This article is a commentary on a study published in the journal J Occup Environ Med 2005;62:543-460. While the short-term links between air pollution and mortality have been extensively studied in both Europe and North America, prior to the publication of the article discussed here, only a few studies on long-term links were available in Europe, and none in France. The Paarc study was launched in the mid-1970s in seven French cities with the aim of studying the effects of air pollution on chronic respiratory diseases. The sample collected for this study made it possible to assess the long-term effects of air pollution and to examine the factors likely to influence them. Although the study has limitations—similar to those encountered in many studies on the same topic and inherent in particular to the difficulties of assessing long-term exposure to air pollution—it is one of the few to provide an assessment of the long-term risks of air pollution in Europe. Estimates of the long-term effects of particulate air pollution appear to be quite comparable in Europe and the United States. This provides some insight into a recurring question regarding the validity of using North American risk ratios to assess the long-term health impacts of air pollution in Europe. While only the implementation of large-scale cohort studies in European countries will allow for a detailed answer to this question, the results of this study, as well as those of other European studies whose findings have been published recently (see the other articles analyzed in this issue of Extrapol), show that the use of North American results appears appropriate while awaiting the results of these cohort studies, which by their nature take a long time to implement. (Excerpts from the article)