Ambient particulate matter air pollution associated with acute respiratory distress syndrome in Guangzhou, China

Limited evidence exists concerning the impact of particulate pollution on acute respiratory distress syndrome (ARDS). We examined the effects of particulate pollution on emergency ambulance dispatches (EAD) for ARDS in Guangzhou, China. Daily air pollution concentrations for PM10, PM2.5, and PM1, as well as PM2.5 chemical compositions, were available from a central air monitoring station. The association between incident ARDS and air pollution on the concurrent and previous 5 days was estimated by an over-dispersed Poisson generalized additive model controlling for meteorological factors, temporal trends, public holidays and day of the week. We identified a total of 17,002 EADs for ARDS during the study period. There were significant associations between concentrations of PM10, PM2.5, PM1, and ARDS; corresponding excess risk (ER) for an interquartile range IQR increase in 1-day lagged concentration was 5.45% [95% confidence interval (CI): 1.70%, 9.33%] for PM10 (45.4 mu g/m(3)), 4.71% (95% CI: 1.09%, 8.46%) for PM2.5 (31.5 mu g/m(3)), and 4.45% (95% CI: 0.81%, 8.23%) for PM1 (28.8 mu g/m(3)), respectively. For PM2.5 chemical compositions, we found that OC, EC, sulfate and ammonium were significantly associated with ARDS. The observed effects remained even after adjusting for potentially confounding factors. This study suggests that PM10, PM2.5, and PM1, as well as chemical constituents from combustion and secondary aerosols might be important triggers of ARDS in Guangzhou.