Assessing subgroup differences and underlying causes of ozone-associated mortality burden in China using multi-source data

Long-term ozone exposure is a significant public health concern. To mitigate its impact, it is crucial to identify diseases, populations, and regions that are particularly sensitive to ozone. In this study, we used high-quality data and updated relative risk estimates to investigate subgroup differences in mortality burden due to ozone exposure in China. In 2020, nationwide ozone-associated deaths totaled 276,800 (95 % CI: 106,700–451,900), representing 3.2 % of all deaths, with respiratory and cardiovascular diseases accounting for 16.8 % and 83.2 %, respectively. The per capita ozone-associated mortality in China was 20 per 100,000 person-years, with a significantly higher rate observed in elderly individuals aged ≥75 years (189 deaths per 100,000) compared to young individuals aged 30–44 years (1 death per 100,000). There were notable spatial patterns of ozone-associated deaths among the regions, indicating a critical response to ozone levels and population density. Interestingly, urban areas exhibited a 22.4 % lower mortality rate related to ozone compared to rural areas. This difference was attributed to the combined influence of ozone exposure (+19.9 %), population size (+17.7 %), age structure (−39.2 %), and baseline mortality (−20.8 %). By emphasizing subgroup differences and driving factors, these findings significantly enhance the understanding of the ozone-associated mortality burden, providing valuable insights for policymakers.