This article is a commentary on the following study: Chen LH, Knutsen SF, Shavlik D, Beeson WL, Petersen F, Ghamsary M, Abbey D. The association between fatal coronary heart disease and ambient particulate air pollution: Are females at greater risk? Environ Health Perspect. 2005 Dec;113(12):1723-9. Epidemiological studies have shown an increased risk of death from cardiopulmonary diseases, non-cancerous respiratory diseases, and respiratory tract cancer associated with chronic exposure to ambient particulate matter. Studies examining short-term effects have shown that ambient particulate matter increases the risk of cardiac arrhythmia, inflammatory responses, plasma viscosity, and other blood markers. These observed effects provide mechanisms through which chronic exposure to ambient pollution is associated with a risk of coronary heart disease. The objective of this study was to examine the risk of death from coronary heart disease associated with long-term exposure to ambient particulate matter in the AHSMOG (Adventist Health Study on the Health Effects of Smog) cohort. This study presents results consistent with those of other published cohorts showing an effect on mortality associated with chronic exposure to urban air pollution. (Excerpts from the article)