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ANALYSIS OF COMPONENTS OF PARTICULATE MATTER (PM2.5) FOR AN EXPOSURE ASSESSMENT STUDY OF TWO SENSITIVE COHORTS IN ATLANTA, GA
Citation:
Wheeler, A., H. Suh, P. Koutrakis, C. Reid, L A. Wallace, AND B. Ryan. ANALYSIS OF COMPONENTS OF PARTICULATE MATTER (PM2.5) FOR AN EXPOSURE ASSESSMENT STUDY OF TWO SENSITIVE COHORTS IN ATLANTA, GA. Presented at International Society of Exposure Analysis 2002 Conference, Vancouver, Canada, August 11-15, 2002.
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:
Introduction
An exposure assessment study was conducted in Atlanta, GA during fall 1999 and spring 2000 to examine the short-term effects of exposure to particulate matter and gaseous air pollutants on heart rate variability (HRV). Characterization of particulate matter (PM2.5) for personal, indoor and outdoor environments will be presented for both seasons.
Methodology
Personal exposure monitoring along with indoor and outdoor sampling was conducted for a group of individuals with chronic obstructive pulmonary disease (COPD) or recent myocardial infarction (MI). In the Fall component of the study, 24 participants were included in the study. Fifteen of these individuals had moderate to severe physician diagnosed COPD, while nine were three to twelve months post MI. Each individual was monitored for seven 24-h periods. During each period, personal, indoor, and outdoor multi-pollutant concentrations were measured, with five individuals monitored simultaneously. Daily information on air exchange rates, time/activity patterns, and housing characteristics was also obtained. 24-h air exchange rates were measured using a constant release perfluorocarbon tracer (PFT) and capillary absorption tubes (CAT). During each monitoring day, participants also completed time/activity diaries, in which they recorded their activities in 15-minute intervals. Technicians administered a daily housing questionnaire each monitoring day to identify any specific activities that could influence particulate concentrations within the homes.
Components of PM2.5 will be analyzed to determine the influence of specific sources upon personal, indoor and outdoor exposure patterns. Mixed effects models will be used to assess seasonal and individual specific variability.
Analysis
Preliminary results of the mixed models indicate that there is a significant difference between the fall and spring. Personal exposure to PM2.5 is more strongly associated with outdoor PM2.5 concentrations during the fall. Individuals with COPD show weaker associations between personal PM2.5 exposure with the corresponding outdoor concentrations than individuals who had a myocardial infarction. Further analysis of the effects of ventilation and time activity diaries will be presented along with other PM2.5 components.
This work has been funded wholly by the United States Environmental Protection Agency under EPA Cooperative Agreement number (CR827159). It has been subjected to Agency review and approved for publication