This article is a commentary on the following study: "Baccarelli A, Zanobetti A, Martinelli I, Grillo P, Hou L, Giacomini S, Bonzini M, Lanzani G, Mannucci PM, Bertazzi A, J Schwartz. Effects of exposure to air pollution on blood coagulation. J Throm Haemost. 2006;5:252-60."