Abstract: The effect of motor vehicle exhaust on urban air quality in Jinan City was studied herein. Based on the on-line monitoring data at Sites 1 and 2, and the projected results from CMAQ (community multi-scale air quality) for four simulated scenarios, the characteristics of air pollutants in Jinan City during the heating season were investigated to evaluate the influence of vehicle types on six air pollutants. The results are as follows:(1) The average monthly ρ(PM_2.5), ρ(PM₁₀), ρ(NO₂), ρ(CO), ρ(O₃) and ρ(SO₂) are 435 μg/m³, 702 μg/m³, 84.2 μg/m³, 6.8 mg/m³, 4.5 μg/m³ and 92 μg/m³ during the heating season. (2) On December 24^th, 2015 (haze days), ρ(CO), ρ(PM_2.5) and ρ(PM₁₀) at Site 1 increased significantly, while ρ(SO₂), ρ(O₃) and ρ(NO₂) concentrations did not change significantly. The occurrence of these peaks coincided with the peak commuting times. Studies have shown that all pollutants except O₃ and SO₂ exceed the national Level 2 standard specified in Ambient air quality standard (GB 3095-2012), and that the characteristics of air pollution in the Jinan City heating season are those of particulate pollution. Moreover, motor vehicles are significant contributors of NO₂ and PM₁₀. (3) The contribution rates of different types of vehicles to the four kinds of conventional air pollutants varies greatly because of differences in quantity and speed. The small car has the largest contribution rate to CO, NO₂, PM₁₀ and PM_2.5 and these values are 87.5%, 50.1%, 53.4% and 52.8%, respectively. Motor vehicle emission can reduce the mass concentration of air O₃ with a total contribution of -25.5%. The contribution rates of large car, medium car and small car to air O₃ are -8.8%, -2.7% and -8.9%, respectively. The total contribution rate of the mass concentration of the air pollutants on haze days is higher than that of the heating season. On haze days, the contributions of various vehicle types to different pollutant concentrations in the air increased. The results show that the characteristics of environmental air pollution in Jinan City is particulate pollution, and vehicle emission sources contribute a lot to NO₂ and PM_2.5 in the air.