Does temperature enhance acute mortality effects of ambient particle pollution in Tianjin City, China.

Only a few epidemiological studies have explored whether there were interactive effects between temperature and particulate matter <10μm in aerodynamic diameter (PM(10)) on mortality, especially in Asian countries. The present study used time-series analysis to explore the modification effects of temperature on the association between PM(10) and the cause-specific mortality for cardiovascular, respiratory, cardiopulmonary, stroke and ischemic heart diseases (IHD), as well as non-accidental mortality in Tianjin between 2007 and 2009. Results showed that the PM(10) effects were stronger on high temperature level days than that on low temperature level days. The interactions between PM(10) and temperature were statistically significant on cardiovascular, cardiopulmonary, and IHD mortalities. The effect estimates per 10-μg/m(3) increase in PM(10) concentrations at the moving average of lags 0 and 1 day in high temperature level were 0.62% (95% confidence interval (CI): 0.27, 0.97) for non-accidental, 0.92% (0.47, 1.36) for cardiovascular, 0.74% (-0.33, 1.82) for respiratory, 0.89% (0.47, 1.32) for cardiopulmonary, 0.65% (0.00, 1.31) for stroke and 1.20% (0.63, 1.78) for IHD mortalities. In addition, the PM(10) effects on high temperature level days were stronger on older (≥65 years) compared with younger subjects (<65 years). This suggests that the modifying effects of the temperature should be considered when analyzing health impacts of ambient PM(10).