An article published by the American Thoracic Society in the March 15, 2006 edition of the American Journal of Respiratory and Critical Care Medicine discusses the findings of investigators who extended the Harvard Six Cities fine particulate air pollution study by eight years and found that reduced levels of tiny particle pollution during this period lowered mortality risk for participants. The study population consisted of 8,096 white participants residing in Watertown, Massachusetts; Kingston and Harriman, Tennessee; St. Louis, Missouri; Steubenville, Ohio; Portage, Wyocena, and Pardeeville, Wisconsin; and Topeka, Kansas. Lead investigator Dr. Francine Laden of Channing Laboratory in Boston, Massachusetts, and three associates found that the largest drops in adjusted mortality rates were in cities with the greatest reduction in fine particulate air pollution (PM2.5). They report that this reduction was observed specifically for deaths due to cardiovascular and respiratory disease and not from lung cancer, a disease with a longer latency period and less reversibility. To view the abstract click here: //ajrccm.atsjournals.org/cgi/content/abstract/173/6/667