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PERSONAL PARTICULATE MATTER EXPOSURE MONITORING: IDENTIFYING IMPORTANT SOURCES, ACTIVITIES, AND LOCATIONS BASED ON DATA FROM THE NERL RTP PM PANEL STUDY
Citation:
Rea, A W., R W. Williams, L S. Sheldon, J. Thornburg, AND C. Rodes. PERSONAL PARTICULATE MATTER EXPOSURE MONITORING: IDENTIFYING IMPORTANT SOURCES, ACTIVITIES, AND LOCATIONS BASED ON DATA FROM THE NERL RTP PM PANEL STUDY. Presented at American Association for Aerosol Research, Portland, OR, October 15-19, 2001.
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 longitudinal particulate matter (PM) exposure study was conducted in the Research Triangle Park, NC area between June 2000 and June 2001. Participants were selected from two groups of potentially susceptible sub-populations: a group of African-Americans living in an environmental justice area in southeast Raleigh, and a group of cardiac patients with implanted cardiac defibrillators in Chapel Hill, NC. All of the participants were over 50 years old, ambulatory, and non-smokers. Approximately 35 participants were sampled for 7 consecutive days during each of 4 sampling seasons (~28 days total for each participant). Personal and indoor monitoring included PM2.5 mass as well as continuous (1 min. avg. time) nephelometer measurements (personal DataRAM, MIE Inc.). Detailed time activity information (15 min time resolution), follow up questionnaire data on exposure to particle sources, and residential information were also collected.
Participants from both cohorts spent the majority (>70%) of their time inside at home during the summer and fall seasons (winter and spring data are unavailable at this time, but will be presented). Both groups also spent about the same amount of time outside away from home (1-4%), in transit (4-6%), and inside away from home (9-10%). The cardiac participants spent ~5% of their time outdoors at home during both the summer and fall seasons, whereas the African-American participants spent 2.5% of the time outside at home. Despite the similarities in time activity patterns between each season, PM exposures measured by the personal nephelometers varied similarly for both cohorts. Most notably, PM exposure outside at home was about six times higher in the summer than in the fall. Personal PM exposure while being inside away from home was about five times higher in the summer than in the fall. These differences were likely due to different activities noted during each season. For example, participants noted more outdoor grilling, mowing, and burning trash in the summer season. Mean (? std. dev.) PM exposure while at home (49 ? 923 microg/m-3 summer; 35 ? 117 micrograms per cubic meter fall), at work (41 ? 61 micrograms per cubic meter summer; 50 ? 71 micrograms per cubic meter fall), traveling (39 ? 80 micrograms per cubic meter summer; 30 ? 48 micrograms per cubic meter fall), and outside away from home (39 ? 37 micrograms per cubic meter summer; 32 ? 42 micrograms per cubic meter fall) were similar during both summer and fall seasons. The variability associated with being at home was due to more frequent frying and other types of cooking in the summertime. Other personal activities that contributed to personal PM exposure included spraying aerosols (air fresheners, cleaners, or hair spray), cleaning cat litter boxes, burning wood in a fireplace, burning trash outside, outdoor grilling, and automobile/diesel exhaust.
This work has been funded wholly or in part by the US EPA under Contract No. 68-D99-012 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.