Trace metals and ionic components associated with airborne PM 2.5 samples collected from a roadside sampling station Daejeon city, Korea, were measured from April to December 2008. The sampling site was located several kilometers from the heavy-traffic intersection of the four-lane Honam highway and Yusung hot spring region. A total of six source types were identified to be important, i.e., sulfate related, vehicle exhaust, nitrate related, road dust, fossil fuel combustion, and soil dust. Vehicle exhaust was dominated by such elements as Br, Sb, and Cu. The road dust emits, when the emissions (vehicle exhaust from mobile sources, abrasion of tire and brake linings, other oils, etc.) were combined with resuspended soil dust deposited previously on the roads. Fossil fuel combustion was reflected by the high percentage of As, Cl, Se, Zn, and black carbon. This is an abstract of a paper presented at the 104th AWMA Annual Conference and Exhibition 2011 (Orlando, FL 6/21-24/2011).