Comparison of Air Pollution and the Inflammatory Response of Local Residents in Urban and Rural Beijing, China -- Results of Airless Project

Abstract

Introduction Owing to rapid urbanization, residents in urban and rural greater Beijing area may be exposed to a diverse mixture and varying concentrations of ambient air pollution, resulting in different health responses. However, such comparative investigations are largely lacking.Methodology This study is a part of AIRLESS project, a China-UK joint research which has integrated two intensive air pollution monitoring campaigns, and individual-based panel studies with 250 subjects (aged 40-70 years) recruited from two well established cohorts in urban and rural Beijing. This study aims to quantify and compare 1) ambient PM2.5 concentrations in rural and urban Beijing, and 2) the acute effect of PM2.5 exposure on respiratory and systemic inflammatory biomarkers in local residents. During winter 2016 and summer 2017, each subject completed 4 individual clinical measurements of exhaled NO (FeNO) and blood monocytes counts. These health outcome data were then linked with ambient PM2.5 concentrations obtained from parallelly conducted local monitoring campaigns. Linear mixed-effect models were used to estimate any association.Results Preliminary results showed a clear spatial and seasonal variation of ambient PM2.5 concentration, where daily mean(SD) of PM2.5 during winter and summer were 85.5(78.7) and 48.7(19.2) μg/m3 at the urban site, and 134.0(110.9) and 31.4(14.6) μg/m3 at the rural site, respectively. An IQR increase in previous 1-day ambient PM2.5 (58.0 μg/m3) was significantly associated with the elevation of FeNO [17.8%(95% confidence interval: 14.4-21.3%)] and monocyte counts [1.8%(1.5-2.1%)], after adjusting for covariates (P<0.05). Compared with urban subjects, rural residents showed a lower percentage change in FeNO (R vs. U = 13.1 vs. 30.1%) and higher in monocyte counts (R vs. U = 2.2 vs. 0.7%).Conclusions Residents in urban and rural Beijing are exposed to different ambient PM2.5 concentrations, and have different PM2.5-associated inflammatory responses.