Impact of ambient ozone exposure on the incidence of unintentional injuries among the elderly aged 60 and above in Shanghai

Objective To explore the acute effects of ambient ozone (O₃) pollution on the occurrence of unintentional injuries among the elderly aged 60 and above in Shanghai, so as to provide a scientific basis for assessing the disease burden attributable to O₃ and for formulating effective prevention strategies. Methods Data on unintentional injury patients aged 60 and above treated at Shanghai Acute Trauma Emergency Centers between 2022 and 2024 were collected, along with the daily data of concurrent ambient air pollutants and meteorological variables from the Shanghai Environmental Monitoring Centre. A generalized additive model (GAM) was used to analyze the association between O₃ exposure and the risk of unintentional injuries. The exposure metric was the daily maximum 8-h moving-average O₃ concentration (O₃-8 h). The excess risk (ER) and its 95% confidence interval (CI) for unintentional injuries were calculated per 10 μg·m^-3 increase in O₃-8 h, thereby evaluating the acute health effects of O₃. Two-pollutant models were used after controlling for other ambient pollutants to evaluate the robustness of the result. Results During the research period, the median M (P₂₅, P₇₅) O₃-8 h concentration was 93.00 (71.00, 122.75) μg·m^-3, exhibiting a seasonal pattern with higher levels in summer and lower levels in winter. A total of 19 009 unintentional injury casesaged 60 and above were included , with a median M (P₂₅, P₇₅) daily admission count of 15 (9, 21). Immediate exposure (lag0) showed the strongest association with injuries: per 10 μg·m^-3 increase in O₃-8 h, the risk of unintentional injuries caused by accidents, falls, and traffic accidents increased by 6.69% (95%CI: 6.11%-7.28%), 6.62% (95%CI: 5.98%-7.26%), and 6.69% (95%CI: 4.87%-8.53%), respectively. The effects were more pronounced in women and adults aged <75 years. In two-pollutant models, O₃ remained significantly associated with increased injury risks after adjusting for other pollutants. Conclusion Ambient O₃ pollution has acute effects on unintentional injuries among the elderly aged 60 and above in Shanghai, elevating the risk of injury occurrence.