摘要：Most particulate matter (PM) health effects studies use outdoor (ambient) PM as a surrogate for personal exposure. However, people spend most of their time indoors exposed to a combination of indoor-generated particles and ambient particles that have infiltrated. Thus, it is important to investigate the differential health effects of indoor- and ambient-generated particles. We combined our recently adapted recursive model and a predictive model for estimating infiltration efficiency to separate personal exposure ( E ) to PM2.5 (PM with aerodynamic diameter ≤2.5 μm) into its indoor-generated ( E ig) and ambient-generated ( E ag) components for 19 children with asthma. We then compared E ig and E ag to changes in exhaled nitric oxide (eNO), a marker of airway inflammation. Based on the recursive model with a sample size of eight children, E ag was marginally associated with increases in eNO [5.6 ppb per 10-μg/m3 increase in PM2.5; 95% confidence interval (CI), −0.6 to 11.9; p = 0.08]. E ig was not associated with eNO (−0.19 ppb change per 10μg/m3). Our predictive model allowed us to estimate E ag and E ig for all 19 children. For those combined estimates, only E ag was significantly associated with an increase in eNO ( E ag: 5.0 ppb per 10-μg/m3 increase in PM2.5; 95% CI, 0.3 to 9.7; p = 0.04; E ig: 3.3 ppb per 10-μg/m3 increase in PM2.5; 95% CI, −1.1 to 7.7; p = 0.15). Effects were seen only in children who were not using corticosteroid therapy. We conclude that the ambient-generated component of PM2.5 exposure is consistently associated with increases in eNO and the indoor-generated component is less strongly associated with eNO.
关键词：ambient air pollution; asthma; exhaled nitric oxide; infiltration; PM 2.5
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