Fine particulate air pollution and daily mortality in Shenyang, China.

Fine particulate matter (PM₂.₅) is not a criteria pollutant in China, and few studies were conducted in the country to investigate the health impact of PM₂.₅. In this study, we did a time-stratified case-crossover analysis to examine the association between PM₂.₅ and daily mortality in Shenyang, an industrial center in northeast China. Daily mortality, air pollution and weather data from August 1, 2006 to December 31, 2008 in Shenyang were collected. A time-stratified case-crossover approach was used to estimate the association of PM₂.₅ with both total and cause-specific mortality. Controls were selected as matched days of the week in the same month. Potential effect modifiers, such as age, gender, and season, were also examined. We found significant associations between PM₂.₅ and daily mortality in Shenyang. A 10 μg/m³ increment in the 2-day moving average (lag 01) concentrations of PM₂.₅ corresponded to 0.49% (95% CI: 0.19%, 0.79%), 0.53% (95% CI: 0.09%, 0.97%), and 0.97% (95% CI: 0.01%, 1.94%) increase of total, cardiovascular, and respiratory mortality, respectively. The associations appeared to be stronger in older people (aged ≥ 75 years), in females and during the warm season. To our knowledge, this is the longest PM₂.₅ health study in time duration in China. Our findings provide new information on the adverse health effects of PM₂.₅, and may have implications for environmental policy making and standard setting in China.