Publications (2)0 Total impact
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Ron Williams, Jack Suggs,
Anne Rea,
Kelly Leovic,
Alan Vette,
Carry Croghan,
Linda Sheldon,
Charles Rodes,
Jonathan Thornburg,
Ademola Ejire,
Margaret Herbst,
William Sanders
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ABSTRACT: The US Environmental Protection Agency has recently performed the Research Triangle Park Particulate Matter Panel Study. This was a 1-year investigation of PM and related co-pollutants involving participants living within the RTP area of North Carolina. Primary goals were to characterize the relationships between ambient and residential PM measures to those obtained from personal exposure monitoring and estimate ambient source contributions to personal and indoor mass concentrations. A total of 38 participants living in 37 homes were involved in personal, residential indoor, residential outdoor and ambient PM2.5 exposure monitoring. Participants were 30 non-smoking hypertensive African-Americans living in a low-moderate SES neighborhood (SE Raleigh, NC) and a cohort of eight individuals having implanted cardiac defibrillators (Chapel Hill, NC). Residential and ambient monitoring of PM10 and PM10–2.5 (coarse by differential) was also performed. The volunteers were monitored for seven consecutive days during each of four seasons (summer 2000, fall 2000, winter 2001, spring 2001). Individual PM2.5 personal exposure concentrations ranged from 4 to 218 μg m−3 during the study. The highest personal exposures were determined to be the result of passive environmental tobacco exposures. Subsequently, ∼7% of the total number of personal exposure trials were excluded to minimize this pollutant's effect upon the overall analysis. Results indicated that a pooled data set (seasons, cohorts, residences, participants) was appropriate for investigation of the basic mass concentration relationships. Daily personal PM2.5 mass concentrations were typically higher than their associated residential or ambient measurements (mean personal=23.0, indoor=19.1, outdoor=19.3, ambient=19.2 μg m−3). Mean personal PM2.5 exposures were observed to be only moderately correlated to ambient PM2.5 concentrations (r=0.39).
Atmospheric Environment.
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ABSTRACT: The Research Triangle Park (RTP) Particulate Matter (PM) Panel Study represented a 1-year investigation of personal, residential and ambient PM mass concentrations across distances as large as 70 km in central North Carolina. One of the primary goals of this effort was to estimate ambient PM2.5 contributions to personal and indoor residential PM mass concentrations. Analyses indicated that data from the two distinct non-smoking subject populations totaling 38 individuals and 37 residences could be pooled. This resulted in nearly 800 data points for each variable. A total of 55 measurements believed to have been potentially influenced by personal or residential exposure to passive environmental tobacco smoke were not included in the analysis database. Variables to be examined included Cig (concentration of indoor generated PM), Eig (personal exposure to indoor generated PM), Finf (ambient PM infiltration factor), and Fpex (personal exposure to PM of ambient origin factor). Daily air exchange rates (AER) were measured and statistical modeling to derive estimates of particle penetration (P) and particle deposition (k) factors was performed. Seasonality, cohort grouping, participant or combinations of these variables were determined not to be significant influences in estimating group infiltration factors. The mean (±std) mixed model slope estimates were AER=0.72±0.63, P=0.72±0.21, k=0.42±0.19, and Finf=0.45±0.21. These variables were then used in a number of mixed effects models having varying features of single, random or fixed intercepts and/or slopes to determine the most appropriate means of estimating ambient source contributions to personal and residential settings. A mixed model slope for Fpex (±SE) was 0.47±0.07 using the model with the highest degree of fit.
Atmospheric Environment.
