Short-term exposure to coarse particulate matter and outpatient visits for cardiopulmonary disease in a Chinese city

Limited studies have been conducted to evaluate the short-term relationships between exposure to coarse particulate matter (PM2.5-10) and outpatient visits in China. We designed this time-series analysis in a Chinese city Yancheng, to explore the relationship of PM2.5-10 with outpatient visits for cardiopulmonary diseases. The study period was from 2013 to 2015. A typical generalized additive model was used. We explored the lag patterns by building a series of lag of exposure. We also built two-pollutant models to ascertain the independence of PM2.5-10. Stratified analyses were applied to compare the season-specific associations. Finally, we pooled the concentration-response (C-R) curves for PM2.5-10 and outpatient visits. We recorded a daily average of 85 and 43 outpatient visits for cardiovascular and respiratory causes, respectively. PM2.5-10 exposures of lag 05 day yielded the best estimates for both outcomes. Per 10-mu g/m(3) increase in PM2.5-10, there was a 1.69% (95% confidence interval [CI]: 0.68%-2.72%) increase in outpatient visits for respiratory causes, and a 0.85% (95% CI: 0.13%-1.57%) increase for cardiovascular causes. The association kept robust after adjusting for PM2.5 and O-3, and there were larger associations in warm seasons. The C-R curves had a larger slope for respiratory diseases in relatively lower concentrations (< 30 mu g/m(3)), and PM2.5-10 was positively associated with cardiovascular diseases in higher concentrations (> 30 mu g/m(3)). This study indicated significant associations of PM2.5-10 with cardiopulmonary outpatient visit. Such results may be used for health risk assessment and policy making for particulate air pollution control.