA research project designed to improve understanding
of the human exposure to and origins of carcinogenic pollutants. The IACP initially
focused on PICs. The goals of the research program are (1) to identify the principal
carcinogens in the air to which humans are exposed, (2) to determine which emission
sources are the major contributors to the atmospheric burden of carcinogens, and (3) to
improve the scientific capability for estimating both human exposure and the resultant
comparative human cancer risk arising from exposure to air pollution, particularly those
from the PICs. Incomplete combustion products include POM primarily adsorbed to
respirable particles. PICs were identified as a major source of carcinogenic risk in urban
areas (US EPA, 1985). Therefore, the research strategy focused on PICs, especially
those from residential home heating and motor vehicles that are major, ubiquitous
emission sources in populated areas. The PICs constitute a large fraction of the
atmospheric burden of pollutants on a national basis (US EPA, 1985, 1990).
The IACP is organized as a matrix management project within the three EPA
Laboratories-Air and Energy Engineering Research Laboratory (AEERL), Atmospheric
Research and Exposure Assessment Laboratory (AREAL), and Health Effects Research
Laboratory (HERL) to ensure that each Laboratory's expertise is applied in the most
effective manner. The Project is managed by a Steering Committee, which is composed
of a representative from each Laboratory and five technical teams made up of scientists
from each Laboratory.
The IACP research strategy integrated field and laboratory studies to address its
goals in a systematic, step-wise fashion (Lewtas, 1989). The field programs were planned
to progress from simple airsheds to more complex environments. PICs were identified as
a major source of carcinogenic risk in urban areas (US EPA, 1985). Therefore, the
research strategy focused on PICs, especially those from motor vehicles and from
residential heating. The PICs constitute a large fraction of the atmospheric burden of
pollutants on a national basis, and motor vehicles and residential heating are major,
ubiquitous emission sources of PICs in populated areas.
The first residential heating source to be studied was RWC. This source was
selected because: (1) it represented a major fraction of PIC emissions on a national
basis; (2) it was under review for regulatory action; and (3) the high mass loading?
associated with wood smoke would ensure that sufficient mass could be collected during
the field study to, in turn, conduct the chemical and biological analyses needed to prog-
ress toward the IACP goals.
3
-------
Pilot Studies
The IACP was conceived in FY84 and conducted its preliminary field studies in
Raleigh, NC, and Albuquerque, NM, during the winter of FY85. The objectives of the
preliminary field studies were to develop and test the methodology capable of identifying
and quantifying mutagens and carcinogens emitted from RWC systems and motor
vehicles. Albuquerque was selected because of studies showing the wintertime
particulate matter (PM) concentrations were heavily impacted by wood smoke and
vehicle emissions (Lewis et al., 1988a). Raleigh was selected as the second site to
maximize the participation of EPA experts located at the Research Triangle Park facility
for methods development and evaluation studies. The first major field study was
conducted in Boise, ID, in 1986-1987.
Selection of Boise
Boise was selected as the first field study site from a potential list of more than 30
towns and cities for several reasons: (1) RWC was known to be a significant contributor
to the high particle loadings which normally occurred in Boise during the fall and winter;
(2) the airshed appeared to be relative^ simple, with no large background or confound-
ing emission sources; (3) there were numerous sampling sites available in the Boise area
which seemed promising for the objectives of this study, (4) the terrain and meteorology
seemed appropriate for extrapolation to other locations; and (5) the local government
and environmental agencies expressed strong support for the project. Boise is the capital
city of Idaho and has a population of slightly more than 100,000 people (1980). The city
is a center of state and local government functions and is home to a variety of corporate
headquarters. There are no large or heavy industrial sources. The urbanized area is
located along the Boise River, which flows through the city from the southeast toward the
northwest. The valley floor is approximately 800 m above sea level. The area is
bordered on the north and east by mountains that rise to an elevation of more than 2000
m. To the south and west, the land rises in a series of steps, called-benches, until a
broad plain is reached at 140 m above the valley floor (Figure 1). Meteorologically, the
wind flow during the sampling period should be dominated by up-valley flow during the
day and down-valley flow at night.
Overview of Boise Field Study
During the heating season of 1986-87, a major sampling program was conducted in
Boise. The Boise field program consisted of both ambient and residential sampling. The
data generated in the sampling programs have been detailed in several papers
(Highsmith et al., 1988; 1992a; 1992b) and are only briefly described herein.
The ambient sampling in Boise was conducted at three primary sites and four
auxiliary sites. One primary site, Elm Grove Park (EGP), was in a residential area. A
second primary site, Fire Station (FS), was near well-traveled roadways. A third primary
site , Federal Aviation Agency Radio-Controlled Air-to-Ground (RCAG) facility, was the
4
-------
background sampling location. Four fixed auxiliary sites-Adams School (ADAM),
Camelback Park (CBP), Fairgrounds (FAIR), and Winstead Park (WINS)--were also
operated during the study. Sampling periods were 12 hours long, with changeover times
at 7 A.M. and 7 P.M. There were 13 sampling periods scheduled per week, and one
period was dedicated to calibration, maintenance, etc. (Highsmith et al., 1992b).
IACP
Sampling Sites
1986-1987
Boise, Idaho
.•'p'} Primary Sites
EQP
FS
RCAG
(A) Auxiliary Sites
FAIR
CBP
WINS
ADAM
| Residential Sites
Figure 1. Map of Boise, ID, Showing Sites Used in the IACP
The residential sampling involved a matched pair of nearby houses each week.
During the study, ten pairs of houses were sampled. One of the houses in each pair used
either a wood stove, a fireplace insert, or a fireplace. The other house did not burn
wood. Sampling was conducted in 12 hour periods identical to those at the ambient
sampling sites. Sampling began each Saturday morning and terminated after the
nighttime sampling period, which ended at 7 A.M. Wednesday. For analysis purposes,
the eight sampling periods were combined into four samples: weekend daytime, weekend
nighttime, weekday daytime, and weekday nighttime. Whenever samples were collected
5
-------
at the houses, corresponding samples were also taken at the primary sites. Samples of the
RWC emissions from the wood burning appliances were obtained with a Wood Stove
Dilution Sampling System (WSDSS). Each pair of houses was matched for age, size, etc.
None of the residents in the sampled houses were smokers.
Figure 1 is a map of the Boise metropolitan area showing the primary, auxiliary,
and residential sampling locations. Each house symbol on the map represents a matched
pair of houses. The houses were clustered between the two primary sites shown on the
map (EGP and FS). Several pairs of houses were located outside this cluster but
relatively near auxiliary sites. The auxiliary sites were located across the valley in order
to examine the distribution of pollutants across the airshed. Resource limitations
prevented the design of a residential monitoring study sufficiently large to represent the
Boise population statistically. Although the 10 pairs of houses were not statistically
representative of the Boise population, the data may be used to understand the processes
that affect exposures across the community. In addition, the auxiliary sites provided
supplementary data to support the extension of population exposure assessment across
the total population.
STUDY DESIGN AND GOALS
First Goal: Identification of Carcinogens
To help identify the carcinogens present in the atmosphere, the field program
included measuring as broad a range of pollutants as possible. Samples of the volatile,
semivolatile, and nonvolatile pollutants were collected for detailed chemical analysis and
bioassay. The nonvolatile pollutants were collected on filters. Cartridges of XAD-2
adsorbent "backed up" the filter samples to collect the semivolatile pollutants, and vapor-
phase organic pollutants were collected in passivated canisters, while the volatile
aldehydes were collected with specialty treated cartridges. One emphasis in the effort to
identify the airborne carcinogens was to determine the contribution of the particle-bound,
semivolatile, and the gaseous pollutants to the potential carcinogenicity, as measured by
short-term mutagenicity bioassay. A second component of this effort was to use
bioassay-directed chemical fractionation of the extracts from the ambient samples to
identify which chemical fractions and classes of chemicals maW*. the major contribution to
the total mutagenicity of the samples. Using this procedure, a bulk sample is separated
into various chemical classes or groups. Each class, or fraction, is then bioassayed. The
object is to devise a fractionation procedure that separates the mutagenic/carcinogenic
species from the innocuous materials. Chemical identification of specific mutagenic
species can be accomplished more efficient^ by identifying only those chemicals in the
mutagenic fractions.
Second Goal: Source Apportionment of Carcinogens
The second goal of the IACP is to develop new methods and data to apportion
the cancer risk between pollution sources. Because the IACP focuses on identifying
6
-------
those species presently in the air that are most likely to be carcinogenic, the IACP source
apportionment emphasis is on a receptor-oriented, rather than source-oriented, ap-
proach. This has the advantage of requiring minimal emissions inventory and meteoro-
logical information in arriving at quantitative estimates of each source's contribution to
measured ambient concentrations.
Since the largest anticipated sources of PICs in Boise were automobiles and RWC,
field samples were collected during daytime (7 AM. - 7 P.M.) and nighttime (7 P.M. - 7
AM.) periods to more effectively separate the contributions of the two sources. The
primary sampling sites were also situated to assist in identifying the contributions of the
major sources. One primary site, EGP, was situated in a residential area that was
impacted by emissions from wood burning houses. A second primary site, FS, was
selected near well-traveled roadways to emphasize the MS emissions. A third primary
site, RCAG, was selected to measure the regional background contribution of pollutants
being transported into the city.
Specific samples were collected and analyzed for the source apportionment
analysis including filter samples for (1) elemental analysis by X-ray fluorescence
spectrometry, (2) elemental and volatilizable carbon, and (3) carbon dating (14C to 12C
ratio). Denuder samples were collected for various inorganic ions and acid gases. The
apportionment approach uses multiple linear regression and chemical mass balance
techniques. Application of the multiple linear regression method requires a data set of
adequate size (e.g., 30 - 50 complete sampling periods) and should include periods of
both high and low contribution of each source to the ambient loadings. The field
programs were designed to extend over the full heating season, to ensure collection of a
sufficient number of complete sample sets covering a wide range of source input
conditions. The IACP data sets are the first ever to permit apportionment of not only
the particle-bound mass, but also of the mutagenicity associated with those particles.
Because MS emissions are "old" carbon (from oil that has been underground for millions
of years), while wood smoke contains "new" carbon, the IACP has been able to validate
the mathematically derived apportionment model through radiocarbon (14C) dating of
the "age" of the collected ambient carbon samples.
Third Goal: Tmnrovement of Human Exposure and Comparative Cancer Risk
Assessment
Finally, the sampling strategies implemented in this study were designed to
estimate human exposure to airborne pollutants. Because people spend much of their
time indoors, measurements were made inside houses to assess and apportion the levels
of mutagens and range of chemical species found in residences. For comparison,
identical measurements were made just outside the home and at the primary site nearby.
The residential sampling was similar to the primary site ambient sampling in that (1)
nonvolatile, semivolatile, and gaseous pollutants were collected for chemical analysis and
mutagenicity testing; and (2) samples were also collected to allow apportionment to the
original sources. Two houses, matched for neighborhood, age, size, etc., were sampled
7
-------
each week, with one house using RWC and the other house not burning any wood. The
participants whose houses were monitored also kept activity log books, which have been
used to develop a microenvironmental model of exposures in Boise. Questionnaire
surveys of automobile and home heating fuel usage were also completed, as were special
meteorological studies of air pollutant dispersion, to assist with extrapolation of the expo-
sure estimates to other locations and times. These data have been used to estimate
human exposure and dose to the EOM component of each combustion source in the
Boise airshed for both the winter period and for the annual average.
To improve cancer risk estimates of the particle bound pollutants from PIC
sources in urban airsheds, comparative potency methods were developed (previous
Deliverable Report, Lewtas, 1991) and comparative carcinogenicity studies were
conducted on samples collected in the Boise airshed. The POM component of PICs is
primarily contained in the EOM from the respirable air particles. The EOM from the
ambient filter samples collected during each sampling period was apportioned to related
emission sources and combined into composites for comparative cancer potency studies.
One sample was composited to maximi™* the EOM from RWC emissions, while the
other composite was designed to maximi™ the EOM from automotive emissions. Tumor
initiation studies of these composites conducted in Senear mice demonstrated a signifi-
cant difference in tumor potency between these composites. These data permitted for
the first time a direct measure of the tumorigenicity of airborne EOM and will provide
input data to estimate of the comparative human cancer risk for ambient air.
IDENTIFICATION OF CARCINOGENS
Mutagenicity
The EOM adsorbed to particles and the SVOCs in Boise were mutagenic in
Salmonella typhimurium (Claxton et al., 1992; Lewtas and Warren, 1992). Fractionation
of the particle EOM and characterization of the mutation spectra show that 90% of the
mutations are induced by a CG or GC deletion and that half of the remaining mutations
are complex mutations (DeMarini et al., 1992). These results suggest that the mutagens
present in these mixtures are the large, bulky, poly cyclic aromatic compounds that form
DNA adducts with the DNA base, guanosine (G). These results are also consistent with
the types of mutations found in oncogenes from the lung tumors of mice exposed to
PAHs (Reynolds and Anderson, 1991) and from humans exposed to cigarette smoke
(Reynolds et al, 1991). Previous studies on wood smoke and vehicle emissions have
clearly identified combustion emissions as genotoxic carcinogens (Lewies, 1990). These
findings are consistent with many independent studies showing that POM from ambient
air and combustion emissions are genotoxic carcinogens.
