ABSTRACT
Objective To carry out a quantitative estimate that related to the effects of shortterm exposure to PM2.5 on all-cause mortality and emergency visits in China by using the systematic review and Meta-analysis.Methods We selected all the studies published before March 2018 from China National Knowledge Infrastructure,Wanfang database,PubMed and EMBASE and data on relative risk (RR),excess risk (ER) and their 95％CIs:appeared in these papers were extracted.According to the differences in the size or direction (heterogeneity) of the results,we computed summary estimates of the effect values using a random-effect or fixed effect model.We also conducted the subgroup analysis and Meta-analysis to have assessed the selected studies for the evidence of study bias.Results A total of 33 original studies,indexed in databases,were identified.Among those studies,39 sets of data on mortality and 4 sets of data on emergency were valid to show that within the daily concentration range from 47.7 to 176.7 pg/m3,for 10 μg/m3 increases in PM2.5 concentrations,it would increase the daily numbers of deaths by 0.49％ (95％CI:0.39％-0.59％) and 0.30％ (95％CI:0.10％-0.51％) for all-cause deaths and all-cause emergency-room visits,respectively.For subgroup analysis,the combined effect of PM2.5 in causing short-term all-cause deaths in the northern areas (ER=0.42％,95％CI:0.30％-0.54％) seemed lower than that in the southern areas (ER=0.63％,95％CI:0.44％-0.82％).The combined effect of PM2.5 concentration below 75 μg/m3 (ER=0.50％,95％CI:0.37％-0.62％) was higher than that of PM25 concentration ≥75 μ g/m3 (ER=0.39％,95％ CI:0.26％-0.52％).Conclusion Within the concentration range from 47.7 to 176.7 μg/m3,short-term exposure to current level of PM2.5 might increase both the all-cause daily mortality and daily emergency visits in China.
ABSTRACT
Objective To carry out a quantitative estimate that related to the effects of shortterm exposure to PM2.5 on all-cause mortality and emergency visits in China by using the systematic review and Meta-analysis.Methods We selected all the studies published before March 2018 from China National Knowledge Infrastructure,Wanfang database,PubMed and EMBASE and data on relative risk (RR),excess risk (ER) and their 95％CIs:appeared in these papers were extracted.According to the differences in the size or direction (heterogeneity) of the results,we computed summary estimates of the effect values using a random-effect or fixed effect model.We also conducted the subgroup analysis and Meta-analysis to have assessed the selected studies for the evidence of study bias.Results A total of 33 original studies,indexed in databases,were identified.Among those studies,39 sets of data on mortality and 4 sets of data on emergency were valid to show that within the daily concentration range from 47.7 to 176.7 pg/m3,for 10 μg/m3 increases in PM2.5 concentrations,it would increase the daily numbers of deaths by 0.49％ (95％CI:0.39％-0.59％) and 0.30％ (95％CI:0.10％-0.51％) for all-cause deaths and all-cause emergency-room visits,respectively.For subgroup analysis,the combined effect of PM2.5 in causing short-term all-cause deaths in the northern areas (ER=0.42％,95％CI:0.30％-0.54％) seemed lower than that in the southern areas (ER=0.63％,95％CI:0.44％-0.82％).The combined effect of PM2.5 concentration below 75 μg/m3 (ER=0.50％,95％CI:0.37％-0.62％) was higher than that of PM25 concentration ≥75 μ g/m3 (ER=0.39％,95％ CI:0.26％-0.52％).Conclusion Within the concentration range from 47.7 to 176.7 μg/m3,short-term exposure to current level of PM2.5 might increase both the all-cause daily mortality and daily emergency visits in China.