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Human Exposure and Atmospheric Sciences Division Publications: 2007

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This page lists publication titles, citations and abstracts produced by NERL's Human Exposure and Atmospheric Sciences Division for the year 2007, organized by Publication Type. Your search has returned 130 Matching Entries.

See also Human Exposure and Atmospheric Sciences Division citations with abstracts: 1999,  2000,  2001,  2002,  2003,  2004,  2005,  2006,  2007,  2008,  2009

Technical Information Manager: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov

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Presented/Published
BOOK CHAPTER Ground-Based Measurement of Solar Ultraviolet Radiation 02/06/2009
HALL, E. S. Ground-Based Measurement of Solar Ultraviolet Radiation. 2009.Chapter A-Z, David Blumel, Stefan Malmoli, Jessa Netting (ed.), McGraw-Hill Yearbook of Science and Technology. McGraw-Hill Companies, New York, NY, 150-155, (2009).
Abstract: The National Exposure Research Laboratory (NERL) of the U.S. Environmental Protection Agency implemented a research program between 1996 and 2004 to measure UV at 21 unique locations through out the U.S. The program conducted long-term monitoring of UV to detect trends due to changes in the amount of stratospheric O3.

BOOK CHAPTER The Importance of Exposure in Addressing Current and Emerging Air Quality Issues 08/03/2008
WATKINS, T. H., R. W. WILLIAMS, A. F. VETTE, J. M. BURKE, B. J. GEORGE, AND V. ISAKOV. The Importance of Exposure in Addressing Current and Emerging Air Quality Issues. , Chapter 7, Carlos Borrego and Ana Isabel Miranda (ed.), Air Pollution Modeling and Its Application XIX. Springer, New York, NY, 640-647, (2008).
Abstract: The air quality issues that we face today and will face in the future are becoming increasingly more complex and require an improved understanding of human exposure to be effectively addressed. The objectives of this paper are (1) to discuss how concepts of human exposure and exposure science and should be applied to improve air quality management practices and (2) to show how air quality modeling tools can be used to improve exposures estimates used for understanding associations between air quality and human health. Data from a large human exposure monitoring study is presented to demonstrate the value of exposure in understanding important air quality issues, such as health effects associated with exposure to components of particulate matter (PM), to PM of different size fractions (coarse and ultrafine), and to air pollution in near roadway environments. Various approaches for improving estimates of exposure via application of air quality modeling are discussed and results from example modeling applications are presented. These air quality modeling approaches include: the integration of regional scale eulerian air quality models with local scale gaussian dispersion models; the fusion of modeled estimates with air quality observations; the integration of air quality and human exposure modeling tools; and the use of exposure factors, such as housing ventilation, to adjust modeled estimates of ambient air quality.

BOOK CHAPTER Asbestos Measurement 02/01/2008
Kominsky, J., D. A. VALLERO, AND M. E. BEARD. Asbestos Measurement. , 2008., Chapter A-Z, Yearbook of Science & Technology. McGraw-Hill Companies, New York, NY, 2008:20-26, (2008).
Abstract: Environmental engineers are generally concerned with two types of air pollutants, gases and particulate matter (PM). Generally, the mass of PM falling in two size categories is measured, i.e. ≤2.5 µm diameter, and between 2.5 µm and 10 µm diameter. These measurements are taken by instruments (see Fig. 1) with inlets using size exclusion mechanisms to segregate the mass of each size fraction (i.e. “dichotomous” samplers). Particles with diameters ≥10 µm are generally of less concern, since their mass is sufficiently large that they rarely travel long distances. However, they are occasionally measured if a large particulate emitting source (e.g. a coal mine) is nearby.

BOOK CHAPTER Dispersion Modeling in Complex Urban Systems 02/01/2008
VALLERO, D. A., A. H. HUBER, AND P. J. LIOY. Dispersion Modeling in Complex Urban Systems. , 2008., Chapter A-Z, David Blumel, Stefan Malmoli, Jessa Netting (ed.), Yearbook of Science and Technology. McGraw-Hill Companies, New York, NY, 95-101, (2008).
Abstract: Models are used to represent real systems in an understandable way. They take many forms. A conceptual model explains the way a system works. In environmental studies, for example, a conceptual model may delineate all the factors and parameters for determining how a particle moves in the atmosphere after it has been released from a power plant. A conceptual model may also help identify the major influences on where a chemical is emitted and how likely it is to be found in the environment. Such models need to be developed to help target sources of data for assessing environmental problems. In general, developing an air pollution model involves two steps. First, a model of the domain and processes being studied must be defined and mathematical algorithms selected to represent the system. Then, the model boundary conditions are defined to represent the influence of the environment and other factors associated with the study. The quality of the model study is related to the accuracy and representativeness of the actual study.

COMMUNICATION PRODUCT The Detroit Exposure and Aerosol Research Study (Dears) Article in National Ambient Air Quality Status and Trends Through 2007 06/04/2008
WILLIAMS, R. W. The Detroit Exposure and Aerosol Research Study (Dears) Article in National Ambient Air Quality Status and Trends Through 2007. U.S. Environmental Protection Agency, Washington, DC, EPA/600/F-08/008, 2008.
Abstract: A research study that the U.S. Environmental Protection Agency conducted in Detroit, Michigan, named the Detroit Exposure and Aerosol Research Study (DEARS), will help develop data that improves our understanding of human exposure to various air pollutants in our environment.

DATA Exposure Related Dose Estimating Model (Erdem) 06/20/2007
BLANCATO, J. N., F. W. POWER, A. RUIZ, A. TSANG, M. S. OKINO, J. C. JOHNSON, C. C. DARY, N. HERAVI, R. N. BROWN, AND L. S. SHELDON. Exposure Related Dose Estimating Model (Erdem). U.S. Environmental Protection Agency, Washington, DC, EPA/600/C-07/010, 2007.
Abstract: ERDEM is a physiologically-based pharmacokinetic (PBPK) model with a graphical user interface (GUI) front end. Such a mathematical model was needed to make reliable estimates of the chemical dose to organs of animals or humans because of uncertainties of making route-to route, low-to-high exposure, and species-to-species extrapolations when there are exposures to one, or to multiple chemicals.

EPA PUBLISHED PROCEEDINGS Proceedings: Isea Bioavailability Symposium, Durham, North Carolina Use of Invitro Bioaccessibility/Relative Bioavailability Estimates for Metals in Regulatory Settings: What Is Needed? 04/15/2008
BRADHAM, K. D., M. BERINGER, AND A. YEOW. Proceedings: Isea Bioavailability Symposium, Durham, North Carolina Use of Invitro Bioaccessibility/Relative Bioavailability Estimates for Metals in Regulatory Settings: What Is Needed? ISEA Bioavailability Symposium , Durham, NC, October 14 - 18, 2007. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/102 (NTIS PB2008-113476), 2008.
Abstract: Oral ingestion of soil and dust is a key pathway for human exposures to metal and metalloid contaminants. It is widely recognized that the site-specific bioavailability of metals in soil and dust may be reduced relative to the metal bioavailability in media such as water and food, and adjustments for oral relative bioavailability are becoming more accepted. Both animal models and in vitro bioaccessibility models have been used to estimate relative bioavailability of metals in soil and dust. Although animal models are often considered the "gold standard", they may be costly or otherwise prohibitive at certain sites and may not be sensitive enough to test environmentally relevant samples for all contaminants. Routine application of in vitro metal bioaccessibility models in regulatory settings is being held up by different perceptions of what is required of these models in terms of validation. This symposium provided the opportunity for international experts to exchange their views on methods for assessing relative bioavailability/bioaccessibility for application in risk assessments at contaminated sites. The symposium speakers presented recent developments in animal models, new in vitro models, the role of mineralogical analyses in assessing relative bioavailability, and the application of physiologically based models as research tools. In addition, two panel discussions addressed specific research questions and discussed future research needs in this area. Recognizing the multi-disciplinary nature of exposure assessment, this symposium included representation from many disciplines including risk assessment, toxicology, environmental geochemistry, geology, soil, and analytical chemistry from the U.S., Europe, and Canada.

ETV DOCUMENT An Environmental Technology Verification (Etv) Testing of a Ballast Exchange Assurance Meter (Beam) 100 10/23/2007
BATTELLE MEMORIAL INSTITUTE, M. Schrock, W. Ivancic, C. Hunt, Z. Willenburg, AND A. Dindal. An Environmental Technology Verification (Etv) Testing of a Ballast Exchange Assurance Meter (Beam) 100. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/134 (NTIS PB-2008-106040), 2007.
Abstract: Mid-ocean ballast water exchange (BWE) is mandatory for all vessels entering U.S. waters from outside the 200-mile exclusive economic zone. To support such regulation, accurate and portable verification tools are needed for determining that BWE has taken place. One parameter proposed as a means of distinguishing between coastal and open ocean water content in ballast water is CDOM. CDOM refers to the fraction of colored dissolved organic matter that absorbs light and fluoresces in the UV and visible regions of the spectrum. This BWE technology provides a portable, quick measurement of CDOM. The technologies function by measuring the amount of fluorescent CDOM in ballast water and with the results reported via a digital display or electronic output signal. The technology verified with this testing was a Ballast Exchange Assurance Monitor -100 (Dakota, Inc.)

ETV DOCUMENT An Environmental Technology Verification (Etv) Testing of Four Mercury Emission Sampling Systems 05/07/2007
BATTELLE MEMORIAL INSTITUTE, T. KELLY, J. SATOLA, Z. WILLENBERG, AND A. DINDAL. An Environmental Technology Verification (Etv) Testing of Four Mercury Emission Sampling Systems. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/052 (NTIS PB2007-108680), 2007.
Abstract: CEMs - Tekran Instrument Corp. Series 3300 and Thermo Electron's Mercury Freedom System Continuous Emission Monitors (CEMs) for mercury are designed to determine total and/or chemically speciated vapor-phase mercury in combustion emissions. Performance for mercury CEMs are contained in Chapter 40 of the Code of Federal Regulations, Part 75 and Part 60 (40 CFR Parts 75 and 60) and require assessment of the performance of newly installed mercury CEMs only for their determination of HgT. This total is the sum of vapor-phase mercury in all chemical forms in the combustion gas, including Hg0 and HgOX. The CEMs tested claim to measure HgT, Hg0, and HgOX. They both use atomic fluorescence for detection. Sorbent-based Sampling System-Apex Instruments and Environmental Supply Co.HG-324K Appendix K of 40CFR Part 75 established sorbent-based sampling systems as an acceptable approach for determining mercury in the stack of utility generating stations. Sorbent-based systems collect integrated samples of mercury from stack gas onto selected sorbent material over an extended time period (from a few hours to several days). The collected mercury samples are then analyzed and the stack gas mercury concentrations are then calculated. Appendix K defines procedures for use of such systems to collect total vapor-phase mercury in combustion source emissions and require the use of multi-stage sorbent traps pre-spiked with mercury as a quality assurance measure. Apex used atomic absorption for final analysis, while ESC uses cold vapor atomic fluorescence spectrometry.

ETV DOCUMENT An Environmental Technology Verification (Etv) Testing of Three Immunoassay Test Kits for Anthrax, Botulinum Toxin and Ricin 01/09/2007
BATTELLE MEMORIAL INSTITUTE, M. SCHROCK, R. JAMES, A. DINDAL, Z. WILLENBURG, AND K. RIGGS. An Environmental Technology Verification (Etv) Testing of Three Immunoassay Test Kits for Anthrax, Botulinum Toxin and Ricin. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-06/147 (NTIS PB2007-105370), 2006.
Abstract: Immunoassay test kits are based on immunoassay methods, where specific antibodies are used to detect and measure the contaminants of interest. Immunoassay test kits rely on the reaction of a contaminant or antigen with a selective antibody to give a product that can be measures. Many types of technologies involved enzymes, fluorescence, phosphorescence, electrochemiluminescence, and chemiluminescence, have been used for quantifying the assay. The sample concentration can be either directly or inversely proportional to color intensity, depending on the technology. Results from these methods can be qualitative or quantitative. While there are several types of immunoassays, enzyme-linked immunoabsorbent assays are most common.
Of the three test kit technologies tested in the verification test, the QTL Biosystems, LLC's QTL Biosensor technology uses an immunomagnetic technique which produces a magnetic and a fluorescent component, while the PharmaLeads's EzyBot uses a fluorescence quenching technology. The BioVeris Corporation's BioVerify test kit uses an electrochemical stimulated technology. These three technologies do not all that the capabilities to detect all three of the tested contaminants.

JOURNAL Summary of the Workshop on Methodologies for Environmental Public Health Tracking of Air Pollution Effects 12/01/2009
Matte, T. D., A. Cohen, F. DIMMICK, J. M. SAMET, J. SARNAT, F. Yip, AND N. Jones. Summary of the Workshop on Methodologies for Environmental Public Health Tracking of Air Pollution Effects. Air Quality, Atmosphere & Health. Springer Netherlands, , Netherlands, 2(4):177-184, (2009).
Abstract: The U.S. Centers for Disease Control and Prevention (CDC) established the Environmental Public Health Tracking (EPHT) program to support state and local projects to compile, link, analyze, and disseminate environmental and health data thereby engaging stakeholders and guiding actions to improve public health.

JOURNAL Mass Fraction Spatiotemporal Geostatistics and Its Application to Map Atmospheric Polycyclic Aromatic Hydrocarbons After 9/11 12/01/2009
Allshouse, W. B., J. D. PLEIL, S. M. Rappaport, AND M. L. Serre. Mass Fraction Spatiotemporal Geostatistics and Its Application to Map Atmospheric Polycyclic Aromatic Hydrocarbons After 9/11. Stochastic Environmental Research and Risk Assessment . Springer Science + Business Media, LLC, New York, NY, 23(8):1213-1223, (2009).
Abstract: Extensive research has been conducted on effects resulting from exposure to ambient particulate matter. Particulate matter has been linked to cardiovascular diseases, respiratory problems, and reproductive effects. A large body of work on particulate matter focuses on atmospheric particles less than 10 microns in size (PM10); more recently, research has been extended to investigation of fine particulate matter (particles less than 2.5 microns in aerodynamic diameter, PM2.5), which travel deeper into the lungs and increase the risks of health effects.

JOURNAL Application of Novel Method to Measure Endogenous Vocs in Exhaled Breath Condensate Before and After Exposure to Diesel Exhaust 11/01/2009
HUBBARD, H., J. SOBUS, J. D. PLEIL, M. C. MADDEN, AND S. Tabucchi. Application of Novel Method to Measure Endogenous Vocs in Exhaled Breath Condensate Before and After Exposure to Diesel Exhaust. JOURNAL OF CHROMATOGRAPHY: B BIOMEDICAL SCIENCES AND APPLICATIONS. Elsevier Science Ltd, New York, NY, 877(29):3652-3658, (2009).
Abstract: Polar volatile organic compounds (PVOCs) such as aldehydes, ketones, and alcohols are byproducts of normal human metabolism and are present in exhaled breath and blood. Environmental exposures, individual activities, and disease states can perturb normal metabolic processes and can be expressed as a change in the patterns of the PVOCs. Under controlled or monitored conditions it may be possible to directly attribute changes to external sources. Results of these controlled exposures could then be used to assess unknown exposures in population based studies.

JOURNAL A Review of Advancements in Particulate Matter Sampling and Analysis and Its Application to Identifying Source Impacts at Receptor Locations 11/01/2009
SOLOMON, P. A. AND N. FRANK. A Review of Advancements in Particulate Matter Sampling and Analysis and Its Application to Identifying Source Impacts at Receptor Locations. Air Quality and Climate Change. Clean Air Society of Australia and New Zealand, Olinda, Australia, 43(4):35-42, (2009).
Abstract: Time-integrated (typically 24-hr) filter-based methods (historical methods) form the underpinning of our understanding of the fate, impact of source emissions at receptor locations (source impacts), and potential health and welfare effects of particulate matter (PM) in air. Over the last 40 years, many of these methods have been thoroughly evaluated and there is reasonable confidence with what they measure and associated uncertainties. These methods require transport of samples collected in the field to a laboratory for analysis of PM properties of interest. Over the last decade, significant progress has occurred in the development and evaluation of continuous and semi-continuous methods that combine the collection and chemical or physical property analysis into one instrument. These methods are placed in the field, providing often near-real time data, most with hourly time-resolution or better from bulk to single practical information from a few nanometers to 10 μm. Many of the continuous chemical property methods developed and tested still require additional evaluation and comparison between themselves and to historical methods. The latter are the primary basis for comparison since in-the-field tests, through the inlet reference standards are not available for most PM components. Despite lesser confidence in these methods relative to historical methods, data generated from these methods have greatly enhanced the application of approaches to link and quantify the impact of source emissions at receptor sites and to associate PM with health effects, as well as significantly advancing our understanding of atmospheric chemistry and the fate of PM in air. This paper briefly reviews the two primary modeling methods for estimating source contributions at receptor locations and current measurement methods with a focus on continuous measurements.

JOURNAL The Design and Field Implementation of the Detroit Exposure and Aerosol Research Study 11/01/2009
WILLIAMS, R. W., A. W. REA, A. F. VETTE, C. W. CROGHAN, D. A. WHITAKER, C. D. STEVENS, S. R. MCDOW, R. C. FORTMANN, L. S. SHELDON, H. WILSON, J. Thornburg, M. P. PHILLIPS, P. Lawless, C. E. RODES, AND H. DAUGHTREY. The Design and Field Implementation of the Detroit Exposure and Aerosol Research Study. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 19(7):643-659, (2009).
Abstract: The primary goal of the study was to evaluate and describe the relationship between air toxics, particulate matter (PM), PM constituents, and PM from specific sources measured at a central site monitor with those from the residential and personal locations.

JOURNAL Source Apportionment of Primary and Secondary Organic Aerosol Using Positive Matrix Factorization (Pmf) of Molecular Markers 11/01/2009
Zhang, Y., R. J. SHEESLEY, J. J. SCHAUER, M. LEWANDOWSKI, MOHAMMAD JAOUI, J. H. OFFENBERG, T. E. KLEINDIENST, AND E. O. EDNEY. Source Apportionment of Primary and Secondary Organic Aerosol Using Positive Matrix Factorization (Pmf) of Molecular Markers. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 43(34):5567-5574, (2009).
Abstract: Monthly average ambient concentrations of more than eighty particle-phase organic compounds, as well as total organic carbon (OC) and elemental carbon (EC), were measured from March 2004 through February 2005 in five cities in the Midwestern United States. A multi-variant source apportionment receptor model, positive matrix factoriztion (PMF), was applied to explore the average source contributions to the five sampling sites using molecular markers for primary and secondary organic aerosols (POA, SOA).

JOURNAL Spatial Gradients and Source Apportionment of Volatile Organic Compounds Near Roadways 11/01/2009
OLSON, D. A., D. HAMMOND, R. L. SEILA, J. M. BURKE, AND G. A. NORRIS. Spatial Gradients and Source Apportionment of Volatile Organic Compounds Near Roadways. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 43(35):5647-5653, (2009).
Abstract: Concentrations of 55 volatile organic compounds (VOCs) are reported near a highway in Raleigh, NC (traffic volume of approximately 125,000 vehicles/day). Levels of VOCs generally decreased exponentially with perpendicular distance from the roadway 10-100m). The EPA Chemical Mass Balance (CMB8.2) was used to apportion VOCs into four sources (motor vehicles, natural gas, propane gas, evaporative gasoline).

JOURNAL Impact of Mining Waste on Airborne Respirable Particulates in Northeastern Oklahoma, United States 11/01/2009
Zota, A., R. WILLIS, R. Jim, G. A. NORRIS, J. P. SHINE, R. M. DUVALL, L. A. Schaider, AND J. D. SPENGLER. Impact of Mining Waste on Airborne Respirable Particulates in Northeastern Oklahoma, United States. JOURNAL OF AIR AND WASTE MANAGEMENT. Air & Waste Management Association, Pittsburgh, PA, 59(11):1347-1357, (2009).
Abstract: Atmospheric dispersion of particles from mine waste is potentially an important route of human exposure to metals in communities close to active and abandoned mining areas. In this study, we assessed sources of mass and metal concentrations in two size fractions of respirable particles using positive matrix factorization (Environmental Proteciton Agency [EPA] 3.0.

