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THE ROLE OF SUBPOPULATION, DISEASE STATE, HOUSING, SEASON AND OTHER FACTORS UPON PERSONAL EXPOSURES TO PM OF AMBIENT ORIGIN
Citation:
Williams, R W., J C. Suggs, G F. Evans, A W. Rea, L S. Sheldon, A F. Vette, J M. Burke, C Croghan, K W. Leovic, J P. Creason, D Walsh, C. Rodes, J. Thornburg, P. A. Lawless, A. Ejire, M. Herbst, AND W. Sanders Jr. THE ROLE OF SUBPOPULATION, DISEASE STATE, HOUSING, SEASON AND OTHER FACTORS UPON PERSONAL EXPOSURES TO PM OF AMBIENT ORIGIN. Presented at 2002 AAAR PM Meeting, Pittsburgh, PA, March 31-April 4, 2003.
Impact/Purpose:
The primary study objectives are:
1.To quantify personal exposures and indoor air concentrations for PM/gases for potentially sensitive individuals (cross sectional, inter- and intrapersonal).
2.To describe (magnitude and variability) the relationships between personal exposure, and indoor, outdoor and ambient air concentrations for PM/gases for different sensitive cohorts. These cohorts represent subjects of opportunity and relationships established will not be used to extrapolate to the general population.
3.To examine the inter- and intrapersonal variability in the relationship between personal exposures, and indoor, outdoor, and ambient air concentrations for PM/gases for sensitive individuals.
4.To identify and model the factors that contribute to the inter- and intrapersonal variability in the relationships between personal exposures and indoor, outdoor, and ambient air concentrations for PM/gases.
5.To determine the contribution of ambient concentrations to indoor air/personal exposures for PM/gases.
6.To examine the effects of air shed (location, season), population demographics, and residential setting (apartment vs stand-alone homes) on the relationship between personal exposure and indoor, outdoor, and ambient air concentrations for PM/gases.
Description:
A series of longitudinal particulate matter (PM) and related co-pollutant human exposure panel field studies have recently been completed. Studies were conducted in Baltimore, Maryland (1997,1998) Fresno, California (1999) and Research Triangle Park, North Carolina (2002-2001) and were designed to evaluate the effects of personal exposures to PM of ambient origin under differing sub-populations, regions of the country, seasons, and housing conditions. Participants were monitored over time (28 days) to investigate both longitudinal and cross-sectional correlations between personal, residential indoor, residential outdoor, and ambient measurements. Measurements of PM2.5, PM10 and PM10-2.5 were routinely performed. Copollutant monitoring included CO, O3, NO2, SO2, elemental-organic carbon and metals. Daily time activity diaries and questionnaires were used to document potential sources and influences of PM from all sources. The studies involved a variety of potentially susceptible subpopulations made up of non-smoking, ambulatory volunteers being at least 55 years old. The various cohorts included healthy participants as well as a majority with various pulmonary and cardiovascular disease states such as hypertension. Some of the subjects lived in communal (apartment or cottage-style) housing while others lived in single family residences. The influence of participant lifestyle and employment status was also examined. Approximately 7000 PM mass measurements were obtained from all of these studies. Results revealed a wide range in the magnitude and variability of daily personal PM2.5 exposures (3 to 200 ug/m3). Time activity patterns and estimated exposures to indoor generated sources appeared to be some of the primary factors influencing personal to ambient PM mass concentration associations (ranging from 0.0 to 0.95). Working status did not appear to be highly influential relative to total personal PM2.5 exposure. Mean personal PM2.5 clouds ranged from 3 to 10 ug/m3 relative to the various study populations and were clearly influenced by individual time activity patterns among the participants. PM2.5 ambient mass concentration homogeneity across areas up to 70 km was observed. Results from the RTP-based study show that ambient PM2.5 sources contributed to approximately 50% of the total personal exposure mass concentration regardless of season, residence, occupational status or disease state.
This work has been funded wholly by the United States Environmental Protection Agency under contract #68-D5-0040 and 68-D-99-012 to the Research Triangle Institute and assistance agreement #CR-828186-01-0 to Shaw University. It has been subjected to Agency review and approved for publication.