Short-term ozone exposure significantly elevates paediatric respiratory disease risk in Foshan, Southern China

Although an association between ozone (O₃) exposure and respiratory disease (RD) in children has been established, there is significant heterogeneity in global epidemiological evidence. The aim of this study was to fill a regional scientific gap by evaluating the impact of short-term O₃ exposure on hospitalisations for RD among children in Foshan, a city in southern China.

This ecological time-series study used electronic medical records from a hospital in Foshan between 1 July 2021 and 30 June 2024, which included hospitalised children aged 0-14 years with a primary diagnosis of all RD classified according to the International Classification of Diseases 10th Revision (J00-J99). The distributed lag nonlinear model was applied to evaluate the association between O₃ exposure and RD in children.

A total of 3944 hospitalisations for paediatric RD were enrolled, including 2218 boys (56.2%) and 1726 girls (43.8%). With the 2.5th percentile of O₃ concentration as the reference, a 10 μg/m³ increase in O₃ was associated with a peak relative risk at lag days 6 and 7, with relative risk of 1.034 (lag day 6: 95% CI 1.014 to 1.054; lag day 7: 95% CI 1.016 to 1.051). Stratified analyses revealed no significant effect modification by season or sex in the association between O₃ exposure and paediatric RD.

Short-term O₃ exposure significantly increased the risk of paediatric RD hospitalisations in Foshan. These results support the need for region-specific interventions to mitigate health risks from O₃ in children.