JOURNAL Determination of Ten Perfluorinated Compounds in Bluegill Sunfish (lepomis Macrochirus) Fillets 11/01/2009
DELINSKY, A., M. STRYNAR, S. F. Nakayama, J. L. VARNS, X. Ye, P. McCann, AND A. B. LINDSTROM. Determination of Ten Perfluorinated Compounds in Bluegill Sunfish (lepomis Macrochirus) Fillets. ENVIRONMENTAL RESEARCH. Academic Press Incorporated, Orlando, FL, 109(8):975-984, (2009).
Abstract: Limited information is known about the environmental distributions of the perfluorinated compounds (PFCs) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), in part due to a lack of well characterized analytical methods that can be used to accurately measure these contaminants in key environmental matrices. In this work, a rigorous SPE/liquid chromatography/tandem mass spectrometry method for the measurement of 10 PFCs in fish fillets is described and applied to bluegill sunfish (Lepomis macrochirus) fillets collected from selected areas of Minnesota and North Carolina. The 4 PFC analytes that were routinely detected in bluegill fillets were PFOS, perfluorodecanoic acid (C10), perfluoroundecanoic acid (C11), and perflurododecanoic acid (C12). Measures of method accuracy and precision for these compounds showed that calculated concentrations of PFCs in spiked samples differed by less than 20% from their theoretical values and that the %RSD for these measurements were also less than ± 20%. The Minnesota samples show increasing concentrations of the 4 detectable PFCs on the Mississippi River in proximity to known potential PFC sources and low levels of PFCs in the St. Croix River, which receives minimal known industrial inputs. Bluegill from Lake Calhoun, located in the Minneapolis-St. Paul area, had higher levels of PFCs than were found in the Mississippi River near known potential PFC sources. PFOS was the most prevalent PFC found in Minnesota samples, with median concentrations of 47.0 – 102 ng/g in locations along the Mississippi River, 2.08 ng/g in the St. Croix River, and 275 ng/g in Lake Calhoun. North Carolina samples, which were collected from two rivers with no known historical PFC sources, had PFC concentrations that were well above the limit of quantitation (LOQ). PFOS was the predominant analyte in fish taken from the Haw and Deep Rivers in the Cape Fear River Basin, with median concentrations of 30.3 and 62.2 ng/g, respectively. Mean concentrations of C10, C11, and C12 in NC samples were among the highest reported in the literature, with respective median values of 9.08, 23.9, and 6.60 ng/g in fish from the Haw River and 2.90, 9.15, and 3.46 ng/g in fish from the Deep River. Application of this method suggests that PFC contamination occurs in some U.S. freshwater fish and may not be limited to areas with historical PFC inputs.

JOURNAL Influence of Aerosol Acidity on the Formation of Secondary Organic Aerosol from Biogenic Precursor Hydrocarbons 10/15/2009
OFFENBERG, J. H., M. LEWANDOWSKI, E. O. EDNEY, T. E. KLEINDIENST, AND MOHAMMAD JAOUI. Influence of Aerosol Acidity on the Formation of Secondary Organic Aerosol from Biogenic Precursor Hydrocarbons. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(20):7742-7747, (2009).
Abstract: Secondary organic aerosol (SOA) formation and dynamics may be important factors for the role of aerosols in adverse health effects, visibility and climate change. Formation of SOA occurs when a parent volatile organic compound is oxidized to create products that form in a condensed phase. The suit of major precursor compounds is not fully known, though several precursor compounds are currently thought to contribute to ambient SOA.

JOURNAL Enhancing Air Pollution Exposure Assessment in the 21st Century By Measurement and Modeling 10/01/2009
LIOY, P. J., T. H. WATKINS, AND G. ALLEN. Enhancing Air Pollution Exposure Assessment in the 21st Century By Measurement and Modeling. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, (10/2009):42-45, (2009).
Abstract: Exposure assessments may be conducted using measurement data, modeling results, or through a combination of measurements and models. Models are required to estimate exposure when measurement data is insufficient due to spatial or temporal gaps (e.g., for refined local scale assessments) or if an estimate of exposure is required when no measurements exist (e.g., 10 evaluate alternative risk management options). However, the advanced modeling tools needed for exposure assessments in the future require measurement data for both their development, including exposure information to evaluate models the estimate exposures and dose for similar conditions. This article discusses why current and future air quality management issues require enhanced exposure assessment approaches, the role of exposure assessment in past monitoring studies, what measurements are needed to enhance exposure models, and new measurement and modeling approaches for estimating human exposures to air pollution.

JOURNAL The Formation of Secondary Organic Aerosol from the Isoprene + Oh Reaction in the Absence of NOx 09/10/2009
KLEINDIENST, T. E., M. LEWANDOWSKI, J. H. OFFENBERG, M. JAOUI, AND E. O. EDNEY. The Formation of Secondary Organic Aerosol from the Isoprene + Oh Reaction in the Absence of NOx. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, Germany, 9(17):6541-6558, (2009).
Abstract: The reaction of isoprene (C5H8) with hydroxyl radicals has been studied in the absence of nitrogen oxides (NOx) to determine physical and chemical characteristics of the secondary organic aerosol formed. Experiments were conducted using a smog chamber operated in a steady-state mode permitting measurements of moderately low aerosol levels. GC-MS analysis was conducted to measure methyl butenediols in the gas phase and polyols in the aerosol phase. Analyses were made to obtain several bulk aerosol parameters from the reaction including values for the organic mass to organic carbon ratio, the effective enthalpy of vaporization (Δ Heff >vapeff), the organic peroxide fraction, and the aerosol yield.

JOURNAL Spatial and Temporal Variability of Outdoor Coarse Particulate Matter Mass Concentrations Measured With a New Coarse Particulate Sampler During the Detroit Exposure and Aerosol Research Study 09/01/2009
Thornburg, J., C. E. RODES, P. A. Lawless, AND R. W. WILLIAMS. Spatial and Temporal Variability of Outdoor Coarse Particulate Matter Mass Concentrations Measured With a New Coarse Particulate Sampler During the Detroit Exposure and Aerosol Research Study. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 43(28):4251-4258, (2009).
Abstract: The Detroit Exposure and Aerosol Research Study (DEARS) provided data to compare outdoor residential coarse particulate matter (PM10-2.5) concentrations in six different areas of Detroit with data from a central monitoring site. Daily and seasonal influences on the spatial distribution of PM10-2.5 concentrations during Summer 2006 and Winter 2007 were investigated using data collected with the newly developed coarse particle exposure monitor (CPEM). These data allowed the representativeness of the community monitoring site to be assessed for the greater Detroit metro area. Multiple CPEMs collocated with a dichotomous sampler determined the precision and accuracy of the CPEM PM10-2.5 and PM2.5 data. CPEM PM2.5 concentrations agreed with the dichotomous sampler data. The slope was 0.97 and the correlation coefficient was 0.91. CPEM PM10-2.5 concentrations had an average 23% negative bias and correlation coefficient of 0.81. The directional nature of the CPEM sampling efficiency probably caused the negative CPEM concentration bias. Coarse particle concentrations were observed to vary spatially and temporally across Detroit, reflecting the seasonal impact of local sources. Summer PM10-2.5 concentrations were 5 μg/m3 higher in the two industrial areas near downtown than the average concentrations in other areas of Detroit. An area impacted by vehicular traffic had concentrations 8 μg/m3 higher than the average concentrations in other parts of Detroit in the winter due to the suspected suspension of road salt. Pearson correlations for PM10-2.5 concentrations between monitoring locations varied from 0.03 to 0.76. All summer PM10-2.5 concentration correlations were greater than 0.28 and statistically significant (p-value < 0.05). Winter PM10-2.5 concentration correlations greater than 0.33 were statistically significant (p-value < 0.05). The PM10-2.5 correlations found to be insignificant were associated with the area impacted by mobile sources during the winter. The suspected suspension of road salt from the Southfield Freeway, combined with a very stable atmosphere, caused PM10-2.5 concentrations to be greater in this area compared to other areas of Detroit. These findings indicated that PM10-2.5 concentrations, although correlated in some instances, vary in magnitude sufficiently that a central monitoring site may not adequately represent the population exposure in a complex urban airshed.

JOURNAL Intra-and Inter-Individual Variability in Location Data for Two U.S. Health-Compromised Elderly Cohorts 08/20/2009
Frazier, E. L., T. R. MCCURDY, R. W. WILLIAMS, W. S. LINN, AND B. J. GEORGE. Intra-and Inter-Individual Variability in Location Data for Two U.S. Health-Compromised Elderly Cohorts. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 19(6):580-592, (2009).
Abstract: This study provides descriptive statistical data on daily time spent in three locations of exposure assessment interest for two panel studies of health-compromised elderly individuals > 65 y old having multi-days of human activity data. The panel studies include individuals living in Los Angeles CA and Baltimore MD in various housing types.

JOURNAL Epoxying Isoprene Chemistry 08/07/2009
KLEINDIENST, T. E. Epoxying Isoprene Chemistry. SCIENCE. American Association for the Advancement of Science (AAAS), Washington, DC, 325(5941):687-688, (2009).
Abstract: It seems that every few months we read about another missing aspect of atmospheric chemistry: missing products, missing reactivity, missing sources, missing understanding. Thus, it is with some relief that we read in this issue the paper of Paulot et al. The paper provides more answers then questions on a topic of considerable interest to atmospheric scientists, the formation of gas- and aerosol-phase products from the atmospheric oxidation of isoprene.

JOURNAL Spatial Analysis and Land Use Regression of Vocs and No2 from School-Based Urban Air Monitoring in Detroit-Dearborn, USA 08/01/2009
MUKERJEE, S., L. SMITH, M. M. JOHNSON, L. M. NEAS, AND C. STALLINGS. Spatial Analysis and Land Use Regression of Vocs and No2 from School-Based Urban Air Monitoring in Detroit-Dearborn, USA. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier Science Ltd, New York, NY, 407(16):4642-4651, (2009).
Abstract: Passive ambient air sampling for nitrogen dioxide (NO2 and volatioe organic compounds (VOCs) was conducted at 25 schools and two compliance sites in Detroit and Dearborne, Michigan. Geographic Information System (GIS) data were calculated at each of 116 schools. The 25 selected schools were monitored to assess and model intra-urban gradients of air pollutants to evaluate impact of traffic and urban emissions on respiratory effects in children.

JOURNAL Library Optimization in Edxrf Spectral Deconvolution for Multi-Element Analysis of Ambient Aerosols 07/01/2009
KELLOGG, R. AND R. WILLIS. Library Optimization in Edxrf Spectral Deconvolution for Multi-Element Analysis of Ambient Aerosols. X-ray Spectrometry. John Wiley & Sons, Ltd., Indianapolis, IN, 38(4):283-286, (2009).
Abstract: In multi-element analysis of atmospheric aerosols, attempts are made to fit overlapping elemental spectral lines for many elements that may be undetectable in samples due to low concentrations. Fitting with many library reference spectra has the unwanted effect of raising the analytical uncertainty of over lapping elements. By carefully choosing the order of elemental processing, library reference spectra can be omitted for non-analyte lines of undetected elements without loss of information, thus lowering the number of library spectra needed for the fit and thereby reducing the uncertainty. The magnitude of the reduction so achieved is shown for blanks and a sample for 64 elements.

JOURNAL Spatial Variability of Mercury Wet Deposition in Eastern Ohio: Summertime Meteorological Case Study Analysis of Local Source Influences 07/01/2009
White, E. M., G. J. KEELER, AND M. S. LANDIS. Spatial Variability of Mercury Wet Deposition in Eastern Ohio: Summertime Meteorological Case Study Analysis of Local Source Influences. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(13):4946-4953, (2009).
Abstract: Extensive exploration of event precipitation data in the Ohio River Valley indicates that coal combustion emissions play an important role in mercury (Hg) wet deposition. During July-September 2006, an intensive study was undertaken to discern the degree of local source influence. Source-receptor relationships were explored by establishing a near field network of wet deposition sites in and around Steubenville, Ohio with sample collection on an event basis. For the three month period of study, volume weighted mean Hg concentrations observed at the eight network sites range from 10.2 to 22.3 ng L-1, but this range increases drastically on an event basis with a maximum concentration of 89.4 and a minimum of 4.1 ng L-1. A subset of nine individual events was explored in depth and the degree of Hg concentration variability among concurrently collected samples is linked to the degree of local source enhancement. Samples collected at sites approximately one km from the base of coal fired utilities exhibited up to 72% Hg enhancement over regionally representative samples on an event basis. Overall, precipitation depth was found to account for only 7% of Hg concentration variability and only events that exhibited regionally well mixed characteristics and low sample variability among the sites demonstrated a significant depth/concentration relationship. Air mass transport and precipitating cell histories were traced in order to evaluate relationships between local point sources and the receptor sites. It was found that the interaction of several dynamic atmospheric parameters combined to favor local Hg concentration enhancement versus a more regional signature. When significant meteorological factors (wind speed during maximum rain rate, wind speed 24 hours prior to precipitation, mixing height and observed ceiling) are explored, it is estimated that near field precipitation in and around Eastern Ohio was 42% enhanced in Hg concentration by local sources compared to regionally representative samples collected over the three month intensive period

JOURNAL American Healthy Homes Survey: A National Study of Residential Pesticides Measured from Floor Wipes. 06/15/2009
STOUT, D. M., K. D. BRADHAM, P. P. EGEGHY, P. A. JONES, C. W. CROGHAN, P. Ashley, E. Pinzer, W. Friedman, M. C. BRINKMAN, M. G. Nishioka, AND D. Cox. American Healthy Homes Survey: A National Study of Residential Pesticides Measured from Floor Wipes. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 43(12):4294-4300, (2009).
Abstract: The U.S. Department of Housing and Urban Development in collaboration with the United States Environmental Protection Agency conducted a survey measuring lead, allergens, and insecticides in a randomly selected nationally representative sample of resodential homes. Multistage sampling with clustering was used to select the 1,131 homes of which a subset of 500 randomly selected homes were included in the study forhe collection of hard surface floor wipes . Samples were collected by trained field technicians between June, 2005

JOURNAL Near Roadway Concentrations of Organic Source Markers 06/01/2009
OLSON, D. A. AND S. R. MCDOW. Near Roadway Concentrations of Organic Source Markers. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 43(18):2862-2867, (2009).
Abstract: Recent epidemiological and health studies have shown an association between roadway traffic and health effects. It is likely that specific size fractions of chemical components may be more indicative of near-road related health effects than PM2.5 or PM2.5-10 mass. The objective of this study is to quantify spatial differences in organic source markers near a highway.

JOURNAL Source Region Identification Using Kernel Smoothing 06/01/2009
HENRY, R. C., G. A. NORRIS, R. VEDANTHAM, AND J. R. Turner. Source Region Identification Using Kernel Smoothing. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(11):4090-4097, (2009).
Abstract: As described in this paper, Nonparametric Wind Regression is a source-to-receptor source apportionment model that can be used to identify and quantify the impact of possible source regions of pollutants as defined by wind direction sectors. It is described in detail with an example of its application to SO2 data from East St. Louis, IL. The model uses nonparametric kernel smoothing methods to apportion the observed average concentration of a pollutant to sectors defined by ranges of wind direction and speed.

JOURNAL Analysis of Pfoa in Dosed Cd1 Mice Part 1: Methods Development for the Analysis of Tissues and Fluids from Pregnant and Lactating Mice and Their Pups 06/01/2009
Reiner, J. L., S. F. Nakayama, A. DELINSKY, J. STANKO, S. E. FENTON, A. B. LINDSTROM, AND M. J. STRYNAR. Analysis of Pfoa in Dosed Cd1 Mice Part 1: Methods Development for the Analysis of Tissues and Fluids from Pregnant and Lactating Mice and Their Pups. REPRODUCTIVE TOXICOLOGY. Elsevier Science Ltd, New York, NY, 27(3-4):365-372, (2009).
Abstract: The number of studies involving the analysis of perfluorooctanoic acid (PFOA) has 33 increased recently because PFOA is routinely detected in human blood samples from around the world. Recent studies with mice have shown that dosing pregnant dams with PFOA during gestation gives rise to a dose-dependent mortality in the litters, a reduction in neonatal body weight for the surviving pups, and subsequent deficits in mammary gland development when compared to control animals. The actual body burdens of PFOA in dams and pups associated with these endpoints have not been determined, in part due to a lack of robust analytical methods for these matrices. The goal of the current study was to develop reliable methods with acceptable performance characteristics for the analysis of PFOA in several matrices relevant to pregnant mouse studies. Dam and pup serum, amniotic fluid, urine, milk, mammary tissue, and whole mouse pups were isolated for method development and analysis. The resulting method provided excellent accuracy (92.1%-111%) and reproducibility (relative standard deviation 4.3%-21%) making them very useful for future studies. These methods were then applied to dosed animal fluids and tissues in order to conduct a thorough evaluation of the pharmacokinetics in utero. Resulting tissue specific measurements of PFOA in serum, amniotic fluid, urine, milk, mammary tissue, and whole pup homogenate will be used to more completely describe the dose-response relationships for the most sensitive health outcomes and inform pharmacokinetic models that are being developed and evaluated.

JOURNAL The National Ambient Air Monitoring Stategy: Rethinking the Role of National Networks 05/01/2009
SCHEFFE, R., P. A. SOLOMON, R. Husar, T. HANLEY, M. SCHMIDT, M. Koerber, AND M. Gilroy. The National Ambient Air Monitoring Stategy: Rethinking the Role of National Networks. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, 59(5):579-590, (2009).
Abstract: A current re-engineering of the United States routine ambient monitoring networks intended to improve the balance in addressing both regulatory and scientific objectives is addressed in this paper. Key attributes of these network modifications include the addition of collocated instruments to produce multiple pollutant characterizations across a range of representative urban and rural locations in a new network referred to as the National Core Monitoring Network (NCore). The NCore parameters include carbon monoxide (CO), sulfur dioxide (SO2), reactive nitrogen (NOy), ozone (O3), and ammonia (NH3) gases and the major fine particulate matter (PM2.5) aerosol components (ions, elemental and organic carbon fractions, and trace metals). The addition of trace gas instruments, deployed at existing chemical speciation sites and designed to capture concentrations well below levels of national air quality standards, is intended to support both long-term epidemiological studies and regional-scale air quality model evaluation. In addition to designing the multiple pollutant NCore network, steps were taken to assess the current networks on the basis of spatial coverage and redundancy criteria, and mechanisms were developed to facilitate incorporation of continuously operating particulate matter instruments.

JOURNAL Factorial Based Response Surface Modeling With Confidence Intervals for Optimizing Thermal Optical Transmission Analysis of Atmospheric Black Carbon 03/09/2009
Conny, J. M., G. A. NORRIS, AND T. R. Gould. Factorial Based Response Surface Modeling With Confidence Intervals for Optimizing Thermal Optical Transmission Analysis of Atmospheric Black Carbon. ANALYTICA CHIMICA ACTA. Elsevier Science Ltd, New York, NY, 635(2):144-156, (2009).
Abstract: We demonstrate how thermal-optical transmission analysis (TOT) for refractory light-absorbing carbon in atmospheric particulate matter was optimized with empirical response surface modeling. TOT employs pyrolysis to distinguish the mass of black carbon (BC) from organic carbon (OC); however, it does not physically separate them. The optimization compared response surface for the cross sections, which revealed the effects of varying instrument conditions, in particular, the high-temperature pyrolysis step in helium.

JOURNAL Reconstructing Population Exposures to Environmental Chemicals from Biomarkers: Challenges and Opportunities 02/01/2009
GEORGOPOULOS, P. G., A. F. Sasso, S. ISUKAPALLI, P. J. LIOY, D. A. VALLERO, M. S. OKINO, AND L. W. REITER. Reconstructing Population Exposures to Environmental Chemicals from Biomarkers: Challenges and Opportunities. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 19(2):149-171, (2009).
Abstract: A conceptual/computational framework for exposure reconstruction from biomarker data combined with auxiliary exposure-related data is presented, evaluated with example applications, and examined in the context of future needs and opportunities. This framework employs Physiologically Based Toxicokinetic (PBTK) modeling in conjunction with numerical “inversion” techniques. In order to quantify the value of different types of exposure data “accompanying” biomarker data, a study was conducted focusing on reconstructing exposures to chlorpyrifos, from measurements of its metabolite levels in urine. The study employed biomarker data as well as supporting exposure-related information from the National Human Exposure Assessment Survey (NHEXAS), Maryland, while the MENTOR-3P system (Modeling ENvironment for TOtal Risk with Physiologically-based Pharmacokinetic modeling for Populations) was used for PBTK modeling. Recently proposed, simple numerical reconstruction methods were applied in this study, in conjunction with PBTK models. Two types of reconstructions were studied using: (a) just the available biomarker and supporting exposure data, and (b) synthetic data developed via augmenting available observations. Reconstruction using only available data resulted in a wide range of variation in estimated exposures. Reconstruction using synthetic data facilitated evaluation of numerical inversion methods and characterization of the value of additional information, such as study-specific data that can be collected in conjunction with the biomarker data. Although the NHEXAS data set provides a significant amount of supporting exposure-related information, especially when compared to national studies such as the National Health and Nutrition Examination Survey (NHANES), this information is still not adequate for detailed reconstruction of exposures under several conditions, as demonstrated here. The analysis presented here provides a starting point for introducing improved designs for future biomonitoring studies, from the perspective of exposure reconstruction; identifies specific limitations in existing exposure reconstruction methods that can be applied to population biomarker data, and suggests potential approaches for addressing exposure reconstruction from such data.