8
-------
Carcinogenicity
The EOM from respirable airborne particles in Boise was found to initiate tumors
in a two-stage mouse skin tumor initiation assay (Lewtas et al, 1992b). Dose-response
studies were conducted to determine the tumorigenic potency of the ambient samples as
discussed later. In these same studies, DNA adducts were detected and quantitated in
both the lungs and skin. DNA adduct forming efficiency was found to be highest at the
lowest doses of ambient EOM (Lewtas et al., 1992b). Initial characterization of the
DNA adducts suggests that they are large bulky aromatic adducts similar to those formed
from carcinogenic PAHs.
Rinassav-Directed Fractionation fBDF)
The BDF of two composite extracts from ambient samples was undertaken to
identify those compounds responsible for the observed mutagenicity. Two composite
samples were prepared with partial resolution of the chemicals from Boise's two main
sources: a wood smoke mobile source composite (WSMSC) sample, with an estimated
composition of 51% wood smoke, 33% mobile sources; and a wood smoke composite
(WSC) sample; with an estimated composition of 78% wood smoke, 11% mobile sources.
Methods were optimized for separating the samples into neutral, polar neutral/weak acid,
weak acid, and strong add fractions using solid-phase nonaqueous ion exchange tech-
niques. The neutral fraction containing PAH, nitro-PAH and other nonacidic POMs was
found to be the most mutagenic in Salmonella typhimurium, containing 48% of the total
in the WSC sample and 59% in the WSMSC sample. The concentration of many PAHs
and nitro-PAHs was higher in the WSMSC sample, which was also the most tumorigenic.
Chemical Characterization and Quantitation of Carcinogens
Carcinogenic air toxics, especially those emitted from combustion sources, were
characterized and quantitated throughout the IACP study. In addition to the specific
PIC/POM measurements, including measurements of PAHs, carcinogenic VOCs,
aldehydes, and metals were measured. Carcinogens quantitated in the IACP include:
chromium, benzene, and formaldehyde. These are only a few of the over 185 different
chemical species quantitated both outdoors and indoors in the Boise IACP study.
Hazard Identification Summary
The EOM from ambient particles contains primarily POM, if the extracting
solvent is dichloromethane (DCM). It has been proposed that although various sources of
POM will have different cancer unit risk numbers, there is sufficient evidence that all
POM should be considered carcinogenic to humans (Lewtas, 1991). In addition, the
Clean Air Act Amendments (CAAA) list POM as one of the important toxic air
pollutants for regulation. Studies of chimney sweeps, coke oven workers, roofers,
9
-------
aluminum production workers, tobacco smokers and passive smokers, diesel railroad and
bus workers, vehicle examiners, vehicle drivers, and several populations exposed to
elevated concentrations of air pollution (containing elevated POM) have shown increased
risk of mortality from cancer of the lung and, in some cases, also skin, bladder, trachea
and bronchus, and cancer of all sites combined. In animals, POM (e.g., EOM from
particulate matter) from many sources (e.g., fuel combustion, vehicle emissions, tobacco
smoke, coke oven and aluminum smelter emissions, roofing coal tar, and plastic burning)
was found to be carcinogenic in skin-painting studies. The particle emissions or POM
from several of these sources (e.g., coal tar, diesel emissions) are also carcinogenic in
inhalation studies and lung implantation studies. The mutagenicity of POM, as well as
fractions and components of the POM from all of these sources, provides important
supportive evidence for carcinogenicity in demonstrating that these carcinogens are
capable of acting via a genotoxic mechanism. This mechanism provides justification for
using the low-dose extrapolations, which do not invoke a threshold (Albert et al., 1983,
Lewtas et al., 1983). For these reasons there was sufficient hazard identification evidence
to pursue developing new methods and data to assess quantitatively the comparative
carcinogenicity of combustion sources in the Boise airshed, as described in this report.
SOURCES OF RISK
Source Apportionment
Source apportionment by receptor modeling refers to a methodology by which the
ambient concentrations of an air pollutant are mathematically separated into their
contributions from individual sources or source categories. The source apportionment
focused on the fine particulate EOM, because it is the fraction of air particulate matter
in which most of the carcinogenic POM is found. We now have evidence that mutagenic
organics, possibly POM, is present in the SVOC collected on XAD after the filter. The
contribution of the SVOC component to the carcinogenicity is not known and will be
studied in the future. All subsequent references in this report on the source
apportionment and comparative carcinogenicity of the EOM is referring to the
extractable organic matter associated with the respirable particles.
The source apportionment of EOM in Boise built on the success of a strategy
demonstrated in earlier IACP studies in Albuquerque and Raleigh. This approach
requires the availability of unique tracers-a chemical species whose presence in the
atmosphere is due essentially to its emission from a single source category only-whose
ambient concentrations are measured simultaneously with the pollutant of interest
(EOM). Each measured EOM concentration is then represented by a sum of source
contribution terms, with each term being the product of a measured tracer concentration
and an initially unknown coefficient. Through the multiple regression of a series of such
EOM and tracer measurement sets, the coefficient for each source can be determined
and, thus, can be used with each tracer concentration to calculate the source contribution
in each EOM sample.
10
-------
The tracer species that were used
were fine particle lead and potassium-
indicators for motor vehicle emissions anc
wood smoke, respectively. A review of
existing emissions inventories in Boise
(Downs, 1986) strongly suggested these
two source categories would be the domi-
nant contributors to ambient EOM in
wintertime Boise. The resulting regres-
sion analysis with the two tracers was
consistent with this expectation, showing
that, on average, 90% of the measured
ambient EOM was contributed by these
two sources, with the remainder undiffer-
entiated between all other sources (Figure
2). Details of this analysis and its results
can be found in Lewis et al., (1988a),
including the procedure used to improve
the potassium tracer by removing its soil
contamination ("soil-corrected potassi-
um"). The principal results were (1)
wood smoke contribution dominated the EOM at both primaiy sites and during both dav
and night periods; (2) wood smoke made its greatest impact during nighttime periods-
and (3) the contribution from motor vehicle emissions was greater at the FS froadwav'i
site than at the EGP (residential) site. J
An important use of the EOM source apportionment results was in the
preparation of composite samples for the tumorigenicity studies. Because source
apportionment provides an estimate of the wood smoke and motor vehicle contributions
to the total EOM measured in each sample, this information allowed sample selection in
such a way that two composite samples could be constructed to maximize the
contribution of wood smoke while minimizing the motor vehicle contribution, and vice
versa.
Considerable effort (and expense) was made to validate the regression methodolo-
gy through the use of radiocarbon (14C) measurements. Because fossil fuels like
petroleum products are devoid of 14C, the amount of 14C that is measured in ambient
particles can be directly related to the amount of organic particles originating from
nonfossil sources (i.e., wood burning). Source apportionment results that were found
with the deterministic 14C measurements were in excellent agreement with those found
with the statistical potassium-based measurements. Details are given in Klouda et al
(1991).
extractable organic matter
Mob I l»
6 ~/- 2 uQ/m3
Figure 2. Average Source Contributions to
EOM, Measured at EGP and FS
11
-------
Additional regression validation work identified several VOCs as alternatives to
fine particle lead as motor vehicle emissions tracers. The source apportionment results
obtained with those VOCs were virtually identical with the original results based on lead.
This is considered a significant finding for use of the regression approach at a future time
when the phaseout of leaded gasoline is complete. The VOC tracer work is described in
Zweidinger et al., (1990).
In addition to the source appor-
tionment of ambient particulate EOM, its
mutagenicity was also apportioned by the
same tracer species approach (Figure 3).
The mutagenicity measurements were
based on a plate incorporation bioassay
using Salmonella typh.imu.rium strain TA98
with metabolic activation (+S9). Details
are given in Lewis et al., (1991).
MUTAGENICITY (TA98, +59)
Wood
12 ¦»/- 3 rev/m3
Mobi le \
18 ~/- 3 rev/m3
Other
3 ~/- 4 rev/m3
i
Figure 3. Average Source Contributions to
Mutagenicity (TA98 +S9), Measured at
EGP and FS
The noteworthy feature of the
EOM +S9 mutagenicity apportionment is
the dominance of the motor vehicle con-
tribution to the mutagenicity, opposite to
the wood smoke domination of EOM
mass. Quantitatively, this can be expre-
ssed in terms of potency: approximately 1
and 3 revertants per microgram (rev//xg)
were found for ambient EOM originating
. r™ , from wood smoke and motor vehicle
emissions, respectively. Thus the greater potencv of FOM . , ,
outweighs the 'smaller" amount of Lor
experimental uncertainties (approximately 30%) the twn nntpL, , witnin
consistent with results found in the Albuquerque and Raleigh 1ACP studies. C°mp Y
Finally, a quite different method of source annnrti™™^
data collected at the residences. The objective was to senarate" Wfi! " t0 analyze
trations of pollutant species measured indoors into their contribmiY,hematically concen-
sources and all outside sources, regarded as two comnmit^ inside
accomplished through use of a standard mass balanced inH S°UrCe cate8°ries. This was
applied to a large number of VOC, aldehyde, and to na^r ^ ^
results may be found in Lewis (1991) and Lewis and ZweidingerS) ^Th detailet?
are discussed later in this report. wger (1992). These results
12
-------
Characterization of Wood Combustion Emissions
The purpose of this work was to develop quantitative and qualitative data on the
kinds of chemical compounds emitted by wood stoves in a typical wood stove-impacted
area (in this case, Boise, Idaho). The information developed was to be both general and
specific dealing, generally, with total grams emitted of condensible (nonvolatile), volatile,
and semivolatile organics. More specifically, information was developed dealing with the
identities of specific compounds and their segregation into classes. The study made use
of sampling and analytical techniques, which had previously been developed by the
AEERL as part of their Level 1 source assessment strategy and as part of the Wood
Stove Dilution Sampling System (WSDSS), a device developed especially for the IACP
program. The Level 1 analytical methods included the total chromatographable organics
(TCO) method for volatile and semivolatile organics C-, and above, the gravimetric
(GRAV) method for condensibles, and gas chromatograph mass spectrometry (GC/MS)
for identification of specific compounds. Samples were acquired using 4 CFM samplers
with Teflon-coated filters to collect the particulate matter and XAD-2 cartridges for the
VOCs and SVOCs. Canisters and aldehyde cartridges were also used with the WSDSS to
collect VOCs and aldehydes. As a corollary to the field work, a wood stove study was
also conducted in the laboratory and extensive data developed relating burn conditions
and wood stove type to organic material, trace metal, and mutagen emissions.
The Boise residential samples were taken at the EGP and FS primary ambient sites,
on the inside and immediately outside the residences being studied (houses with and
without wood stoves), and at the exit stacks of wood stoves. The outdoor sites had the
lowest concentrations of total collectible organic material ranging from 50 to 100 /xg/m3.
The total collectible organic material is a sum of the TCO and the GRAV. The total
organic mass concentrations inside the houses were two to three times higher than
outside, ranging from 200 to 300 ng/m3 and were predominately made up of VOCs and
SVOCs. Stack concentrations were between three and four orders of magnitude greater
with nearly 60% of the organic material being emitted as particulate matter (Merrill et
al., 1988). The dominant classes of compounds were oxygenated monoaromatics,
particularly the methoxybenzenes and the methoxy phenols, the PAHs, and the alkylated
benzenes. The presence of these compounds is consistent with the thermal destruction of
lignin, a major constituent of all woods (Steiber and Dorsey, 1988).
A laboratory study was carried out using both catalytic and noncatalytic wood stoves.
Lodgepole pine imported from the Boise area and North Carolina oak were used as the
fuels. Lodgepole pine makes up about 30% of the wood stove fuel used in Boise and
was, therefore, thought to be indicative of what would be found in the field study. The
oak was used to relate data from the laboratory study to the results of previous studies.
In both the catalytic and noncatalytic stoves, the TCO and the GRAV showed the same
trend: high emission rates at low burn rates decreasing rapidly and finally leveling out as
burn rate increased. The amount of PAHs as a percentage of total emissions increased
-------
with increasing burn rate, although total emissions decreased (McCrillis and Burnet,
1988; 1990).
The bioassay results for mutagenicity (TA98, +S9) were obtained using the Ames
plate incorporation method and the microsuspension assay. Mutagenicity of the wood
stove stack emissions in the absence of a catalyst ranged from 0.35 to 3.9 revertants/joule
(rev/J) of heat input with an average of 1.1 rev/J. The average for wood stoves with a
catalyst was 1.5 rev/J. To put this in perspective, an oil furnace sampled by the same
method emitted 0.12 rev/J (Steiber and McCrillis, 1991).
Inorganic measurements were made using inductively coupled argon plasma (ICP)
spectrometry. Of the metals surveyed, potassium had the highest emission rate at 78
mg/hr. Sodium was second with 56 mg/hr, and barium and calcium were also relatively
high, ranging from 0 to 18 mg/hr. Trace amounts of aluminum, cadmium, copper, iron,
lead, magnesium, manganese, phosphorus, strontium, tin, titanium, and zinc were also
present All measurements were made using solutions of the total particulate sample
(Burnet et al., 1990).
Two major conclusions to be drawn from this work are that (1) wood stove opera-
tions are the most important variables affecting both type and rate of the compounds
emitted, and (2) wood stoves emit a characteristic mix of compound classes, and this mix
constitutes a signature for this type of source.
Characterization of Mobile Source Emissions
The IACP has relied on previous studies to characterize mobile source emissions
with respect tt> chenucal imposition mutagenic activity, and carcinogenic activity
(Lewtas, 1983; Lewtas and Williams, 1986; Schuetzle and Lewtas, 1986; Qaxton, 1983).
Atmospheric Transformation: A Potential Srmrr#.
Atmospheric transformations may appear to be either a "source" or a "sink" of
hazardous air potaants. Chemical reactions or phyacal processes may either destroy the
SSlrttZT?6 Pf',an,S fa,° «"» more dang*™* compolds.
