Air Pollution, Road Proximity, Greenspace, Indoor Air Pollution and Reduced Lung Function Incidence in Children : A Case-control Study

Abstract Objectives Reduced lung function during childhood could substantially influence the health states of the respiratory system in adults, so, the relationships between air pollution, road proximity, greenspace, indoor air pollution and reduced lung function incidence in children were investigated in this study. Methods The lung function of children was tested every year from 2015 to 2018 and the method of case-control study was applied. Propensity score matching (PSM) was performed to minimize confounding bias and the conditional logistic regression model was carried out to evaluate the effects of indoor and outdoor environmental risk factors on reduced lung function of children. Results Each-one quartile increment in the mixture of the six air pollutants at lag1, lag2 and lag3 periods were related to 46.2%, 9.57% and 8.28% increased risk levels of getting the unhealthy outcome. The protective effect of greenness at lag2 period (Odds ratios (OR) = 0.01 (95% confidence interval (CI): 0–0.02)) was stronger than that at lag1 period (OR = 0.03 (95% CI: 0.01–0.05)). Conclusions Separate and combined effects of most air pollutants at different lag periods represented the hazard effects to the lung function of students. And the distance band of 101–200 m between the home address of each student and the major road could be detrimental to the health of the lung of children significantly. Exposure levels of greenness had protective effects on lung health for students. Only the indoor factor of secondhand smoke exposure was significantly associated with an elevated risk of having reduced lung function.