There were limited studies concerning ambient air pollution exposure on development of bronchitic symptoms among children. These studies provided suggestive but inconclusive results. Therefore, the objective of this study is to assess the association between air pollutants and the prevalence of bronchitic symptoms in the Taiwan Children Health Study.
We conducted a nationwide cross-sectional study of 5,049 Taiwanese children in 2007. Routine air pollution monitoring data were used for sulfur dioxide (SO2), nitrogen dioxides (NO2), ozone (O3), carbon monoxide (CO), and particles with an aerodynamic diameter ≤ 2.5 μm (PM2.5). The exposure parameters were calculated using the between-community 3-year average concentration. The effect estimates were presented as odds ratios (ORs) per interquartile changes for SO2, NO2, O3, CO, and PM2.5.
In the two-stage hierarchical model adjusting for confounding, the prevalence of bronchitic symptoms with asthma was positively associated with the between-community 3-year average concentrations of NO2 (adjusted OR, 1.81 per 8.79 ppb; 95% CI, 1.14-2.86), and CO (OR, 1.31 per 105 ppb; 95% CI, 1.04-1.64). The prevalence of phlegm with no asthma was related to O3 (OR, 1.32 per 8.77 ppb; 95% CI, 1.06-1.63).
The results suggest that long-term exposure to outdoor air pollutants, such as NO2, CO, and O3, may increase the prevalence of bronchitic symptoms among children.