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. 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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. 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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 ------- |