Meta-analysis of relationship between short-term ozone exposure and population mortality in China

Background In recent years, our country's atmospheric particulate matter pollution has improved significantly, while ozone (O₃) pollution has become increasingly serious. As a secondary pollutant, O₃ is closely related to human health.

Objective To study the effect of short-term exposure to ozone in ambient air on population mortality in China.

Methods A computer search with key words of "ozone or O₃", "death", and "time series" in Chinese or "ozone", "mortality", and "China" in English was performed in Web of Science, PubMed, China National Knowledge Infrastructure, Wanfang, and VIP databases to find literature on effects of short-term ozone exposure on population mortality covering a time period from January 1, 1990 to December 31, 2021. According to a set of inclusion and exclusion criteria developed for this study, literaturescreening, quality evaluation, andrelevant data extraction were carried out. Finally, R 4.1.2 software was used to perform meta-analysis to estimate target effect sizes.

Results A total of 978 articles were retrieved. According to the inclusion and exclusion criteria, 18 articles were finally included, including 39 effect size estimates. The results showed that every 10 μɡ·m⁻³ increase in ambient ozone concentration was associated with an increase of 0.45% (95%CI: 0.39%-0.51%), 0.50% (95%CI: 0.33%-0.68%), and 0.60% (95%CI: 0.48%-0.72%) in total, respiratory, and cardiovascular disease mortalities , respectively. The results of subgroup analysis by age, sex, and season showed that when ozone concentration increased 10 μɡ·m⁻³, an increase of 0.34% (95%CI: 0.17%-0.51%) in mortality was observed in the ≥ 65-year-old population, higher than 0.09% (95%CI: −0.21%-0.39%) increase in the <65-year-old population; the mortality increase in females 0.44% (95%CI: 0.30%-0.58%) was greater than that in males 0.35% (95%CI: 0.22%-0.48%); compared with the warm season 0.29% (95%CI: 0.16%-0.42%), mortality increase was higher in the cold season 1.03% (95%CI: 0.71%-1.35%).

Conclusion Ambient ozone is an important factor affecting population mortality. The elderly and women ≥ 65 years old in China are more sensitive to ozone, and the impact of ozone exposure on population mortality is greater in cold season.