SUMMARYSurface ozone (O 3 ) pollution, a critical environmental challenge facing government agencies at all levels, is becoming more and more serious in China, especially in rapidly developing urban areas like Beijing. However, in China, few studies have evaluated the contribution of various pollution sources to surface O 3 , e.g. motor vehicles. In this paper, we combined a non-linear model with an analysis of motor vehicle emissions of NO x and VOCs in an integrated approach to estimate the contribution of motor vehicle emissions to surface O 3 . The model showed that, in urban areas of Beijing in 2000, the contribution of motor vehicle emissions to surface O 3 was 45.9%, and that elimination of 20.0% of motor vehicle emissions will lead to a 7.4% reduction in surface O 3 , while elimination of 20.0% of NO x or VOC emissions from motor vehicles will result in a 5.0% and 2.5% decline, respectively, in surface O 3 . In addition, elimination of 10,000 t of NO x from motor vehicles results in the same reduction in surface O 3 as elimination of 25,631 t of VOCs. Thus, controlling NO x emissions from motor vehicles is an effective way to control surface O 3 pollution in the study area.