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 d istribution of vehicle emissions and concentrations in Beijing based on the limited database. The vehicle sources were treated as both line sources an d area sources to make full use of the available data. For line sources, su bstantial 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 o n population density and road area in the grids. A mathematical dispersion model, Industrial Sources Complex Short Term Version 3 (ISCST3), was used t o simulate the pollutant concentration distribution in urban areas based on the meteorological data and the emissions distribution mentioned above. Th e verification data show that method is accurate in the Beijing urban area, and the results show that the vehicle emissions in Beijing contributed sig nificantly to the simulated pollutant impact, and the polluted areas correl ate with population. (C) 1999 Elsevier Science Ltd. All rights reserved.