Gaseous air pollution and atopy

Background Photochemical air pollutants are commonly thought to be implicat ed in the gradual increase in the prevalence of atopy. However, no epidemio logical data are available. Methods To clarify this issue, we performed a cross-sectional epidemiologic al survey in 2604 primary school children, 10 and ii years old, living in s even communities among which some have the highest photochemical exposure i n France. The mean levels of the main gaseous air pollutants (SO2, NO2 and O-3) were measured during a 2-month period in 1993. The protocol included a standardized questionnaire, skin prick tests to common aeroallergens and i n the atopic children, collection of a sample of mattress dust to measure g roup 1 mite allergens. Atopy was only defined on the basis of the skin pric k tests. Results Percentage of positive skin tests and the number of positive skin t ests were similar in the different communities looked at. The distribution of dust samples with a,group allergen level greater than 2 mu g/g dust, was also similar. Logistic regression analysis including potential confounding factors, as well as the mean level of air pollutants, did not demonstrate any association between atopy and mean SO2, NO2 and O-3 levels. Conclusion The increase in photochemical air pollutants is unlikely to be a major determinant for the recent increase in the prevalence of atopy.