JOURNAL Development of a Distance-to-Roadway Proximity Metric to Compare Near-Road Pollutant Levels to a Central Site Monitor 02/01/2009
BARZYK, T. M., B. J. GEORGE, A. F. VETTE, R. W. WILLIAMS, C. W. CROGHAN, AND C. D. STEVENS. Development of a Distance-to-Roadway Proximity Metric to Compare Near-Road Pollutant Levels to a Central Site Monitor. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 43(4):787-797, (2009).
Abstract: The primary objective of the Detroit Exposure and Aerosol Research Study (DEARS) was to compare air pollutant concentrations measured at various neighborhoods, or exposure monitoring areas (EMAs), throughout a major metropolitan area to levels measured at a central site or community monitor. One of the EMAs was located near a busy freeway (annual average daily traffic (AADT) of w130,000) so that impacts of mobile sources could be examined. Air pollution concentrations from the roadway-proximate sites were compared to the central site monitor. The volatile organic compounds (VOCs) selected (benzene, toluene, ethylbenzene, m,p- and o-xylene, 1,3 butadiene, 1,3,5-trimethylbenzene and 4-ethyltoluene) are typically associated with mobile sources. Gradients were also evident that demonstrated the amplification of pollutant levels near the roadway compared to the community monitor. A novel distance-to-roadway proximity metric was developed to plot the measurements and model these gradients. Effective distance represents the actual distance an air parcel travels from the middle of a roadway to a site and varies as a function of wind direction, whereas perpendicular distance is a fixed distance oriented normal to the roadway. Perpendicular distance is often used as a proxy for exposures to traffic emissions in epidemiological studies.

JOURNAL Rapid New Methods for Paint Collection and Lead Extraction 01/02/2009
Gutknecht, W. F., S. L. HARPER, W. Winstead, K. Sorrell, D. A. Binstock, C. A. Salmons, C. Haas, M. McCombs, W. Studabaker, C. V. Wall, AND C. Moore. Rapid New Methods for Paint Collection and Lead Extraction. JOURNAL OF ENVIRONMENTAL MONITORING. Royal Society of Chemistry, Cambridge, Uk, 11(1):166-173, (2008).
Abstract: Chronic exposure of children to lead (Ph) can result in permanent physiologic impairment. In adults, it can cause irritability, poor muscle coordination, and nerve damage to the sense organs and nerves controlling the body. Surfaces coated with Pb-containing paints are potential sources of exposure to Ph. In January 2007, the U.S. Environmental Protection Agency (EPA) proposed new requirements that would reduce exposure to Ph hazards created by renovation, repair, and painting activities, which disturb Ph-based paint. On-site, inexpensive identification of Pb-based paint is required. Two steps have been taken to meet this challenge. First, this paper presents a new, highly efficient method for paint collection that is based on the use of a modified wood drill bit. Second, this paper presents a novel, one-step approach for quantitatively grinding and extracting Pb from paint samples for subsequent Pb determination. This latter method is based on the use of a high revolutions-per-minute rotor with stator to break up the paint into approximately 50 micron size particles. Nitric acid (25%, v/v) is used to extract the Pb in less than 3 minutes. Recoveries are consistently greater than 95% for real-world paints, National Institute of Standards and Technology's standard reference materials and audit samples from the American Industrial Hygiene Association's Environmental Lead Proficiency Analytical Testing Program. This quantitative extraction procedure, when paired with quantitative paint sample collection and Pb determination, may enable the development of a Pb paint test kit that will meet the specifications of the proposed EPA rule.

JOURNAL Field Comparison of Passive Air Samplers With Reference Monitors for Ambient Volatile Organic Compounds and Nitrogen Dioxide Under Week-Long Integrals 01/01/2009
MUKERJEE, S., K. OLIVER, R. L. SEILA, H. JACUMIN, C. W. CROGHAN, H. DAUGHTREY, L. M. NEAS, AND L. A. Smith. Field Comparison of Passive Air Samplers With Reference Monitors for Ambient Volatile Organic Compounds and Nitrogen Dioxide Under Week-Long Integrals. JOURNAL OF ENVIRONMENTAL MONITORING. Royal Society of Chemistry, Cambridge, Uk, 11(1):220-227, (2008).
Abstract: This study evaluates performance of nitrogen dioxide NO2 and volatile organic compounds (VOC) passive samplers with corresponding reference monitors at two sites in the Detroit, Michigan area during the summer of 2005.

JOURNAL Efficiency of Sampling and Analysis of Asbestos Fibers on Filter Media: Implications for Exposure Assessment 01/01/2009
VALLERO, D. A., J. R. Kominsky, M. E. BEARD, AND O. S. Crankshaw. Efficiency of Sampling and Analysis of Asbestos Fibers on Filter Media: Implications for Exposure Assessment. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE. Taylor and Francis, Philadelphia, PA, 6(1):62-72, (2009).
Abstract: To measure airborne asbestos and other fibers, an air sample must represent the actual number and size of fibers. Typically, mixed cellulose ester (MCE, 0.45 or 0.8 µm pore size) and to a much lesser extent, capillary-pore polycarbonate (PC, 0.4 µm pore size) membrane filters are used to collect airborne asbestos for count measurement and fiber size analysis. In this research study chrysotile asbestos (fibers both shorter and longer than 5 µm) were generated in an aerosol chamber and sampled by 25-mm diameter MCE filter media to compare the fiber retention efficiency of a 0.45 µm pore size filters versus 0.8 µ pore size filter media. In addition, the effect of plasma etching times on fiber densities was evaluated. This study demonstrated a significant difference in fiber retention efficiency between 0.45 µm and 0.8 µm pore size MCE filters for asbestos aerosols (structures longer than or equal to 0.5 µm length). The fiber retention efficiency of a 0.45 µm pore size MCE filter is statistically significantly higher than that of the 0.8 µm pore size MCE filter. However, for asbestos structures longer than 5µm, there is no statistically significant difference between the fiber retention efficiencies of the 0.45 µm and 0.8 µm pore size MCE filters. The mean density of asbestos fibers (longer than or equal to 0.5 µm) increased with etching time. Doubling the etching time increased the asbestos filter loading in this study by an average of 13%. The amount of plasma etching time had no effect on the filter loading for fibers longer than 5 µm. Many asbestos exposure risk models attribute health effects to fibers longer than 5 µm. In these models, both the 0.45 µm and 0.8 µm pore size MCE filter can produce suitable estimates of the airborne asbestos concentrations. However, some models suggest a more significant role for asbestos fibers shorter than 5 µm. Exposure monitoring for these models should consider only the 0.45 µm pore size MCE filters as recommended by the U.S. Environmental Protection Agency (EPA) AHERA protocol and other methods.

JOURNAL Measurement of Total Site Mercury Emissions from Chlor-Alkali Plant Using Ultraviolet Differential Optical Absorption Spectroscopy and Cell Room Roof-Vent Monitoring 01/01/2009
THOMA, E. D., C. SECREST, E. S. HALL, D. L. Jones, R. C. SHORES, M. MODRAK, R. HASHMONAY, AND P. Norwood. Measurement of Total Site Mercury Emissions from Chlor-Alkali Plant Using Ultraviolet Differential Optical Absorption Spectroscopy and Cell Room Roof-Vent Monitoring. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 43(3):753-757, (2009).
Abstract: This technical note describes a United States Environmental Protection Agency (U.S. EPA) measurement project to determine elemental mercury (Hg0) emissions from a mercury cell chlor-alkali (MCCA) facility in the southeastern U.S. during a 53-day monitoring campaign in the fall of 2006. The optical remote sensing (ORS) area source measurement method EPA OTM 10 was used to provide Hg0 flux data for the site. These results are reported and compared with cell room roof vent monitoring data acquired by the facility for similar time periods. The 24-hour extrapolated mercury emission rate estimates determined by the two monitoring approaches are shown to be similar with overall averages in the 400 g/day range with maximum values around 1,200 g/day. Results from the OTM 10 measurements, which include both cell room emissions and potential fugitive sources outside the cell room, are shown to be approximately 10% higher than cell room monitoring results indicating that fugitive emissions from outside the cell room produce a small but measurable effect for this site.

JOURNAL Contributions of Diesel Truck Emissions to Indoor Elemental Carbon Concentrations in Home Proximate to Ambassador Bridge 12/15/2008
BAXTER, L. K., T. M. BARZYK, A. F. VETTE, C. W. CROGHAN, AND R. W. WILLIAMS. Contributions of Diesel Truck Emissions to Indoor Elemental Carbon Concentrations in Home Proximate to Ambassador Bridge. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 42(40):9080-9086, (2008).
Abstract: Ambassador Bridge, connecting Detroit, Michigan and Windsor, Ontario, is the busiest international commercial vehicle crossing in North America, with a large percentage of heavy duty diesel trucks. This study seeks to examine the contribution of diesel truck traffic across Ambassador Bridge to indoor exposure patterns of elemental carbon (EC), a common surrogate for diesel exhaust particles, in homes in close proximity to the bridge. We also aim to understand the relative importance of home ventilation characteristics and wind speed. Measurements were collected as part of the Detroit Exposure and Aerosol Research Study (DEARS). Residential indoor and outdoor EC measurements were collected over five consecutive 24 h periods in both the summer and winter at 16 homes in close proximity to Ambassador Bridge. Ambient concentrations and meteorological data were collected at a central-site monitor, and home air exchange rates were estimated using a perfluorocarbon tracer. The contributions of ambient concentrations and Ambassador Bridge, and potential effect modification by wind speed and home ventilation status were quantified with regression analyses. Both ambient concentrations and the percentage of time a home was downwind from the bridge were associated with an increase in indoor concentrations. Ambient concentrations significantly contributed to indoor concentrations regardless of wind speed category but were a greater influence in home experiencing calm winds. The effect of the percent of time downwind variable on indoor levels was only significant in homes where the ventilation status was high. The distance a home was from the bridge tollbooth complex was not significantly associated with indoor concentrations. We conclude that diesel traffic emissions related to Ambassador Bridge may have an impact on indoor EC exposures. Given that people spend the majority of their time indoors, it is important to evaluate the impact of traffic-related pollution in the home environment.

JOURNAL Key Scientific and Policy-and Health-Relevant Findings from EPA's Particulate Matter Supersites Program and Related Studies: An Integration and Synthesis of Results. 12/01/2008
SOLOMON, P. A., P. K. HOPKE, J. Foines, AND R. SCHEFFE. Key Scientific and Policy-and Health-Relevant Findings from EPA's Particulate Matter Supersites Program and Related Studies: An Integration and Synthesis of Results. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, 58(13):S-1 - S-92, (2008).
Abstract: In 1998, the Environmental Protection Agency (EPA) initiated a major air quality program, known as the Particulate Matter (PM) Supersites Program. The Supersites Program was a multi year, $27 million air quality monitoring program consisting of eight regional air quality projects located throughout the U.S., each with differing atmospheric pollution conditions resulting from variations in source emissions and meteorology. The overall goal of the program was to elucidate source–receptor relationships and atmospheric processes leading to PM accumulation on urban and regional scales, and thus, provide the scientific underpinning for modeling and data analysis efforts to support State Implementation Plans and more effective risk management approaches for PM. The program had three main objectives: 1) conduct methods development and evaluation, 2) characterize ambient PM, and 3) support health effects and exposure research. This paper provides a synthesis of key policy-relevant, scientific findings from the Supersites Program and related studies. EPA developed sixteen science/policy-relevant questions in conjunction with state agencies, Regional Planning Organizations, and the private sector. These questions were addressed to the extent possible, even given the vast amount of new information available from the Supersites Program, in a series of papers published as a special issue of JAWMA (February, 2008). This synthesis also includes discussions of: a) initial Supersites Program support for air quality management efforts in specific locations throughout the U.S.; b) selected policy-relevant insights, based on atmospheric science findings, useful to air quality managers and decision makers planning emissions management strategies to address current and future PM NAAQS and network planning and implementation; c) selected health-relevant findings interpreted from atmospheric sciences findings in light of future directions for health and exposure scientists planning studies of the effects of PM on human health; and d) selected knowledge gaps to guide future research. Finally, given the scope and depth of research and findings from the Supersites Program, this paper provides a reference source so readers can glean a general understanding of the overall research conducted and its policy-relevant findings. Supporting details for the results presented are available through the cited references. An annotated table of contents allows readers to find easily specific subject matter within the text.

JOURNAL Identification of Surrogate Measures of Diesel Exhaust Exposure in a Controlled Chamber Study 12/01/2008
SOBUS, J., J. D. PLEIL, M. C. MADDEN, W. E. Funk, H. HUBBARD, AND S. M. Rappaport. Identification of Surrogate Measures of Diesel Exhaust Exposure in a Controlled Chamber Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(23):8822-8828, (2008).
Abstract: Exposure to diesel exhaust (DE) has been associated with acute cardiopulmonary and vascular responses, chronic noncancer health effects, and respiratory cancers in humans. To better understand DE exposures and eventually their related health effects, we established a controlled chamber experiment wherein human volunteer subjects were exposed to approximately 100 μm3 of DE. In general, human exposure assessment for DE is based on ambient air measurements of surrogates such as elemental carbon (EC) or total organic carbon (OC) collected on filters. As specific health effect mechanisms and dose response are obscured by the complex composition of DE, the linkage from exposure to internal dose can presumably be improved using specific biomarkers and metabolites in blood, breath, or urine. Because EC or OC are not suitable as biomarkers, in this study, we focus on identifying compounds that are demonstrated indicators of DE and can also be found in biological fluids. We measured an assortment of volatile, semi-volatile, and particle-bound aromatic compounds in the chamber air and report their airborne concentrations in DE and purified air, as well as the estimated values of the corresponding exposure ratios (mean DE air concentration: mean purified air concentration). These estimated exposure ratios were used to identify naphthalene (Nap) and phenanthrene (Phe) as potentially useful surrogates for DE exposure that could also serve as biomarkers. Estimated mean levels of Nap and Phe associated with the nominal 100 μg/m3 of DE were 2600 ng/m3 and 765 ng/m3 with estimated exposure ratios of 252 and 92.4, respectively. Nap levels were significantly correlated with OC, and total particle-bound PAHs; Phe levels were significantly correlated with total volatile+semivolatile PAHs. These results suggest that Nap and Phe may be particularly useful surrogates for DE concentrations. While Nap and Phe are not validated here as internal biomarkers of DE exposure, we are currently assessing human biological specimens collected during this study, and will discuss those results in ensuing articles.

JOURNAL Pyrethroid Pesticides and Their Metabolites in Vacuum Cleaner Dust Collected from Homes and Day-Care Centers 11/01/2008
STARR, J. M., S. E. GRAHAM, D. M. STOUT, K. Andrews, AND M. Nishioka. Pyrethroid Pesticides and Their Metabolites in Vacuum Cleaner Dust Collected from Homes and Day-Care Centers. ENVIRONMENTAL RESEARCH. Elsevier Science Ltd, New York, NY, 108(3):271-279, (2008).
Abstract: The purpose of this study was to quantify the concentrations of 13 selected pyrethroid pesticides and their degradation products in samples of indoor dust that had been collected in vacuum cleaner bags during the Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study, of homes and day cares in North Carolina and Ohio.

JOURNAL Isea 2007 Panel: Integration of Better Exposure Characterizations Into Disaster Preparedness for Responders and the Public 11/01/2008
RODES, C. E., E. D. PELLIZZARI, M. J. DELLARCO, M. D. Erickson, D. A. VALLERO, D. B. Reissman, P. J. LIOY, M. LIPPMANN, T. A. Burke, AND B. D. Goldstein. Isea 2007 Panel: Integration of Better Exposure Characterizations Into Disaster Preparedness for Responders and the Public. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 18(6):541-550, (2008).
Abstract: An expert panel was convened in October 2007 at the International Society for Exposure Analysis (ISEA) Annual Meeting in Durham, NC, entitled “The Path Forward in Disaster Preparedness Since WTC—Exposure Characterization and Mitigation: Substantial Unfinished Business!” The panel prospectively discussed the critical exposure issues being overlooked during disaster responses and highlighted the needs for an optimal blending of exposure characterizations and hazard controls within disaster settings. The cases were made that effective and timely exposure characterizations must be applied during responses to any disaster, whether terrorist, manmade, or natural in origin. The consistent application of exposure sciences across acute and chronic disaster timelines will assure that the most effective strategies are applied to collect the needed information to guide risk characterization and management approaches. Exposure sciences must be effectively applied across all phases of a disaster (defined as rescue, re-entry, recovery, and rehabitation - The 4R’s) to appropriately characterize risks and guide risk mitigation approaches. Failure to adequately characterize and control hazardous exposures increases the likelihood of excess morbidity and mortality. Advancing the infrastructure and the technologies to collect the right exposure information before, during and immediately after disasters would advance our ability to better define risks and protect responders and the public. The panel provided conclusions, recommendations, and next steps toward effective and timely integration of better exposure science into disaster preparedness, including the need for a subsequent workshop to facilitate this integration.

JOURNAL Supercritical Fluid Extraction of Aflatoxin B 1 from Soil 10/31/2008
STARR, J. M. AND M. I. Selim. Supercritical Fluid Extraction of Aflatoxin B 1 from Soil. JOURNAL OF CHROMATOGRAPHY A. Elsevier Science Ltd, New York, NY, 1209(1-2):37-43, (2008).
Abstract: This research describes the development of a Supercritical Fluid Extraction (SFE) method to recover aflatoxin B1 from fortified soil. The effects of temperature, pressure, modifier (identity and percentage), and extraction type were assessed. Using the optimized SFE conditions, the mean recovery from air dried soil was 72%. The variables associated with changes in recovery of aflatoxin B1 were co-solvents, static extraction, and temperature. The results indicate that desorption from the soil was the limiting factor in recovery and that the static phase was more important than the dynamic.

JOURNAL Apportionment of Primary and Secondary Organic Aerosols in Southern California During the 2005 Study of Organic Aerosols in Riverside (Soar-1) 10/15/2008
Docherty, K. S., E. A. Stone, I. M. Ulbrich, P. F. DECARLO, D. C. Snyder, J. J. SCHAUER, R. E. Peitier, R. J. WEBER, S. M. Murphy, J. SEINFELD, B. D. GROVER, D. J. EATOUGH, AND J. L. JIMENEZ. Apportionment of Primary and Secondary Organic Aerosols in Southern California During the 2005 Study of Organic Aerosols in Riverside (Soar-1). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(20):7655-7662, (2008).
Abstract: Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionment techniques.

JOURNAL Measurement of Nitrogen Mustard Degredation Products By Poly(dimethylsiloxane) Microchip Electrophoresis With Contactless Conductivity Detection 10/01/2008
Ding, Y. AND K. R. ROGERS. Measurement of Nitrogen Mustard Degredation Products By Poly(dimethylsiloxane) Microchip Electrophoresis With Contactless Conductivity Detection. ELECTROANALYSIS. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, 20(20):2192-2198, (2008).
Abstract: The potential risk of human exposure from an accidental or intentional release of CWAs into a civilian population continues to drive the need for screening and monitoring techniques for these compounds. In particular, rapid and reliable methods for detecting CWAs such as the nitrogen mustards and their degradation products are important for cleanup and remediation of potentially contaminated sites. Microchip-based separation and detection methods have attracted increased interest over the last decade. The most frequently used methods for the unambiguous detection of nitrogen mustards and their break-down products have been gas chromatography-mass spectrometry (GC-MS) or liquid chromatography mass spectrometry (LC-MS). Due to the polarity and water solubility of the nitrogen mustards, GC-MS requires the use of derivitization prior to analysis. In addition, the presence of extraneous materials in environmental samples may interfere with the derivitization process resulting in low recoveries. Although both of these methods have been well characterized for these compounds, they require high-cost and high maintenance instrumentation, a qualified technician and are typically limited to off-site analysis.

