Study On Atmospheric Environmental Capacity Of PM_2.5 In Heilongjiang Province

Recently,about 80% of the city’s air quality exceeded the standard and PM_2.5 has become the index which should be focused and controlled in China.According to the "Air Pollution Control Action Plan" and the "People’s Republic of China Air Pollution Control Law",it will be the shift from point source treating to focusing managerment,from comprehensive city governance to regional joint prevention and control and from consistency control to total emission control in air pollution prevention.And in Heilongjiang,which stands for Chinese northern cold city with heavy industries,PM_2.5 as the primary pollutants has seriously affected daily life and work.In order to provide scientific emission reduction basis for the “Heilongjiang Province Air Pollution Control Special Action Program（2016²018）”,it’s of great significance to calculate the atmospheric environmental capacity of PM_2.5 in Heilongjiang.In this paper,setting 2015 as the base year,the basic data of Heilongjiang are analyzed comprehensively and systematically by geographical terrain,economic development,meteorological condition,investigation of pollution source and polluted status.It provides the technical preparation to calculate the atmospheric environmental capacity of PM_2.5.Combined with Weather Research Forecast（WRF）model and CALPUFF dispersion model,the ideal environmental capacity and the actual environmental capacity were calculated and compared.We can get the atmospheric environmental capacity of PM_2.5 and emission reduction in Helongjiang from the comparative result.And reduction programme in heavy haze would be given by applying the above-mentioned method.There are about 644,100 tons of dust emissions in Heilongjiang.Combined with the requirements of pollution source division and CALPUFF dispersion model input,the pollution sources are divided into 38 point sources and 13 non-point sources in Heilongjiang.The monthly average concentration’s trend of PM_2.5 in 2015 is U-shaped and the highest average concentration appears on November.The average concentration of PM_2.5 in heating period is about twice as the average concentration in non-heating period.The ideal environmental capacity of PM_2.5 is calculated by amending A-value method with introducing dry and wet deposition factors and partitioning environmental function division rationally.By calculating,the ideal environmental capacity of PM_2.5 is about 1710,100 tons in Heilongjiang.It is about 4 times as emissions at present.When we chosed the lowest the height of mixing layer and didn’t consider the wet and dry deposition,the ideal environmental capacity in the worst conditions is about 422,500 tons.The actual environmental capacity of PM_2.5 is based on distribution and emission of air pollution source and set the national secondary standard as restricted target.WRFCALPUFF is used to obtain the transfer coefficient between each pollution source and control point in heating and non-heating period.By the B-value distribution method and the multipoint iteration method,the actual environmental capacity of PM_2.5 is about 314,800 tons in Heilongjiang.The ratio of PM_2.5 emissions between point sources and non-point sources is 1:4.According to the ideal environmental capacity and the actual environmental capacity,we determine the actual environmental capacity as the atmospheric environmental capacity of PM_2.5 which is 314,800 tons in Heilongjiang and should reduce emissions of 97,400 tons.The key cities are Harbin,Qiqihar and Jixi,the emission reductions accounting for 72.52% of Heilongjiang province.In order to clarify the PM_2.5 emission reduction in heavy haze,we chose 1 to 7 November for the research.The daily emission reductions are between 0³66.05t/d.The point source emission reduction only 1.34⁵.20% of the total emission reduction.So the pollution control should focus on the non-point source.