A study of the emission and concentration distribution of vehicular pollutants in the urban area of Beijing

A method was developed in this paper to estimate the spatial and temporal distribution of vehicle emissions and concentrations in Beijing based on the limited database. The vehicle sources were treated as both line sources and area sources to make full use of the available data. For line sources, substantial counting of vehicles on site had been conducted to determine the traffic flow and vehicle type mixture; for area sources, the total non-line-source vehicle-traveled mileage was distributed to different grids based on population density and road area in the grids. A mathematical dispersion model, Industrial Sources Complex Short Term Version 3 (ISCST3), was used to simulate the pollutant concentration distribution in urban areas based on the meteorological data and the emissions distribution mentioned above. The verification data show that method is accurate in the Beijing urban area, and the results show that the vehicle emissions in Beijing contributed significantly to the simulated pollutant impact, and the polluted areas correlate with population.