Effects of ambient air pollution on allergic rhinitis among preschool children in Changsha, China

Prevalence of allergic rhinitis has rapidly increased among Chinese children, but the reasons are unclear. Recent findings have suggested that exposure to outdoor air pollutants may increase the risk of allergic rhinitis, but the results were inconsistent. This study further investigated the effect of outdoor air pollutants on allergic rhinitis among preschool children. A standardized questionnaire on health, home and environmental factors was conducted for 4988 children aged 1-8 in the city of Changsha, and the concentrations of PM10 (particle diameter <= 10 mu m), sulfur dioxide (SO2) and nitrogen dioxide (NO2) during 2006-2011 were acquired from the official web of Changsha Environmental Protection Agency. Results showed that the prevalence of children's doctor diagnosed rhinitis was 8.4% (95% confidence interval [CI] 7.0%-10.0%). It was found that the prevalence of rhinitis was not associated with site-specific background concentrations of air pollutants, but significantly positively correlated with age-related accumulative personal exposure of PM10, SO2 and NO2. We conclude that age-related accumulative personal exposure to ambient air pollution may play an important role in the development of rhinitis.