Relationship between Ambient PM_2.5 Exposure and Outpatient Number for Respiratory Diseases in Chaoyang District, Beijing, China: A Time Series Analysis

Objective To explore the effect of ambient PM_2.5 exposure on the outpatient number for respiratory diseases in Chaoyang District, Beijing, China.

Methods The clinical data of outpatient visits for respiratory diseases were collected in a general hospital, a pediatric hospital, and a traditional Chinese medicine (TCM) hospital in Chaoyang District, Beijing in 2013. Meanwhile, daily average PM_2.5, SO₂, NO₂, and PM₁₀ concentrations, temperature, and relative humidity in Chaoyang District, Beijing during the same period were collected as well. The relationship between PM_2.5 concentrations and outpatient number was analyzed using a generalized additive model (GAM).

Results PM_2.5 concentrations had a significant impact on the outpatient number for respiratory diseases in the general hospital and the pediatric hospital (P < 0.05) but not for the TCM hospital (P>0.05). For every increase of 10 μg/m³ in PM_2.5, the excess risks for outpatient visits for respiratory diseases were 0.239 4 (0.099 9~0.378 6) and 0.099 9 (0.010 0~0.199 6), respectively, in the general hospital and the pediatric hospital, with a lag effect.

Conclusion An increase in the atmospheric PM_2.5 concentration in Chaoyang District, Beijing may promote outpatient visits for respiratory diseases in general hospitals and pediatric hospitals.