This article is a commentary on the following study: "A case-crossover analysis of out-of-hospital coronary deaths and air pollution in Rome, Italy." Forastiere F, Stafoggia M, Picciotto S, Bellander T, D'Ippoliti D, Lanki T, von Klot S, Nyberg F, Paatero P, Peters A, Pekkanen J, Sunyer J, Perucci CA. Am J Respir Crit Care Med. 2005;172(12):1549-55.