JOURNAL Organosulfate Formation in Biogenic Secondary Organic Aerosol 09/11/2008
SURRATT, J. D., Y. Gomez-Gonzalez, A. W. Chan, R. Vermeylen, M. Shahgholi, T. E. KLEINDIENST, E. O. EDNEY, J. H. OFFENBERG, M. LEWANDOWSKI, MOHAMMAD JAOUI, W. Maenhaut, M. Claeys, R. FLAGAN, AND J. H. SEINFELD. Organosulfate Formation in Biogenic Secondary Organic Aerosol. Journal of Physical Chemistry. American Chemical Society, Washington, DC, 112(36):8345-8378, (2008).
Abstract: Organosulfates of isoprene, α-pinene, and β-pinene have recently been identified in both laboratory-generated and ambient secondary organic aerosol (SOA). In this study, the mechanism and ubiquity of organosulfate formation in biogenic SOA is investigated by a comprehensive series of laboratory photooxidation (i.e., OH-initiated oxidation) and nighttime oxidation (i.e., NO3-initiated oxidation under dark conditions) experiments using nine monoterpenes (α-pinene, β-pinene, d-limonene, l-limonene, α-terpinene, γ-terpinene, terpinolene, Δ3-carene, and β-phellandrene) and three monoterpenes (α-pinene, d-limonene, and l-limonene), respectively. Organosulfates were characterized using liquid chromatographic techniques coupled to electrospray ionization combined with both linear ion trap and high-resolution time-of-flight mass spectrometry. Organosulfates are formed only when monoterpenes are oxidized in the presence of acidified sulfate seed aerosol, a result consistent with prior work. Archived laboratory-generated isoprene SOA and ambient filter samples collected from the southeastern U.S. were reexamined for organosulfates. By comparing the tandem mass spectrometric and accurate mass measurements collected for both the laboratory-generated and ambient aerosol, previously uncharacterized ambient organic aerosol components are found to be organosulfates of isoprene, α-pinene, β-pinene, and limonene-like monoterpenes (e.g., myrcene), demonstrating the ubiquity of organosulfate formation in ambient SOA. Several of the organosulfates of isoprene and of the monoterpenes characterized in this study are ambient tracer compounds for the occurrence of biogenic SOA formation under acidic conditions. Furthermore, the nighttime oxidation experiments conducted under highly acidic conditions reveal a viable mechanism for the formation of previously identified nitrooxy organosulfates found in ambient nighttime aerosol samples. We estimate that the organosulfate contribution to the total organic mass fraction of ambient aerosol collected from K-puszta, Hungary, a field site with a similar organosulfate composition as that found in the present study for the southeastern U.S., can be as high as 30%.

JOURNAL Characterizing Air Pollution in Two Low-Income Neighborhoods in Accra, Ghana 09/01/2008
Arku, R. E., J. Vallarino, K. L. Dionisio, R. WILLIS, H. Choi, J. Wilson, C. Hemphill, S. Agyei-Mensah, J. D. SPENGLER, AND M. Ezzati. Characterizing Air Pollution in Two Low-Income Neighborhoods in Accra, Ghana. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier Science Ltd, New York, NY, 402(2-3):217-231, (2008).
Abstract: Sub-Saharan Africa has the highest rate of urban population growth in the world, with a large number of urban residents living in low-income “slum” neighborhoods. We conducted a study for an initial assessment of the levels and spatial and/or temporal patterns of multiple pollutants in the ambient air in two low-income neighborhoods in Accra, Ghana.

JOURNAL Adult and Children's Exposure to 2,4-D from Multiple Sources and Pathways 09/01/2008
MORGAN, M. K., L. S. SHELDON, K. W. THOMAS, P. P. EGEGHY, C. W. CROGHAN, P. A. JONES, J. C. Chuang, AND N. K. WILSON. Adult and Children's Exposure to 2,4-D from Multiple Sources and Pathways. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 18(5):486-494, (2008).
Abstract: In this study, we investigated the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide exposures of 135 preschool-aged children and their adult caregivers at 135 homes in North Carolina (NC) and Ohio (OH). Participants were randomly recruited from six NC and six OH counties. Monitoring was performed over a 48-h period at the participants’ homes. Environmental samples included soil, outdoor air, indoor air, and carpet dust. Personal samples collected by the adult caregivers concerning themselves and their children consisted of solid food, liquid food, hand wipe, and spot urine samples. All samples were analyzed for 2,4-D (free acid form) by gas chromatography/mass spectrometry. 2,4-D was detected in all types of environmental samples but the most often in carpet dust samples, with detection frequencies of 83% and 98% in NC and OH, respectively. The median level of 2,4-D in the carpet dust samples was about three times higher in OH homes compared to NC homes (156 vs. 47.5 ng/g , p<0.0002). For personal samples, 2,4-D was more frequently detected in the hand wipe samples from OH participants (> 48%) than from NC participants (< 9%). Hand wipe levels at the 95th percentile were about five times higher for OH children (0.1 ng/cm2) and adults (0.03 ng/cm2) than for the NC children (0.02 ng/cm2) and adults (<0.005 ng/cm2). 2,4-D was detected in greater than 85% of the child and adult urine samples in both states. The median urinary 2,4-D concentration was more than twice as high for OH children compared to NC children (1.2 vs. 0.5 ng/mL, p<0.0001); however, the median concentration was identical at 0.7 ng/mL for both NC and OH adults. The intraclass correlation coefficient of reliability ( r) for an individual’s urinary 2,4-D measurements, estimated from the unadjusted (0.31 to 0.62) and specific gravity-adjusted (0.37 to 0.73) 3 values, were somewhat low for each group in this study. The variability in urinary 2,4-D measurements over the 48-h period for both children and adults in NC and OH suggests that several spot samples were needed to adequately assess these participants’ exposures to 2,4-D in residential settings. Results from this study showed that children and their adult caregivers in NC and OH were likely exposed to 2,4-D through several pathways at their homes. In addition, our findings suggest that the OH children may have been exposed to higher levels of 2,4-D through the dermal and nondietary routes of exposure than the NC children and the NC and OH adults.

JOURNAL Personal Coarse Particulate Matter Exposures in An Adult Cohort 09/01/2008
WILLIAMS, R. W., M. W. CASE, K. YEATTS, F. CHEN, J. Scott, E. R. SVENDSEN, AND R. B. DEVLIN. Personal Coarse Particulate Matter Exposures in An Adult Cohort. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 42(28):6743-6748, (2008).
Abstract: Volunteers associated with the North Carolina Adult Asthma and Environment Study (NCAAES) participated in an investigation of personal daily exposures to coarse and fine particulate matter size fractions (PM10-2.5, PM2.5). Data from these personal measurements were then compared to community-based measures that might typically represent surrogate measurements of exposure often used in epidemiological assessments. To determine personal exposures to various particulate matter (PM) size fractions, a recently evaluated personal PM monitor capable of direct PM10-2.5 size fraction collection was used. Participants living in the central region of North Carolina and enrolled in the NCAAES were asked to wear the monitor attached to a supporting backpack for 24-h collection periods. These volunteers were monitored from two to four days with subsequent gravimetric analysis of their PM samples. Personal PM10-2.5 mass concentrations were observed to be highly variable and ranged from 7.6 to 40.2 μg/m3 over an eight month period. The median for this measurement from all participants (50th percentile) was 13.7 μg/m3. A coefficient of determination (r2) of 0.02 was established for community-based PM10-2.5 mass concentrations versus personal exposures. Similar coefficients established for PM2.5 mass revealed only a modest improvement in agreement (r2 = 0.12). Data from the exposure findings are reported here.

JOURNAL The Correlation of Secondary Organic Aerosol With Odd Oxygen in Mexico City 08/05/2008
Herndon, S. C., T. B. Onasch, E. C. Wood, J. H. KROLL, M. R. Canagaratna, J. T. Jayne, M. A. Zavala, W. Knighton, C. Massoleni, M. K. Dubey, I. M. Ulbrich, J. L. JIMENEZ, R. L. SEILA, J. A. de Gouw, B. de Foy, J. Fast, L. T. Molina, C. E. KOLB, AND D. R. WORSNOP. The Correlation of Secondary Organic Aerosol With Odd Oxygen in Mexico City. GEOPHYSICAL RESEARCH LETTERS. American Geophysical Union, Washington, DC, 35(L15804):1-6, (2008).
Abstract: Data from a mountain location intercepting the Mexico City emission plume demonstrate a strong correlation between secondary organic aerosol and odd-oxygen (O3 + NO2). The measured oxygenated-organic aerosol correlates with odd-oxygen measurements with an apparent slope of (104-180) μm-3 ppmv -1 (STP) and r2 >0.9.

JOURNAL Relationships Between Levels of Volatile Organic Compounds in Air and Blood from the General Population 07/01/2008
LIN, Y. S., P. P. EGEGHY, AND S. M. RAPPAPORT. Relationships Between Levels of Volatile Organic Compounds in Air and Blood from the General Population. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 18(4):421-429, (2007).
Abstract: Background: The relationships between levels of volatile organic compounds (VOCs) in blood and air have not been well characterized in the general population where exposure concentrations are generally at ppb levels. Objectives: This study investigates relationships between the levels of 9 VOCs, namely, benzene, chloroform, 1,4-dichlorobenzene (1,4-DCB), ethylbenzene, methyl tert-butyl ether (MTBE), tetrachloroethene, toluene, and m-/p- and o-xylene, in blood and air from a stratified random sample of the general U.S. population. Methods: We used data collected from 354 participants, including 89 smokers and 265 nonsmokers, aged 20-59 years, who provided samples of blood and air in the National Health and Nutrition Examination Survey (NHANES) 1999-2000. Demographic and physiological characteristics were obtained from self-reported information; smoking status was determined from levels of serum cotinine. Multiple linear regression models were used to investigate the relationships between VOC levels in air and blood, while adjusting for effects of smoking and demographic factors. Results: Although levels of VOCs in blood were positively correlated with the corresponding air levels, the strength of association (R 2) varied from 0.02 (ethylbenzene) to 0.68 (1,4-DCB). Also, the blood-air relationships of benzene, toluene, ethylbenzene, and the xylenes (BTEX) were influenced by smoking, exposure-smoking interactions, and by gender, age, and BMI, whereas those of the other VOCs were not. Interestingly, the particular exposure-smoking interaction for benzene was different from those for toluene, ethylbenzene, and the xylenes. Whereas smokers retained more benzene in their blood at increasing exposure levels, they retained less toluene, ethylbenzene, and xylenes at increasing exposure levels. Conclusions: Investigators should consider interaction effects of exposure levels and smoking when exploring the blood-air relationships of the BTEX compounds in the general population.

JOURNAL The Role of Exposure Science in Air Quality Management 07/01/2008
WATKINS, T. H., S.T. RAO, AND R. Wyzga. The Role of Exposure Science in Air Quality Management. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, (July 2008):24-27, (2008).
Abstract: Air quality standards and regulations are designed to protect public health and the environment. However, there are issues regarding whether the current standards and regulations should be adjusted to be more protective or to more effectively target air quality management activities. People experience health impacts because of their exposure to air pollutants. Therefore, an understanding of exposure is vital for properly addressing air quality management issues. This article presents concepts of exposure and how these concepts could be applied to gain a better understanding of the relationships between air quality and human health, which, in turn, should help improve air quality management practices. While air pollution impacts both humans and ecological resources, the focus here is on human health outcomes.

JOURNAL An Interlaboratory Study of Perfluorinated Alkyl Compound Levels in Human Plasma 06/01/2008
Longnecker, M. P., C. S. Smith, G. E. Kissling, J. HOPPIN, J. L. Butenhoff, E. Decker, D. J. Ehresman, M. E. Ellefson, J. Flaherty, M. S. Gardner, E. Langlois, A. LeBlanc, A. B. LINDSTROM, W. K. Reagen, M. J. STRYNAR, AND W. B. Studabaker. An Interlaboratory Study of Perfluorinated Alkyl Compound Levels in Human Plasma. ENVIRONMENTAL RESEARCH. Academic Press Incorporated, Orlando, FL, 107(2):152-159, (2008).
Abstract: The present study was designed to investigate intra- and interlaboratory variability in results from six laboratories experienced in the analysis of perfluorinated alkyl compounds in blood matrices and that use stringent procedures to control and assure accuracy and precision. Each received an identical set of 60 plasma specimens that were analyzed in 6 completely independent batches. Split specimens were included so that within- and between-batch coefficients of variation could be calculated. All laboratories used liquid chromatography-tandem mass spectrometry (LC-MS/MS). In general, the concentrations of perfluorooctanesulfonate (PFOS), perfluorooetanoate (PFOA), and perfluorohexanesulfonate (PFHxS) measured in the specimens showed a high degree of concordance across laboratories. The average within- and between-batch coefficient of variation for PFOS was 9.1% and 9.3%; for PFOA was 14.5% and 14.5%; and for PFHxS was 14.5% and 17.0%. The recent availability of labeled internal standards, among other advances, has facilitated improvement in the accuracy and precision of the assays. Considering the degree of between-subject variation in levels among people in background exposed populations, the results indicate that biomarker-based epidemiologic studies of associations with health could have reasonable precision.

JOURNAL Evaluation of a Direct Personal Coarse Particulate Matter Monitor 06/01/2008
CASE, M. W., R. W. WILLIAMS, K. YEATTS, F. CHEN, J. W. SCOTT, E. R. SVENDSEN, AND R. B. DEVLIN. Evaluation of a Direct Personal Coarse Particulate Matter Monitor. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 42(19):4446-4452, (2008).
Abstract: One aspect of the North Carolina Adult Asthma and Environment study (NCAAES) was to evaluate personal exposures to coarse particulate matter (PM 10-2.5) and their associated variability. As part of this, we examined the ability of a community-based monitor to act as a surrogate for an individual’s true exposure to this size fraction in linked health effect studies. To assess personal exposures to various particulate matter (PM) size fractions, a personal PM monitor was evaluated. This monitor featured a multi-stage cascade impactor that allowed for the simultaneous collection of PM10-2.5 and PM2.5 size fractions. The monitor was evaluated for collocated bias and comparability with a dichotomous (dichot) sampler (device for dividing aerosol particulate matter population into two size fractions during sampling) at an outdoor monitoring site. Results of this evaluation indicated that the prototype was capable of agreement within ± 20% of that provided by the reference methodology as well as 20% daily precision for PM10-2.5 mass measurements.

JOURNAL Volatile Polar Metabolites in Exhaled Breath Condensate (Ebc): Collection and Analysis 06/01/2008
PLEIL, J. D., H. HUBBARD, J. R. Sobus, K. Sawyer, AND M. C. MADDEN. Volatile Polar Metabolites in Exhaled Breath Condensate (Ebc): Collection and Analysis. Journal of Breath Research. Institute of Physics Publishing, Bristol, Uk, 2(2):1-9, (2008).
Abstract: Environmental exposures, individual activities, and disease states can perturb normal metabolic processes and be expressed as a change in the patterns of polar volatile organic compounds (PVOCs) present in biological fluids. We explore the measurement of volatile endogenous biomarkers to infer previous exposures to complex mixtures of environmental stressors. It is difficult to extract such compounds for ultra-trace level analysis due to their high solubility in water especially when assaying complex liquid biological media such as exhaled breath condensate (EBC). Existing methods tend to be limited in sample volume processed and restricted in sample throughput. We have developed an alternative passive extraction method wherein a 2 ml sample is injected into a 75 ml glass bulb creating a small pool of liquid; a standard Tenax® sampling tube is inserted above the fluid and allowed to equilibrate with the headspace for ~ 24 hours. The biomarker compounds are preferentially transferred by diffusion from the aqueous sample onto the Tenax® adsorbent; blanks and calibration samples are similarly processed. Numerous samples can be simultaneously prepared and stored awaiting routine analysis for a suite of alcohols and aldehydes using thermal desorption GC-MS. We have optimized the procedures and have estimated the sensitivity, precision, and extraction efficiency resulting from the preparation and analytical procedures using synthetic samples. We subsequently demonstrated the method using anonymous biological specimens of EBC from healthy adults. The ultimate goal is to develop normal ranges and patterns for PVOCs to infer population based environmental health states with simple spot measurements based on outlier determinations.

JOURNAL Perfluorinated Compounds in House Dust from Ohio and North Carolina, USA 05/15/2008
STRYNAR, M. J. AND A. B. LINDSTROM. Perfluorinated Compounds in House Dust from Ohio and North Carolina, USA. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 42(10):3751-3756, (2008).
Abstract: The perfluoroalkyl acids (PFAAs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), have come under increasing scrutiny due to their persistence in the environment, global distribution, and animal toxicity. Given that human exposure routes for these compounds remain poorly characterized, the potential role of house dust needs to be more completely evaluated. In this study, new methods for the analysis of 10 target PFAAs and 3 fluorinated telomer alcohols (FTOHs) were developed and applied to dust samples collected from homes (n=102) and day care centers (10) in Ohio and North Carolina. FTOHs were analyzed by GC/MS after sonic extraction and solid phase extraction cleanup. PFAAs were analyzed after extraction by LC-MS/MS. PFOS and PFOA were found to be the most prominent compounds in this analysis, occurring in over 95% of the samples at median concentrations of 201 and 142 ng/g of dust, respectively. Maximal concentrations of PFOS were at 12,100 ng/g, PFOA at 1,960 ng/g, and perfluorohexanesulfonate (PFHS) at 35,700 ng/g. The 8:2 FTOH, which is volatile and can degrade to PFOA, had a maximum concentration of 1660 ng/g dust. These results indicate that perfluorinated compounds are present in house dust at levels that may be important for human exposure.

JOURNAL Formation of Secondary Organic Aerosol from Irradiated a-Pinene/Tolueme/Nox Mixtures and the Effect of Isoprene and Sulfur Dioxide 05/10/2008
JAOUI, M., E. O. EDNEY, T. E. KLEINDIENST, M. LEWANDOWSKI, J. H. OFFENBERG, J. D. SURRATT, AND J. SEINFELD. Formation of Secondary Organic Aerosol from Irradiated a-Pinene/Tolueme/Nox Mixtures and the Effect of Isoprene and Sulfur Dioxide. JOURNAL OF GEOPHYSICAL RESEARCH. American Geophysical Union, Washington, DC, 113(D09303):1-12, (2008).
Abstract: Secondary organic aerosol (SOA) was generated by irradiating a series of a-pinene/toluene/NOx mixtures in the absence and presence of isoprene or sulfur dioxide. The purpose of the experiment was to evaluate the extent to which chemical perturbations to this base-case (a-pinene/toluene) mixture led to changes in the gas-phase chemistry which strongly influences mass and composition of SOA and secondary organic carbon (SOC) formed.

JOURNAL A New Method of Longitudinal Diary Assembly for Human Exposure Modeling 05/01/2008
GLEN, G., L. SMITH, K. K. ISAACS, T. R. MCCURDY, AND J. LANGSTAFF. A New Method of Longitudinal Diary Assembly for Human Exposure Modeling. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 18(3):299-311, (2008).
Abstract: Human exposure time-series modeling requires longitudinal time-activity diaries to evaluate the sequence of concentrations encountered, and hence, pollutant exposure for the simulated individuals. However, most of the available data on human activities are from cross-sectional surveys that typically sample one day per person. A procedure is needed for combining cross-sectional activity data into multiple-day (longitudinal)sequences that can capture day-to-day variability in human exposures. Properly accounting for intra- and inter-individual variability in these sequences can have a significant effect on exposure estimates and on the resulting health risk assessments. This paper describes a new method of developing such longitudinal sequences, based on ranking one-day activity diaries with respect to a user-chosen key variable. Two statistics, "D" and "A", are targeted. The D statistic reflects the relative importance of within- and between-person variance with respect to the key variable. The A statistic quantifies the day-to-day (lag-one) autocorrelation. The user selects appropriate target values for both D and A. The new method then stochastically assembles longitudinal diaries that collectively meet these targets. Based upon numerous simulations, the D and A targets are closely attained for exposure analysis periods >30 days in duration, and reasonably well for shorter simulation periods. Longitudinal diary data from a field study suggest that D and A are stable over time, and perhaps over cohorts as well. The new method can be used with any cohort definitions and diary pool assignments, making it easily adaptable to most exposure models. Implementation of the new method in its basic form is described, and various extensions beyond the basic form are discussed.

