Objective To investigate the relationship between acute exacerbation of chronic obstructive pulmonary disease (COPD) and exposure to air pollutants, including fine particulate matter (PM_2.5), in Anqing, Anhui province, China.

Methods The clinical data of 380 patients with acute exacerbation of COPD who were admitted to Anqing Municipal Hospital in Anhui province from January 2023 to December 2024 were selected from the hospital information system. Patient data, admissions for acute exacerbations, and contemporary monitoring data for air pollutants including PM_2.5 were analyzed. Spearman rank correlation analysis was used to examine the relationship of daily mean concentrations of air pollutants (such as PM_2.5) with the number of acute exacerbations of COPD and changes in clinical indicators. A generalized additive model (GAM) was used to analyze the effects of PM_2.5 on the risk of acute exacerbations in patients with COPD and its lag effect.

Results From 2023 to 2024, the daily median mass concentration of PM_2.5 in Anqing was 28 μg/m³. Correlation analysis showed that PM_2.5 was positively correlated with the number of COPD-induced admissions (r_s=0.452, P < 0.01), FVC (r_s=0.306, P < 0.01), and FEV₁ (r_s=0.378, P < 0.01). GAM analysis revealed that the risk of COPD-induced admissions associated with PM_2.5 exposure peaked on the same day of exposure (lag0 d). For each 10 μg/m³ increase in PM_2.5 concentration, the excess risks (ER) and 95% confidence intervals (CI) for total COPD admissions and male patient admissions were 2.78% (0.29%, 5.14%) and 3.21% (0.68%, 5.77%), respectively. Significant cumulative lag effects were observed from lag01 d to lag05 d (P < 0.05). The maximum ER for total COPD-induced admissions and male admissions occurred at lag05 d and lag04 d, with ER (95% CI) of 5.20% (2.51%, 10.12%) and 5.92% (2.01%, 9.74%), respectively. The maximum ER for female admissions occurred at lag03 d, with an ER (95% CI) of 4.37% (0.72%, 8.09%). In two-pollutant models adjusted for SO₂, CO, O₃-8 h, NO₂, and PM₁₀, the ER (95% CI) for COPD-induced admissions were 2.92% (0.28%, 5.57%), 5.00% (2.29%, 7.71%), 3.99% (1.46%, 6.52%), 3.20% (0.75%, 5.65%), and 1.85% (0.12%, 3.58%), respectively. In the multi-pollutant model simultaneously adjusted for CO and O₃-8 h, the ER (95% CI) for COPD-induced admissions was 4.95% (1.88%, 8.02%).

Conclusion Increased mass concentrations of air pollutants, particularly PM_2.5, in Anqing, Anhui province, are associated with an increased number of patients with acute exacerbations of COPD, exhibiting some time-lag effect.