This article is a commentary on the following study: Horak F Jr, Studnicka M, Gartner C, Spengler JD, Tauber E, Urbanek R, Veiter A, Frischer T. Particulate matter and lung function growth in children: a 3-year follow-up study in Austrian schoolchildren. Eur Respir J. 2002 May;19(5):838-45. Numerous epidemiological studies have demonstrated a short-term negative effect of particulate matter on respiratory function; however, few of them have examined the impact of air pollution on the development of respiratory function. The objective of this prospective cohort study, which included 975 Austrian schoolchildren from 21 schools selected across eight study areas in Lower Austria and conducted between September 1994 and September 1997, was to investigate the impact of PM10 particles and other air pollutants on the development of children’s respiratory function. Preliminary results covering the first two years of follow-up have been previously published. This study is one of the few cohort studies examining the long-term impact of air pollution on the development of respiratory function in children. Most epidemiological studies have, in fact, examined the short-term effects of air pollution on respiratory function by correlating one-time measurements of pollutant levels with respiratory function. The results of this study regarding the associations between NO₂ and FVC, between NO₂, O₃, and PM₁₀ on the one hand and FEV₁ on the other, and between PM₁₀ and DMS25-75 are compared in the article with those obtained by Gauderman et al. in their cohort of school-aged children in 12 urban areas in Southern California. Since then, Gauderman et al. have published new and very interesting findings regarding their cohort of California children (followed from ages 10 to 18) in the New England Journal of Medicine (2004), further confirming the harmful effect of pollutants, particularly PM2.5 and NO2, on the development of respiratory function. Children most exposed to pollutants suffered from a clinically significant deficit in FEV1 in adulthood. (Excerpts from the articles)