北京交通环境污染诊断模拟初步研究

NUMERICAL SIMULATION STUDY OF POLLUTION FROM TRAFFIC EXHAUST-GAS IN BEIJING URBAN AREA

建立了能够用于评估大型城市交通环境污染与气象条件关系的数值模拟技术 ,即三维边界层光化学数值模式。其中 ,高分辨率的精细城市边界层气象场、细致的城市地理与环境参数、空气污染物输送扩散与大气化学模拟以及交通废气污染源的分布等诸多因子是实施模拟研究的几个重要环节。从模拟结果看出 ,各污染物在地面附近浓度相对高值区位于排放源附近和下风方。在边界层顶附近 ,污染物浓度分布较均匀 ,分布趋势和气流一致。虽然仅仅考虑了城区污染物本底浓度和主要交通干道机动车的排放 。

A three dimensional photochemical pollution model with high spatial resolution for the urban atmospheric boundary layer is used to simulate the environment pollution under some meteorological conditions. Such factors as the meteorological fields (non hydrostatic closure, strong stability and high resolution), the simulation of air pollutants (diffusion, transportation and reaction) and the distribution of emission sources are the key points of the successful simulation. From the simulation result, we can see that the higher concentration areas lay near the emission sources and the down wind direction. Near the top of PBL, the distribution of pollutants follows the wind. Though only the background concentrations and the emissions from the traffic exhaust gas on the main roads are considered, the traffic emissions take a very important part in the whole average pollution level.