^ "I1™' have demonstrated that
normal atmospheric processes can produce significant changes, in both the chemical com-
posmon and mutagen,^ of the complex pollutant mixture (Shepson et al„ 1987) Ffe"
14
-------
Mutagenic Activity of irradiated Auto Exhaust
Legend
After Irradiation
Before Irradiation
r 1
Gas Phase Particulate Phase
TA 100
Gas Phase Particulate Phase
TA 98
*• Concentration of Mutagenic Activity Measured in Revertants per Cubic Meter
Figure 4. Mutagenicity from Automotive Emissions
TA 100: Gas phase before irradiation 83 ± 24, after irradiation 3680 ± 1095, particle phase before and after less than 10.
TA 98: Gas phase before irradiation below detectable limit, after irradiation 370 ± 108, particle phase before and after less that 10.
1. Normal photochemical processes transform many chemicals, including emissions
from RWC (Kleindienst et al., 1986) and automobiles, into both gas-phase and
particle-bound mutagenic products.
2. The gas-phase mutagenic transformation products are direct-acting in bacteria.
They can alter the genetic code without microsomal metabolic activation. This
suggests that they are either nitrated organic compounds (e.g. peroxyacetyl nitrate)
which may be activated by en2ymes present in the bacteria or are reactive species
which don't require any activation (e.g., methylating agents).
3. The gas-phase mutagenic products are persistent and may remain in the air for
hours after they are produced. Exposures may occur over large areas and for long
periods.
4. The exposure concentration of mutagens (rev/m3) from the gas-phase
products is often greater than that from the particle-bound products.
Differences in mammalian dosimetry between gases and particles, however,
must be considered in estimating the target dose of a particle bound
organic compound as compared to a gaseous organic compound, since
particles accumulate in the lung.
15
-------
Figure 5. Mutagenicity of Wood Smoke
Mutagenic Activity of Irradiated Wood Smoke
15000
10000
5000
Legend
H After Irradiation
¦ Before Irradiation
** Concentration of Mutagenic Activity Measured In Revertants per Cubic Meter
20000
0
Gas Phase Particulate Phase
TA 100
Gas Phase Particulate Phase
TA 98
TA 100: Gas phase before irradiation 113 ± 90, after irradiation 18,200 ± 1625, particle phase before 180 ± 60 and after 180 ± 100.
TA 98 : Gas phase before irradiation 0 ± 85, after irradiaton 3100 ± 378, particle phase before 165 ± 45 and after 830 ± 265.
These observations from laboratory smog chamber simulations suggest that
atmospheric transformations may play an important role in the formation of mutagens
and air toxics. Although, wintertime conditions in Boise are not normally considered
conducive for extensive photochemical reactions, appreciable concentrations (up to
5/ig/m3) of nitrous acid (HONO) were consistently measured throughout the Boise study.
HONO is readily photolyzed to produce hydroxyl radicals, OH, which can then initiate
the atmospheric transformation processes. Many of the OH reactions are not strongly
affected by temperature, so the reactions can occur even at wintertime temperatures.
(Indeed, some OH reactions are even faster at lower temperatures.) Nitro-aromatic and
hydroxy-nitro-aromatic species, previously shown to occur primarily from atmospheric
transformation reactions, were found in ambient Boise samples (Nishioka and Lewtas,
1992). The data from Boise suggest that atmospheric transformations did occur during
the Boise field study, at least on sunny days.
HUMAN EXPOSURE
Exposure Concentrations
16
-------
4V °K"e°f thC ?°alS °f th* is t0 improve our ability to assess exposure and risk
from airborne carcinogens. To address this issue, the IACP included efforts to
characterize both outdoor and indoor exposure levels and to improve our understanding
of the relationships between indoor and outdoor concentrations of carcinogens.
Particles
The primary ales' (EGP andIPS) fine-particle levels were two to three times
greater than the backyound (RCAG site). Nighttime EGP and FS fine-particle
eventrations were 5040% higher than the corresponding daytime levels and exceeded
100 Mg/m3 dunng three mghttme periods. Concentrations at auxiliary sites indicated a
nearly uniform distribution of source emissions across the Boise airshed. Mean fine-
particle concentrations inside the houses with wood burning were generally slightly higher
than inside houses without wood burning, but were lower than outdoor levels. During
the weekend daytime period when most active wood burning occurred, fine-particle levels
inside houses with wood burning averaged twice those inside the paired houses without
wood burning; however, the average is strongly influenced by two houses with leaky wood
burning appliances. Outdoor air particle concentrations appeared to be the primarv
source influencing fine-particle concentrations inside the houses without wood burnine
(Lewis, 1991). 6
Extractable Organic Matter (EOM)
• u T^^?npl? uere COUert™? Teflon~coated fiber filters and were extracted
with DCM, and the mass of EOM was determined gravimetrically Overall EOM
averaged 1between 55; and 65% of the fine-particle mass collected at the primary sites
with the EOM 40-75% higher at nighttime, which is consistent with the increased
presence of RWC. The EOM % of fine particle mass ranged from 50-72% indoors
versus 44-65% outdoors for comparable time periods. The EOM from 36 primary site
S^^a!ar!£r 3°cdfe/ent ?AH% from Phenanthrene to coronene
(NIST Report, 1989). Mean EOM concentrations were 23.4 /ig/m3, and benzo(a)pyrene
(BaP) concentrations averaged 6.49 ng/m3 (0.03% of the EOM).
Semivolatile Organic Compounds (SVOCs)
SVOC samples collected on XAD-2 were extracted with DCM. The SVOC
extractable mass is made up of two components, the lower boiling total
chromatographical organics (TCO) and the higher boiling gravimetric (GRAV) mass
The low boiling compounds ranging from up 100 °C to 300 °C are measured by gas
chromatography and the mass expressed as TCO. The higher boiling GRAV mass is
determined gravimetrically. Total SVOCs are the sum of the GRAV and TCO mass.
Total SVOCs ranged from 173-316 /u,g/m3 indoors and were three to five times higher
than outdoor levels. The TCO comprised 80-90% of the total SVOCs from the indoor
samples.
17
-------
Aldehydes
Samples for aldehyde analysis were collected on 2,4-dinitrophenylhydrazine
(DNPH)-coated silica cartridges. The DNPH derivatives were eluted from the cartridges
with acetonitrile and were analyzed by high performance liquid chromatography (HPLC).
Of 13 aldehydes measured in samples, formaldehyde and acetaldehyde accounted for 50-
75% of the total. Mean formaldehyde concentrations at the EGP and FS primary sites
were four times higher than the background RCAG site. Indoor levels of aldehydes were
greater than four times those outdoors. The mean formaldehyde concentration was 22
ppb inside houses with wood burning and 16 ppb inside houses without wood burning
(Lewis and Zweidinger, 1992). It appears that elevated concentrations of aldehydes
inside several homes with improperly operated wood burning appliances may account for
the elevated mean concentrations of aldehydes in the wood burning homes. Much of the
higher levels seen indoors are likely related to construction, furnishings, and other
activities (such as cooking).
Volatile Organic Compounds (VOCs)
Samples for hydrocarbon analysis were collected in canisters. The concentration
of 70 specific hydrocarbons, which generally comprised 80% of the total nonmethane
organic carbon (NMOC) in most samples, was identified by gas chromatography.
Average ambient benzene concentrations were 16 ppb carbon (ppbC), with
concentrations being slightly higher at the mobile source site. Mean NMOC
concentrations inside the houses were two to three times the outdoor levels; however,
many individual species of hydrocarbons had similar indoor and outdoor levels indicating
that sources outside the house were the primary source of indoor concentrations (Lewis,
1991). Many of these species were related to motor vehicle emissions, which appeared to
be the dominant source of VOCs (Zweidinger et al., 1991). High indoor concentrations
of total NMOCs were often the result of large concentrations of one or two compounds,
possibly related to the use of consumer products.
Inorganic Species
Elements were determined by X-ray fluorescence of fine fraction dichot filters;
inorganic ions, acids and bases were determined using annular denuders and ion chroma-
tography. Fine-particle potassium (K) that is corrected for soil potassium (K^) is
considered a primary inorganic indicator of RWC. Nighttime EGP and FS
concentrations were 75-100% higher than daytime concentrations. A near 3:1 ratio for
fine particle lead (Pb) and bromine (Br) was observed at primary and background sites,
reflecting the mobile source signature that is typical of leaded gasoline. Concentrations
of Pb were much lower than those observed in previous field studies, reflecting the
increased use of unleaded gasoline. Nitrous acid concentrations were two times higher
during the night than during the day, which is consistent with the nocturnal formation of
HONO and its photodissociation during daylight hours. Nitric acid (HN03) concen-
18
-------
trations were typically low and near the experimental detection limit. Ratios of HN03:-
fine particle N03* were typically less than 1.0 in Boise, which is consistent with
wintertime studies in the eastern U.S.
Human Time-Activity Profiles in Boise
The residential sampling portion of the Boise field study was critical to the
exposure estimate, because people normally spend about two-thirds of their time in their
houses. The indoor sampling provides insight and data that can be used to estimate
indoor exposures by the population in Boise. In addition, residents completed daily
"diaries" of their activities during sampling studies at their homes. Forty-three diaries
have been compiled to estimate the fraction of time spent in different locations or
activities.
Exposure to pollutants is
dependent on the product of
the concentration of the pollut-
ant and the time of exposure.
One way to estimate daily expo-
sures is to divide the day into
distinctive periods that each
person spends in a particular
"microenvironment.'1 A
microenvironment represents a
location or activity that is dis-
tinctive in terms of the expo-
sure under investigation. One
may characterize both the con-
centrations and times in each
microenvironment and calculate
the exposure for each micro-
environment. The total expo-
sure is the sum of the exposures
in the various microenviron-
ments. Both the concentrations
and the times spent in each
microenvironment are expected
to be a distribution of values,
and the resultant exposures
should also be a distribution of values. Average concentrations and average times in
each microenvironment may be used to represent a population average, but there can
still be much variability about the average.
Table 1. Percentage of Time Spent in Each Zone or
Microenvironment, as Reported from the Boise Activi-
ty Diaries and from a National Survey
Time Allocation
(Percentage of Total)
Zone
Boise
Data:
Winter-
Time
National
Data:
Annual
| Average
Indoors
68.6 ±1.6
64.7
Outdoors
1.8 ± 0.4
4.5
in-Transit
3.3 ± 0.2
6.6
Workplace
18.4 ± 1.7
15.4
X, other
7.9 ± 0.7
8.9 |
Uncertainties are standard errors for 43 participants in Boise.
Uncertainties of the national data can not be estimated from the reported
tabulations of data.
19
-------
The daily activity diaries from the Boise study were used to characterize the
average time periods spent in five microenvironments: indoors at houses, (I); outdoors,
(O); in-transit, (T); at the workplace, (W); and at other indoor locations like stores,
churches, and post offices (X). Table 1 shows the percentage of time spent in each of
the five zones, as determined from the Boise winter diary data. The table also shows the
percentage of timet for each zone, as determined from a national survey (Glen et al.,
1991) for year-round activity patterns. The time allocations for Boise seem reasonable
compared with the national survey data. One would expect the time indoors during the
winter in Boise to be greater than the national annual average, and for the time outdoors
to be less. Boise is a modest sized city, so the commute time, T, would also be expected
to be less than the national average.
The even distribution of fine particle mass across the Boise airshed and across the
population distribution facilitated the exposure extrapolation from the relatively small
population for which we obtained time-activity profiles to the general population in
Boise. This is supported by the reasonably good agreement between Boise and the
National Average shown in Table 1 for the time allocations in different activity zones.
Furthermore, the exposure assessment results were sufficiently robust statistically that use
of either the Boise or National Average Time Allocation gave similar results.
Apportionment and Estimation of Human Dose to EOM
Apportionment of the Boise field study data indicated that, on average, the EOM
from the ambient particles in Boise came primarily (>89%) from RWC and MS. The
remaining 11% of the EOM may have come from a different source, or it may also have
derived from RWC and MS, with the 11% residual representing the combined uncertain-
ty in the measurements and the apportionment model. Nonetheless, to a first ap-
proximation, one may assume that all of the EOM in the Boise airshed is attributable to
RWC and MS. A similar relationship exists for the PM-10 mass values observed during
the Boise study, with RWC and MS accounting for 87% ± 4% of the PM-10 wa« The
EOM from RWC accounted for 64% ± 1% of the PM-10 mass attributable to RWC,
while the EOM from MS represented only 26% ± 2% of the PM-10 mass associated
with vehicles. Not only may the emissions from vehicular traffic be less extractable, but
some portion of the PM-10 mass attributable to MS may be insoluble dust or other
particles that are introduced into the air by mechanic^] action.
The factors that determine the concentrations of pollutants in the ambient air are
the magnitude of the emissions (the source strength) and the volume of air into which
the emissions are mixed. The source strength for MS and RWC is dependent on the
vehicle use and on the amount of wood burned. The mixing volume is a function of two
meteorological parameters, the mixing depth (or inversion height) and the wind speed.
The mixing volume is often smallest during the winter months, leading to the highest
concentrations. To estimate the annual exposures to RWC and MS particles in Boise,
the source strength terms were first adjusted to provide the contribution to the PM-10
20
-------
mass that was observed during the field study for December and January. The source
strength term for MS was held constant for the remainder of the year, and the ambient
loadings were adjusted for changes in mixing volume. The RWC source strength term
was adjusted by both heating-degree days and by the mixing volume.
