Urban air pollution has been gradually increasing by the increase of population and vehicles recently. There are shown larger effects of air pollution in Incheon city which has more than 2 million people and has heavy holding amounts ratio of transportation vehicles as compared with other cities. However, it is very difficult to predict the air quality condition of their moving pollutants. Therefore, in this study air pollution measuring model was designed to estimate the air pollution level by line sources(transprtation vehicles ) of air pollutants and to detect the $NO_x$ emission amounts in ordinary times, and it became clear that it is functionally operative.