Estimated Acute Effects of Ozone on Mortality in a Rural District of Beijing, China, 2005-2013: A Time-Stratified Case-Crossover Study

Studies have shown that ozone (O-3) has adverse impacts on human health. In China, O-3 levels have continued to increase since 2010. When compared to the large number of studies concerning the health effects of PM2.5 in China, there have been limited explorations of the effects of O-3. The Beijing region has one of the highest O-3 concentrations in the country, but there appear to be no published studies regarding the health effects of O-3 in Beijing. In this study, we applied a time-stratified case-crossover design to explore the effects of O-3 on cause-specific mortality for a rural location near Beijing over the period 2005-2013. For year-round effects, we found that for all-causes mortality, with a 10-unit increase in O-3 concentration, the odds ratios (ORs) were in the range of 1.009-1.020 for different lag days. The ORs for cardiovascular mortality with a 10-unit increase in O-3 concentration were in the range of 1.011-1.017 for different lag days. For warm season effects, the ORs with a 10-unit increase in O-3 concentration for all-cause mortality were in the range of 1.025-1.031 for different lag days. The ORs for cardiovascular mortality with a 10-unit increase of O-3 concentration were in the range of 1.020-1.024 for different lag days. Our findings fill a knowledge gap that has hitherto existed in studies regarding O-3 health impacts, and our results will strengthen the rationale for O-3 control in China.