Abstract: Objective：To assess the association between particulate air pollution and hospital admissions for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in Beijing, and to eva-luate the differences of association among different subgroups.Methods: Hospital admissions to intertiary hospitals for AECOPD from  January 1，2014, through  December 31, 2015 were obtained from the electronic hospitalization summary reports (HSRs).We obtained the data on air pollution during the study period from the national air pollution monitoring system. The data on meteorological variables were obtained from the Chinese meteorological bureau. A poison generalized additive model was used to assess the effects of particulate pollution on AECOPD with adjustment for the long term trend, day of week, holiday effect and meteorological variables. Subgroup analyses were also conducted by age and gender, which would help identify higher-risk groups. Results: A total of 7 884 hospitalizations from 15 tertiary hospitals were recorded during the study period, and 69.3% were male patients, 37.1% were ≥80 years of age, 45.5% were 65－79 years of age, and 17.4% were younger than 65. The mean (SD) daily concentrations of PM2.5, PM10 were 77.1 (66.6) μg/m3, 111.9 (75.8) μg/m3. Every 10 μg/m3 increase in particulate pollution concentration for a lag of 4 d was associated with an increase in hospital admissions for AECOPD as follows: 0.53% (95% CI: 0.01%－1.06%, P=0.0478) of PM2.5, 0.53% (95% CI: 0.07%－1.00%, P=0.0250) of PM10, respectively. We found differences in risk for AECOPD admissions among the different subgroups. For every 10 μg/m3 increase in PM2.5, PM10 exposure in the female group there was a 1.13% (95% CI: 0.19%－2.07%, P=0.018 3) increase, 1.06% (95% CI: 0.22%－1.91%, P=0.013 6) increase in admissions, respectively, while in the male group, the association was non-significant. The patients of 80 years of age and older demonstrated a hi-gher risk of AECOPD, 1.25% (95% CI: 0.40%－2.11%, P=0.004 0) increase of PM2.5, 1.18% (95% CI: 0.42%－1.95%, P=0.002 4) increase of PM10, respectively, while other subgroups didn’t find significant association. Conclusion: Our findings showed that particulate air pollution was significantly associated with hospital admissions for AECOPD in Beijing. The susceptibility to particulate pollution varied by gender and age.

Key words: Air pollution, Particulate maller, Pulmonary disease, chronic obstructive, Generalized additive model