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ASSOCIATIONS BETWEEN OUTDOOR PARTICULATE (PM2.5) CONCENTRATIONS AND GASEOUS CO-POLLUTANT EXPOSURE LEVELS FOR COPD AND MI COHORTS IN ATLANTA, GA
Reid, C. M., P. B. Ryan, A. Wheeler, L A. Wallace, AND H. H. Suh. ASSOCIATIONS BETWEEN OUTDOOR PARTICULATE (PM2.5) CONCENTRATIONS AND GASEOUS CO-POLLUTANT EXPOSURE LEVELS FOR COPD AND MI COHORTS IN ATLANTA, GA. 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.
Epidemiological studies indicate that daily ambient particulate matter (PM2.5) concentrations are associated with increased mortality, hospital admissions, and respiratory and cardiovascular effects. It is possible that the observed significant associations are the result of confounding by ozone, nitrogen dioxide, or sulfur dioxide, as ambient concentrations of these pollutants are often correlated with those of PM2.5. This paper presents some of the results from an exposure and health conducted during fall 1999 and spring 2000 in metropolitan and suburban Atlanta, GA. In this study, repeated personal, indoor, and outdoor PM2.5, PM10, sulfate, carbon monoxide, elemental and organic carbon measurements were made, together with air exchange rate and cardiac health measurements for persons with chronic obstructive pulmonary disease (COPD) or who had a recent heart attack (MI). In the fall and spring, 24 and 22 individuals participated in the study, respectively. During each season, measurements were made for each participant over seven consecutive 24-hr periods using a multi-pollutant sampling device.
This paper uses the PM2.5 and gaseous pollutant data to assess the potential for confounding of observed associations between PM and adverse health. Preliminary mixed modeling regression analyses indicate that personal PM2.5 levels were significantly associated with corresponding outdoor levels, as the slope of the regression line equaled 0.8 (s.e.=0.07, p<0.0001) in the fall and 0.27 (s.e.=0.09, p=0.004) in the spring. The regression of personal ozone levels on outdoor ozone levels yielded regression lines with small but statistically significant slopes, equaling 0.12 (s.e.=0.02, p<0.0001) and 0.08 (s.e.=0.02, p=0.0005) in the fall and spring respectively. In both seasons, outdoor PM2.5 and outdoor ozone have associations that are marginally significant at the 0.10 level . Personal PM2.5 levels were not significantly associated with personal or outdoor ozone levels in either season.
This work has been funded by the United States Environmental Protection Agency under EPA Cooperative Agreement number (CR827159). It has been subjected to Agency review and approved for publication.