JOURNAL Primary and Secondary Contributions to Ambient PM in the Midwestern United States 05/01/2008
LEWANDOWSKI, M., MOHAMMAD JAOUI, J. H. OFFENBERG, T. E. KLEINDIENST, E. O. EDNEY, R. J. SHEESLEY, AND J. J. SCHAUER. Primary and Secondary Contributions to Ambient PM in the Midwestern United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(9):3303-3309, (2008).
Abstract: Ambient PM2.5 samples were collected in five Midwestern US cities throughout 2004: East St. Louis, Illinois; Detroit, Michigan; Cincinnati, Ohio; Bondville, Illinois; and Northbrook, Illinois. Monthly composites were analyzed using chemical derivatization coupled with GC-MS analysis to estimate the contributions of several sources to the total ambient organic carbon. A chemical mass balance (CMB) approach was used to estimate contributions from several primary sources. An additional, organic tracer-based technique was employed to estimate secondary contributions, including secondary organic carbon derived from isoprene, a-pinene, β-caryophyllene, and toluene. The sum of these contributions was compared with the total. Organic carbon measured at each sampling site, and reasonable carbon mass balances were observed for four of the five sites. In Bondville, Northbrook, Cincinnati, and Detroit, a strong correlation was observed between the sum of the estimated primary and secondary contributions and the measured organic carbon (R2 = 0.73). The estimated secondary organic carbon concentrations were observed to vary considerably with season, with the strongest contributions coming from isoprene and a-pinene during the summer. While further research is required, there is some evidence the contribution estimates for a-pinene, β-caryophyllene, and toluene SOC may to some degree represent the contributions from the broader classes of monoterpenes, sesquiterpenes, and aromatics.

JOURNAL Modeling Energy Expenditure and Oxygen Consumption in Human Exposure Models: Accounting for Fatigue and Epoc 05/01/2008
ISAACS, K. K., G. GLEN, T. R. MCCURDY, AND L. SMITH. Modeling Energy Expenditure and Oxygen Consumption in Human Exposure Models: Accounting for Fatigue and Epoc. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 18(3):289-298, (2007).
Abstract: Human exposure and dose models often require a quantification of oxygen consumption for a simulated individual. Oxygen consumption is dependent on the modeled Individual's physical activity level as described in an activity diary. Activity level is quantified via standardized values of metabolic equivalents of work (METS) for the activity being performed and converted into activity-specific oxygen consumption estimates. However, oxygen consumption remains elevated after a moderate- or high-intensity activity is completed. This effect, which is termed excess post-exercise oxygen consumption (EPOC), requires upward adjustment of the METS estimates that follow high energy expenditure events, in order to model subsequent increased ventilation and intake dose rates. In addition, since an individual's capacity for work decreases during extended activity, methods are also required to adjust downward those METS estimates that exceed physiologically-realistic limits over time. A unified method for simultaneously performing these adjustments is developed. The method simulates a cumulative oxygen deficit for each individual and uses it to impose appropriate timedependent reductions in the METS time series and additions for EPOC. The relationships between the oxygen deficit and METS limits are non-linear and are derived from published data on work capacity and oxygen consumption. These modifications result in improved modeling of ventilation patterns, and should improve intake dose estimates associated with exposure to airborne environmental contaminants.

JOURNAL Design and Evaluation of An Inlet Conditioner to Dry Particles for An Aerodynamic Particle Sizer 04/01/2008
Peters, T. M., A. L. Riss, R. L. Holm, M. Singh, AND R. W. VANDERPOOL. Design and Evaluation of An Inlet Conditioner to Dry Particles for An Aerodynamic Particle Sizer. JOURNAL OF ENVIRONMENTAL MONITORING. Royal Society of Chemistry, Cambridge, Uk, 10(4):541-551, (2008).
Abstract: Atmospheric particulate matter is one of six pollutants for which the Environmental Protection Agency (EPA) has set National Ambient Air Quality Standards. Particulate matter standards are specified by particle size as PM 2.5 defined as the mass concentration of ′fine′ particles smaller than 2.5 µm aerodynamic diameter, and PM10 defined as the mass concentration of particles with an aerodynamic diameter smaller than 10 µm.

JOURNAL Recognition of Pyrene Using Molecularly-Imprinted Electrochemically-Deposited Poly (2-Mercaptobenzimidazole) or Poly(resorcinol) on Gold Electrodes 10/01/2007
LUO, N., D. W. HATCHETT, AND K. R. ROGERS. Recognition of Pyrene Using Molecularly-Imprinted Electrochemically-Deposited Poly (2-Mercaptobenzimidazole) or Poly(resorcinol) on Gold Electrodes. ELECTROANALYSIS. John Wiley & Sons, Ltd., Indianapolis, IN, 19(19-20):2117-2124, (2007).
Abstract: The feasibility of using thiol chemistry to form molecularly imprinted polymer-coated gold electrodes to measure pyrene is reported. For the first approach, poly(2-mercaptoimidazole) (2-MBI) was electrochemically deposited on gold electrodes in the presence or absence of the template pyrene. For the second approach, the pyrene derivative N-(1-pyrenyl)maleimide was covalently bound to 1,3-propane thiol that had been previously self-assembled on a cleaned gold surface. Resorcinol was then electrochemically polymerized onto the electrode followed by electrochemical stripping of the thiolated pyrene from the polymer-coated electrode. For both electrode configurations, the binding of pyrene to the MIP-coated electrode was detected indirectly through pyrene-dependent access of a ferricyanide probe to the electrode surface as measured using squarewave voltammetry.

JOURNAL Bayesian Hierarchical Modeling of Personal Exposure to Particulate Matter 09/01/2007
MCBRIDE, S. J., R. W. WILLIAMS, AND J. P. CREASON. Bayesian Hierarchical Modeling of Personal Exposure to Particulate Matter. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 41(29):6143-6155, (2007).
Abstract: In the US EPA's 1998 Baltimore Epidemiology-Exposure Panel Study, a group of 21 residents of a single building retirement community wore personal monitors recording personal fine particulate air pollution concentrations (PM2.5) for 27 days, while other monitors recorded concurrent apartment, central indoor, outdoor and ambient site PM2.5 concentrations. Using the Baltimore panel study data, we develop a Bayesian hierarchical model to characterize the relationship between personal exposure and concentrations of PM2.5indoors and outdoors. Personal exposure is expressed as a linear combination of time spent in microenvironments and associated microenvironmental concentrations. The model incorporates all available monitoring data and accounts for missing data and sources of uncertainty such as measurement error and individual differences in exposure. We discuss the implications of using personal versus ambient PM2.5 measurements in characterization of personal exposure to PM2.5.

JOURNAL Pesticide Exposure and Chiral Chemistry: the Pyrethroid Family 09/01/2007
ULRICH, E. M. Pesticide Exposure and Chiral Chemistry: the Pyrethroid Family. Chimica Oggi (Chemistry Today). TEKNOSCIENZE, Milano, Italy, 25(5):37-39, (2007).
Abstract: Advances in chiral chromatography significantly advanced the ability to analyze individual enantiomers of chiral compounds. These techniques are being employed at the U.S. EPA for human exposure and ecological research studies. Enantiomer fractions (EFs) were measured for cispermethrin, a pyrethroid insecticide. Nonracemic EFs in some environmental samples indicate that some nantioselective biological degradation has occurred, either in the indoor environment or prior to translocation indoors. These results highlight the importance of chiral methods because some degradation pathways can change the distribution of enantiomers in the environment and may lead to differential exposure. The toxicity of enantiomers can also vary. When these two factors are combined, a differential risk to humans and other organisms may be revealed.

JOURNAL A Pilot Study Using An Accelerometer to Evaluate a Caregiver's Interpretation of An Infant or Toddler's Activity Level as Recorded in a Time Activity Diary 09/01/2007
TULVE, N. S., P. A. JONES, T. R. MCCURDY, AND C. W. CROGHAN. A Pilot Study Using An Accelerometer to Evaluate a Caregiver's Interpretation of An Infant or Toddler's Activity Level as Recorded in a Time Activity Diary. Research Quarterly for Exercise and Sport. American Alliance for Health, Physical Education, Recreation & Dance, Reston, VA, 78(4):375-383, (2007).
Abstract: Linking a young child's activity pattern data with samples that are collected during an exposure assessment is important in evaluating uptake dose rates associated with environmental contaminant exposures. A pilot study (N=9) was performed to test how well categorical activity-level data for young children (≤ 24 months old) collected from paper time activity diaries normally used in exposure studies compared with objective activity-level information (i.e., counts) obtained using an accelerometer. The infants and toddlers wore an accelerometer for up to 4 days, while their primary caregiver simultaneously completed a time activity diary and intermittently videotaped them engaged in eating, quiet play, and active play type activities. Our findings indicate that infants and toddlers tolerate wearing an accelerometer for multiple days of data collection and that caregiver compliance was good on completing all study components. Statistical analyses showed a relatively strong positive relationship between diary entries and accelerometer output (Spearman r=0.42; p<0.0001). When the diary entries and accelerometer data were classified categorically, the classifications were identical for 70% of all entries for the entire cohort during the monitoring period. Gender and age were not significant predictors of variability in activity levels, but this was probably due to the small sample size and narrow age range of study participants.

JOURNAL Exploring Relationships Between Outdoor Air Particulate-Associated Polycyclic Aromatic Hydrocarbon and PM2.5: A Case Study of Benzo(a)PYRENE in California Metropolitan Regions 09/01/2007
LOBSCHEID, A. B., T. MCKONE, AND D. A. VALLERO. Exploring Relationships Between Outdoor Air Particulate-Associated Polycyclic Aromatic Hydrocarbon and PM2.5: A Case Study of Benzo(a)PYRENE in California Metropolitan Regions. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 41(27):5659-5672, (2007).
Abstract: Polycyclic aromatic hydrocarbons (PAHs) and particulate matter (PM) are co-pollutants emitted as by-products of combustion processes. Convincing evidence exists for PAHs as a primary toxic component of fine PM (PM2.5). Because PM2.5 is listed by the US EPA as a "Criteria Pollutant", it is monitored regularly at sites nationwide. In contrast, very limited data is available on measured ambient air concentrations of PAHs. However, between 1999-2001, ambient air concentrations of PM2.5 and benzo(a)pyrene (BaP) are available for California locations. We use multivariate linear regression models (MLRMs) to predict ambient air levels of BaP in four air basins based on reported PM2.5 concentrations and spatial, temporal and meteorological variables as variates. We obtain an R2 ranging from 0.57-0.72 among these basins. Significant variables (p<0.05) include the average daily PM2.5 concentration, wind speed, temperature and relative humidity, and the coastal distance as well as season, and holiday or weekend. Combining the data from all sites and using only these variables to estimate ambient BaP levels, we obtain an R2 of 0.55. These R2-values, combined with analysis of the residual error and cross validation using the PRESS-statistic, demonstrate the potential of our method to estimate reported outdoor air PAH exposure levels in metropolitan regions. These MLRMs provide a first step towards relating outdoor ambient PM2.5 and PAH concentrations for epidemiological studies when PAH measurements are unavailable, or limited in spatial coverage, based on publicly available meteorological and PM2.5 data.

JOURNAL Effect of Acidity on Secondary Organic Aerosol Formation from Isoprene 08/01/2007
SURRATT, J. D., M. LEWANDOWSKI, J. H. OFFENBERG, M. JAOUI, T. E. KLEINDIENST, E. O. EDNEY, AND J. SEINFELD. Effect of Acidity on Secondary Organic Aerosol Formation from Isoprene. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 41(15):5363-5369, (2007).
Abstract: The effect of particle-phase acidity on secondary organic aerosol (SOA) formation from isoprene is investigated in a laboratory chamber study, in which the acidity of the inorganic seed aerosol was controlled systematically. The observed enhancement in SOA mass concentration is closely correlated with increasing aerosol acidity (R2 = 0.979). Direct chemical evidence for acid-catalyzed particle-phase reactions was obtained from the SOA chemical analyses. Aerosol mass concentrations for the 2-methyltetrols, as well as the newly identified sulfate esters, both of which serve as tracers for isoprene SOA in ambient aerosols, increased significantly with enhanced aerosol acidity. Aerosol acidities, as measured in nmol H+ m-3, employed in the present study are in the same range as those observed in tropospheric aerosol collected from the eastern U.S.

JOURNAL Perfluorinated Compounds in the Cape Fear Drainage Basin in North Carolina 07/04/2007
NAKAYAMA, S., M. J. STRYNAR, L. HELFANT, P. P. EGEGHY, X. YE, AND A. B. LINDSTROM. Perfluorinated Compounds in the Cape Fear Drainage Basin in North Carolina. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 41(15):5271-5276, (2007).
Abstract: Concern over perfluorinated organic compounds (PFCs), e.g., perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), is due to a number of recent studies which show that the PFCs are persistent, bioaccumulative, and toxic. Despite sustained interest in this topic, little information is available concerning the environmental distributions of the compounds. In this study, a new method was developed for the analysis of 10 target PFCs and its performance was examined in a systematic evaluation of the Cape Fear River Basin in North Carolina, USA. One hundred samples from 80 different locations were collected during the spring of 2006. Detectable levels of the target PFCs were found in all samples, with maximum PFOS at 132 ng/L, PFOA at 287 ng/L, perfluorononanoic acid (C9) at 194 ng/L, and perfluoroheptanoic acid (C7) at 329 ng/L. In general, the lowest concentrations of the PFCs were found in the smallest tributaries while the highest levels were found in middle reaches of the Drainage Basin. Variability of PFC concentrations suggests a series of source inputs throughout the Basin. Seventeen sample sites (22%) had PFOS concentrations greater than 43 ng/L, a conservative safe water concentration estimated to be protective of avian life. In addition, a total of 26 sites (32%) had PFOA concentrations above 40 ng/L.

JOURNAL Making Sense of Human Biomonitoring Data: Findings and Recommendations of a Workshop 07/01/2007
BAHADORI, T., R. PHILLIPS, C. MONEY, J. J. QUACKENBOSS, H. J. CLEWELL, J. BUS, S. ROBISON, C. HUMPHRIS, A. PAREKH, K. OSBORN, AND R. KAUFFMAN. Making Sense of Human Biomonitoring Data: Findings and Recommendations of a Workshop. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 17(4):308-313, (2007).
Abstract: The ability to measure chemicals in humans (often termed biomonitoring) is far outpacing the ability to reliably interpret these data for public health purposes, creating a major knowledge gap. Until this gap is filled, the great promise of routinely using biomonitoring data to support decisions to protect public health cannot be realized. Research is needed to link biomonitoring data quantitatively to the potential for adverse health risks, either through association with health outcomes or using information on the concentration and duration of exposure, which can then be linked to health guidelines. Developing such linkages in the risk assessment paradigm is one of the primary goals of the International Council of Chemical Associations' (ICCA) Long-Range Research Initiative (LRI) program in the area of biomonitoring. Therefore, ICCA sponsored a workshop to facilitate development of a coordinated agenda for research to enable an improved interpretation of human biomonitoring data. Discussions addressed three main topics: (1) exploration of the link between exposure, dose, and human biomonitoring data, (2) the use of computational tools to interpret biomonitoring data, and (3) the relevance of human biomonitoring data to the design of toxicological studies.

JOURNAL Pesticides and Their Metabolites in the Homes and Urine of Farmworker Children Living in the Salinas Valley, Ca 07/01/2007
BRADMAN, A., D. A. WHITAKER, L. QUIROS, R. CASTORINA, B. C. HENN, M. NISHIOKA, J. N. MORGAN, D. B. BARR, M. HARNLY, J. A. BRISBIN, L. S. SHELDON, T. MCKONE, AND B. ESKENAZI. Pesticides and Their Metabolites in the Homes and Urine of Farmworker Children Living in the Salinas Valley, Ca. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY. Nature Publishing Group, London, Uk, 17(4):331-349, (2007).
Abstract: This paper describes a study to test field methods for characterizing pesticide exposures to 20 farmworker children aged 5-27 months old living in the Salinas Valley of Monterey County, California. Methods for collecting house dust, indoor and outdoor air, dislodgeable residues from surfaces and toys, residues on clothing (sock and union suits), food, as well as spot and overnight diaper urine samples were tested. Twenty-nine common agricultural and home use pesticides were measured in multiple exposure media samples. A subset of organophosphorus (OP), organochlorine (OC) and pyrethroid pesticides were measured in food. Urine samples were analyzed for OP pesticide metabolites. Four field-based exposure assessment instruments: a questionnaire; food diary; home inspection; and a self-administered child activity timeline were administered.

JOURNAL Exposure Reconstruction for Reducing Uncertainty in Risk Assessment: Example Using Mtbe Biomarkers and Simple Pharmacokinetic Model 07/01/2007
PLEIL, J. D., D. KIM, J. D. PRAH, AND S. M. RAPPAPORT. Exposure Reconstruction for Reducing Uncertainty in Risk Assessment: Example Using Mtbe Biomarkers and Simple Pharmacokinetic Model. BIOMARKERS. Taylor & Francis, Inc., Philadelphia, PA, 12(4):331-348, (2006).
Abstract: Adverse health risks from environmental agents are generally related to average (long term) exposures. We used results from a series of controlled human exposure tests and classical first order rate kinetics calculations to estimate how well spot measurements of methyl tertiary butyl ether (MTBE) and the primary metabolite, tertiary-butyl alcohol (TBA), can be expected to predict different hypothetical scenarios of previous exposures. We concluded that individual biomarker measurements are a valuable tool in reconstruction of previous exposures and that a simple pharmacokinetic model can limit the time frames over which a particular exposure - biomarker pair of compounds is useful.

JOURNAL Composition of PM 2.5 During the Summer of 2003 in Research Triangle Park, Nc 06/01/2007
LEWANDOWSKI, M., M. JAOUI, T. E. KLEINDIENST, J. H. OFFENBERG, AND E. O. EDNEY. Composition of PM 2.5 During the Summer of 2003 in Research Triangle Park, Nc. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 41(19):4073-4083, (2007).
Abstract: A field study was carried out during the summer of 2003 to examine the overall composition of fine particulate matter (PM2.5) in Research Triangle Park, North Carolina, USA, with particular emphasis on polar compounds from secondary organic aerosol (SOA). Collected samples were examined for gravimetric mass, organic and elemental carbon concentrations, inorganic ion concentrations, and detailed organic composition. On average, the ambient PM2.5 was found to consist of 41% organic matter, 2% elemental carbon, 12% ammonium, 37% sulfate, and less than 1% nitrate and oxalate. Mass concentrations ranged from 6.4 to 31.4 µg m-3. The acidity of the aerosol was also estimated, and higher PM2.5 and organic mass concentrations were generally observed under acidic conditions. A suite of chemical derivatization methods was used in conjunction with gas chromatography-mass spectrometry (GC-MS) to identify and quantify 29 polar organic compounds. Most of these compounds have been previously identified in laboratory photooxidation studies from hydrocarbon precursors, including isoprene, monoterpenes, ß-caryophyllene, and toluene. From laboratory studies, several of these polar compounds have been proposed as tracers for SOA, and concentrations measured in this study indicate the contributions of the precursor hydrocarbons to ambient SOA could be important. Some of the organic tracers, particularly those associated with isoprene SOA, represented a greater fraction of the organic carbon when the aerosol was acidic.

JOURNAL An Observational Study of 127 Preschool Children at Their Homes and Daycare Centers in Ohio: Environmental Pathways to Cis-and Trans-Permethrin Exposure 06/01/2007
MORGAN, M. K., L. S. SHELDON, C. W. CROGHAN, P. A. JONES, J. C. CHUANG, AND N. K. WILSON. An Observational Study of 127 Preschool Children at Their Homes and Daycare Centers in Ohio: Environmental Pathways to Cis-and Trans-Permethrin Exposure. ENVIRONMENTAL RESEARCH. Academic Press Incorporated, Orlando, FL, 104(2):266-274, (2007).
Abstract: The potential exposures of 127 preschool children to the pyrethroid insecticides, cis- and trans-permethrin, in their everyday environments were examined. Participants were recruited randomly from 127 homes and 16 daycare centers in six Ohio (OH) counties. Monitoring was performed over a 48-h period at the children's homes and/or daycare centers. Samples collected included soil, carpet dust, indoor air, outdoor air, diet, hand wipes, surface wipes, transferable residues, and urine. The environmental samples were analyzed for the cis and trans isomers of permethrin, and the urine samples were analyzed for the pyrethroid urinary metabolite, 3-phenoxybenzoic acid (3-PBA), by gas chromatography/mass spectrometry. The isomers were detected most often in the dust (100%) and hand wipe (>78%) samples collected at both homes and daycare centers. The median levels of cis-permethrin (470 and 1,010 ng/g) were higher than the median levels of trans-permethrin (344 and 544 ng/g) in the dust samples at both the children's homes and daycare centers, respectively. In the children's hand wipe samples, the median levels of cis- and trans-permethrin were similar, ranging from 0.03 - 0.04 ng/cm2, at both locations. The urinary metabolite 3-PBA was detected in 67% of the children's urine samples. The median urinary 3-PBA concentration for the children was 0.3 ng/mL, and the maximum value for one child was 33.8 ng/mL. The primary route of the children's exposure to the combined isomers was through dietary ingestion, followed by indirect ingestion. In addition, our calculated aggregate absorbed doses of permethrin accounted for about 60% of the excreted amounts of 3-PBA found in the children's urine. In conclusion, these children were potentially exposed to low levels of permethrin from several sources, and through several pathways and routes.

