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INDOOR-OUTDOOR PM2.5 AND PM10 IN NEW YORK CITY
Citation:
Kendall, M., L. Bonnano, L A. Wallace, AND M. Lippmann. INDOOR-OUTDOOR PM2.5 AND PM10 IN NEW YORK CITY. 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:
PM health effects have been reported to be highest in sensitive subpopulations such as COPD patients. Since such individuals are spend higher proportions of their day indoors, the relationship between indoor and outdoor concentrations is therefore particularly important. The identification of the determinants of indoor concentrations - e.g., outdoor PM and indoor sources - is therefore also a priority for these individuals. In this study, the indoor-outdoor PM2.5 and PM10 concentrations of eight COPD patient homes in NYC were monitored over two 12 day periods during winter and summer. Simultaneous measurements of indoor-outdoor PM2.5 and PM10 concentrations were made at a central monitoring site (CMS) at 1st Ave. and 26th St. in Manhattan. Sampling locations were within a five mile radius of the CMS. Time-activity diaries were filled in by all study participants.
The 24 hour mean indoor PM2.5 concentration was 27.8 ug m-3 in summer and 20.1 ug m-3 in winter for the group. PM2.5 concentrations were higher indoors compared to outdoors, and higher in summer than in winter. The mean PM2.5 indoor-outdoor ratio was 1.2 for winter and 1.5 for summer. PM2.5 indoor-outdoor ratios ranged between 0.9-1.4 for winter and 0.4-2.5 in summer. On average, the indoor PM2.5 concentration represented 77% and 76% of indoor PM10 concentrations in winter and summer, respectively. PM2.5 concentrations indoor and outdoors were more closely correlated than the corresponding PM10 indoor and outdoor measurements.
Peak PM10 concentrations also occurred indoors and during summer. Mean PM10 indoor-outdoor ratios were 1.4 for winter and 1.8 during summer. PM10 indoor-outdoor ratios ranged between 1.0-1.9 for winter and 1.0-3.4 in summer. PM10 indoor-outdoor ratios were higher than PM2.5 indoor-outdoor ratios in both winter and summer.
The relationship between the 24 hour mean PM2.5 and PM10 concentrations over the 12 day sampling period varied between subjects. In some cases, PM2.5 was a good predictor of PM10, a poor predictor in others. R2 values of correlations between indoor and outdoor concentrations over time varied subject to subject, with an overall mean of r2 = 0.52 for PM2.5 and r2 = 0.34 for PM10. The relationships between the indoor and outdoor concentrations were assumed to be a function of the home micro-environment, since a high correlation between PM2.5 tended to predict a good correlation between PM10.
Comparison of central and distributed sampling locations demonstrated good agreement between outdoor PM concentrations. PM2.5 concentrations (in and outdoor) were more correlated than the corresponding PM10. However correlations between PM2.5 and PM10 concentrations over the sampling period varied. On average, indoor PM2.5 accounted for approximately 80% of indoor PM10 in both summer and winter. In general, PM2.5 concentrations were higher indoors than outdoors and higher in summer than winter. Maximum intra-PM sample type concentrations were consistently recorded in summer. Indoor-outdoor ratios of both PM2.5 and PM10 were also higher in summer than in winter.
This work was funded by EPA cooperative agreement #CR827164. This abstract has been reviewed by EPA and approved for publication.