Pollution Characteristics And Sources Analysis Of Atmospheric Fine Particles In Southeast Handan

Air pollution has always been the focus of attention in recent years.From coal to gas and coal to electricity in the 13th five year plan to the three-year blue sky defense war in 2018 to carbon peak and carbon neutralization in 2021,China has implemented a series of prevention and control measures against air pollution.However,the haze weather is still frequent in some areas.The southeast of Handan is at the junction of Hebei,Shandong and Henan,with serious particulate pollution.This study analyzed PM_2.5and gaseous pollutants in the southeast of Handan in recent three years.Considering the serious pollution in autumn and winter,PM_2.5samples were collected during the period of heavy pollution from November 2020 to January 2021.The mass concentration and chemical components of PM_2.5were analyzed,and the source analysis was carried out in combination with positive definite matrix factor method（PMF）and potential source analysis model（pscf）,so as to explore the pollution characteristics and sources of PM_2.5in the southeast of Handan.From 2018 to 2020,the average annual concentration of PM_2.5in Southeast Handan was 68.48μg·m^-3,56.57μg·m^-3,49.47μg·m^-3,respectively,and showed a decreasing trend year by year,and the seasonal performance was winter>autumn>spring>summer.PM_2.5has the highest correlation with CO and NO₂,and NO₂and CO were also significantly correlated,indicating that that the motor vehicle pollution in the southeast of Handan is more serious.PM_2.5concentration showed obvious diurnal variation trend,and it’s concentration at night(113.83μg·m^-3)was higher than the daytime(96.64μg·m^-3)17.78%.During the study,the mass concentration of 10 water-soluble ions was 48.76±25.60μg·m^-3,accounting for 39.47%of the mass concentration of PM_2.5(123.54μg·m^-3),in which NO₃^-,SO₄^2-and NH₄⁺account for 88.33%of the total water-soluble ions,mainly in the form of（NH₄）₂SO₄and NH₄NO₃.The average value of OC/EC is6.02,and the ratio range is 2.59～35.64.In the early stage,the main sources are motor vehicle exhaust and coal combustion.In the later stage,a small number of high values average 26.81±5.92,which may be affected by biomass combustion.SOC estimate11.77μg·m^-3,accounting for 60.61%of OC.The secondary air pollution in the southeast of Handan is relatively serious.The total concentration of 24 inorganic elements was 12.06μg·m^-3,accounting for 9.77%of the mass concentration of PM_2.5.The elements of S,Cl,Zn,Pb and As are mainly from natural sources;Se mainly comes from man-made pollution and is greatly affected by coal combustion.During the heavy pollution period,the humidity is high,the air pressure is high and the wind speed is small,which is obviously affected by meteorological conditions and transmission.During the pollution process,the NO₂concentration increases significantly with the PM_2.5concentration,and the SO₂/NO₂ratio decreases with the PM_2.5concentration,which is greatly affected by vehicle sources.The transmission mainly comes from the easterly direction.Shandong,Hebei,Tianjin and Beijing Shanghai lines are the main potential source areas in the southeast of Handan.PMF source analysis shows that the main sources of PM_2.5in the southeast of Handan are vehicle sources（21.2%）,dust sources（13.8%）,secondary aerosols（10.1%）,biomass combustion sources（23.4%）,coal-fired sources（19.5%）and industrial process sources（12.0%）.