JOURNAL Contributions of Toluene and Α-Pinene to Soa Formed in An Irradiated Toluene/Α-Pinene/Nox/Air Mixture: Comparison of Results Using 14c Content and Soa Organic Tracer Methods 05/04/2007
OFFENBERG, J. H., C. W. LEWIS, M. LEWANDOWSKI, M. JAOUI, T. E. KLEINDIENST, AND E. O. EDNEY. Contributions of Toluene and Α-Pinene to Soa Formed in An Irradiated Toluene/Α-Pinene/Nox/Air Mixture: Comparison of Results Using 14c Content and Soa Organic Tracer Methods. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 41(11):3972-3976, (2007).
Abstract: An organic tracer method, recently proposed for estimating individual contributions of toluene and α-pinene to secondary organic aerosol (SOA) formation, was evaluated by conducting a laboratory study where a binary hydrocarbon mixture, containing the anthropogenic aromatic hydrocarbon, toluene, and the biogenic monoterpene, α-pinene, was irradiated in air in the presence of NOx to form SOA. The contributions of toluene and α-pinene to the total SOA concentration, calculated using the organic tracer method, were compared with those obtained with a more direct 14C content method. In the study, SOA to SOC ratios of 2.07 ± 0.08 and 1.41 ± 0.04 were measured for toluene and α-pinene SOA, respectively. The individual tracer-based SOA contributions of 156 µg m-3 for toluene and 198 µg m-3 for α-pinene, which together accounted for 82% of the gravimetrically determined total SOA concentration, compared well with the 14C values of 182 and 230 µg m-3 measured for the respective SOA precursors. While there are uncertainties associated with the organic tracer method, largely due to the chemical complexity of SOA forming chemical mechanisms, the results of this study suggest the organic tracer method may serve as a useful tool for determining whether a precursor hydrocarbon is a major SOA contributor.

JOURNAL Spatial Analysis of Volatile Organic Compounds from a Community-Based Air Toxics Monitoring Network in Deer Park, Texas, USA 05/01/2007
SMITH, L. A., T. H. STOCK, K. CHUNG, S. MUKERJEE, X. L. LIAO, C. STALLINGS, AND M. AFSHAR. Spatial Analysis of Volatile Organic Compounds from a Community-Based Air Toxics Monitoring Network in Deer Park, Texas, USA. ENVIRONMENTAL MONITORING AND ASSESSMENT. Springer, New York, NY, 128(1-3):369-379, (2007).
Abstract: This RARE Project with EPA Region 6 was a spatial analysis study of select volatile organic compounds (VOC) collected using passive air monitors at outdoor residential locations in the Deer Park, Texas area near the Houston Ship Channel. Correlation analysis of VOC species confirmed transportation and other petroleum-dominated sources and possible process-related (industrial) influences. As shown in other spatial studies, wind direction relative to source location had an effect on VOC concentrations.

JOURNAL Investigation of a Systematic Offset in the Measurement of Organic Carbon With a Semi-Continuous Analyzer 05/01/2007
OFFENBERG, J. H., M. LEWANDOWSKI, MOHAMMAD JAOUI, E. O. EDNEY, AND T. E. KLEINDIENST. Investigation of a Systematic Offset in the Measurement of Organic Carbon With a Semi-Continuous Analyzer. JOURNAL OF AIR AND WASTE MANAGEMENT. Air & Waste Management Association, Pittsburgh, PA, 57(5):596-599, (2007).
Abstract: Organic carbon was measured semi-continuously in laboratory experiments of steady-state secondary organic aerosol formed by hydrocarbon + NOx irradiations. Examination of the mass of carbon measured on the filter for various sample volumes reveals a systematic offset that is not observed when performing an instrumental blank. These findings suggest that simple subtraction of instrumental blanks determined as the standard analysis without sample collection (i.e. by cycling the pump and valves yet filtering zero liters of air followed by routine chemical analysis) from measured concentrations may be inadequate. This may be especially true for samples collected through the filtration of small air volumes wherein the influence of the systematic offset is greatest. All experiments show that filtering a larger volume of air minimizes the influence of contributions from the systematic offset. Application of these results to measurements of ambient concentrations of carbonaceous aerosol suggests a need for collection of sufficient carbon mass to minimize the relative influence of the offset signal.

JOURNAL Performance of a New Diffusive Sampler for Hg0 Determination in the Troposphere 04/17/2007
SKOV, H., B. T. SORENSEN, M. S. LANDIS, M. S. JOHNSON, P. SACCO, M. E. GOODSITE, C. LOHSE, AND K. S. CHRISTIANSEN. Performance of a New Diffusive Sampler for Hg0 Determination in the Troposphere. ENVIRONMENTAL CHEMISTRY. CSIRO Publishing, Collingwood Victoria, Australia, 4(2):75-80, (2007).
Abstract: Mercury behaves uniquely in the atmosphere due to its volatility and long lifetime. The existing methods for measuring atmospheric mercury are either expensive or labour intensive. The present paper presents a new measurement technique, the diffusive sampler, that is portable, inexpensive, easy to use, and does not need a power supply. The sampler is sufficiently sensitive that it can measure Hg at low ambient levels with an exposure time of 1 to 3 days. The sampler is based on the Radiello diffusive sampler. The sampler is a modified version of the original design, where it was used to collect volatile organic compounds. In the present paper the method is validated under controlled laboratory conditions. The uptake rate of the Radiello diffusive sampler is determined using known concentrations of GEM, and is measured as a function of wind speed, relative humidity and temperature. The Radiello sampler has a detection limit of 0.14 ng m-3 for 1 day of exposure and thus can be used to measure mercury concentrations at the low levels found in ambient air. The Radiello sampler is therefore useful for mapping concentrations close to sources and sinks, in addition to ambient concentrations. For example the sampler can be used to describe the geographical extent of Arctic mercury depletion episodes where GEM is removed and stays close to zero ng m-3 for days, and it can be a powerful tool for mapping gradients around e.g. point sources.

JOURNAL A Meta-Analysis of Children's Hand-to-Mouth Frequency Data for Estimating Non-Dietary Ingestion Exposure 04/01/2007
XUE, J., V. G. ZARTARIAN, J. MOYA, N. C. FREEMAN, P. BEAMER, K. BLACK, N. S. TULVE, AND S. L. SHALAT. A Meta-Analysis of Children's Hand-to-Mouth Frequency Data for Estimating Non-Dietary Ingestion Exposure. RISK ANALYSIS. Blackwell Publishing, Malden, MA, 27(2):411-420, (2007).
Abstract: Because of their mouthing behaviors, children have a higher potential for exposure to available chemicals through the non-dietary ingestion route; thus, frequency of hand-to-mouth activity is an important variable for exposure assessments. Such data are limited and difficult to collect. Few published studies report such information, and the studies that have been conducted used different data collection approaches (e.g., videography versus real-time observation), data analysis and reporting methods, ages of children, locations, and even definitions of mouthing. For this paper, hand-to-mouth frequency data were gathered from 9 available studies representing 429 subjects and more than 2000 hours of behavior observation. A meta-analysis was conducted to study differences in hand-to-mouth frequency based on study, age group, gender, and location (indoor vs. outdoor), to fit variability and uncertainty distributions that can be used in probabilistic exposure assessments, and to identify any data gaps.

JOURNAL Refined PBPK Model of Aggregate Exposure to Methyl Tertiary-Butyl Ether 03/30/2007
KIM, D., M. E. ANDERSEN, J. D. PLEIL, L. A. NYLANDER-FRENCH, AND J. D. PRAH. Refined PBPK Model of Aggregate Exposure to Methyl Tertiary-Butyl Ether. TOXICOLOGY LETTERS. Elsevier Science Ltd, New York, NY, 169(3):222-235, (2007).
Abstract: Aggregate (multiple pathway) exposures to methyl tertiary-butyl ether (MTBE) in air and water occur via dermal, inhalation, and oral routes. Previously, physiologically-based pharmacokinetic (PBPK) models have been used to quantify the kinetic behavior of MTBE and its primary metabolite, tertiary-butyl alcohol (TBA), from inhalation exposures. However, the contribution of dermal and oral exposures to the internal dose of MTBE and TBA were not characterized well. The model was based entirely on blood MTBE and TBA measurements from controlled human exposures. The PBPK model consists of seven primary compartments representing the lung, skin, fat, kidney, liver, rapidly perfused tissue, and slowly perfused tissue. The MTBE and TBA models are linked by a single metabolic pathway. Although the general structure of the model is similar to previously published models of volatile organic compounds, we have now developed a detailed mathematical description of the lung, skin, and gastrointestinal tract. This PBPK model represents the most comprehensive and accurate description of MTBE and TBA pharmacokinetics in humans to date. The aggregate exposure model application for MTBE can be generalized to other environmental chemicals under this framework given appropriate empirical measurement data.

JOURNAL Ss-Caryophyllinic Acid: An Atmospheric Tracer for Ss-Caryophyllene Secondary Organic Aerosol 03/10/2007
JAOUI, M., M. LEWANDOWSKI, T. E. KLEINDIENST, J. H. OFFENBERG, AND E. O. EDNEY. Ss-Caryophyllinic Acid: An Atmospheric Tracer for Ss-Caryophyllene Secondary Organic Aerosol. GEOPHYSICAL RESEARCH LETTERS. American Geophysical Union, Washington, DC, 34(5):L05816 1-4, (2007).
Abstract: The chemical compositions of ambient PM2.5 samples, collected in Research Triangle Park, North Carolina, USA, and a sample of secondary organic aerosol, formed by irradiating a mixture of the sesquiterpene, ß-caryophyllene, and oxides of nitrogen in a smog chamber, were chemically analyzed using derivative-based GC-MS methods. The analyses showed the presence of an oxidized compound, tentatively identified as ß-caryophyllinic acid, in both the ambient PM2.5 field samples and in the smog chamber sample. The seasonal concentrations of ß-caryophyllinic acid in the ambient PM2.5 samples were 0.5, 0.9, 7.0, and 0.5 ng m-3 during the winter, spring, summer and fall respectively. To our knowledge, this is the first time that an oxidation product of a sesquiterpene, a hydrocarbon with high secondary organic aerosol yields and emitted from plants and trees in significant quantities, has been detected in ambient PM2.5 samples.

JOURNAL Comparing Field Performances of Denuder Techniques in the High Arctic 03/01/2007
IANNIELLO, A., H. J. BEINE, M. S. LANDIS, R. K. STEVENS, G. ESPOSITO, A. AMOROSO, AND I. ALLEGRINI. Comparing Field Performances of Denuder Techniques in the High Arctic. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 41(8):1604-2625, (2007).
Abstract: A field evaluation between two annular denuder system configurations was conducted during the spring of 2003 in the marine Arctic (Ny-Ålesund, Svalbard). The IIA annular denuder system (ADS) employs a series of five single channel annular denuders, a cyclone and a filter pack to discriminate between gas and aerosol species, while the deployed EPA-Versatile Air Pollution Sampler (VAPS) configuration employs a single multichannel annular denuder to protect the integrity of PM2.5 sample filters by collecting acidic gases. The concentrations of gaseous nitric acid (HNO3), nitrous acid (HONO), sulfur dioxide (SO2) and hydrochloric acid (HCl) determined using the IIA-ADS denuder system were compared to those measured with the EPA-VAPS denuder system. Results for HNO3 and SO2 suggested losses of gas phase species within the EPA-VAPS inlet surfaces due to low temperatures, high relative humidities, and coarse particle sea salt deposition to the VAPS inlet during sampling. The difference in HNO3 concentration (55%) between the EPA-VAPS and IIA-ADS data might also be due to the reaction between HNO3 and NaCl on inlet surfaces within the EPA-VAPS system. Furthermore, we detected the release of HCl from marine aerosol particles in the EPA-VAPS inlet during sampling that contributed to higher observed concentration values. Based on this work we present recommendations on the application of denuder sampling techniques for low concentration gaseous species in Arctic and remote marine locations to minimize sampling errors. We suggest an annular denuder technique without a large surface area inlet device in order to minimize adsorption, absorption, and/or production of gaseous atmospheric pollutants during sampling.

JOURNAL Hydroxydicarboxylic Acids: Markers for Secondary Organic Aerosol from the Photooxidation of a-Pinene 03/01/2007
Claeys, M., R. Szmigielski, I. Kourtchev, P. Van der Veken, R. Vermeylen, W. Maenhaut, MOHAMMAD JAOUI, T. E. KLEINDIENST, M. LEWANDOWSKI, J. H. OFFENBERG, AND E. O. EDNEY. Hydroxydicarboxylic Acids: Markers for Secondary Organic Aerosol from the Photooxidation of a-Pinene. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 41(5):1628-1634, (2007).
Abstract: Detailed organic analysis of fine (PM 2.5) rural aerosol collected during summer at K-puszta, Hungary, a mixed deciduous/coniferous forest site, shows the presence of polar oxygenated compounds that are also formed in laboratory irradiated a-pinene/NOx/air mixtures. In the present work, two major photooxidation products of a-pinene were characterized as the hydroxydicarboxylic acids, 3-hydroxyglutaric acid and 2-hydroxy-4-isopropyladipic acid, on the basis of chemical, chromatographic and mass spectral data. Different types of volatile derivatives, including trimcthylsilyl ester/elher, metbyl ester trimethylsilyl ether, and ethyl ester trimethylsilyl ether derivatives were measured by gas chromatographY/mass spectrometry (GCIMS), and their electron ionization (EI) spectra were interpreted in detail. The proposed structure of the hydroxydicarboxylic acids were confirmed or supported with reference compounds. 2-Hydroxy-4-isopropyladipic acid formally corresponds to a further reaction product of pinic acid involving addition of a molecule of watcr and opening of the dimethylcyclobutane ring; this proposal is supported by a laboratory irradiatjon experiment with a-pinene/NOx/air. In addition, we report the presence of a structurally related minor a-pinene photooxidation product, which was tentatively identified as the C7 homolog of 3-hydroxyglutaric acid, 3-hydroxy-4,4-dimethylglutaric acid. The detection of 2-hydroxy-4-isopropyladipic acid in ambient aerosol provides an explanation for the relatively low atmospheric concentrations of pinic acid found during daytime in forest environments.

JOURNAL Coarse Particulate Matter Concentrations from Residential Outdoor Sites Associated With the North Carolina Asthma and Children's Environment Studies (Nc Aces) 02/01/2007
CHEN, F., R. W. WILLIAMS, E. R. SVENDSEN, K. YEATTS, J. P. CREASON, J. W. SCOTT, D. TERRELL, AND M. W. CASE. Coarse Particulate Matter Concentrations from Residential Outdoor Sites Associated With the North Carolina Asthma and Children's Environment Studies (Nc Aces). ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 41(6):1200-1208, (2007).
Abstract: Residential outdoor monitoring was performed at 26 homes in the RTP area of NC from September 2003 to June 2004. PM10-2.5 values were estimated using the differential between independent PM10 and PM2.5 collocated MiniVol measurements. The dichotomous sampler was used as the central site PM monitor and located on a roof of the EPA/HSF in Chapel Hill, NC. The results show that while PM10-2.5 mass concentration can be highly correlated across areas as large as 40 km, poor correlation can result at much shorts distances. The PM10-2.5 differential method evaluated in the study was observed to be highly associated with a direct dichotomous measurement and holds potential for use in other PM10-2.5 research applications.

JOURNAL RESPONSE TO LETTER TO EDITOR OF RISK ANALYSIS ON ZARTARIAN ET AL., 2006 , "A PROBABILISTIC ARSENIC EXPOSURE ASSESSMENT FOR CHILDREN WHO CONTACT CCA-TREATED PLAYSETS AND DECKS, PART 1: MODEL METHODOLOGY, VARIABILITY RESULTS, AND MODEL EVALUATION 02/01/2007
ZARTARIAN, V. G. AND J. XUE. RESPONSE TO LETTER TO EDITOR OF RISK ANALYSIS ON ZARTARIAN ET AL., 2006 , "A PROBABILISTIC ARSENIC EXPOSURE ASSESSMENT FOR CHILDREN WHO CONTACT CCA-TREATED PLAYSETS AND DECKS, PART 1: MODEL METHODOLOGY, VARIABILITY RESULTS, AND MODEL EVALUATION. RISK ANALYSIS. Blackwell Publishing, Malden, MA, 27(1):1-5, (2007).
Abstract: Product is a letter to the editor of the Risk Analysis journal in reply to an industry's letter to the editor regarding a CCA paper published earlier this year.

JOURNAL Development and Application of Immunoaffinity Column Chromatography as a Cleanup Method for the Determination of Atrazine in Complex Environmental Sample Media 01/30/2007
CHUANG, J. C., J. M. VAN EMON, R. JONES, J. DURNFORD, AND B. LORDO. Development and Application of Immunoaffinity Column Chromatography as a Cleanup Method for the Determination of Atrazine in Complex Environmental Sample Media. ANALYTICA CHIMICA ACTA. Elsevier Science Ltd, New York, NY, 583(1):32-39, (2007).
Abstract: A rabbit antibody immunoaffinity (IA) column procedure was evaluated as a cleanup method for the determination of atrazine in soil, sediment, and food. Four IA columns were prepared by immobilizing a polyclonal rabbit anti-atrazine antibody solution to HiTrap Sepharose columns. Atrazine effectively bound to the IA columns with loading solvents of either 100% water, 2% acetonitrile in water, or 10% methanol in phosphate buffer. Quantitative removal of atrazine from the IA columns was achieved with elution solvents of either 70% ethanol in water, 70% methanol in water, or 100% methanol. One control column was prepared using nonspecific rabbit IgG antibody. This control column did not retain any applied atrazine indicating the compound did not bind indiscriminately to protein or the Sepharose support. The four IA columns showed reproducible coupling efficiency for the immobilization of the atrazine antibody and consistent binding and releasing of atrazine. The coupling efficiency (4.25 mg of antibody in 1 mL of resin bed) for the four IA columns ranged from 93 to 97% with an average of 96±2% (2.1%). Recoveries of the 500, 50, and 5 ng mL-1 atrazine standard solutions from the four IA columns were 107±7%(6.5%), 122±14% (12%), and 114±9% (8.0%) respectively, based on enzyme-linked immunosorbent assay (ELISA) data. The maximum loading was approximately 700 ng of atrazine for each IA column (~0.16 micro g of atrazine per mg of antibody). The IA columns could withstand 100% methanol as the elution solvent and be reused more than 50 times with no change in performance. The IA columns were challenged with real-world soil, sediment, and duplicate-diet food samples and effectively removed interferences from these various matrices for subsequent gas chromatography/mass spectrometry (GC/MS) and ELISA analysis. The log-transformed ELISA and GC/MS data were significantly correlated for soil, sediment and food samples although the ELISA values were slightly higher than those obtained by GC/MS. The IA column cleanup procedure coupled with ELISA analysis could be used as an alternative effective analytical method for the determination of atrazine in complex sample media such as soil, sediment, and food samples.

