Abstract:

Using cluster analysis, potential source analysis (PSCF, CWT) and obliquely rotated T-mode principal component analysis (PCT) method, the transmission channels and potential source areas were studied, and the prone circulation patterns was revealed for different stages (formation, maintenance and dissipation) of heavy air pollution in Huaibei in winter half year, based on the data of the monthly variation of six types of air pollutants from 2015 to 2018.The results show that monthly average mass concentrations of the main air pollutants, i.e.PM_2.5, PM₁₀, CO, NO₂ and SO₂ are higher in winter half year.For heavy pollution in Huaibei, short distance trajectory is dominant, and the important potential sources include the southeast of west of Shandong province and north central of Jiangsu province.There are similarities and difference during the different stages (formation, maintenance, and dissipation) of heavy air pollution.The common point is that there are uniform pressure field with different proportions in the three stages.The differences among the three stages are mainly expressed in circulation type, pressure value, pressure gradient, wind direction and wind speed.In the formation stage of persistent heavy pollution, circulation patterns are divided into five types and more than 90% of them are related to uniform pressure field.In the maintenance stage, six circulation patterns are related to uniform pressure field, but the control range of uniform pressure field is significantly larger than that in the formation stage.The pressure value was close to the formation stage and the wind speed was mostly static.In the dissipation stage of persistent heavy pollution, Huaibei city was mostly in the front of cold high pressure, with the uniform pressure field just accounting for 15%.The pressure gradient, sea-level pressure, and wind speed increased significantly.

Key words: Backward trajectory, Potential source analysis, PCT algorithm