An increased concentration of air pollution within metropolitan areas is associated with progression in coronary calcification and with acceleration of atherosclerosis, according to a study published in The Lancet.In the prospective, 10-year cohort study, Northwestern Medicine scientists and collaborators at other institutions repeatedly measured coronary artery calcium by CT scan in 6,795 participants aged 45 to 84 years, who were enrolled in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) in six metropolitan areas in the U.S.