TOC SUMMARY: It is unclear how air pollution contributes to the development of cardiovascular disease. We investigated the change of coronary atherosclerosis using serial CCTAs in relation to the cumulative amount of PM2.5 exposure between the two CCTAs in 3,127 healthy adults. Coronary calcification progressed in 1,361 (43.5%) subjects with a positive relationship between the cumulative amount of PM2.5 exposure and CACS. The cumulative amount of PM2.5 exposure, rather than the average concentration of PM2.5, was independently associated with progression of coronary calcification and diffuse development of de novo calcified plaques, with its impact higher than any other traditional cardiovascular risk factors.