The effect of early life exposure to air pollution on lung function in non-asthmatic Taiwan school children born in 1996-2004

Background: Although air pollutants have been associated with lung function changes in children, only few studies investigated life-long exposure to ambient air pollution on the schoolchildren’s lung function. This study examined effects of air pollutants on schoolchildren’s lung function in different time period. Methods: In 2011, spirograms were obtained from a random sample of non-asthmatic children from 22 middle schools in 22 administrative districts in Taiwan after a questionnaire survey for atopic diseases. Based on air pollutant data obtained from Taiwan Environmental Protection Agency monitoring stations, concentrations of pollutants in each township was estimated using the Arc9 Geographic Information System''s Kriging method. Yearly exposure of the participants to CO, NO2, O3, PM10, and SO2 was estimated according to their living townships. Hierarchical linear regression and was used to calculate lung function percent and simple linear regression was used analyze the relationship between lung function parameters and exposures in the first year after birth, and in 2-6 years of life. Results: A total of 535 girls and 481 boys without asthma history were enrolled in the study. After adjustment with 2-month average exposure, forced expiratory volume in forced expiratory flow at 25% of FVC (FEF25%) was negatively associated with O3 in 2-6 years of life. Each 4 ppb O3 increment 2-6 years of life was related to 4.38% decrement of FEF25% with 95% confidence interval [-8.61%, -0.14%]. Exposure to CO, NO2, PM10, or SO2 in the first year of life and 2-6 years had no significant association with forced vital capacity, forced expiratory volume in 1 second, forced expiratory flow at 25% of FVC, and maximal-mid expiratory flow (MMEF) in complete study group or in other subgroup analysis. Conclusion: In addition to the negative effect of past two-months level of PM2.5 and ozone, early life exposure to ozone has significant negative influence on lung function in schoolchildren with allergic rhinitis. This effect is not observed in children without allergic rhinitis. This observation indicates that allergic rhinitis may be the susceptible marker of ozone’s effect on lung function.