The annual exposure and dose of EOM from RWC and MS for Boise residents
was calculated by taking into account the times spent in each zone, reasonable inhalation
rates for the activities in each zone, and the probable concentrations from RWC and MS
in each zone. During the winter months of the Boise field study, the ambient
concentrations averaged 15.3 fig/m3 of EOM from RWC and 4.2 fig/m3 of EOM from
MS. Human exposures for the same period are estimated to average 9.5 ± 3.2* fig/m3
EOM for RWC and 2.1 ± 0.7 fig/m3 EOM from MS. Annual estimates for exposure to
EOM from RWC and MS are 3.4 ± 0.9 fig/m3 and 1.2 ± 0.3* fig/m3, respectively. Thus,
RWC accounts for about 73% of the annual exposure to EOM found attributable to
RWC and MS. A full account of these exposure calculations is in Cupitt et al., (1992).
•
The uncertainty represents the ± one a value of the standard deviation of the estimator, based upon the observed variabilities in
the Boise data that were used to calculate the estimator.
COMPARATIVE CARCINOGENICITY
Mutagenicity and Carcinogenicity Relationships
Evidence has been growing since the 1960's to support the theory that
electrophilic chemicals react covalently with the nucleophilic centers in DNA and
subsequently induce genetic changes (e.g., mutations). When such reactive electrophilic
chemical mutagens react with DNA, this event may become the initiating event in a
multistage process leading to cancer. The mutational theoiy of cancer is supported by
evidence that many electrophilic mutagens also induce cancer in animals. This theory
that the event which initiates cancer is caused by a genetic change in the DNA of an
oncogene or tumor suppressor gene, and the evidence supporting it, has become the
basis for using short-term genetic bioassays to detect carcinogens.
Previous studies comparing the mutagenic potency of a series of POM from diesel
and gasoline vehicle emissions in Salmonella typhimurium with the tumorigenic potency
showed high correlations between the two bioassays (^=0.90 for -S9 and 0.72 for +S9)
(Lewtas, 1983). Both the tumorigenic potencies and the mutagenic potencies of EOM
from this series of diesel vehicles and one unleaded gasoline catalyst vehicle were highly
correlated with the concentration of nitrated PAH and PAH in the POM mixture
(Lewtas, 1985, 1988). Wood stove emissions contain PAH, which require the mammalian
S9 activation system for mutagenic activity in Salmonella typhimurium, but do not contain
nitrated PAH. To expand our understanding of the relationship between mutagenic
potency in bacteria and tumor initiating potency in the mouse, with the emission sources
which are present in Boise, we have added wood stove emissions and an additional
gasoline emission sample which require the S9 activation. Figure 6 shows the correlation
21
-------
BIOASSAY CAmes Test) Cevertants/ug) TA98
~S9
figure 6. Correlation Between Tumor Initiation Potency and Mutagenic Potency in the
S. tvphimurium Plate Incorporation Assay
of the tumor initiating potency in mouse skin with the mutagenic potency in the Salmo-
nella typkanurium plate incorporation bioassay (TA98+S9) when recent tumor initiation
and mutagenicity data for emissions from a noncatalyst vehicle operated on leaded gaso-
line, wood stove emissions, and residential oil emissions from a home heater are added to
the previous series of mobile source emissions. These data (r2=0.88) suggest that bio-
monitoring studies with the Salmonella typhimurium assay will be useful in monitoring
airborne genotoxic activity including trends over time. Tlie IACP has demonstrated the
utility of this bioassay in apportioning the source of mutagens and potential carcinogens
in an airshed.
To provide data for a comparative potency assessment of the potential cancer risk
of ambient POM, the tumor potency of the EOM from the Boise ambient air particulate
matter was determined in dose-response studies in the Senear mouse skin tumor
initiation assay (Nesnow et al., 1982). The slope of the dose response measured in
papillomas/mouse/mg for each Boise composite sample is shown in Table 2.
22
-------
Table 2. Tumor Initiation Potency of the Boise Composite Samples of Extractable
Organic Matter (EOM) from Respirable Particles.
Composite EOM Sample
papillomas/mouse/mg*
WSC (78/1 l)b
0.095 (0.065-0.13)
WSMSC (51/33)c
0.21 (0.16.28)
a Maximum likelihood estimate (lower bound-upper bound).
b Wood smoke composite (WSC) containing 78% wood smoke, 11% mobile source emissions, and 11%
residual mass
c Wood smoke-mobile source composite (WSMSC) containing 51% wood smoket 33% mobile source
emissions, and 16% residual mass
The relative tumor initiation potency of the Boise composite samples is based on a
linear model using the maximum likelihood estimate (Lewtas et al., 1992b). The WSC
sample, that contains less mobile source emissions, is approximately half as tumorigenic
as the WSMSC sample which contains a higher contribution of mobile source emissions.
The results of the comparative carcinogenicity evaluation using tumor initiation potency
for the two ambient aerosol samples, compared to estimates for wood stove, and
automotive source samples, and other comparative POM sources are shown in Table 3.
Also included at the bottom of this table are the three human carcinogens (coke oven
emissions, roofing tar emissions, and cigarette smoke) that have been used in the
development of the comparative potency method (Lewtas, 1992).
23
-------
Table 3. Tumor Initiation Potency Estimates from Comparative Tumorigenicity Studies of
Combustion and Related using Senear Mouse Skin Tumor Model
Samples
papillomas/mouse/mg3
Diesel vehicle: Nissan
0.61 (0.52-0.72)
Diesel vehicle: Oldsmobile
0.16 (0.10-0.24)
Diesel vehicle: VW Rabbit
0.046 (0.028-0.068)
Diesel vehicle: Mercedes
0.16 (0.065-0.34)
Gasoline Catalyst vehicle:
Ford Mustang (unleaded gasoline)
0.071 (0.023-0.13)
Gasoline Noncatalyst vehicle:
Ford Van (leaded gasoline)
0.18 (0.15-0.22)
Wood stove: Hardwood (Oak)
0.0087 (0.0018-0.017)
Wood stove: Softwood Mixture
0.046 (0.031-0.063)
Ambient air: WSC (78%WS/11%MS)
0.095 (0.065-0.13)
Ambient air: WSMSC (51%WS/33%MS)
0.21 (0.16-0.28)
Coke Oven Emissions
2.1 (1.8-2.5)
Roofing Tar Emissions
0.61 (0.40-0.88)
Cigarette Smoke Condensate
0.0029 (0.0020-0.0038) [
Maximum likelihood estimate (lower bound-upper Dound).
The animal tumor potency from exposure to the EOM from particles directly
emitted from mobile sources (e.g., diesel and gasoline vehicles) average 6 fold greater
than the wood stove emissions. The average tumorigenicity estimate for the vehicles is
0.12-0.2 papillomas/mouse/mg while the average for the two wood stove emissions is
0.027 papillomas/mouse/mg. In Boise, since the wood burned is primarily softwoods, the
estimated average tumorigenicity for vehicles would be 3 to 4 fold greater than the
softwood combustion emissions tumorigenicity of 0.046. This 3 to 4 fold greater tumor
potency is identical to the comparative mutagenic potency estimated from the ambient
receptor modeling studies for the Boise airshed and is similar to the previous estimates
for Albuquerque and Raleigh (Lewis et al., 1988a and 1991; Stevens et al., 1990). The
ambient EOM composite sample, which contained 78% wood smoke and 11% mobile
source contribution, had a lower tumor potency (44% lower) estimate than the ambient
EOM composite, which contained a significantly higher mobile source contribution of
33% (Lewtas et al., 1992a).
24
-------
This study presents the first direct quantitative estimate of the comparative
carcinogenicity from the organic component of ambient aerosol in an urban airshed using
tumor initiation potency. This airshed contained wood smoke and motor vehicle
emissions. We found the tumor potency of the ambient organic matter to be significantly
higher than that of wood smoke directly from the stack. These data are consistent with
the 3 to 4 fold higher tumor potency measured for mobile source emissions when
compared to emissions from wood stoves. The average tumor potency for the mobile
source emissions is three times higher than the tumor potency of wood stove softwood
emissions.
The estimated composition of the annual average EOM exposure for Boise was
73% RWC and 27% MS (Cupitt et al., 1992). This ratio is intermediate between the two
composite samples from Boise that were used to estimate the tumorigenicity from
exposure to the ambient particulate pollutants. Excluding the residual mass from filter
blanks and from uncertainties in the apportionment model, the re-normalized composite
samples were 87:13 RWC:MS and 61:39 RWC:MS. Interpolating between the tumor
potency values, the tumor potency for a 73:27 mixture of RWC and MS was estimated to
be 0.15 papillomas/mouse/mg. Figure 7 shows the estimated tumorigenicity of the Boise
ambient samples as a function of the percentage of RWC in the sample together with the
two wood stove source samples and several of the diesel and gasoline vehicle emissions.
The data at 100% RWC represent tumor potency estimates for wood stove source sam-
ples. The points at 0% RWC are the results of samples from a variety of gasoline or
diesel-fueled vehicles. The Boise ambient composite samples are also shown as circles,
and the diamond represents the 73:27 mixture estimated for the annual exposure mixture.
The RWC component only accounts for about 20% of the tumorigenicity in the ambient
sample, while the remaining 80% of the tumorigenicity appears to be associated with the
mobile source component and possibly an additional, more potent source.
Extrapolation of the line in Figure 7 to 0% RWC would result in a tumorigenicity
which would be over two fold higher than the tumorigenicity estimated for five of the six
mobile source emissions in Table 3 (Lewtas et al., 1992a). This higher tumorigenicity
could be due to several possible factors: (1) atmospheric transformation of
noncarcinogenic organics (either from the RWC or MS sources) to carcinogenic
compounds not present in the vehicle or wood stove emissions, (2) vehicle emissions
from in-use cars may generally be more carcinogenic than emissions from vehicles in test
facilities generally operated as specified in certification procedures due to age of the
vehicle, malfunctioning, illegal removal of catalysts, (3) a few "super-emitting" older
vehicles may be contributing more to the tumorigenicity than can be estimated by
evaluating relatively new, properly operating vehicles, or (4) there is an additional source
of tumorigenicity in the airshed which we have not recognized. Future studies are being
designed to determine which of these factors may be responsible for this additional
source of tumorigenicity.
Even though Boise was selected for the IACP field study because of the
25
-------
RWC Sources
CwoodstovesD
*
MS Cvehicles}
*
Bo 1se AmbIent
Composltes
O
0 20 tO 60 80 100
Percent RWC
Figure 7. Tumorigenicity of Boise Ambient Composites and Various Source Samples as a
Function of the Percent Wood Smoke in the Ambient Samples
significant RWC contribution to the ambient pollution, the RWC pollution is responsible
for only a small fraction of the total tumor potency of the particulate-bound pollutants
present in the Boise airshed based on what we know about the tumor potency of the
RWC emissions themselves. It is also possible, however, that the RWC sources emit
noncarcinogenic organics to the airshed which are later transformed, through reactions
catalyzed by sunlight and nitrogen oxides, to carcinogens. These data suggest that
ambient air containing low RWC and high automotive emissions will be substantially
more carcinogenic than the direct emissions from vehicles. This may be due to
atmospheric transformation of organics in the airshed, and further studies have been
initiated to understand this observation.
Characterization in Related Airsheds
Comparison of Boise data to other wintertime ambient air studies conducted at
four residential areas that were heavily impacted by wood smoke (Table 4) shows how
similar these airsheds are with respect to the exposure concentrations, nature of the
particles and mutagenic activity of the EOM. The data shown in Table 4 are from
composites of day and night sampling periods for EGP in Boise and from the other three
cities. The study conducted in Juneau, Alaska was part of a Cold Climate Research
Program (Watts et al., 1988). The mean fine particle concentrations at all four sites
ranged from 36 to 56 jig/m3. The EOM associated with these fine particles was very
comparable between the sites, with the percent extractable organic mass clustering in a
narrow range of 54 +/- 7%. Hie Ames plate incorporation assay, which was used to
measure the mutagenic potency (mutagenicity per unit of mass) of these condensed
organics on air particles, showed potency values in a range from 0.7 to 1.9 rev/ue of
EOM.
26
-------
Table 4. Comparison of Particle Concentrations, EOM, RWC Contribution and
Mutagenicity with TA98 +S9 in Several Winter Ambient Air Studies
=-saBBaBS_a_a___SBaB=_=sss=^=-==_—Ba_B_a===_!
City
Fine part.
jw-g/m3
(S.D.)
Organic
%
(SD.)
Wood
smoke
%*
EOM
rev//ig
(S£>)
Particle rev//xg
(S.D.)
Juneau, AK
56.5
58.8
82b
0.73
0.42
(35.3)
(8.6)
(0.26)
(0.13)
Raleigh, NC
36.1
49.8
67
1.07
0.53
(27.5)
(13.0)
(0.26)
(0.16)
Albuquerque,
44.8
46.7
59
1.89
0.82
NM
(31.6)
(15.7)
(0.73)
(0.31)
Boise, ID
40.3
60.6
38°
1.60
0.96
(22.6)
(11.6)
(0.48)
(0.36)
a Estimated contribution to mutagenicity that is attributable to wood smoke.
b Contribution to fine particle mass only.
c Combined value for the residential and mobile source sites.
Because wood smoke organics are less mutagenic than those from vehicle
emissions (Lewis et al., 1988a), the lower potency values as shown in rev//u,g for Juneau
indicate particle-condensed organics that are predominately derived from wood smoke
(Cooper et al., 1984). Correspondingly, the table indicates an increase in potency, when
expressed in rev//x,g of particle, for sites with decreasing percentage of wood smoke and
increasing contribution from vehicle emissions (Lewis et al., 1991). These potency values
span only a narrow range with little more than a two-fold difference between the highest
and lowest values. These particle potencies, of course, reflect differences both in the
amount of organics associated with particles (% EOM) and differences in mutagenic
potency of the organics (rev/pig of EOM).
