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COARSE PARTICULATE MATTER CONCENTRATIONS FROM RESIDENTIAL OUTDOOR SITES ASSOCIATED WITH THE NORTH CAROLINA ASTHMA AND CHILDREN'S ENVIRONMENT STUDIES (NC-ACES)
Citation:
CHEN, F., R. W. WILLIAMS, E. R. SVENDSEN, J. P. CREASON, J. W. SCOTT, D. TERRELL, M. W. CASE, AND K. YEATTS. COARSE PARTICULATE MATTER CONCENTRATIONS FROM RESIDENTIAL OUTDOOR SITES ASSOCIATED WITH THE NORTH CAROLINA ASTHMA AND CHILDREN'S ENVIRONMENT STUDIES (NC-ACES). Presented at International Society for Exposure Analysis Conference, Tucson, AZ, October 30 - November 03, 2005.
Impact/Purpose:
The primary study objective is to quantify the association between day-to-day or experimental variations in ambient air particle mass concentration and selected physiological functions in moderate/severe asthmatic children and adults. The NERL will conduct exposure studies and provide integrated PM mass concentration data to assist the NHEERL collaborators conducting physiological monitoring in establishing selected health effect associations resulting from potential human exposures to PM-related air pollutants. Ambient-based data will be collected to provide source apportionment data pertinent to comparing ambient versus concentrated air pollution (CAP) chamber studies.
Description:
Coarse particulate matter (PM10-2.5) concentration data from residential outdoor sites were collected using portable samplers as part of an exposure assessment for the North Carolina Asthma and Children's Environment Study (NC-ACES). PMcoarse values were estimated using the differential between the independent PM10 and PM2.5 collocated MiniVol measurements. Repeated daily 24-hr integrated PM10 and PM2.5 outdoor monitoring was performed at a total of 26 homes during 9/10/2003 to 6/10/2004. This effort resulted in the collection of 73 total daily measurements. This assessment was conducted to provide data needed to investigate the association of potential exposures to coarse particle PM mass concentrations with observed human health effects. Potential instrument bias between the differential MiniVol methodology and a dichotomous sampler were investigated. A Versatile Air Pollution Sampler and a cyclone inlet were also investigated in the overall comparison by placement of collocated instruments at a central ambient monitoring site. Correction for instrument bias ultimately allowed for a spatial comparison of outdoor residential coarse particle measurements across an area with a radius of 50 km to be performed as part of the NC-ACES . Results indicated that minimal bias (slope=0.97, intercept=0.35) existed between the dichotomous and differential MiniVol procedures. Residential outdoor PMcoarse mass concentrations were observed to be highly variable with respect across measurement days and range from 12.6 to 1.1 µg/m3 (mean of 5.39 µg/m3). The correlation between residential outdoor PMcoarse mass concentrations and those obtained from the central ambient monitoring site were typically greater than r =0.75. These results show that while PMcoarse mass concentrations were quite variable with respect to time they were relatively consistent in relation distances up to 50 km.
Although this work was reviewed by EPA and approved for presentation, it may not necessarily reflect official Agency policy.