| Harbin is the capital city of Heilongjiang province, and it is also the political, economic and cultural center of Northeast China. With rapid development of Industry and economy and population the in recent years, the consumption of the coal and the amount of vehicle is rising, which emitted a large number of pollutants into the atmosphere. Besides, the special weather and geographical conditions together lead to frequent haze weather. In view of the increasingly severe air quality in Harbin, it is imperative to carry out air quality forecasting.In this paper, the mesoscale meteorological model(WRF) and the air quality dispersion model(CALPUFF) were used to simulate the concentrations of SO2, NO2 and PM2.5 in heating or non-heating period and serious haze period of Harbin in 2013, in order to establish the air quality forecasting system in Harbin and basic application. At the same time, based on the concentration contribution results of the pollution sources, the article put forward air pollution prevention and control measures of Harbin.Firstly, based on CALPUFF model to collect and classify emission data in Harbin in 2013. The larger emission sources which have higher height of chimney were set to point sources, and others were divided into area sources with the region as a unit. According to the requirements of the model, setting up the parameters of different types of emissions sources to establish the emissions of pollution sources in Harbin.Secondly, simulation the meteorological conditions of different periods(heating period and non-heating period) of Harbin by WRF/CALMET system. The simulation results show that surface wind direction in heating period is southwest wind and in nonheating period are southeast or southwest wind. As the special terrain in Harbin, the surface wind field in Harbin is always rotating. In contract, the high altitude wind field is not affected by the terrain. In the heating period, because of the lower mixing height and ground radiation make the obvious inversion phenomenon. And large inversion layer easily leads to serious pollution weather. In non-heating period, mixing height is very high and inversion phenomenon occurs less frequently, so it is not easy to cause pollution weather. Besides, the stability in heating period and non-heating period of Harbin are mainly E or F in night, but they are usually A or B or C during the day.Thirdly, based on WRF/CALPUFF model established the air quality forecasting system, the forecasting effect of the system for SO2, NO2 and PM2.5 in Harbin is better and the accuracy degree can reach about 70% compared with monitoring results. That is the results of the air quality forecasting system can reflect the air quality in Harbin. At the same time, the concentrations simulation results of the forecasting system are as follows: in heating period, SO2, NO2 and PM2.5 concentrations are higher than these in non-heating period, and the maximum concentrations appear in different regions; in non-heating period, the overall concentrations of SO2, NO2 and PM2.5 in Harbin are lower, and these are lower than the national secondary standards. The simulation results of haze occurrence process in Harbin are as follows: in meteorology, the most serious pollution period is almost static wind, and the average mixing height is very low, which makes the pollutant spread difficultly in horizontal and vertical direction. In terrain, due to the low terrain of municipal district and surrounding mountains barrier make the pollutants easy to gather in the ground, causing severe haze weather. The contribution concentrations results show that pollution mainly come from area sources contribution in heating period, the point sources contribution has risen in the non-heating period; and whether heating period or non-heating period, municipal district is the main source of pollution concentrations contribution.At last, according to the above results, the article puts forward the air pollution prevention and control measures for Harbin, in order to provide scientific basis for the environmental protection department of Harbin which formulates the air pollution prevention and control regulations. |
