To reduce the vehicular emissions of air pollutants, various trafc control programs (TCPs) have been used. In2002, two TCPs have been implemented in Seoul and Busan, respectively. In this study, based on the study resultson the effectiveness of the TCP in Seoul(Kim et al., 2005) and Busan(Lee et al., 2006), emission reduction by theTCP in Seoul was estimated and their contribution to the ambient air pollutants’ concentrations was discussed.2, 80%for HC, 23% for PM10, and 24% for SO2. Vehicular emission reduction affected the ambient concentrations signi-cantly for NO2. However, for SO2, vehicular emission reduction did not affect the ambient concentration signicant-ly. For PM10fugitive emissions.