TECHNICAL HIGHLIGHTS
Characterization of the Air Toxics and Sources in Outdoor Air
1. Mobile source and RWC were the primary sources impacting the Boise airshed
during the winter heating season.
2. Particulate concentrations were uniformly distributed across the city but were
significantly higher than the remote background location concentrations.
27
-------
3. Nighttime fine particulate concentrations were nearly 50% higher than daytime
values at all the primary and auxiliary sites. This is attributed to increased RWC
emissions and inversion occurring during the night. Fine particle concentrations in excess
of 100 fig/m3 were observed in both residential and commercial areas during winter
meteorological inversions.
4. Dispersion of pollutants in Boise in stable flows is due to wave-like motion
rather than turbulence.
5. Excellent correlations between fine particle mass and fine particle potassium
were observed at the FS and EGP, suggesting that RWC influences the entire airshed.
6. Extractable organics were 55-65% by mass of the fine particles collected at
both the residential and mobile source sites.
Characterization of the Air Toxics and Sources in Indoor Air
1. Wood stove source emission samples were dominated by methaxybenzenes
which are produced during the incomplete combustion of the lignin in wood. Only low
levels of methoxybenzenes were found in wood stove impacted ambient samples, indicat-
ing that these highly reactive compounds were transformed.
2. The residential monitoring study results suggest that, when properly operated,
wood burning appliances do not directly contribute particulate matter, most organic
pollutants, or mutagenicity to the homeowner's indoor air environment. However, high
outdoor levels of wood smoke influence indoor air by infiltration from outdoors.
3. Indoor fine particle concentrations and particulate mutagenicities were lower
than corresponding outdoor levels. Indoor coarse particulate concentrations were highest
during daytime sampling periods and are associated with homeowner activity.
4. Concentrations of formaldehyde and total VOCs were higher indoors than
outdoors. Formaldehyde concentrations were higher in some houses with wood burning
appliances. Indoor benzene concentrations appeared to be related predominantly to
mobile source emissions. The continuously monitored indoor gaseous pollutants, nitrogen
oxides and carbon monoxide had indoor concentration maxima lower and slightly time
delayed when compared to corresponding outdoor concentrations.
5. Fine particle concentrations exceeding 100 /xg/m3 were observed when a
portable ultrasonic humidifier, charged with municipally supplied tap water, was operated
in a Boise household. Subsequent studies showed fine particle concentrations around 600
fig/m3 when an ultrasonic humidifier was operated using tap water containing 300 /xg/L of
total dissolved solids. Fine particle concentrations exceeding 6300 /xg/m3 were observed
when the ultrasonic humidifier was operated in a closed room. Impeller units generated
28
-------
less than one-third the mass generated by ultrasonic humidifiers. Steam units generated
no measurable concentration increase.
6. Concentrations of total SVOCs ranging from 173 to 316 jig/m3 inside the
houses were three to five times higher than the ambient outdoor concentrations. The
concentrations of many volatile species, however, were frequently the same indoors and
outdoors, showing that outside sources were the main cause of the indoor concentrations
for those species. Weekend concentrations were always higher than weekday concentra-
tions possibly due to differences in home activities during the weekends. There was not a
significant difference in SVOCs between houses with wood burning appliances and those
without.
Characterization of the Mutagenic and Carcinogenic Activity
1. The mutagenicity was relatively uniform across the Boise airshed during each
sampling period. The average mutagenicity for the winter at the primary and residential
outside sites ranged from 87 to 102 rev/m3. Generally, over 60% of the outdoor mutage-
nicity was found associated with the filter collected particles and the remainder associated
with the semivolatiles (XAD-2). The average mutagenicity in the ten pairs of houses was
less than the outdoor air and ranged from 37 to 61 rev/m . Although the mutagenicity
associated with the XAD-2 samples was more variable than for the filter samples, the
average mutagenicity associated with the XAD-2 samples was greater indoors (41-S6% of
the total mutagenicity) than outdoors (26-40%). The major source found to systematical-
ly alter the indoor mutagenicity was increases in the outdoor mutagenicity associated with
particles primarily from wood stoves. The presence of a wood stove in a house did not
generally alter the indoor air mutagenicity directly in that house or the relationship
between indoor and outdoor mutagenicity (Lewtas and Warren, 1992).
2. A non-aqueous ion exchange chromatography method was developed for the
separation of acid, base, and neutral fractions of organic extracts. This method recovers
over 90% of the mutagenicity and mass.
3. The POM adsorbed to respirable particles induces gene mutations in bacteria
and characterization of the mutation spectra in bacteria are consistent with the formation
of large bulky polycyclic aromatic DNA adducts in the animal studies. Similar gene
mutations are induced in oncogenes from lung tumors of mice exposed to PAHs and
from humans exposed to cigarette smoke.
4. The ambient POM sample containing 33% contribution of motor vehicle
emissions was more than twice as tumorigenic as the ambient sample with only 11%
motor vehicle emissions. The DNA adducts from both samples were highly correlated
with the tumor formation. Although the two samples differed in tumor initiation and
DNA adduct formation potency, the DNA adduct levels were consistently predictive of
29
-------
the tumor outcome. These data provide further evidence for a nonthreshold genotoxic
mechanism for the induction of tumors from POM present in the ambient air.
Source Apportionment
1. Fine particle EOM from the two primary winter sites in Boise have been
apportioned to wood smoke and motor vehicle emissions. Consistent with expectations,
the motor vehicle contribution is greater at the roadway site than at the residential one,
and the wood smoke contribution is greater at night than during the day and dominant at
both sites.
2. The results of 14C measurements confirmed linear regression receptor modeling
results that apportioned fine particle EOM between residential wood burning and MS.
3. Apportionment of EOM mutagenicity (TA98, +S9) measured at the two
primary sites showed the dominant contribution to be from MS emissions, in contrast to
the dominance of wood smoke for EOM itself.
4. Several volatile organic species were found to be satisfactory replacements for
fine particle Pb as a receptor modeling tracer for MS emissions of EOM.
Source Characterization
1. Source laboratoiy measurements have successfully shown strong correlations
between operating variables such as wood species and burn rate and emission
characteristics such as PAH emission rate and mutagenicity. For example, PAH emission
rate and mutagenicity were higher when burning pine compared to oak. PAH emissions
as a fraction of total organics increased with burn rate. Mutagenicity also increased with
burn rate. Altitude did not have a significant effect on total WSDSS emissions; however,
PAH emission rate was higher at lower altitude.
Atmospheric Transformation
1. Emissions from both RWC and automobiles were investigated in a laboratory
chamber study to assess the effect of atmospheric transformation. Measurable changes in
chemical composition and mutagenicity occurred as the photochemical reactions
progressed, even at reduced temperatures. After reaction, 80-99% of the measurable
mutagenicity was in the gas phase while, prior to reaction, the opposite was true. The
atmospheric pollutants NOj/S^Oj reacted with wood smoke to produce enhanced gas
phase mutagenicity, even in the dark.
2. In Boise, artifact-free concentrations of fine particulate nitrate, and gaseous
nitrous and nitric acids were measured using annular denuder technology. At the two
primary sites particulate nitrate averaged 5 /ig/m^ while nitric acid concentrations were at
30
-------
least 10 times lower. Nitrous acid averaged 4 Mg/m3 overall, with nighttime
concentrations two to three times greater than daytime. These nitrous acid levels are
thought to be important m the formation of mutagenic nitrated organic compounds.
3. Nitroarenes and hydroxylated nitroarenes only known to be formed from
atmospheric transformation reactions were detected in particle and semivolatile samples
from Boise collected during a period when photochemical reactions could have been
catalyzed by nitrous acid photolyzed production of hydroxyl radicals.
CENTRALIZED DATABASE
Data from the sampling, chemical analysis, physical analysis and biological studies
have been integrated into a centralized database. All of the data have been validated by
the EPA scientist or engineer responsible for those measurements. The database is
implemented in a fourth generation, non-procedural, report generation system
(FOCUS*) on the National Computing Center IBM 3090, at Research Triangle Park,
NC. The database contains approximately 185 unique analysis species and more than
78,400 data values. The database is described in Appendices 4A-4G which contain the
following information:
o Appendix 4A describes the database structure.
o Appendix 4B is a dictionary of database field names, field types, and field name
descriptions.
o Appendix 4C describes the data verification criteria and procedures.
o Appendix 4D lists sampling sites, sampling dates, analysis groups, and analyzed
species.
o Appendix 4E presents basic statistics (median, mean, standard deviation, etc.) for
each species.
o Appendix 4F is an inventory of analysis value categories (Good/MDL/Void) by
sampling period, across sampling sites for each analysis group.
o Appendix 4G contains information relevant for requesting data from the central Boise
IACP database.
We anticipate that this database will be useful to EPA's Office of Air and
Radiation; EPA Regional Offices; other State, Regional, and Local air pollution
regulatoiy agencies as well as air pollution scientists in research Universities and
Institutes. The database being developed from the IACP Roanoke, VA study will be
added to this database and made available upon request after the publication of the final
EPA report on the Roanoke, VA study by 1995.
31
-------
CONCLUSIONS
Identification of Carcinogens
Potential human carcinogens were identified using both chemical and biological
methods in this study. The biological methods included bacterial assays for gene
mutation and animal assays for DNA adduct formation and tumor initiation. There is
sufficient human and animal evidence that POM, as measured by the EOM from fine
particles, is carcinogenic. For this reason the apportionment, exposure, and
carcinogenicity assessment components of this study focused on the POM associated with
respirable particles. SVOCs present in very high concentrations indoors and in lower
concentrations outdoors were mutagenic in bacteria. The gaseous components from both
wood combustion and vehicle emissions are mutagenic after atmospheric transformation
reactions. The mammalian dosimetry and animal carcinogenicity of the SVOCs and
gaseous VOCs (e.g., atmospheric transformation products) is not known but will be
investigated in future studies.
Source Apportionment of Carcinogens
Residential wood combustion accounted for 75% of the exposure to POM, but
only 20% of the estimated POM carcinogenicity. The remaining 80% of the
carcinogenicity appears to be associated with the mobile source component and
atmospheric transformation products from these source emissions.
When wood burning stoves were operated properly, they did not directly
contribute particulate matter, most organic pollutants, with the exception of formalde-
hyde, or mutagenicity to the homeowners' indoor air. Wood burning did contribute
substantial particulate matter and organics to the outdoor air and indirectly increased
these pollutants in all houses in the neighborhood, regardless of the presence or absence
of a wood stove, by infiltration of these pollutants from outside air.
Atmospheric transformations in this airshed are contributing to the presence of air
toxics and may account for a component of the increased carcinogenicity predicted to be
associated with mobile sources. Nitrogen oxides appear critical in the formation of
mutagenic transformation products. The gas-phase mutagenic products are also persis-
tent, and may remain in the air for hours after they are produced. Exposures to the
transformation products may occur over large population areas and for long periods of
time.
Human Exposure and Comparative Carcinogenicity
Human exposure estimates and indoor:outdoor relationships were determined for
many of these species. The concentrations of fine particle mass measured indoors were
32
-------
nearly always lower than outdoor concentrations* but generally highly correlated,
indicating that infiltration of outdoor particles had a significant influence on indoor
concentrations. In all of the monitored houses, the indoor concentrations of one or
more VOCs was highly correlated with, and equivalent to, the outdoor concentrations of
the same VOCs. This means that, for many volatile species not associated with particles,
outdoor sources establish the lower limit of exposure concentrations. All of the moni-
tored houses had some indoor source of VOCs and SVOCs. The total NMOC measured
indoors was consistently greater than outdoors by a factor of 2 to 3. The high indoor
concentrations of total NMOC were often the result of only one or two specific chemi-
cals, the identity of which varied from house to house. In addition, the total SVOC
measurements were consistently 3-5 times higher indoors than outdoors.
When estimating exposures to any specific chemical, a distribution of exposure
concentrations must be considered. In Boise, a wide range of indoor.outdoor ratios was
found for many VOCs. For any specific chemical, some houses had no apparent indoor
source; other houses had indoor sources that contributed roughly equally with the
outdoor sources; and still other houses had indoor sources that were order(s) of
magnitude greater than the outdoor sources. In such a case, "average" values do not ade-
quately represent the distribution of exposure concentrations for the individual chemical.
Even one or two houses with very large indoor sources would skew the distribution so
dramatically that the use of "average" indoor:outdoor ratios would grossly misrepresent
the actual distribution of exposure concentrations — overestimating exposures for many
houses and grossly underestimating exposures in a few houses.
The EOM from ambient particles in Boise are both mutagenic and tumorigenic.
The ambient POM induced mutations in bacteria as well as DNA adducts and tumors in
mouse skin and lung after skin initiation. The ambient POM sample containing 33%
contribution of motor vehicle emissions was more than twice as tumorigenic as the
ambient sample with only 11% motor vehicle emissions.
33
-------
REFERENCES FOR SUMMARY REPORT
Albert, R., J. Lewtas, S. Nesnow, T. Thorslund, and E. Anderson, 1983. Comparative
Potency Method for Cancer Risk Assessment: Application to Diesel Particulate
Emissions. Risk Analysis 3: 101-117.
Burnet, P., J. Houck, and R. Roholt, 1990. Effect of Appliance Type and Operating
Variables on Wood Stove Emissions, Vol. 1, EPA-600/2-90-001a (NTIS PB90-
151457).
