T3-C
Vehicle-related exposuresFederal Hill 2:15 PM
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| Chair(s): Carlos Restrepo cer202@nyu.edu
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| Vehicles represent an important source of exposures to numerous substances. This session presents results of studies that discuss vehicle and traffic-related contributions to personal and indoor air exposures and the relationship between personal exposures to VOCs and behavioral, socioeconomic, demographic variables. |
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T3-C.1 2:15 PM Assessment of contributions from heating sources and attached garages to background indoor air levels of volatile organic compounds and air-phase petroleum hyrocarbons in Massachusetts residences. McCafferty R*, Rago RJ, Rezendes A; Environmental Consulting Firm RXM@haleyaldrich.com
Abstract: A background indoor air study has been conducted, which includes the collection of indoor air samples from the living space of 100 residences located throughout Massachusetts in late winter and early spring of 2004 and 2005. The air samples were analyzed for volatile organic compounds (VOCs) by US EPA Method TO-15 and air-phase petroleum hydrocarbons (APH) by the Massachusetts Department of Environmental Protection Method. The objective of the study was to quantify VOC and APH background concentrations in Massachusetts residences. For this presentation, statistical differences in selected volatile compound concentrations in residences that heat with fuel oil or with natural gas are evaluated. In addition, statistical differences in the indoor air concentrations of APH compounds between residences with attached garages used for parking vehicles and those without attached garages are also evaluated. Study methodology, sample group selection criteria, and sampling procedures (sample canister distribution, sample location, collection, and duration) will be described. Chemical data results of as they relate to supplemental study variables, and a comparison of the chemical data to the current recommended background values will be discussed.
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T3-C.2 2:35 PM Characterization of the relationship between personal exposures to VOCs and behavioral, socioeconomic, demographic variables: Analysis of the 1999-2000 NHANES VOC data set. Wang SW*, Tong S, Georgopoulos PG; Environmental and Occupational Health Sciences Institute, UMDNJ - R.W. Johnson Medical School, Rutgers University shengwei@fidelio.rutgers.edu
Abstract: The objectives of the study presented here are (a) to examine the relationship between personal exposures to selected VOCs among individuals in a subpopulation of the National Health and Nutrition Examination Survey (NHANES) participants and demographic, socioeconomic, and behavioral variables using data collected in the 1999-2000 NHANES VOC Project, and (b) to identify the "best predictors" among these variables in determining personal exposure levels of the selected VOCs. These individuals were a representative subsample of NHANES participants between the ages of 20 and 59 years. In addition to personal exposure measurements to ten VOCs, information about individual demographic, socioeconomic status, as well as time and activity data for the exposure period are available for these participants. The time and activity data collected via the specially designed questionnaire can help identify possible sources of exposures and characterize activities that might contribute to exposure. A systematic data analysis procedure is employed to the step-by-step resolution of limitations that may exist in the 1999-2000 NHANES VOC dataset; these include missing values, collinearity, non-linearity, interaction effects etc., which are explored and addressed through graphical exploratory analysis, canonical correlation analysis, and non-parametric exploratory analysis such as Classification And Regression Trees with the Bootstrap Aggregating (Bagging) algorithm. The data analysis outcomes provide valuable information on characterizing significant exposure factors among demographic, socioeconomic, and activity variables to affect personal exposures.*
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T3-C.3 2:55 PM Daily exposure to traffic-related air pollution: Estimating variability in exposure in Vancouver, Canada. Setton E*, Hystad P, Keller CP, Cloutier-Fisher D, Foster L, Copes R, Brauer M; UVIC, BCCDC, UBC elsetton@uvic.ca
Abstract: The objective of our research was to develop an estimate of the difference in exposure risk to traffic-related air pollution for working and nonworking populations in each of 383 census tracts in Vancouver, Canada, as part of the Border Air Quality Study. Using data from 16 fixed monitoring sites, we produced an interpolated surface of mean hourly nitrogen dioxide (NO2) for one day. We used this surface to calculate mean hourly NO2 for each census tract as the base scenario where exposure is indicated by the ambient level of NO2 in the census tract of residence. To investigate the effect of commuting, we developed a spatial exposure simulation model using GIS and C++. Cumulative frequency distributions of exposure risk to NO2 in each census tract were developed by randomly sampling from possible NO2 distributions (derived from the interpolated surface) in six microenvironments. Time-activity patterns from the Canadian Human Activity Pattern Survey and work flow data from Statistics Canada were used to characterize working and nonworking people. We found that estimating exposures based on residential location only was less accurate for workers than for non-workers. For workers, the simulated mean tended to be higher than the mean hourly NO2 in each census tract. For workers, there was at least a 10 percent chance that the simulated exposure was more than +/-10 percent away from the mean hourly NO2 in 382 out of 383 census tracts, and a 50 percent chance in 90 census tracts. For non-workers, there was at least a 10 percent chance that the simulated exposure was more than +/- 10 percent away from the mean hourly NO2 in only 86 of the 382 census tracts, and a 50 percent chance in only 2 census tracts. This approach produces results may be used to conduct sensitivity analyses of epidemiological studies by identifying study subjects to exclude on the basis of residence in a census tract with a high probability of error attributable to commuting.*
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T3-C.4 3:15 PM Traffic hotspots, highways and proximity to sensitive receptors as inputs to environmental health risk management in the South Bronx, New York. Restrepo CE*, Naphtali ZS, Zimmerman R; New York University cer202@nyu.edu
Abstract: Air pollution resulting from traffic and transportation-related activities has been linked to a number of health risks, including respiratory morbidity and mortality. In this study we use GIS as an analytical tool to examine the proximity of risk factors such as high traffic volume intersections and highways to sensitive receptors such as public elementary schools, hospitals and nursing homes. The analyses are conducted for the South Bronx, New York City. The study area is characterized by some of the highest asthma rates in the United States and air pollution is considered a contributing factor to asthma exacerbations and hospitalizations. The South Bronx is surrounded by a number of highways, including the Cross Bronx Expressway, Major Deegan Expressway and Bruckner Expressway. Traffic volumes of 1,500-2,500 vehicles per hour in the morning rush hours are not uncommon along these highways. In addition, the area includes a high number of waste transfer stations, food markets, and other facilities associated with high volumes of diesel truck traffic. For elementary schools the number and percentage of students within 500 meters of highways, as well as within 1/8 and 1/4 of a mile of the highways and the highest traffic volume intersections are presented. The same analysis is presented for the number and percentage of hospital and nursing home beds. Understanding the proximity of environmental health risks such as high traffic volume intersections and highways to sensitive receptors provides a GIS-based analytical risk management tool for urban planners and policy makers to formulate environmental risk management strategies to mitigate health problems and improve quality of life for residents in the area.
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