Emergency room visits for respiratory diseases associated with ambient fine particulate matter in Taiwan in 2012: A population-based study

This population-based study explored the effects of ambient fine particulate matter (PM2.5) on hospital emergency room visits (ERVs) for respiratory diseases (RDs) in Taiwan in 2012. Data on hospital ERVs for RDs and ambient PM2.5 levels in 2012 were obtained from the National Health Insurance Research database and the Environmental Protection Administration, respectively. The lag structure of relative risks (RRs) of hospital ERVs for RDs was estimated using the Quasi-Poisson generalized additive model. During the study period, the average daily number of hospital ERVs for RDs, chronic obstructive pulmonary disease (COPD), acute exacerbation chronic obstructive pulmonary disease (AECOPD), asthma, and pneumonia were 17, 15, 17, 17, and 17, respectively, and the mean 24-h average PM2.5 concentration was 27.8 μg/m3. Increased hospital ERVs for RDs were significantly associated with PM2.5; moreover, geographic variation in PM2.5 hospital ERVs for RDs was observed. In terms of RRs for each 10 μg/m3 increase in PM2.5, Kao-Ping air quality zone (with districts: Kaohsiung and Pingdong) had the largest RRs associated with PM2.5; the RRs were 1.23 [95% confidence interval (CI) = 1.05-1.45] for AECOPD (at lag 0-1 days), 1.07 (95% CI = 1.01-1.13) for asthma (at lag 0-1 days), and 1.07 (95% CI = 1.01-1.13) for pneumonia (at lag 0-1 days). On hot season, the RRs were 1.05 (95% CI = 1.01-1.08) for AECOPD (at lag 0-3 days); moreover, on cold season, the RRs were 1.15 (95% CI = 1.03-1.28) for asthma (at lag 0-1 days) and 1.15 (95% CI = 1.03-1.28) for pneumonia (at lag 0-1 days). Overall, PM2.5 exposure had lag effects on hospital ERVs for RDs; elevated RRs started at 2-day (lag 0-1 days), and larger RR estimates were observed at longer lags. In summary, this study revealed an association between PM2.5 and hospital ERVs for RDs in Taiwan.