Qaxton, L.D., 1983. Characterization of Automotive Emissions by Bacterial Mutagenesis
Bioassays: A Review. Environmental Mutagenesis 5:609-631.
Qaxton, L.D., S. Warren, R. Zweidinger, and J. Creason, 1992. A Comparative Assess-
ment of Wood Smoke Impacted Ambient Air Samples Using the Plate and Micro-
suspension Salmonella Assays. Prepared for Environ. Sci. Technol. (this report).
Cooper, J.A., CA. Frazier, and L.C. Pritchett, 1984. Characterization of Air Quality
Impacts from Residential Wood Combustion in Juneau and Fairbanks, Alaska.
Alaska Department of Environmental Conservation.
Cupitt, L.T., L.D. Qaxton, T.E. Kleindienst, D.F. Smith, and P.B. Shepson, 1988.
Transformation of Boise Sources: TTie Production and Distribution of Mutagenic
Compounds in Wood Smoke and Auto Exhaust. In Proceedings of the 1988
EPA/AWMA International Symposium on Measurement of-Toxic and Related Air
Pollutants, VIP-10. Air & Waste Management Association, Pittsburgh: pp.885-889
(EPA 600/9-88-015, NTIS PB90-225863).
Cupitt, L., G. Glen, and J. Lewtas, 1992. Exposure and Risk from Ambient Particle
Bound Pollution in an Airshed Dominated by Residential Wood Combustion and
Mobile Sources. Prepared for Environmental Health Perspectives (this report).
DeMarini, D.M., D.A. Bell, J.G. Levine, M.L. Shelton, and A. Abu-Shakra, 1992.
Molecular Analysis of Mutations Induced at the hkmns? Allele of Salmonella by
Single Chemicals and Complex Mixtures. Environmental Health Perspectives, (in
press).
Downs, J.L., 1986. Final Report on Integrated Air Cancer Project Site Source Inven-
tory: Boise, Idaho. EMSI 1135.27FR. Environmental Monitoring and Services, Inc.,
Camarillo, CA.
34
-------
Glen, W.G., V.R. Highsmith, and L.T. Cupitt, 1991. Development of an Exposure Model
for Application to Wintertime Boise. In Proceedings of the 84th Annual Air and
Waste Management Association Meeting, Manuscript 91-131.7.
Highsmith, V.R., R.B. Zweidinger, J. Lewtas, A. Wisbith, and R.J. Hardy, 1988. Impact of
Residential Wood Combustion and Automotive Emissions on the Boise, Idaho,
Airshed. In Proceedings of the 1988 EPA/AWMA International Symposium on
Measurement of Toxic and Related Air Pollutants, VIP-10. Air & Waste
Management Association, Pittsburgh: pp. 804-813 (EPA 600/9-88-015, NTIS PB90-
225863).
Highsmith, V.R., JJLewtas, L. Cupitt, R.B. Zweidinger, G. Glen, and J. Wu, 1992a.
Characterizing the Influence of Residential Wood Combustion and Mobile Source
Emissions on the Indoor Air Quality of Selected Boise, Idaho Residences.
Prepared for Atmospheric Environment (this report).
Highsmith, V.R., R.B. Zweidinger, C.W. Lewis, R.K. Stevens, L.D. Claxton, and J. Wu,
1992b. Characterization of the Wintertime Boise, Idaho, Airshed. Prepared for
Atmospheric Environment (this report).
Kleindienst, T.E., P.B. Shepson, E.O. Edney, L.D. Claxton, and L.T. Cupitt, 1986. Wood
Smoke: Measurement of the Mutagenic Activities of Its Gas- and Particulate-
Phase Photoxidation Products. Environmental Science and Technology. 20:493-501.
Klouda, G.A., D. Barraclough, LA Currie, R.B. Zweidinger, CW. Lewis, and R.K.
Stevens, 1991. Source Apportionment of Wintertime Organic Aerosols in Boise,
ID, by Chemical and Isotopic (14C) Methods. In Proceedings of the 84th Annual
Meeting of the Air & Waste Management Association, Manuscript 91-131.2.
Lewis, C.W., R.E. Baumgardner, L.D. Claxton, J. Lewtas, and R.K. Stevens, 1988a. The
Contribution of Wood Smoke and Motor Vehicle Emissions to Ambient Aerosol
Mutagenicity. Environ Sci Technol, 22:968-971.
Lewis, C.W., T.G. Dzubay, R.B. Zweidinger, and V.R. Highsmith, 1988b. Sources of
Fine Particle Organic Matter in Boise. In Proceedings of the 1988 EPA/AWMA
International Symposium on Measurement of Toxic and Related Air Pollutants.
VIP-10, Air and Waste Management Association, Pittsburgh: pp. 864-869
(EPA600/9-88-015, NTIS PB90-225863).
Lewis, C.W., R.K. Stevens, R.B. Zweidinger, L.D. Claxton, D. Barraclough, and G.A.
Klouda, 1991. Source Apportionment of Mutagenic Activity of Fine Particle
Organics in Boise, Idaho. In Proceedings of the 84th Annual Meeting of the Air
& Waste Management Association, Manuscript 91-131.3.
35
-------
Lewis, C.W., 1991. Sources of Air Pollutants Indoors: VOC and Fine Particulate
Species. J. Exposure Anal. Environ. Epidemiol. 1:31-44.
Lewis, C.W. and R.B. Zweidinger, 1992. Apportionment of Residential Indoor Aerosol,
VOC, and Aldehyde Species to Indoor and Outdoor Sources, and their Source
Strengths. Atmospheric Environment, 26A:2179-2184.
Lewtas, J., S. Nesnow, and R.E. Albert, 1983. A Comparative Potency Method for
Cancer Risk Assessment: Clarification of the Rationale, Theoretical Basis, and
Application to Diesel Particulate Emissions. Risk Analysis, 3(2):133-137.
Lewtas, J., 1983. Evaluation of the Mutagenicity and Carcinogenicity of Motor Vehicle
Emissions in Short-Term Bioassays. Environmental Health Perspectives, 47:141-
152.
Lewtas, J., 1985. Development of a Comparative Potency Method for Cancer Risk
Assessment of Complex Mixtures using Short-Term in vivo and in vitro Bioassay.
Tax. Indust Health, 4:193-203.
Lewtas, J. and K. Williams, 1986. A Retrospective Review of the Value of Short-Term
Genetic Bioassays in Predicting the Chronic Effects of Diesel Soot. Carcinogenici-
ty and Mutagenicity of Diesel Engine Exhaust Eds. N. Ishinishi, A. Koizumi, R.O.
McClellan and W. Stober, Amsterdam, Elsevier, pp. 119-140.
Lewtas, J., 1988. Genotoxicity of Complex Mixtures: Strategies for the Identification and
Comparative Assessment of Airborne Mutagens and Carcinogens from Combus-
tion Sources. Fundamental and Applied Toxicology, 10: 571-589.
Lewtas, J., 1989. Emerging Methodologies for Assessment of Complex Mixtures:
Application of Bioassays in the Integrated Air Cancer Project. Tox. Indust
Health, 5(5):839-850.
Lewtas, J., 1990. Experimental Evidence for the Carcinogenicity of Air Pollutants. Air
Pollution and Human Cancer, L. Tomatis, Ed., Springer-Verlag, Berlin, pp. 49-61.
Lewtas, J., R.B. Zweidinger, and L. Cupitt, 1991. Mutagenicity, Tumorigenicity and
Estimation of Cancer Risk from Ambient Aerosol and Source Emissions from
Wood Smoke and Motor Vehicles. In Proceedings of the 84th Annual Meeting of
the Air & Waste Management Association, Manuscript 91-131.6.
Lewtas, J., 1991. Carcinogenic Risks of Polycyclic Organic Matter (POM) From Selected
Emission Sources - Development of a Comparative Potency Method. HERL
Report# 0803.
36
-------
Lewtas, J., 1992. Carcinogenic Risks of Polycyclic Organic Matter (POM) Development
of a Comparative Potency Method. ISBN-.0-936712-90-2, American Conf. of
Governmental Indust Hyg. Inc., 131-135..
Lewtas, J., C. Lewis, R. Zweidinger, R. Stevens, and L. Cupitt, 1992a. Sources of
Genotoxicity and Cancer Risk in Ambient Air. Pharmacogenetics, 2:288-296.
Lewtas, J., M. Moore, C.T. Helms, and S. Nesnow, 1992b. Comparative Tumor-Initiating
Activity of Urban Aerosol and Source Emissions from Wood Smoke and Motor
Vehicles. Prepared for Carcinogenesis (this report).
Lewtas, J. and S. Warren, 1992. Influence of Wood Burning Stoves and Fireplaces on the
Mutagenicity of Indoor and Outdoor Air. Prepared for Mutagenesis (this report).
McCrillis, R. and P. Burnet, 1990. Effects of Burnrate, Wood Species, Altitude, and Stove
Type on Wood Stove Emissions. Toxicology and Industrial Health, Vol. 6, No. 5,
pp. 95-102.
McCrillis, R. and P. Burnet, 1988. Effects of Operating Variables on Emissions from
Wood Stoves. In Proceedings of the 1988 EPA/APCA International Symposium
on Measurement of Toxic and Related Air Pollutants, VIP-10, Air & Waste
Management Association, Pittsburgh: pp. 835-840 (EPA 600/9-88-015, NTIS PB90-
225863).
Merrill, R., R. Zweidinger, J. Dorsey , R.F. Martz, and T.X. Koinis, 1988. Semivolatile
and Condensible Extractable Organic Materials Distribution in Ambient Air and
Wood Stove Emissions. In Proceedings of the 1988 EPA/APCA International
Symposium on Measurement of Toxic and Related Air Pollutants, VIP-10, Air &
Waste Management Association, Pittsburgh: pp. 821-827 (EPA 600/9-88-015, NTIS
PB90-225863).
Nesnow, S., L. Triplett, and T. Slaga, 1982. Comparative Tumor-Initiating Activity of
Complex Mixtures from Environmental Particulate Emissions on Senear Mouse
Skin. Journal National Cancer Institute) 68: 829-834.
Nishoka, M. and J. Lewtas, 1992. Quantification of Nitro- and Hydroxylated Nitro-
Aromatic/Polycyclic Aromatic Hydrocarbons in Selected Ambient Air Daytime
Winter Samples. Atmospheric Environment, 26A:2077-2087.
NIST Report of Analysis, 1989. The Determination of Polycyclic Aromatic Hydrocarbons
in Extracts of Air Particulate Matter Collected in Boise, ID. Report No. 552 89-
049.
37
-------
Reynolds, S.H. and M.W. Anderson, 1991. Activation of Proto-oncogenes in Human and
Mouse Lung Tumors. Environmental Health Perspectives, 93:143-145.
Reynolds, S.H., C. Anna, K. Brown, J. Wiest, E. Beattie, R. Pero, J. Iglehart, and M.
Anderson. 1991. Activated Proto-oncogenes in Human Lung Tumors from
Smokers. Proc. Natl. Acad. Sci. (U.S.A.) 88:1085-1089.
Schuetzle, D. and J. Lewtas, 1986. Bioassay-Directed Chemical Analysis in Environmental
Research. Analytical Chemistry, 58:1060A-1075A.
Shepson, P.B., T.E. Kleindienst, and E.O. Edney, 1987. The Production of Mutagenic
Compounds as a Result of Urban Photochemistry. EPA 600/3-87/020, NTIS
PB87-199675).
Steiber, R. and J. Dorsey, 1988. GC/MS Analysis of Wood Stove Emissions and Ambient
Samples from a Wood Smoke Impacted Area. In Proceedings of the 1988 EPA-
/APCA International Symposium on Measurement of Toxic and Related Air
Pollutants, VIP-10, Air & Waste Management Association, Pittsburgh: pp. 828-834
(EPA 600/9-88-015, NTIS PB90-225863).
Steiber, R. and R. McCriliis, 1991. Comparison of Emissions and Organic Fingerprints
from Combustion of Oil and Wood. In Proceedings of the 84th Annual Air and
Waste Management Association Meeting, Manuscript 91-136.2.
Stevens, R.K., C.W. Lewis, T.G Dzubay, L.T. Cupitt, and J. Lewtas, 1990. Sources of
Mutagenic Activity in Urban Fine Particles. Tox. Indust Health, 6(5):81-94.
US EPA, 1985. Hie Air Toxics Problem in the United States: An Analysis of Cancer
Risks for Selected Pollutants, EPA-450/1-85-001, May 1985.
US EPA, 1990. Cancer Risk from Outdoor Exposure to Air Toxics, EPA-450/l-90-004a,
September 1990.
Watts, R.R., RJ. Drago, R.G. Merrill, R.W. Williams, E. Peny, and J. Lewtas, 1988.
Wood Smoke Impacted Air: Mutagenicity and Chemical Analysis of Ambient Air in
a Residential Area of Juneau, Alaska. JAPCA, 38:652-660.
Zweidinger, R.B., R.K. Stevens, CW. Lewis, and H. Westburg, 1990. Identification of
Volatile Hydrocarbons as Mobile Source Tracers for Fine-Particulate Organics.
Environmental Sciences and Technology, 24:538-542.
Zweidinger, R.B., J. Lewtas, and D. Thompson, 1991. Chemical Characterization of
Ambient Particulate Organic Aerosols from Boise, Idaho. In Proceedings of the
84th Annual Air and Waste Management Association Meeting, Manuscript 91-131.4.
