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USE OF PERSONAL-INDOOR-OUTDOOR SULFUR CONCENTRATIONS TO ESTIMATE THE INFILTRATION FACTOR AND OUTDOOR EXPOSURE FACTOR FOR INDIVIDUAL HOMES AND PERSONS
Citation:
WALLACE, L. A. AND R. W. WILLIAMS. USE OF PERSONAL-INDOOR-OUTDOOR SULFUR CONCENTRATIONS TO ESTIMATE THE INFILTRATION FACTOR AND OUTDOOR EXPOSURE FACTOR FOR INDIVIDUAL HOMES AND PERSONS. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 39(6):1707-1714, (2005).
Impact/Purpose:
The primary objectives are:
1) to complete the validation and development of exposure databases resulting from the NERL PM panel studies (data produced under TDs 5676 and 3937),
2) to perform analyses on these databases and identify key factors that have the potential of influencing human exposures to PM constituents, and
3) to summarize and report the findings of these additional analyses.
Description:
A study of personal, indoor, and outdoor exposure to PM2.5 and associated elements has been carried out for 37 residents of the Research Triangle Park area in North Carolina. Participants were selected from persons expected to be at elevated risk from exposure to particles, and included 29 persons with hypertension and 8 cardiac patients with implanted defibrillators. Participants were monitored for 7 consecutive days in each of four seasons. One goal of the study was to estimate the contribution of outdoor PM2.5 to indoor concentrations. Using the daily estimated infiltration factor for each house, we calculated the contribution of outdoor PM2.5 to indoor air concentrations. The indoor-generated contributions to indoor PM2.5 had a wider range (0-33 µg/m3) than the outdoor contributions (5-22 µg/m3). However, outdoor contributions exceeded the indoor-generated contributions in 27 of 36 homes.
A second goal of the study was to determine the contribution of outdoor particles to personal exposure. The estimates ranged from 0.33 to 0.77 with a median value of 0.53. Outdoor air particles were less important for personal exposures than for indoor concentrations, with the median outdoor contribution to personal exposure just 49%. These values provide an indication of the extent of misclassification error in epidemiological estimates of the effect of outdoor particles on health.