JOURNAL Evidence for Organosulfates in Secondary Organic Aerosol 01/15/2007
SURRATT, J. D., J. H. KROLL, T. E. KLEINDIENST, E. O. EDNEY, M. CLAEYS, A. SOROOSHIAN, N. L. NG, J. H. OFFENBERG, M. LEWANDOWSKI, M. JAOUI, R. FLAGAN, AND J. SEINFELD. Evidence for Organosulfates in Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 41(2):517-527, (2007).
Abstract: Recent work has shown that particle-phase reactions contribute to the formation of secondary organic aerosol (SOA), with enhancements of SOA yields in the presence of acidic seed aerosol. In this study, the chemical composition of SOA from the photooxidations of α-pinene and isoprene, in the presence or absence of sulfate seed aerosol, is investigated through a series of controlled chamber experiments in two separate laboratories. By using electrospray ionization - mass spectrometry, sulfate esters in SOA produced in laboratory photooxidation experiments are identified for the first time. Sulfate esters are found to account for a larger fraction of the SOA mass when the acidity of seed aerosol is increased, a result consistent with aerosol acidity increasing SOA formation. Many of the isoprene and α-pinene sulfate esters identified in these chamber experiments are also found in ambient aerosol collected at several locations in the southeastern U.S. It is likely that this pathway is important for other biogenic terpenes, and may be important in the formation of humic-like substances (HULIS) in ambient aerosol.

JOURNAL Ozone-Isoprene Reaction: Re-Examination of the Formation of Secondary Organic Aerosol 01/05/2007
KLEINDIENST, T. E., M. LEWANDOWSKI, J. H. OFFENBERG, M. JAOUI, AND E. O. EDNEY. Ozone-Isoprene Reaction: Re-Examination of the Formation of Secondary Organic Aerosol. GEOPHYSICAL RESEARCH LETTERS. American Geophysical Union, Washington, DC, 34(1):01/05/07, (2007).
Abstract: The reaction of ozone and isoprene has been studied to examine physical and chemical characteristics of the secondary organic aerosol formed. Using a scanning mobility particle sizer, the volume distribution of the aerosol was found in the range 0.05 - 0.2 µm. The aerosol yield was estimated to be 0.01, a value which is a factor of 5 - 10 higher than previous reports. The aerosol formation is complicated by the presence of minor impurities in the isoprene and the fact that OH-radicals produced in the ozonolysis can react with isoprene to produce organic aerosol. Without an OH-radical scavenger present, up to 50% of the observed aerosol comes from the OH channel. A GC-MS analysis of the products of the composite aerosol showed that two methyl tetrols and 2-methylglyceric acid are formed which can be attributed to the OH reaction channel. A measurement of the effective enthalpy of vaporization using a volatility differential mobility analyzer found the aerosol to have ΔHeff of -42 kJ mol-1, a value at the upper end of the range of organic aerosols previously studied. Even with the increased yield found in this study, the ozonolysis reaction probably remains a minor contributor to secondary organic aerosol in PM2.5 from the atmospheric oxidation of isoprene.

JOURNAL A Fluorescence-Based Screening Assay for Dna Damage Induced By Genotoxic Industrial Chemicals 01/01/2007
KAILASAM, S. AND K. R. ROGERS. A Fluorescence-Based Screening Assay for Dna Damage Induced By Genotoxic Industrial Chemicals. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, 66(1):165-171, (2007).
Abstract: The possibility of deliberate or accidental release of toxic chemicals in industrial, commercial or residential settings has indicated a need for rapid, cost-effective and versatile monitoring methods to prevent exposures to humans and ecosystems. Because many toxic industrial chemicals are not only acutely toxic but genotoxic as well, there is a need for simple and rapid screening techniques to measure these genotoxins.
A rapid screening assay to detect chemically-induced DNA damage resulting from exposure of surrogate DNA to genotoxic compounds is reported.

JOURNAL An Observational Study of the Potential Exposures of Preschool Children to Pentachlorophenol, Bisphenol-a, and Nonylphenol at Home and Daycare 01/01/2007
WILSON, N. K., J. C. CHUANG, M. K. MORGAN, B. LORDO, AND L. S. SHELDON. An Observational Study of the Potential Exposures of Preschool Children to Pentachlorophenol, Bisphenol-a, and Nonylphenol at Home and Daycare. ENVIRONMENTAL RESEARCH. Academic Press Incorporated, Orlando, FL, 103(1):9-20, (2007).
Abstract: The Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study investigated the potential exposures of 257 preschool children, ages 1 1/2 to 5 yr, and their primary adult caregivers to more than 50 anthropogenic chemicals. Field sampling took place in selected counties in North Carolina (NC) and Ohio (OH) in 2000-2001. Over a 48-h period in each child's daycare center and/or home, food, beverages, indoor air, outdoor air, house dust, soil, participants' hand surfaces and urine were sampled. Additional samples - transferable residues, food preparation surface wipes, and hard floor surface wipes - were collected in the approximately 13% of the homes that had pesticide applications within the seven days prior to field sampling.
Three phenols were among the measured chemicals: pentachlorophenol, bisphenol A [2,2 bis(4-hydroxyphenyl)propane], and nonylphenol (4-n-nonylphenol). Nonylphenol was detected in less than 11% of the samples in any medium. Among samples that were collected at all participants' homes and daycare centers, pentachlorophenol was detected in >50% of indoor air, outdoor air, house dust, and urine samples; bisphenol A was detected in >50% of indoor air, hand wipe, solid food, and liquid food samples.

The concentrations of the phenols in the sampled media were measured, and estimates of the children's potential exposures and potential absorbed doses resulting from intake through the inhalation, dietary ingestion, and indirect ingestion routes of exposure were estimated. The children's potential exposures to pentachlorophenol were predominantly through inhalation: 78% in NC and 90% in OH. In contrast, their potential exposures to bisphenol-A were predominantly through dietary ingestion: 99%, for children in both states. The children's estimated exposures to pentachlorophenol, calculated from the amounts excreted in their urine, exceeded their estimated maximum potential intake, calculated from the multimedia pentachlorophenol concentrations, by a factor greater than 10. This inconsistency for pentachlorophenol highlights the need for further research on the environmental pathways and routes of pentachlorophenol exposure, investigation of possible exposures to other compounds that could be metabolized to pentachlorophenol, and on the human absorption, metabolism, and excretion of this phenol over time periods longer than 48 hours.

JOURNAL The Dry Deposition of Speciated Mercury to the Florida Everglades: Measurements and Modeling 01/01/2007
MARSIK, F. J., G. J. KEELER, AND M. S. LANDIS. The Dry Deposition of Speciated Mercury to the Florida Everglades: Measurements and Modeling. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 41(1):136-149, (2007).
Abstract: The Florida Everglades Dry-Deposition Study (FEDDS) was designed to test the viability of using new and existing measurement techniques in the estimation of the dry-depositional loading of speciated mercury (elemental gaseous, reactive gaseous and particulate) to a mixed sawgrass (Cladium jamaicense) and cattail (Typha domingensis)stand within the Florida Everglades.

PAPER IN NON-EPA PROCEEDINGS Water Quality Analysis in An Environmental Justice Community in Durham, Nc 06/12/2009
ADAIR, B., J. J. BANG, Y. B. ANDERSON, S. F. DELAUDER, M. BRADSHAW, M. LAMBERT, F. MEHEUX, R. MALHOTRA, R. C. FORTMANN, P. P. EGEGHY, R. W. WILLIAMS, AND D. A. WHITAKER. Water Quality Analysis in An Environmental Justice Community in Durham, Nc. In Proceedings, 3rd National Conference on Environmental Science and Technology, Greensboro, NC, September 12 - 14, 2007. Springer, New York, NY, 55-60, (2009).
Abstract: Environmental Justice Communities are usually minority communities of low socio-economic status with a concern of increased risk from point source pollution not present in other communities. A priority of the U.S. EPA is to empower these communities to advocate for themselves. Toward that end, EPA has entered into a cooperative agreement with the Department of Environmental Earth and Geospatial Sciences at North Carolina Central University, Durham, NC, to perform preliminary community based participatory studies and to establish the infrastructure for long-term interactions with environmental justice communities. In central Durham, housing and commercial properties are intermingled creating a concern for increased pollution and poor water quality in area creeks. To determine if current or past commercial practices impacted creeks, organochlorines (pesticides and polychlorinated biphenyls), polycyclic aromatic hydrocarbons and heavy metals were quantified in water and sediment samples collected during the summer of 2007 from nine creeks located in six parks in the study area. Water quality measurements and contaminant concentrations were compared to regulatory values. To date, few water quality and no contaminant concentrations were above regulatory levels. The results are being shared with members of community organizations at community functions.

PAPER IN NON-EPA PROCEEDINGS The Impact of Social Capital on Environmental Risk Reduction in Moncure 06/12/2009
BANG, J. J., Y. B. ANDERSON, S. F. DELAUDER, M. BRADSHAW, F. MEHEUX, R. MALHOTRA, R. C. FORTMANN, P. P. EGEGHY, R. W. WILLIAMS, AND D. A. WHITAKER. The Impact of Social Capital on Environmental Risk Reduction in Moncure. In Proceedings, 3rd National Conference on Environmental Science and Technology, Greensboro, NC, September 12 - 14, 2007. Springer, New York, NY, 61-66, (2009).
Abstract: Despite rigorous efforts to understand and resolve environmental justice (EJ) issues, the complexity of the issues associated with many of these EJ communities continues to bring challenges to community residents and environmental researchers. Moncure, NC, located in northern Chatham County, is a rural community proximal to a cluster of several major industries. While the presence of these industries has helped the local residents maintain higher than average household incomes, it has also created environmental concerns (air quality and potential respiratory illness) for the community. In this study, the authors examine the impact of social capital in the form of a community coalition called the Southeastern Chatham Citizens Advisory Council (SCCAC) on the resolution of EJ issues in Moncure. EJ issues in Moncure have been investigated by examining trends in archived data from the U.S. EPA's Toxic Release Inventory (TRI) and by addressing residents' pollution concerns, identified in Town Hall meetings, by designing a field monitoring study. Monitoring for the field study was conducted during one week periods in January and June of 2007. Preliminary results from the January sampling was compared with regulatory standard values, TRI data, and with results from a modeling study conducted by NC DENR Division of Air Quality (DAQ). Data indicate that the levels of released pollutants from local industries have been reduced during the overlapping time period when the SECCA has been active in trying to resolve the pollution issues, illustrating the potential impact of social capital on EJ risk reduction.

PRESENTATION (California) Meta-Analysis of the Life Style Factors Relevant to Environmental Hazards for the Aging Population 11/16/2007
CHAO, E., T. R. MCCURDY, K. W. THOMAS, AND N. S. TULVE. (California) Meta-Analysis of the Life Style Factors Relevant to Environmental Hazards for the Aging Population. Presented at The Gerontological Society of America Scientific Meeting, San Francisco, CA, November 16 - 20, 2007.
Abstract: The goal of this U.S. Environmental Protection Agency (EPA) Aging Initiative study is to characterize activity patterns, physiological changes, and environmental exposures for the aging population. Meta-analysis was performed on more than 2000 reviewed articles to evaluate the lifestyle factors most relevant to environmental hazards for the aging population, and to develop statistical distributions of inputs to EPA's time series exposure models. In addition, these data should provide age-specific information for EPA's Exposure Factors Handbook.

PRESENTATION An Observational Study on the Potential Exposures of 111 Preschool Children to Phthalates in Their Everyday Environments 11/03/2007
FIGUEROA, Z., M. K. MORGAN, P. A. JONES, C. W. CROGHAN, L. S. SHELDON, AND A. M. CALAFAT. An Observational Study on the Potential Exposures of 111 Preschool Children to Phthalates in Their Everyday Environments. Presented at American Public Health Association Annual Conference, Washington, DC, November 03 - 07, 2007.
Abstract: The purpose of this work was to identify potential sources and routes of preschool children exposures to two phthalate diesters used in household and personal care products and building materials. Exposure and biomonitoring data was reviewed. The abstract included the preliminary conncentration results found in the collected media. Urine samples were analyzed for two main metabolites of interest in collaboration with CDC.

PRESENTATION Meta-Analysis of the Life Style Factors Relevant to Environmental Hazards for the Aging Population 11/03/2007
CHAO, Y., T. R. MCCURDY, K. W. THOMAS, AND N. S. TULVE. Meta-Analysis of the Life Style Factors Relevant to Environmental Hazards for the Aging Population. Presented at American Public Health Association Annual Meeting, Washington, DC, November 03 - 07, 2007.
Abstract: The goal of this U.S. Environmental Protection Agency (EPA) study is to characterize activity patterns, physiological changes, and environmental exposures for the aging population. Meta analysis was performed on more than 2000 reviewed articles to evaluate the lifestyle factors most relevant to environmental hazards for the aging population, and to develop statistical distributions of inputs to EPA's time series exposure models. In addition, these data should provide age-specific information for EPA's Exposure Factors Handbook.

PRESENTATION Planned Integration of Measurement and Survey Data from the Dears With Local and Regional Research Efforts: Preliminary Data Findings and Observations 09/27/2007
WILLIAMS, R. W., A. F. VETTE, C. W. CROGHAN, C. D. STEVENS, T. M. BARZYK, P. A. JONES, D. A. WHITAKER, S. R. MCDOW, G. A. NORRIS, S. MUKERJEE, J. M. BURKE, B. J. GEORGE, AND M. HEINDORF. Planned Integration of Measurement and Survey Data from the Dears With Local and Regional Research Efforts: Preliminary Data Findings and Observations. Presented at Canada-US Border Air Quality Studies Workshop, Windsor, ON, CANADA, September 27, 2007.
Abstract: The Canadian-US Border Air Quality Studies represent collaborative research being performed by both parties. This abstract details the efforts of the Detroit Exposure and Aerosol Research Study (DEARS) to work collaboratively in this regards. A discussion of the collaborations is provided along with select data findings and observations from the ongoing study.

PRESENTATION Source Apportionment of Particulate Matter in the U.S. and Associations With in Vivo and in Vitro Lung Inflammatory Markers 09/24/2007
DUVALL, R. M., G. A. NORRIS, J. M. BURKE, J. K. MCGEE, M. I. GILMOUR, AND R. B. DEVLIN. Source Apportionment of Particulate Matter in the U.S. and Associations With in Vivo and in Vitro Lung Inflammatory Markers. Presented at 29th NATO/SPS International Technical Meeting, Aveiro, PORTUGAL, September 24 - 28, 2007.
Abstract: This is an abstract submitted to the 29th NATO International Technical Meeting on Air Pollution Modelling and its Application. In this research, sources of particulate matter were determined in cities across the U.S. using the chemical mass balance receptor model. The sources were then compared to in vivo and in vitro lung inflammatory markers to examine links between sources and health effects.

PRESENTATION (Portugal)THE Detroit Exposure and Aerosol Research Study 09/24/2007
WILLIAMS, R. W., A. F. VETTE, J. M. BURKE, G. A. NORRIS, K. WESSON, M. STRUM, T. FOX, AND T. H. WATKINS. (Portugal)THE Detroit Exposure and Aerosol Research Study. Presented at International Technical Meeting on Air Pollution Modeling, Aveiro, PORTUGAL, September 24 - 28, 2007.
Abstract: The Detroit Exposure and Aerosol Research Study (DEARS) represents an intensive examination of personal, residential and community-based particulate matter and related co-pollutant measurements in Detroit, Michigan. Data from the DEARS will be used as inputs into air quality, land use regression and pollutant-specific modeling. This presentation describes data collected in the DEARS and the planned modeling component of the study.

PRESENTATION Indoor-Outdoor Characterization of the Elemental Components of PM 2.5 09/05/2007
STEVENS, C. D., R. W. WILLIAMS, A. F. VETTE, AND P. A. JONES. Indoor-Outdoor Characterization of the Elemental Components of PM 2.5. Presented at ISEE Conference, Mexico City, MEXICO, September 05 - 09, 2007.
Abstract: This presentation is based on analyses of outdoor PM2.5 mass concentration, composition and the infiltration associated with indoor PM2.5.

PRESENTATION The Impact of Passive Sampling Methodologies Used in the Dears 08/19/2007
WILLIAMS, R. W., A. F. VETTE, D. A. WHITAKER, C. W. CROGHAN, P. A. JONES, H. DAUGHTREY, K. OLIVER, H. JACUMIN, DENNIS D. WILLIAMS, C. E. RODES, J. W. THORNBURG, J. S. HERRINGTON, AND J. ZHANG. The Impact of Passive Sampling Methodologies Used in the Dears. Presented at 2007 National Environmental Monitoring Conference, Cambridge, MA, August 19 - 23, 2007.
Abstract: This abstract details the use of passive sampling methodologies in the Detroit Exposure and Aerosol Research Study (DEARS). A discussion about the utility of various gas-phase passive samplers used in the study will be described along with examples of field data measurements employing the technology.

PRESENTATION Issues in the Measurement and Assessment of Environmental Exposures for a Large Prospective Cohort Study 07/29/2007
QUACKENBOSS, J. J., W. GALKE, S. VIET, AND D. MARKER. Issues in the Measurement and Assessment of Environmental Exposures for a Large Prospective Cohort Study. Presented at 2007 Joint Statistical Meetings, Salt Lake City, UT, July 29 - August 02, 2007.
Abstract: The National Children's Study (NCS) is a large-scale, multi-agency effort (lead by NIH, EPA, and CDC) to evaluate relationships among multiple exposures and changes in susceptibility over life stages, and subsequent health and developmental outcomes. In an invited presentation to the American Statistical Society's Joint Statistical Meetings, both statistical and logistical considerations for exposure assessment designs and approaches in the NCS will be discussed.

PRESENTATION Exposure Assessment for the National Children's Study: Integrating Biomonitoring With Environmental Measures and Questionnaire/Diary/Observational Information 07/26/2007
QUACKENBOSS, J. J., L. L. NEEDHAM, W. GALKE, S. VIET, AND B. OBRIEN. Exposure Assessment for the National Children's Study: Integrating Biomonitoring With Environmental Measures and Questionnaire/Diary/Observational Information. Presented at International Council of Chemical Associations Workshop, Minneapolis, MN, July 26 - 27, 2006.
Abstract: The National Children's Study (NCS) is proposed to be the largest and most ambitious study of the health and development of children ever to be undertaken in the United States. The Study is led by the U.S. Department of Health and Human Services - through the National Institutes of Health and the Centers for Disease Control and Prevention - and by the U.S. Environmental Protection Agency. The Study plans to enroll a representative sample of America's children (approximately 100,000 from more than 100 locations throughout the U.S.) and their families, and follow them longitudinally from either before conception or early in pregnancy until age 21 years to better understand the multiple factors which influence the physical and mental health and development of children.

PRESENTATION Application of Pscf to Pmf-Modeled Sources of PM2.5 in Riverside Using 1-Hr Averaged Data 06/26/2007
EATOUGH, D. J., B. GROVER, W. WOOLWINE, R. FARBER, AND W. F. CHRISTENSEN. Application of Pscf to Pmf-Modeled Sources of PM2.5 in Riverside Using 1-Hr Averaged Data. Presented at Air and Waste Management Association Annual Conference, Pittsburgh, PA, June 26 - 29, 2007.
Abstract: Data from semi-continuous instruments employed during a sampling campaign in Riverside, CA in July-August 2005 was used in a PMF2 analysis and sixteen sources were identified. Factors attributed to being primarily from local automobile emissions, local diesel emissions, wood combustion and local secondary photochemical associated sources were found. Several transport attributed factors were also identified, including, transported nonvolatile material, transported secondary ammonium nitrate, and transported secondary organic material. The PMF2 results were combined with hourly averaged back-trajectory data from HYSPLIT to identify factors associated with specific meteorological transport conditions.

PRESENTATION A Multi-Residue Method for the Analysis of Insecticides Collected on Cotton Surface Wipes 06/03/2007
CLIFTON, M. AND D. M. STOUT. A Multi-Residue Method for the Analysis of Insecticides Collected on Cotton Surface Wipes. Presented at ASMS Conference on Mass Spectrometry, Indianapolis, IN, June 03 - 07, 2007.
Abstract: A method was developed for the extraction, clean-up, and analysis of multiple pesticides from cotton wipe media used in human exposure studies to collect residues from residential hard surfaces. Measurements of pesticides are critical for estimating dermal and indirect ingestion exposure, particularly for children. Methods used previously for multi-residue analysis of cotton wipes have been difficult to use for routine analysis at trace levels due to extensive problems with matrix effects from the cotton media and the hard surfaces being sampled. This method incorporates a multi-stage SPE clean-up procedure to remove extraneous compounds. An effective approach to correct for extraction efficiency and matrix effects based primarily on response enhancement on the GC/MS system is described.

