This article is a commentary on the following two studies: Nafstad P, Haheim LL, Wisloff T, Gram F, Oftedal B, Holme I, Hjermann I, Leren P. Urban air pollution and mortality in a cohort of Norwegian men. Environ Health Perspect. 2004 Apr;112(5):610-5. Nafstad P, Haheim LL, Oftedal B, Gram F, Holme I, Hjermann I, Leren P. Lung cancer and air pollution: a 27-year follow-up of 16,209 Norwegian men. Thorax. 2003 Dec;58(12):1071-6. While the short-term effects of urban air pollution are well documented, the long-term effects are much less so, particularly in Europe. This study analyzes the impact of urban pollution on overall and cause-specific mortality in a single city using a cohort of men residing in Oslo, Norway, over the period from 1974 to 1998. The second article focuses specifically on the incidence of lung cancer, a disease linked to smoking but also to environmental pollution. What sets this study apart is that the exposure data used are not aggregated data, as was the case in the studies by Pope and Dockery, but rather data estimated annually at the participants’ residential addresses using a geographic information system. (Excerpt from the article)