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INDOOR AND OUTDOOR SOURCE CONTRIBUTIONS TO PERSONAL PM2.5 FOR A PANEL OF INDIVIDUALS WITH CARDIOVASCULAR DISEASE OR COPD LIVING IN BOSTON, MA
Brown, K. W., H. H. Suh, L A. Wallace, AND P. Koutrakis. INDOOR AND OUTDOOR SOURCE CONTRIBUTIONS TO PERSONAL PM2.5 FOR A PANEL OF INDIVIDUALS WITH CARDIOVASCULAR DISEASE OR COPD LIVING IN BOSTON, MA. Presented at International Society of Exposure Analysis 2002 Conference, Vancouver, Canada, August 11-15, 2002.
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.
Repeated personal, home indoor, home outdoor, and ambient particulate and gaseous pollutant levels were characterized for individuals with cardiovascular disease or COPD and their partners living in the Boston area. Health status was determined by self-reported history of myocardial infarction, bypass surgery, angina or physician-diagnosed COPD. These individuals were monitored for seven consecutive days during winter 1999-2000 and/or summer 2000. Subjects wore a multi-pollutant monitor to collect simultaneous 24-hour integrated samples for each of the following pollutants: PM2.5, PM10, sulfate, elemental carbon (EC), O3, NO2, and SO2. In addition, home characteristic information was collected for all participants, and 24-hour air exchange rates were measured for each home during each day of the study. Indoor and outdoor measurements at each home were made using the same multi-pollutant sampler. In addition to wearing the sampling equipment, all participants completed daily time-activity diaries in which they recorded their activities and locations throughout the day. Motion sensors with built-in data loggers were also included in the sampling packs worn by participants to better assess compliance with personal monitoring. During each season of the study 154 person-days of personal data were collected. In each season, approximately half of the 15 homes had two personal measurements on a given day due to participation by partners.
The LOD for personal PM2.5 levels was 5.6 ug/m3 in winter and 6.2 ug/m3 in summer. For EC, the LOD was 0.6 ug/m3 in winter and 0.3 ug/m3 EC in summer. The mean personal PM2.5 concentration was 14.2 ug/m3 in winter (med.=11.2, n=145, sd=10.6) and 13.0 ug/m3 (med.=12.0, n=138, sd=8.1) in summer, while corresponding ambient levels were 9.8 (med.=9.2, n=156, sd=5.3) and 11.2 (med.=10.5, n=147, sd=5.8), respectively. The mean personal EC concentration in winter was 1.5 ug/m3 (med.=1.2, n=148, sd=1.6), while the ambient EC concentration was 1.1 (med=0.8, n=139, sd=0.6). In summer, personal EC was 1.8 ug/m3 (med.=1.8, n=141, sd=0.6) and ambient was 1.3 ug/m3 (med.=1.4, n=138, sd=0.4). The relationship between for personal and ambient PM2.5 differed by season, with a median subject-specific Spearman correlation coefficient of 0.29 in winter and 0.71 in summer. For EC, the personal-ambient association was similar in summer and winter (median rs=0.54 in winter and 0.50 in summer). This paper will use mixed models to address indoor and outdoor contributions to personal PM2.5, PM10 and gaseous pollutant exposures. The influence of activity patterns and housing characteristics on the source contributions to personal PM2.5 will also be evaluated. Finally, to address the reliability of using EC as a tracer for ambient pollution, we will analyze the spatial variability of EC within the Boston region during winter and summer sampling seasons.
This work has been funded wholly by the United States Environmental Protection Agency under EPA Cooperative Agreement # (CR827159). It has been subjected to agency review and approved for publication.