Effects of ambient air pollution on the prevalence of pneumonia in children: Implication for National Ambient Air Quality Standards in China

Pneumonia is the most important cause of child death in the world today. Recent findings suggest that exposure to outdoor air pollutants may increase the pneumonia occurrence, but so far the associations have not been clearly illustrated. Therefore, the effects of outdoor air pollutants and the episode day on childhood pneumonia were investigated by this study. A standardized questionnaire on health, home and environmental factors of 4988 children was conducted in the city of Changsha, China. Average exposure to ambient air pollutants during 2008-2011 was monitored by the air pollution monitoring stations of Changsha Environmental Protection Agency. A two-stage hierarchical regression approach was adopted to estimate the effects of PM10, SO2 and NO2 on pneumonia risk. The prevalence of pneumonia in children aged 3-6 years was 38.2%, which is greatly higher than the developed countries but lower than some developing countries. Furthermore, the increased risk of childhood pneumonia was significantly associated with elevated NO2 concentration (odds ratio (OR) = 1.157, 95% confidence interval (CI): 1.121-1.195) and the episode day (OR = 1.038, 95% CI: 1.024-1.051), but not significantly associated with PM10 and SO2. Exposure to traffic-related air pollution could play an important role in the development of pneumonia in preschool children. The revised National Ambient Air Quality Standards (2012) for NO2 has provided a better control strategy for ambient air quality to reduce the risk of adverse health effects such as pneumonia for children.