Association between ozone and influenza transmissibility in China

BACKGROUND: Common air pollutants such as ozone (O(3)), sulfur dioxide (SO(2)), nitrogen dioxide (NO(2)), and particulate matter play significant roles as influential factors in influenza-like illness (ILI). However, evidence regarding the impact of O(3) on influenza transmissibility in multi-subtropical regions is limited, and our understanding of the effects of O(3) on influenza transmissibility in temperate regions remain unknown. METHODS: We studied the transmissibility of influenza in eight provinces across both temperate and subtropical regions in China based on 2013 to 2018 provincial-level surveillance data on influenza-like illness (ILI) incidence and viral activity. We estimated influenza transmissibility by using the instantaneous reproduction number ([Formula: see text] ) and examined the relationships between transmissibility and daily O(3) concentrations, air temperature, humidity, and school holidays. We developed a multivariable regression model for [Formula: see text] to quantify the contribution of O(3) to variations in transmissibility. RESULTS: Our findings revealed a significant association between O(3) and influenza transmissibility. In Beijing, Tianjin, Shanghai and Jiangsu, the association exhibited a U-shaped trend. In Liaoning, Gansu, Hunan, and Guangdong, the association was L-shaped. When aggregating data across all eight provinces, a U-shaped association was emerged. O(3) was able to accounted for up to 13% of the variance in [Formula: see text] . O(3) plus other environmental drivers including mean daily temperature, relative humidity, absolute humidity, and school holidays explained up to 20% of the variance in [Formula: see text] . CONCLUSIONS: O(3) was a significant driver of influenza transmissibility, and the association between O(3) and influenza transmissibility tended to display a U-shaped pattern. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-023-08769-w.