PRESENTATION Ord Best Practices for Observational Human Exposure Measurement Studies 03/27/2007
FORTMANN, R. C. Ord Best Practices for Observational Human Exposure Measurement Studies. Presented at 2007 Society of Toxicology Annual Meeting, Charlotte, NC, March 25 - 29, 2007.
Abstract: This abstract describes a presentation for the 2007 Society of Toxicology Annual Meeting in Charlotte, NC on March 27, 2007. It will be included in a special Issues Session titled "Scientific and Ethical Considerations in Human Exposure Studies." The presentation describes scientific and ethical approaches for observational exposure studies. It discusses issues to be addressed in the design and implementation of observational exposure studies, the state of the science for these approaches, and information sources available to researchers conducting observational studies.

PRESENTATION Measurement of Polycyclic Aromatic Hydrocarbons (PAHs) Associated With Fine Particulate Matter to Estimate Statewide Cumulative Exposures in North Carolina 03/26/2007
FUNK, W. E., S. M. RAPPAPORT, M. CLARK, AND J. D. PLEIL. Measurement of Polycyclic Aromatic Hydrocarbons (PAHs) Associated With Fine Particulate Matter to Estimate Statewide Cumulative Exposures in North Carolina. Presented at Society of Toxicology Annual Meeting, Charlotte, NC, March 25 - 29, 2007.
Abstract: Airborne particulate matter (PM) is routinely collected at over a thousand air monitoring stations across the nation using Teflon filters. After they are weighed to measure the amount of PM in the air, the filters are stored in refrigerators and, after a year, are thrown away. Three years ago, scientists at the U.S. Environmental Protection Agency (EPA) and the university of North Carolina jointly developed a method for using these stored filters for the additional job of measuring the levels of several carcinogenic polyaromatic hydrocarbons (PAHs) that are bound to the particles. We have now used archived filters from the state of North Carolina to start to assess the potential incremental cancer risk from the cumulative exposures from PAHs across the state. This methodology can be easily and cost effectively implemented in other states across the country using such archived filters.

PRESENTATION A Physiologically Based Pharmacokinetic/Pharmacodynamic (PBPK/Pd) Model for Estimation of Cumulative Risk from Exposure to Three N-Methyl Carbamates: Carbaryl, Aldicarb, and Carbofuran 03/25/2007
XIAOFEI, Z., M. S. OKINO, J. B. KNAAK, A. M. TSANG, F. W. POWER, J. XUE, L. S. HARRISON, C. B. THOMPSON, AND C. C. DARY. A Physiologically Based Pharmacokinetic/Pharmacodynamic (PBPK/Pd) Model for Estimation of Cumulative Risk from Exposure to Three N-Methyl Carbamates: Carbaryl, Aldicarb, and Carbofuran. Presented at 2007 Society of Toxicology Annual Meeting, Charlotte , NC, March 25 - 29, 2007.
Abstract: A physiologically-based pharmacokinetic (PBPK) model for a mixture of N-methyl carbamate pesticides was developed based on single chemical models. The model was used to compare urinary metabolite concentrations to levels from National Health and Nutrition Examination Survey (NHANES III) based on inputs from the Stochastic Human Exposure Dose Simulation (SHEDS) model.

PRESENTATION The Potential for Human Exposures to Pet-Borne Diazinon Residues Following Residential Lawn Applications 03/25/2007
MORGAN, M. K., D. M. STOUT, AND P. P. EGEGHY. The Potential for Human Exposures to Pet-Borne Diazinon Residues Following Residential Lawn Applications. Presented at American Chemical Society,Spring National Meeting, Chicago, IL, March 25 - 29, 2007.
Abstract: This observational study examined the potential for indoor/outdoor pet dogs to be an important pathway for transporting diazinon residues into homes and onto occupants following residential lawn applications. The primary objective was to investigate the potential exposures of children and their pet dogs to diazinon after a lawn application at their homes.

PRESENTATION American Healthy Homes Survey: A National Study of Residential Pesticides Measured from Floor Wipes 03/25/2007
STOUT, D. M., K. D. BRADHAM, R. HIGHSMITH, P. A. JONES, C. W. CROGHAN, W. FREIDMAN, E. PINZER, D. COX, AND G. DEWALT. American Healthy Homes Survey: A National Study of Residential Pesticides Measured from Floor Wipes. Presented at American Chemical Society, Chicago, IL, March 25 - 29, 2007.
Abstract: The US Environmental Protection Agency and the US Department of Housing and Urban Development conducted the American Healthy Homes Survey (AHHS) in 2006 to assess environmental concentrations of lead, allergens, mold, pesticides, and arsenic in and around U.S. residences.

PRESENTATION Pharmacokinetic/Pharmacodynamic Modeling of Permethrin in the Rat 03/25/2007
TORNERO-VELEZ, R., E. SCOLLON, J. M. STARR, M. F. HUGHES, M. J. DEVITO, AND C. C. DARY. Pharmacokinetic/Pharmacodynamic Modeling of Permethrin in the Rat. Presented at 2007 Society of Toxicology Annual Meeting, Charlotte, NC, March 25 - 29, 2007.
Abstract: A physiologically-based pharmacokinetic (PBPK) model was used to describe pharmacokinetics of permethrin and calibrated using experimental data on the concentration time-course of cis- and trans-permethrin in rat blood and brain tissues following oral administration.

PRESENTATION Field Collection Methods Used in the EPA National Exposure Research Laboratory Human Exposure Measurement Program to Evaluate Children's Aggregate Exposure to Pesticides: A Tutorial 03/22/2007
TULVE, N. S. Field Collection Methods Used in the EPA National Exposure Research Laboratory Human Exposure Measurement Program to Evaluate Children's Aggregate Exposure to Pesticides: A Tutorial. Presented at OPP Health Effects Division (HED) Risk Assessment Training Program, Washington, DC, March 22, 2007.
Abstract: A tutorial on the field sampling equipment used to collect multimedia samples.
We conduct observational human exposure measurement studies in order to understand what chemicals people come into contact with, at what levels, what the sources of those chemicals are, and where, when, how often, and why people come into contact with those chemicals in their everyday environments.

A discussion of the other types of ancillary data collected, the algorithms, and example data will be shown.


PRESENTATION Human Exposure Air Monitoring: Examples from the National Exposure Research Laboratory 03/20/2007
WILLIAMS, R. W. Human Exposure Air Monitoring: Examples from the National Exposure Research Laboratory. Presented at US EPA-NCCU Cross Pollination Workshop, Durham, NC, March 20, 2007.
Abstract: The US-EPA and North Carolina Central University (NCCU) have a cross-pollination agenda to help share research opportunities between the two institutions. This presentation provides NCCU with an understanding of current air monitoring research the US EPA is involved in and some of the approaches used in that effort.

PRESENTATION Asbestos Exposure Research Air, Soil and Bulk Material Scenarios 03/17/2007
VALLERO, D. A. Asbestos Exposure Research Air, Soil and Bulk Material Scenarios. Presented at 24th Annual Conference and Exposition of the Environmental Information Association, Charlotte, NC, March 17 - 21, 2007.
Abstract: Presently, asbestos and other mineral fibers are monitored in the workplace and in the environment using several basic analytical techniques, based primarily upon observing the fiber by either optical or electron microscopy. EPA is conducting research to determine which sampling and analytical approaches best support these analyses. In two surveys conducted in 2004, EPA asbestos coordinators identified the highest priority exposure research needs to be improvements to analytical procedures and counting rules for asbestos detection and quantitation in bulk samples, air, settled dust, and soil for field monitoring and risk analysis in various exposure scenarios.

PRESENTATION Exposure Assessment Tools for Cumulative Risk Assessment: Measurement of Endogenous Biomarkers 03/14/2007
HUBBARD, H., J. D. PLEIL, AND M. C. MADDEN. Exposure Assessment Tools for Cumulative Risk Assessment: Measurement of Endogenous Biomarkers. Presented at Society of Environmental Toxicology and Chemistry, Chicago, IL, March 14 - 16, 2007.
Abstract: Direct assessment of cumulative risks is a difficult task due to combinations of multiple chemicals, exposure pathways, and concentration profiles using suites of environmental measurements. We are investigating the use of endogenous compounds commonly present in biological media and their changes in response to environmental stressors to indicate preclinical effects of complex exposures on metabolite expression.

PRESENTATION Immunoassays for Biomarkers and Neutraceuticals/Pharmaceuticals 02/25/2007
VAN EMON, J. M. AND J. C. CHUANG. Immunoassays for Biomarkers and Neutraceuticals/Pharmaceuticals. Presented at PITTICON, Chicago, IL, February 25 - March 02, 2007.
Abstract: Product is an abstract for an invited oral platform presentation to be given at the Pittsburgh Conference to be held February 25 - March 2, 2007 in Chicago, Ilinois. The presentation will describe methods research for the development of bioanalytical methods to measure biomarkers and neautraceutical/pharmaceuticals to support monitoring studies. One method developed was an immunoassay to detect 2,4-D in urine with a detection limit of 30 ng/mL which favorably compared to a GC/MS procedure.

PRESENTATION Sample Extraction and Gc-MS Analysis for Polar Volatile Organic Compounds (Pvocs) in Liquid Biological Media 02/06/2007
PLEIL, J. D., J. R. SOBUS, H. HUBBARD, AND M. C. MADDEN. Sample Extraction and Gc-MS Analysis for Polar Volatile Organic Compounds (Pvocs) in Liquid Biological Media. Presented at Environmental Analysis Conference 2007, Wellington, NEW ZEALAND, February 06 - 09, 2007.
Abstract: Current approaches for assessing the cumulative exposures and effects from broad classes of environmental stressors incorporate the measurement of specific groups of endogenous compounds in human biological fluids. Recent focus has been on interpreting patterns of differentially expressed proteins and large molecule adducts (e.g hemoglobin, albumin, DNA) which are difficult to measure. In contrast, this work exploits classes of simple polar volatile organic compounds (PVOCs) that are abundant and ubiquitous products of human metabolism and can be found in non-invasively collected breath or urine samples. Methodology for measuring metabolic PVOCs is presented using standard laboratory tools and modest gas chromatography/mass spectrometry equipment.

PRESENTATION Ecologic Study of Mesoscale Environments With Excess Disease Prevalence 02/01/2007
SHEPPARD, P. R., J. D. PLEIL, R. J. SPEAKMAN, G. RIDENOUR, AND M. L. WITTEN. Ecologic Study of Mesoscale Environments With Excess Disease Prevalence. Presented at NCSE-2007 , Washington, DC, February 01 - 02, 2007.
Abstract: This work employs an ecologic epidemiological approach to assess the relationship between environmental stressors and excess disease prevalence in small communities. Specifically, the childhood leukemia cluster in Fallon Nevada is used as an example; heavy metals (tungsten and cobalt) exposures are contrasted with disease prevalence in Fallon, control communities, and pristine desert. Further biomedical research is suggested as a follow-up

PUBLISHED REPORT A Scoping-Level Field Monitoring Study of Synthetic Turf Fields and Playgrounds 11/01/2009
HIGHSMITH, R., K. W. THOMAS, AND R. W. WILLIAMS. A Scoping-Level Field Monitoring Study of Synthetic Turf Fields and Playgrounds. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/135, 2009.
Abstract: Recycled tire material, or "tire crumb," is used as a component in many recreational fields, including synthetic turf fields and playgrounds. The use of tire crumbs in these applications provides several benefits, including reduced sports injury. The public recently has raised concerns regarding potential human health and environmental risks associated with the presence of and potential exposures to tire crumb constituents in recreational fields, especially with regard to children's exposures. In early 2008, U.S. Environment Protection Agency (EPA) Region 8 requested that the Agency.consider this issue. A cross-EPA workgroup inventoried and considered the limited available scientific information: some laboratory studies of tire material content, off-gassing, and leaching characteristics and a few European studies describing the extent and availability of tire crumb constituents for potential human exposure. The workgroup recommended that research be conducted to generate additional field monitoring data for potential U.S. environmental conditions and potential exposures.

PUBLISHED REPORT Guidance Document for Pmf Applications With the Multilinear Engine 04/09/2009
NORRIS, G. A., R. VEDANTHAM, K. Wade, P. Zhan, S. Brown, P. Pentti, S. I. EBERLY, AND C. FOLEY. Guidance Document for Pmf Applications With the Multilinear Engine. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/032 (NTIS PB2009-107895), 2009.
Abstract: This document serves as a guide for users of the Multilinear Engine version 2 (ME-2) for source apportionment applications utilizing positive matrix factorization (PMF). It aims to educate experienced source apportionment analysts on available ME rotational tools and provides guidance sensitivity analyses. Prior to using ME-2 for PMF, users should be familiar with the PMF model and its applications. Users should also be familiar with the wide body of literature describing PMF and ME-2. In particular, the End User’s Guide (Paatero, 2004) and me2scrip.txt (Paatero, 2002) are useful companions to this document. This document covers technical details and examples using two versions of ME-2. An individual ME-2 license (IL) can be purchased from Pentti Paatero or ME-2 is provided with the EPA distributed PMF 3.0 public license (PL). Both versions of ME-2 have been developed by Pentti Paatero and the version provided with the IL has a more flexible programming format and the PL version has a more restricted structure since it has been developed for EPA PMF software. Presenting two versions of the ME-2 and the associated input files increases the complexity of the document, however, it provides comprehensive explanation and examples of available ME-2 rotational tools.

PUBLISHED REPORT Sampling and Analysis of Asbestos Fibers on Filter Media to Support Exposure Assessment: Bench-Scale Testing 02/19/2009
VALLERO, D. A., J. R. Kominsky, M. E. BEARD, AND O. Crankshaw. Sampling and Analysis of Asbestos Fibers on Filter Media to Support Exposure Assessment: Bench-Scale Testing. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-08/046 (NTIS PB2009-102750), 2009.
Abstract: Sampling efficiency is essential in exposure assessments of contaminants in air, as well as other matrices. In the measurement of airborne contaminants, it is critical to collect a sample of air containing representative contaminants in the air of concern, that is, contaminant concentration and size distribution in the sampled air must be the same as that of the air of concern.

PUBLISHED REPORT Sheds-Multimedia Model Version 3 (a) Technical Manual; (B) User Guide; and (C) Executable File to Launch Sas Program and Install Model 09/30/2008
ZARTARIAN, V. G., G. Glen, L. SMITH, AND J. XUE. Sheds-Multimedia Model Version 3 (a) Technical Manual; (B) User Guide; and (C) Executable File to Launch Sas Program and Install Model. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/118, 2008.
Abstract: Reliable models for assessing human exposures are important for understanding health risks from chemicals. The Stochastic Human Exposure and Dose Simulation model for multimedia, multi-route/pathway chemicals (SHEDS-Multimedia), developed by EPA’s Office of Research and Development (ORD), National Exposure Research Laboratory (NERL), is a state-of-science computer model for improving estimates of aggregate (single-chemical, multi-route/pathway) and cumulative (multi-chemical, multi-route/pathway) human exposure and dose. SHEDS-Multimedia is the EPA/ORD’s principal model for simulating human exposures to a variety of multimedia, multi-pathway environmental chemicals such as pesticides, metals, and persistent bioaccumulative toxins.

PUBLISHED REPORT EPA Positive Matrix Factorization (Pmf) 3.0 Fundamentals & User Guide 09/22/2008
NORRIS, G. A., R. VEDANTHAM, K. Wade, S. Brown, J. Prouty, AND C. FOLEY. EPA Positive Matrix Factorization (Pmf) 3.0 Fundamentals & User Guide. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/108, 2008.
Abstract: Positive matrix factorization (PMF) is a multivariate factor analysis tool that decomposes a matrix of ambient data into two matrices - factor contributions and factor profiles - which then need to be interpreted by an analyst as to what source types are represented using measured source profile information, wind direction analysis, and emission inventories.The method is reviewed briefly here and described in greater detail.

PUBLISHED REPORT Scientific and Ethical Approaches for Observational Exposure Studies 07/25/2008
FORTMANN, R. C. Scientific and Ethical Approaches for Observational Exposure Studies. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-08/062 (NTIS PB2008-112239), 2008.
Abstract: Researchers conduct observational human exposure studies to understand how and the extent to which people come into contact with chemicals and environmental stressors in their everyday lives, through the air they breathe, the food and liquids they consume, and the things they touch. The U.S. Environmental Protection Agency’s (EPA’s) National Exposure Research Laboratory (NERL) has conducted observational human exposure studies for several decades and uses the information and data from these studies to improve the Agency’s understanding of human exposures to chemicals and other stressors and ultimately to support efforts to improve public health. Because these studies involve people as research participants, they are complex and raise numerous scientific and ethical issues that have to be addressed prior to and during their design and implementation.

PUBLISHED REPORT The Optimization of Thermal Optical Analysis for the Measurement of Black Carbon in Regional PM2.5: A Chemometric Approach Report 09/27/2007
U.S. EPA, AND J. M. Conny. The Optimization of Thermal Optical Analysis for the Measurement of Black Carbon in Regional PM2.5: A Chemometric Approach Report. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/119 (NTIS PB2007-114771), 2007.
Abstract: In thermal-optical analysis (TOA), particulate organic carbon (OC) as well as black carbon (BC) must be quantified. Both the BC that is native to the filter and instrument-produced OC char are products of incomplete combustion and have similar optical as well as chemical properties.

PUBLISHED REPORT EPA Unmix 6.0 User Guide 07/11/2007
NORRIS, G. A., R. VEDANTHAM, AND R. M. DUVALL. EPA Unmix 6.0 User Guide. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/089 (NTIS PB2007-112630), 2007.
Abstract: The underlying philosophy of Unmix is to let the data speak for itself. Unmix seeks to solve the general mixture problem where the data are assumed to be a linear combination of an unknown number of sources of unknown composition, which contribute an unknown amount to each sample. Unmix also assumes that the compositions and contributions of the sources are all positive. Unmix
assumes that for each source there are some samples that contain little or no contribution from that source. Using concentration data for a given selection of species, Unmix estimates the number of sources, source compositions, and

source contributions to each sample.

PUBLISHED REPORT Important Exposure Factors for Children An Analysis of Laboratory and Observational Field Data Characterizing Cumulative Exposure to Pesticides 03/23/2007
EGEGHY, P. P., L. S. SHELDON, D. M. STOUT, E. A. COHEN-HUBAL, N. S. TULVE, L. J. MELNYK, M. K. MORGAN, R. C. FORTMANN, D. A. WHITAKER, C. W. CROGHAN, P. A. JONES, AND A. COAN. Important Exposure Factors for Children An Analysis of Laboratory and Observational Field Data Characterizing Cumulative Exposure to Pesticides. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/013 (NTIS PB2007-106980), 2007.
Abstract: In an effort to facilitate more realistic risk assessments that take into account unique childhood vulnerabilities to environmental toxicants, the U.S. EPA's National Exposure Research Laboratory (NERL) developed a framework for systematically identifying and addressing the most important sources, routes, and pathways of children's exposure to pesticides. Four priority research areas were identified as representing critical data gaps in our understanding of environmental risks to children. Several targeted studies were conducted under NERL's children's exposure research program to specifically address these priority research needs. This document is a comprehensive summary report of data collected in these studies to address the priority research needs and is intended for an audience of exposure scientists, exposure modelers, and risk assessors. The parameters measured and the measurement methods are described. Data on representative organophosphate and pyrethroid pesticides are compared across studies and across compounds with the primary purpose of identifying or evaluating important factors influencing exposures along each relevant pathway. Summary statistics, comparative analyses, and spatial and temporal patterns are presented to address previously identified data gaps. Results are compared across studies in order to identify trends that might provide a better understanding of the factors affecting children's exposures. While highlights of the results of individual studies are presented, the focus is on presenting insights gleaned from the analysis of the aggregated data from several studies. By examining relationships among application patterns, exposures, and biomarkers for multiple compounds from different classes of pesticides, this report strives to help produce more reliable approaches for assessing cumulative exposure.

PUBLISHED REPORT Malathion Exposure During Lice Treatment: Use of Exposure Related Dose Estimating Model (Erdem) and Factors Relating to the Evaluation of Risk 03/02/2007
POWER, F. W., C. C. DARY, J. B. KNAAK, R. TORNERO-VELEZ, AND J. N. BLANCATO. Malathion Exposure During Lice Treatment: Use of Exposure Related Dose Estimating Model (Erdem) and Factors Relating to the Evaluation of Risk. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/023 (NTIS PB2007-106971), 2007.
Abstract: This report is a product of this collaboration as it relates to the exposure assessment of organophosphorus (OP) insecticide, malathion, (O,O-dimethyl phosphorodithioate diethyl mercaptosuccinate; CAS 121-75-5) labeled for use as a pediculicide.

 

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