Effects of air pollution on the respiratory tract of children.

The effects of air pollution on pulmonary function and respiratory status was evaluated in 1,626 school aged children from a European Alpine region. Based on measurements of SO2, NO2, and O3 as well as infrared imaging and lichen mapping, three zones of exposure were defined. Results of standardized respiratory questionnaires, medical examinations, and lung function tests were compared among the children in the three different exposure zones. After controlling for age, sex, height, socioeconomic status, and exposure to environmental tobacco smoking, areas of increased SO2 and NO2 as well as areas of increased ozone (max. half hourly mean value, 146 ppb) were significantly associated with decrements of forced expiratory volume in 1 s (FEV1) and flow rates at 50 and 75% of vital capacity (FEF50, FEF75). In addition, areas with increased ozone had a higher prevalence of asthma In all regions, maternal smoking was associated with reduced expiratory flow rates and increased prevalence of asthma. The results provide evidence that outdoor pollution and exposure to passive smoking are risk factors for childhood respiratory health.