Associations between short-term exposure to air pollution and acute exacerbation of chronic bronchitis: A time-stratified case-crossover study.

Objective: This study aimed to explore the associations between short-term air pollution exposure and acute exacerbation of chronic bronchitis (AECB).

Methods: AECB data were collected from hospital surveillance systems in Shanghai, China, during 2018-2022. Exposure pollution data were obtained from China high resolution high quality near-surface air pollution datasets and assigned to individuals based on their residential addresses. The time-stratified case crossover design combined with the conditional logistic regression model were used to estimate the associations between air pollution and AECB. Weighted quantile sum regression evaluated combined pollution effects and key pollutants.

Results: A total of 2202 hospitalized cases with AECB were included. On day 7 of the average lag (lag 07-day), the odds ratios (OR) of air pollution (Particulate matter with aerodynamic diameters of ≤2.5 μm (PM_2.5), 2.5-10 μm (PM_2.5-10), and ≤ 10 μm (PM₁₀), Ozone (O₃), Sulfur dioxide (SO₂), Nitrogen dioxide (NO₂)) with AECB increased by 10 μg/m³ were 1.07 (95 % confidence interval (CI): 1.02-1.12), 1.13 (1.06, 1.21), 1.06 (1.03-1.09), 1.03 (1.01-1.06), 2.05 (1.51-2.80) and 1.11 (1.05-1.18), respectively. Combined exposure was also positively associated with the risk of AECB (OR 1.04, 95 % CI 1.00-1.08), with O₃ being the most significant.

Conclusions: This study demonstrates that short-term exposure to air pollution was significantly associated with higher risk of AECB. O₃ might contribute the most to AECB. Policymakers should pay more attention to air pollution control.