Changes in the relationship between ambient fine particle concentrations and childhood lung function over 5 years

Abstract

BackgroundExposure to ambient fine particles, particulate matter with an aerodynamic diameter of ≤2.5 μm (PM2.5), is a public health concern. Concentrations of ambient PM2.5 have changed temporally in the past 10 years after a series of action policies for improving air quality were implemented in Taiwan. In this study, temporal changes in the relationship between PM2.5 and lung function among children were investigated. MethodsA nationwide respiratory health survey was conducted among Taiwanese elementary and middle school students in 2011 and again in 2016–2017. A questionnaire was administered to students, for whom forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were measured using spirometry. During the study period, monthly concentrations of ambient PM2.5 were obtained from the monitoring stations of the Environmental Protection Administration. Lung function measurements were compared with ambient PM2.5 exposure using mixed-effects models. ResultsIn the 2011 survey (mean PM2.5: 40.6 μg/m3), exposure to PM2.5 in the preceding 1–2 months was associated with a 2.2% decrease (95% confidence interval [CI]: −4.1%, −0.3%) in FVC and a 2.3% decrease (95% CI: −4.0%, −0.5%) in FEV1. By contrast, a significant relationship between PM2.5 concentrations and lung function was not observed in the 2016–2017 survey (mean PM2.5: 30.0 μg/m3). ConclusionsAs improvement in air quality over time, the negative relationship between PM2.5 and childhood lung function tend to be not significant.