摘要This study evaluated the impact of Particulate Matter 2.5 (PM2.5) and its components on lung function. In total, 2,045 participants aged 40-89 years were recruited for this multi-center cross-sectional study. Lung function measurements were performed. Real-time PM2.5 and its component data were obtained from atmospheric monitoring sites. Linear mixed-effects (LME) models were used to assess the relationships between PM2.5, its components, and lung function. Weighted quantile sum regression, quantile g-computation, and Bayesian kernel machine regression were applied to assess the joint effects of PM2.5 components on lung function. The mean PM2.5 concentration during the study period was 71.92 μg/m3. Among PM2.5 components, nitrate had the highest mean concentration (16.82 μg/m3), followed by organic carbon and sulfate. In the LME models, PM2.5 exposure at a 1-day lag, scaled to its interquartile range, was significantly related to decreased lung function. Specifically, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), one-second rate (FEV1/FVC), peak expiratory flow (PEF), and forced expiratory flow at 25％ FVC (FEF25％) decreased by 3.75％, 6.56％, 2.89％, 10.48％, and 8.71％, respectively. An age-stratified analysis showed stronger negative associations among participants aged ≥ 60 years compared with middle-aged adults. In mixed-exposure models, the PM2.5 mixture was significantly linked to a decline in lung function. Zinc (Zn) and magnesium ion (Mg2+) were significantly linked to reduced FVC and ammonium ion (NH4+) was identified as a key contributor to reduced FEV1, PEF, and FEF75％. Lung function declined with increasing PM2.5 and its components. Zn, Mg2+, and NH4+ were identified as key components.