38
-------
PUBLICATIONS
ON
IACP BOISE STUDY
39
-------
COMPLETE LISTING OF IACP BOISE PUBLICATIONS
Burnet, P., J. Houck, and R. Roholt, 1990. Effect of Appliance Type and Operating
Variables on Wood Stove Emissions, Vol. 1, EPA-600/2-90-001a (NTIS PB90-
151457).
Claxton, L.D., S. Warren, R. Zweidinger, and J. Creason, 1992. A Comparative Assess
ment of Wood Smoke Impacted Ambient Air Samples Using the Plate and Micro-
suspension Salmonella Assays. Prepared for Environmental Sciences and Tech.,
(this report).
Cupitt, L. and T.R. Fitz-Simmons, 1988. The Integrated Air Cancer Project: Overview
and Boise Survey Results. In Proceedings of the 1988 EPA/AWMA International
Symposium on Measurement of Toxic and Related Air Pollutants, VIP-10, Air &
Waste Management Association, Pittsburgh, pp 799-803 (EPA 600/9-88-015, NTIS
PB90-225863).
Cupitt, L.T., L.D. Qaxton, T.E. Kleindienst, D.F. Smith, and P.B. Shepson, 1988.
Transformation of Boise Sources: The Production and Distribution of Mutagenic
Compounds in Wood Smoke and Auto Exhaust. In Proceedings of the 1988
EPA/AWMA International Symposium on Measurement of Toxic and Related Air
Pollutants, VIP-10. Air & Waste Management Association, Pittsburgh: pp.885-889
(EPA 600/9-88-015, NTIS PB90-225863).
Cupitt, L., G. Glen, and J. Lewtas, 1992. Exposure and Risk from Ambient Particle
Bound Pollution in an Airshed Dominated by Residential Wood Combustion and
Mobile Sources. Prepared for Risk Analysis (this report).
Eskridge, R.E., B. Lamb, and E. Allwine, 1990. Velocity Oscillations and Plume
Dispersion in a Residential Neighborhood During Wintertime Nights. Atmospheric
Environment, 24A: 1781-17%.
Glen, W.G., V.R. Highsmith, and L.T. Cupitt, 1991. Development of an Exposure Model
for Application to Wintertime Boise. In Proceedings of the 84th Annual Air and
Waste Management Association Meeting, Manuscript 91-131.7.
Highsmith, V.R., R.B. Zweidinger, J. Lewtas, A. Wisbith, and RJ. Hardy, 1988. Impact of
Residential Wood Combustion and Automotive Emissions on the Boise, Idaho,
Airshed. In Proceedings of the 1988 EPA/AWMA International Symposium on
Measurement of Toxic and Related Air Pollutants, VIP-10, Air & Waste
Management Association, Pittsburgh: pp. 804-813 (EPA 600/9-88-015, NTIS PB90-
40
-------
Highsmith, V.R., C.E. Rodes, R.B. Zweidinger, J. Lewtas, A. Wisbith, and RJ. Hardy,
1988. Influence of Residential Wood Combustion Emissions on Indoor Air Quality
of Boise, Idaho Residences. In Proceedings of the 1988 EPA/AWMA International
Symposium on Measurement of Toxics and Related Air Pollutants, VIP-10, Air &
Waste Management Association, Pittsburgh, pp. 804-813 (EPA 600/9-88-015, NTIS
PB90-225863).
Highsmith, V.R., R.B. Zweidinger, C.W. Lewis, R.K. Stevens, L.D. Claxton, and J. Wu,
1991. Characterization of the Wintertime Boise, Idaho, Airshed: A Comprehensive
Field Study Report for the U.S. EPA Office of Air Quality Planning and Standards.
NTIS PB92-1368803.
Highsmith, V.R., AJ. Hoffman, R.B. Zweidinger, L.T. Cupitt, and D.B. Walsh, 1991.
The IACP: Overview of the Boise, Idaho, and the Roanoke, Virginia, Field Studies.
In Proceedings of the 84th Annual Air and Waste Management Association
Meeting, Manuscript 91-131.1.
Highsmith, V.R., J.Lewtas, L. Cupitt, R.B. Zweidinger, G. Glen, and J. Wu, 1992.
Characterizing the Influence of Residential Wood Combustion and Mobile Source
Emissions on the Indoor Air Quality of Selected Boise, Idaho Residences. Prepared
for Atmospheric Environment (this report).
Highsmith, V.R., R.B. Zweidinger, C.W. Lewis, R.K. Stevens, L.D. Claxton, and J. Wu,
1992. Characterization of the Wintertime Boise, Idaho, Airshed. Prepared for
Atmospheric Environment (this report).
Kleindienst, T.E., P.B. Shepson, E.O. Edney, L.D. Claxton, and L.T. Cupitt, 1986. Wood
Smoke: Measurement of the Mutagenic Activities of Its Gas- and Particulate-Phase
Photoxidation Products. Environmental Science and Technology, 20:493-501.
Kleindienst, T.E., D.F. Smith, E.E. Hudgens, C.D. Mclver, E. Perry, L.T. Cupitt, JJ.
Bulfalini, and L.D. Claxton, 1991. The Atmospheric Transformation of Combustion
Source Emissions and the Formation of Mutagenic Products. In Proceedings of the
84th Annual Air and Waste Management Association Meeting Manuscript 91-
131.5.
Klouda, G.A., D. Barraclough, LA. Currie, R.B. Zweidinger, C.W. Lewis, and R.K.
Stevens, 1991. Source Apportionment of Wintertime Organic Aerosols in Boise, ID
by Chemical and Isotopic (14C) Methods. In Proceedings of the 84th Annual
Meeting of the Air & Waste Management Association, Manuscript 91-131.2.
41
-------
Lewis, C.W., T.G. Dzubay, R.B. Zweidinger, and V.R. Highsmith, 1988. Sources of Fine
Particle Organic Matter in Boise. In Proceedings of the 1988 EPA/A&WMA
International Symposium on Measurement of Toxic and Related Air Pollutants,
VIP-10, Air and Waste Management Association, Pittsburgh, pp. 864-869 (EPA
600/9-88-015, NTIS PB90-225863).
Lewis, C.W., T.G. Dzubay, V.R. Highsmith, R.K. Stevens, and R.B. Zweidinger ,1989.
Indoor-Outdoor Comparisons of Aerosol and VOC Source Tracer Species in a
Residential Wood Smoke Impacted Community. In Proceedings of the 82th Annual
Meeting of the Air & Waste Management Association, Manuscript 89-104.6.
Lewis, C.W., 1991. Sources of Air Pollutants Indoors: VOC and Fine Particulate Species.
J. Exposure Anal. Environ. Epidemiol. 1:31-44.
Lewis, C.W., R.K. Stevens, R.B. Zweidinger, L.D. Claxton, D. Barraclough, and G.A.
Klouda, 1991. Source Apportionment of Mutagenic Activity of Fine Particle
Organics in Boise, Idaho. In Proceedings of the 84th Annual Meeting of the Air &
Waste Management Association, Manuscript 91-131.3.
Lewis, C.W. and R.B. Zweidinger, 1992. Apportionment of Residential Indoor Aerosol,
VOC, and Aldehyde Species to Indoor and Outdoor Sources, and their Source
Strengths. Atmospheric. Environment, 26A:2170-2184.
Lewtas, J., 1989. Emerging Methodologies for Assessment of Complex Mixtures: Applica
tion of Bioassays in the Integrated Air Cancer Project. Tox. Indust. Health
5(5):839-850.
Lewtas, J., R.B. Zweidinger, and L. Cupitt, 1991. Mutagenicity, Tumorigenicity and
Estimation of Cancer Risk from Ambient Aerosol and Source Emissions from
Wood Smoke and Motor Vehicles. In Proceedings of the 84th Annual Meeting of
the Air & Waste Management Association, Manuscript 91-131.6.
Lewtas, J., C. Lewis, R. Zweidinger, R. Stevens, and L. Cupitt, 1992. Sources of
Genotoxicity and Cancer Risk in Ambient Air. Pharmacogenetics, 2:288-2%.
Lewtas, J., M. Moore, C.T. Helms, and S. Nesnow, 1992. Comparative Tumor-Initiating
Activity of Urban Aerosol and Source Emissions from Wood Smoke and Motor
Vehicles. Prepared for Carcinogenesis (this report).
Lewtas, J. and S. Warren, 1992. Influence of Wood burning Stoves and Fireplaces on the
Mutagenicity of Indoor and Outdoor Air. Prepared for Mutagenesis (this report).
42
-------
Lewtas, J., 1992. Carcinogenic Risks of Polycyclic Organic Matter (POM) Development
of a Comparative Potency Method. ISBN: 0-936712-90-2 American Conf. of
Governmental Indust Hyg. Inc., 131-135.
McCrillis, R. and P. Burnet, 1990. Effects of Burnrate, Wood Species, Altitude, and
Stove Type on Wood Stove Emissions. Toxicology and Industrial Health, 6:(5)95-
102.
McCrillis, R.C., R.R. Watts, and S.H. Warren, 1990. Effects of Operating Variables on
PAH Emissions and Mutagenicity of Emissions from Wood Stoves. In Proceedings
of the 83rd Annual Meeting of the Air & Waste Management Association, Manu-
script 90-80.4.
Merrill, R., R. Zweidinger, J. Dorsey , R.F. Martz, and T.X. Koinis, 1988. Semivolatile
and Condensible Extractable Organic Materials Distribution in Ambient Air and
Wood Stove Emissions. In Proceedings of the 1988 EPA/APCA International
Symposium on Toxic and Related Air Pollutants, VIP-10, Air & Waste
Management Association, Pittsburgh, pp.821-827 (EPA 600/9-88-015 NTIS PB90-
225863). '
Nishoka, M. and J. Lewtas, 1992. Quantification of Nitro- and Hydroxylated Nitro-Aro
matic/Polycyclic Aromatic Hydrocarbons in Selected Ambient Air Daytime Winter
Samples. Atmospheric Environment, 26A:2077-2087.
Shepson, P.B., T.E. Kleindienst, and E.O Edney, 1987. Project Summary: The Produc-
tion of Mutagenic Compounds as a Result of Urban Photochemistry. EPA Report
No. 600/S3-87/020.
Shepson, P.B., T.E. Kleindienst, and E.O Edney, 1987. The Production of Mutagenic
Compounds as a Result of Urban Photochemistry. EPA Report No 600/S3
87/020.
Steiber, R. and J. Dorsey, 1988. GC/MS Analysis of Wood Stove Emissions and Ambient
Samples from a Wood Smoke Impacted Area. In Proceedings of the 1988 EPA-
/APCA International Symposium on Measurement of Toxic and Related Air
Pollutants, VIP-10, Air & Waste Management Association, Pittsburgh, dd.828-834
(EPA 600/9-88-015, NTIS PB90-225863).
Steiber, R. and R. McCrillis, 1991. Comparison of Emissions and Organic Fingerprints
from Combustion of Oil and Wood. In Proceedings of the 84th Annual Air and
Waste Management Association Meeting, Manuscript 91-136.2.
43
-------
Steiber, R., R. McCrillis, J. Dorsey, and R. Merrill, 1992. Characterization of Condensible
and Semivolatile Organic Materials from Boise Wood Stove Samples. In
Proceedings of the 85th Annual Air and Waste Management Association Meeting,
Manuscript 92-118.03.
Stevens, R.K., F. King, J. Bell, and J. Whitfield, 1988. Measurement of the Chemical
Species that Contribute to Urban Haze. In Proceedings of the 81th Annual APCA
Manuscript 88-57.3.
Stevens, R.K., R.B. Zweidinger, C.W. Lewis, and T.G. Dzubay, 1989. Volatile Hydrocar
bons as Mobile Source Tracer Species for Receptor Modeling. In Proceedings of
the 8th World Clean Air Congress, 5:201-205.
Stevens, R.K., C.W. Lewis, T.G Dzubay, L.T. Cupitt and J. Lewtas, 1990. Sources of
Mutagenic Activity in Urban Fine Particles. Tox. Indust Health 6(5):81-94.
Thompson, D.J., L. Brooks, J. Lewtas, M.G. Nishioka and R. Zweidinger, 1992. Bioassay
and Chemical Analysis of Ambient Air Particulate Extracts Using Non-Aqueous
Anion-Exchange Chromatography. International Journal of Environmental and
Analytical Chemistry, 50:269-284.
Walsh, D., D.B. Ray, and J. Simonson, 1991. Monitoring IACP Samples and Construe
tion of a Centralized Database. In Proceedings of the 84th Annual Meeting of the
Air & Waste Management Association, Manuscript 91-131.9.
Zweidinger, R., S. Tejada, R. Highsmith, H. Westburg, and L. Gage, 1988. Distribution
of Volatile Organic Hydrocarbons and Aldehydes During the IACP Boise, Idaho
Residential Study. In Proceedings of the 1988 EPA/APCA International
Symposium on Measurement of Toxic and Related Air Pollutants, VIP-10, Air &
Waste Management Association, Pittsburgh, pp.814-820 (EPA 600/9-88-015, NTIS
PB90-225863).
Zweidinger, R.B., R.K. Stevens, CW. Lewis, and H. Westburg, 1990, Identification of
Volatile Hydrocarbons as Mobile Source Tracers for Fine-Particulate Organics.
Environmental Sciences and Technology, 24:538-542.
Zweidinger, R.B., J. Lewtas, and D. Thompson, 1991. Chemical Characterization of
Ambient Particulate Organic Aerosols from Boise, Idaho. In Proceedings of the
84th Annual Air and Waste Management Association Meeting Manuscript 91-131.4.
