Source Identification and Environmental Capacity of PM_2.5 in Tangshan City

In this research,the Weather Research and Forecasting Model （WRF） in combination with Community Multiscale Air Quality Model （CMAQ） was built to simulate the PM_2.5 pollution and industry sources in Tangshan City,and the environmental capacity and overload rate of Tangshan City were calculated under the constraint condition that the average annual PM_2.5 concentration reached the standard.The average annual transmission impact of PM_2.5 in Tangshan was 27.8%,the cities with the higher impact were Tianjin （8.0%）,Beijing （2.5%）,Cangzhou （2.2%）,Baoding （1.7%）,Qinhuangdao （1.5%）,Langfang （1.4%） and Chengde （1.0%）.Local power,industrial,civil,mobile and dust sources contributed 2.8%,23.1%,5.3%,6.7%and 33.9%to the PM_2.5 concentration in Tangshan,respectively.Steel emissions contributed 13.4% to the PM_2.5 concentration in Tangshan.With the average annual concentration of PM_2.5 reaching 35μg/m³ as the constraint condition,the environmental capacity of SO₂,NO_X,VOCs,NH₃ and primary PM_2.5 in Tangshan was 45000 tons,102000 tons,73000 tons,81000 tons and 41000 tons respectively,and the overload rate were 245.7%,248.8%,162.7%,126.6%and 289.0%,respectively.