Short-term exposure to high ambient air pollution aggravates respiratory symptom and lung function in asthma patients in Bejing, China

Background: Air pollution can cause acute exacerbation of asthma. We aimed to investigate the short-term respiratory effects of ambient air pollution in asthma patients in Beijing, China. Methods: A panel of 32 asthma patients was recruited and repeatedly recorded for asthma control test ( ACT ) score, and measured for lung function in November 2015 - December 2016 . Daily ambient air pollution data including PM2.5, PM10, SO2, NO2 and CO were obtained from nearby central air-monitoring stations. Mixed effects models in R 3.3.2 were used. Results: We collected repeated clinical datas every 1 month for 2 to 13 times for 32 asthma patients (totally 266 visits). Interquartile range (IQR) increase in PM2.5 (74.5 μg/m3, 6-d ), PM10 (78 μg/m3, 5-d), SO2 (10 μg/m3, 7-d), NO2 (37 μg/m3, 6-d) and CO (0.7 μg/m3, 6-d) were significantly associated with reduction in ACT score of 3.6 % (95% CI: -6.3%, -0.9%), 2.8% (95% CI:-5.1%, -0.5%), 3.2 % (95% CI: -5.5%, -0.9%), 3.8% (95% CI:-7.0%, -0.5%) and 2.9 % (95% CI: -4.3%, -1.4%), respectively. An IQR of 78μg/m3 in 7-d PM10 moving average concentrations were significantly associated with a 3.6%（95%CI: -5.6%, -1.5%）reduction in FEV1% and a 6.0%（95%CI: -9.2%, -2.7%）reduction in FEF 25%, respectively. Conclusions: Ambient air pollution may aggravate respiratory symptoms and lung function of asthma patients in Beijing, China.