Assessment of vehicular pollution in China

As the motor vehicle population in China continues to increase at an annual rate of similar to 15%, air pollution related to vehicular emissions has b ecome the focus of attention, especially in large cities. There is an urgen t need to identify the severity of this pollution in China. Based on an inv estigation into vehicle service characteristics, this study used a series o f driving cycle tests of in-use Chinese motor vehicles for their emission f actors in laboratories, which indicated that CO and HC emission factors are 5-10 times higher, and NOx 2-5 times higher, than levels in developed coun tries. The MOBILES model was adapted to the Chinese situation and used to c alculate the emission of pollutants from motor vehicles. Results show that vehicle emission is concentrated in major cities, such as Beijing, Guangzho u, Shanghai, and Tianjin. Motor vehicle emissions contribute a significant proportion of pollutants in those cities, with contribution rates of CO and NOx greater than 80% and 40%, respectively, in Beijing and Guangzhou. Urba n air quality is far worse than the national ambient air quality standard. In conclusion, although China has a relatively small number of motor vehicl es, most of them are concentrated within metropolitan areas, and their emis sions are closely related to urban air pollution problems in large cities.