Meta-analysis of the Impact of Different Ozone Metrics on Total Mortality in China

Abstract

This study explores the effect of different ozone metrics on the total mortality risk in China. Using the CNKI, Wanfang, VIP, Web of Science, and PubMed databases, the time series studies and case crossover studies from the establishment of each database to December 31, 2020 were retrieved, and 22 eligible studies were included in this analysis. A meta-analysis was performed for the ozone metrics of O3-M1h, O3-M8h, and O3-24h. The results indicated that the increase in the total mortality risk is more closely associated with O3-M1h (RR #, 1.0052; 95%CI, 1.0031-1.0073) and is more weakly associated with O3-24h (RR #, 1.0036; 95%CI, 1.0025-1.0048) and O3-M8h (RR #, 1.0031; 95%CI, 1.0022-1.0041). A subgroup analysis of the three metrics revealed that the total mortality risk of ozone is higher in the cold season, the elderly (≥ 65) are more vulnerable to ozone pollution, and the total mortality risk in the north is higher than that in the south.