[Motor vehicle source contributions to air pollutants in Beijing]

Beijing's motor vehicle emission inventory based on GIS technology was developed, and used to estimate the contribution rate of different types of vehicles and different areas of vehicles to the total vehicular emissions in the urban area of Beijing. ISCST3, a gaussian dispersion air quality model, was modified at low wind speed condition, and then used to facilitate the study of the spatial and temporal distribution of CO and NOx concentrations in Beijing. It was shown that vehicle source emissions of CO and NOx accounted for 76.8% and 40.2%, respectively, of the total emissions in 1995. The simulation results also showed that emissions from the vehicle sources had contributed 76.5% and 68.4% of the total CO and NOx concentrations in urban atmosphere of Beijing in 1995, and were even higher at down-town and near the arteries. Therefore, strategies for CO and NOx pollution control will of necessity need to focus on the vehicle sources.