This article is a commentary on a study published in the journal Eur Respir J 2002;19:690-8. The role of exposure to traffic-related air pollution (TRAP) in exacerbating respiratory symptoms has already been documented, particularly in cross-sectional studies. The associations between TRAP exposure and asthma or respiratory function remain less well understood. The assessment of TRAP exposure is sometimes imprecise. Since direct measurements are not feasible at the epidemiological level, the use of modeling appears more appropriate. Gehring et al. assess the role of exposure to APE on the respiratory health of children born between 1995 and 1999 and living in Munich during their first two years of life. This study, published in 2002, is one of the first to assess the role of exposure to vehicle exhaust, estimated through modeling, as part of a longitudinal follow-up of newborns. The authors demonstrated an association between exposure to vehicle-related pollutants, estimated through modeling, and the risk of coughing without infection and nocturnal dry cough before the age of one. While this is one of the first publications reporting an effect of AEP on respiratory health in a newborn cohort study, traffic-related pollutant dispersion models appear to have evolved rapidly since then: they are likely more refined and better suited to studying the long-term health impact of AEP. (Excerpts from the article)