Association between ambient air pollution and the risk of hospitalization for acute exacerbation of chronic obstructive pulmonary disease: modifying effects of meteorological factors

Background Ambient air pollution is a major risk factor for acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, evidence on the modifying effects of meteorological factors on air pollutants remains limited and inconsistent. Methods Daily hospitalization data for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in Wanzhou District, Chongqing Municipality, from 2018 to 2022, along with concurrent air pollution and meteorological factor data, were collected. A distributed lag nonlinear model (DLNM) was employed to evaluate the association between ambient air pollutants and the risk of AECOPD hospitalization, and to analyze the modifying effects of wind speed and rainfall on air pollutants. The quantile g-computation (Qgcomp) model was applied to estimate the joint effects of multi-pollutant mixtures. Results DLNM revealed that NO ₂ exposure exhibited a significant acute effect on the day of exposure (lag0) (RR = 1.020, 95% CI: 1.001, 1.038). The effect of PM _2.5 was characterized by a lag pattern, peaking at lag7 (RR = 1.010, 95% CI: 1.002, 1.018). Furthermore, significant cumulative exposure effects were observed for PM _2.5 (RR = 1.028, 95% CI: 1.008, 1.049) and NO ₂ (RR = 1.044, 95% CI: 1.015, 1.075), with the cumulative risk for NO ₂ peaking at lag0-4 (RR = 1.056). Interaction analysis indicated that wind speed significantly amplified the effects of PM _2.5 and PM ₁₀ on hospitalization risk, while rainfall increased the risk associated with NO ₂ . Additionally, the Qgcomp model revealed that the joint effect of pollutant mixtures was particularly pronounced during the cold season, among males, and in the elderly population, with NO ₂ identified as the primary contributing component. Conclusions Short-term exposure to NO ₂ and PM _2.5 significantly increased the risk of AECOPD hospitalization. Notably, this study provides the first evidence that wind speed and rainfall act as important effect modifiers of this association. We provide epidemiological evidence elucidating the role of coexposure to ambient air pollutants and meteorological factors in triggering AECOPD, and underscores the importance of implementing targeted measures to control particulate matter and NO ₂ emissions, as well as enhancing the protection of susceptible populations, for the prevention of AECOPD.