44
-------
PEER-REVIEWED JOURNAL ARTICLES
Claxton, L.D., S. Warren, R. Zweidinger, and J. Creason, 1992. A Comparative Assess
ment of Wood Smoke Impacted Ambient Air Samples Using the Plate and Micro-
suspension Salmonella Assays. Prepared for Environmental Sciences and
Technology (this report).
Cupitt, L., G. Glen, and J. Lewtas, 1992. Exposure and Risk from Ambient Particle
Bound Pollution in an Airshed Dominated by Residential Wood Combustion and
Mobile Sources. Prepared for Environmental Health Perspectives (this report).
Eskridge, R.E., B. Lamb, and E. Allwine, 1990. Velocity Oscillations and Plume
Dispersion in a Residential Neighborhood During Wintertime Nights. Atmospheric
Environment, 24A(7):1781-1796.
Highsmith, V.R., J.Lewtas, L. Cupitt, R.B. Zweidinger, G. Glen, and J. Wu, 1992.
Characterizing the Influence of Residential Wood Combustion and Mobile Source
Emissions on the Indoor Air Quality of Selected Boise, Idaho Residences.
Prpeared for Atmospheric Environment (this report).
Highsmith, V.R., R.B. Zweidinger, C.W. Lewis, R.K. Stevens, L.D. Claxton, and J. Wu,
1992. Characterization of the Wintertime Boise, Idaho, Airshed. Prepared for
Atmospheric Environment (this report).
Kleindienst, T.E., P.B. Shepson, E.O. Edney, L.D. Claxton, and L.T. Cupitt, 1986. Wood
Smoke: Measurement of the Mutagenic Activities of Its Gas- and Particulate-Phase
Photoxidation Products. Environmental Science and Technology, 20:493-501.
Lewis, C.W., 1991. Sources of Air Pollutants Indoors: VOC and Fine Particulate Species.
J. Exposure Anal. Environ. Epidemiol^ 1:31-44.
Lewis, C.W. and R.B. Zweidinger, 1992. Apportionment of Residential Indoor Aerosol,
VOC, and Aldehyde Species to Indoor and Outdoor Sources, and their Source
Strengths. Atmospheric Environment, 26A:2170-2184.
Lewtas, J., 1989. Emerging Methodologies for Assessment of Complex Mixtures: Applica
tion of Bioassays in the Integrated Air Cancer Project. Tox. Indust Health
5(5):839-850.
Lewtas, J., M. Moore, C.T. Helms, and S. Nesnow, 1992. Comparative Tumor-Initiating
Activity of Urban Aerosol and Source Emissions from Wood Smoke and Motor
Vehicles. Prepared for Carcinogenesis (this report).
45
-------
Lewtas, J., C. Lewis, R. Zweidinger, R. Stevens, and L. Cupitt, 1992. Sources of
Genotoxicity and Cancer Risk in Ambient Air. Pharmacogenetics, 2:288-2%.
Lewtas, J. and S. Warren, 1992. Influence of Wood burning Stoves and Fireplaces on the
Mutagenicity of Indoor and Outdoor Air. Prepared for Mutagenesis (this report).
Lewtas, J., 1992. Carcinogenic Risks of Polycyclic Organic Matter (POM) Development
of a Comparative Potency Method. ISBN: 0-936712-90-2 American Conf. of
Governmental Indust Hyg. Inc., 131-135.
McCrfflis, R. and P. Burnet, 1990. Effects of Burarate, Wood Species, Altitude, and
Stove Type on Wood Stove Emissions. Toxicology and Industrial Health, 6(5):95-
102.
Nishoka, M. and J. Lewtas, 1992. Quantification of Nitro- and Hydroxylated Nitro-Aro
matic/Polycyclic Aromatic Hydrocarbons in Selected Ambient Air Daytime Winter
Samples. Atmospheric Environment, 26A:2077-2987.
Stevens, R.K., C.W. Lewis, T.G Dzubay, L.T. Cupitt and J. Lewtas, 1990. Sources of
Mutagenic Activity in Urban Fine Particles. Toxicology and Industrial Health,
6(5):81-94.
Thompson, DJ., L. Brooks, J. Lewtas, M.G. Nishioka and R. Zweidinger, 1992. Bioassay
and Chemical Analysis of Ambient Air Particulate Extracts Using Non-Aqueous
Anion-Exchange Chromatography. International Journal of Environmental and
Analytical Chemistiy, 50:269-284.
Zweidinger, R.B., R.K. Stevens, C.W. Lewis, and H. Westburg, 1990. Identification of
Volatile Hydrocarbons as Mobile Source Tracers for Fine-Particulate Organics.
Environmental Sciences Technology, 24:538-542.
46
-------
PROCEEDINGS ARTICLES
Cupitt, L. and T.R. Fitz-Simmons, 1988. The Integrated Air Cancer Project: Overview
and Boise Survey Results. In Proceedings of the 1988 EPA/AWMA International
Symposium on Measurement of Toxic and Related Air Pollutants, VIP-10, Air &
Waste Management Association, Pittsburgh, pp 799-803 (EPA 600/9-88-015, NTIS
PB90-225863).
Cupitt, L.T., L.D. Claxton, T.E. Kleindienst, D.F. Smith, and P.B. Shepson, 1988.
Transformation of Boise Sources: The Production and Distribution of Mutagenic
Compounds in Wood Smoke and Auto Exhaust. In Proceedings of the 1988
EPA/AWMA International Symposium on Measurement of Toxic and Related Air
Pollutants, VIP-10. Air & Waste Management Association, Pittsburgh: pp.885-889
(EPA 600/9-88-015, NTIS PB90-225863).
Glen, W.G., V.R. Highsmith, and L.T. Cupitt, 1991. Development of an Exposure Model
for Application to Wintertime Boise. In Proceedings of the 84th Annual Air and
Waste Management Association Meeting, Manuscript 91-131.7.
Highsmith, V.R., R.B. Zweidinger, J. Lewtas, A. Wisbith, and RJ. Hardy, 1988. Impact of
Residential Wood Combustion and Automotive Emissions on the Boise, Idaho,
Airshed. In Proceedings of the 1988 EPA/AWMA International Symposium on
Measurement of Toxic and Related Air Pollutants, VIP-10, Air & Waste
Management Association, Pittsburgh: pp. 804-813 (EPA 600/9-88-015, NTIS PB90-
225863).
Highsmith, V.R., C.E. Rodes, R.B. Zweidinger, J. Lewtas, A. Wisbith, and R J. Hardy,
1988. Influence of Residential Wood Combustion Emissions on Indoor Air Quality
of Boise, Idaho Residences. In Proceedings of the 1988 EPA/AWMA International
Symposium on Measurement of Toxics and Related Air Pollutants, VIP-10, Air &
Waste Management Association, Pittsburgh, pp. 804-813 (EPA 600/9-88-015, NTIS
PB90-225863).
Highsmith, V.R., A.J. Hoffman, R.B. Zweidinger, L.T. Cupitt, and D.B. Walsh, 1991.
The IACP: Overview of the Boise, Idaho, and the Roanoke, Virginia, Field Studies.
In Proceedings of the 84th Annual Air and Waste Management Association
Meeting, Manuscript 91-131.1.
Kleindienst, T.E., D.F. Smith, E.E. Hudgens, C.D. Mclver, E. Perry, L.T. Cupitt, JJ.
Bulfalini, and L.D. Claxton, 1991. The Atmospheric Transformation of Combustion
Source Emissions and the Formation of Mutagenic Products. In Proceedings of the
84th Annual Air and Waste Management Association Meeting Manuscript 91-
131.5.
47
-------
Klouda, G.A., D. Barraclough, LA Currie, R.B. Zweidinger, C.W. Lewis, and R.K.
Stevens, 1991. Source Apportionment of Wintertime Organic Aerosols in Boise, ID
by Chemical and Isotopic (14C) Methods. In Proceedings of the 84th Annual
Meeting of the Air & Waste Management Association, Manuscript 91-131.2.
Lewis, C.W., T.G. Dzubay, R.B. Zweidinger, and V.R. Highsmith , 1988. Sources of Fine
Particle Organic Matter in Boise. In Proceedings of the 1988 EPA/A&WMA
International Symposium on Measurement of Toxic and Related Air Pollutants,
VIP-10, Air and Waste Management Association, Pittsburgh, pp. 864-869 (EPA
600/9-88-015, NTIS PB90-225863).
Lewis, C.W., T.G. Dzubay, V.R. Highsmith, R.K. Stevens, and R.B. Zweidinger, 1989.
Indoor-Outdoor Comparisons of Aerosol and VOC Source Tracer Species in a
Residential Wood Smoke Impacted Community. In Proceedings of the 82th Annual
Meeting of the Air & Waste Management Association, Manuscript 89-104.6.
Lewis, C.W., R.K. Stevens, R.B. Zweidinger, L.D. Claxton, D. Barraclough, and G.A
Klouda, 1991. Source Apportionment of Mutagenic Activity of Fine Particle
Organics in Boise, Idaho. In Proceedings of the 84th Annual Meeting of the Air &
Waste Management Association, Manuscript 91-131.3.
Lewtas, J., R.B. Zweidinger, and L. Cupitt, 1991. Mutagenicity, Tumorigenicity and
Estimation of Cancer Risk from Ambient Aerosol and Source Emissions from
Wood Smoke and Motor Vehicles. In Proceedings of the 84th Annual Meeting of
the Air & Waste Management Association, Manuscript 91-131.6.
McCrillis, R.C., RJR. Watts, and S.H. Warren, 1990. Effects of Operating Variables on
PAH Emissions and Mutagenicity of Emissions from Wood Stoves. In Proceedings
of the 83rd Annual Meeting of the Air & Waste Management Association, Manu-
script 90-80.4.
Merrill, R., R. Zweidinger, J. Dorsey , R.F. Martz, and T.X. Koinis, 1988. Semivolatile
and Condensible Extractable Organic Materials Distribution in Ambient Air and
Wood Stove Emissions. In Proceedings of the 1988 EPA/APCA International
Symposium on Toxic and Related Air Pollutants, VIP-10, Air & Waste
Management Association, Pittsburgh, pp.821-827 (EPA 600/9-88-015, NTIS PB90-
225863).
Steiber, R. and J. Dorsey, 1988. GC/MS Analysis of Wood Stove Emissions and Ambient
Samples from a Wood Smoke Impacted Area. In Proceedings of the 1988 EPA-
/APCA International Symposium on Measurement of Toxic and Related Air
Pollutants, VIP-10, Air & Waste Management Association, Pittsburgh, pp.828-834
(EPA 600/9-88-015, NTIS PB90-225863).
48
-------
Steiber, R. and R. McCrillis, 1991. Comparison of Emissions and Organic Fingerprints
from Combustion of Oil and Wood. In Proceedings of the 84th Annual Air and
Waste Management Association Meeting, Manuscript 91-136.2.
Steiber, R., R. McCrillis, J. Dorsey, and R. Merrill, 1992. Characterization of Condensible
and Semivolatile Organic Materials from Boise Wood Stove Samples. In
Proceedings of the 85th Annual Air and Waste Management Assocation Meeting,
Manuscript 92-118.03
Stevens, R.K., F. King, J. Bell, and J. Whitfield, 1988. Measurement of the Chemical
Species that Contribute to Urban Haze. In Proceedings of the 81th Annual APCA
Manuscript 88-57.3.
Stevens, R.K., R.B. Zweidinger, C.W. Lewis, and T.G. Dzubay, 1989. Volatile Hydrocar
bons as Mobile Source Tracer Species for Receptor Modeling. In Proceedings of
the 8th World Clean Air Congress, 5:201-205.
Walsh, D., D.B. Ray, and J. Simonson, 1991. Monitoring IACP Samples and Construe
tion of a Centralized Database. In Proceedings of the 84th Annual Meeting of the
Air & Waste Management Association, Manuscript 91-131.9.
Zweidinger, R., S. Tejada, R. Highsmith, H. Westburg, and L. Gage, 1988. Distribution
of Volatile Organic Hydrocarbons and Aldehydes During the IACP Boise, Idaho
Residential Study. In Proceedings of the 1988 EPA/APCA International
Symposium on Measurement of Toxic and Related Air Pollutants, VIP-10, Air &
Waste Management Association, Pittsburgh, pp.814-820 (EPA 600/9-88-015, NTIS
PB90-225863).
Zweidinger, R.B., J. Lewtas, and D. Thompson, 1991. Chemical Characterization of
Ambient Particulate Organic Aerosols from Boise, Idaho. In Proceedings of the
84th Annual Air and Waste Management Association Meeting Manuscript 91-131.4.
49
-------
REPORTS
Burnet, P., J. Houck, and R. Roholt, 1990. Effect of Appliance Type and Operating
Variables on Wood Stove Emissions, Vol. 1, EPA-600/2-90-001a (NT1S PB90-
151457).
Highsmith, V.R., R.B. Zweidinger, C.W. Lewis, R.K. Stevens, L.D. Claxton, and J. Wu,
1991. Characterization of the Wintertime Boise, Idaho, Airshed: A Comprehensive
Field Study Report for the U.S. EPA Office of Air Quality Planning and Standards.
NTIS PB92-136803.
Shepson, P.B., T.E. Kleindienst, and E.O Edney, 1987. Project Summary: The Produc
tion of Mutagenic Compounds as a Result of Urban Photochemistry. EPA Report
No. 600/S3-87/020.
Shepson, P.B., T.E. Kleindienst, and E.O Edney, 1987. The Production of Mutagenic
Compounds as a Result of Urban Photochemistry. EPA Report No. 600/S3-87/020.
50
-------
EPA Library Region 4
1011939
DATE DUE
------- |