Two Main Urban Districts Of Harbin From 2019 To 2020 Analysis Of PM_2.5Distribution

In recent years,fine particles as the main atmospheric pollutants have gradually attracted more and more attention to the harm to the environment and human health.PM2.5 is one of the main atmospheric pollutants with complex components and diverse sources.However,the study on the main components and source analysis of PM2.5 still lack.This study takes Daoli District and Xiangfang District of Harbin city as the sampling area,the sampling points set up in Anyang Primary School in Daoli District and Wangzhaoxincun Primary School in Xiangfang District.The water-soluble ions,polycyclic aromatic hydrocarbons,heavy metals and metalloid ions in PM2.5 will be monitored and analyzed,and the distribution regulation will be studied to provide relevant theoretical basis for governance.PM2.5 samples were collected from 10th to 16th every month and haze weather（AQI>200）from 2019 to 2020.Then the water-soluble ions were detected by ion chromatography,polycyclic aromatic hydrocarbons were detected by high performance liquid chromatography,the concentrations of heavy metals and metalloids ions were determined by inductively coupled plasma mass spectrometry.The correlation between PM2.5 and meteorological factors were analyzed by cluster analysis and Pearson correlation coefficient.The principal component analysis was used to present the contribution ratios of each component in water-soluble ions,polycyclic aromatic hydrocarbons,heavy metals and metalloid ions.The average mass concentration of PM2.5 in Daoli District was 61.16 μg/m3 from 2019 to 2020,and that in Xiangfang District was 70.26 μg/m3.The PM2.5 concentration decreased in 2020.PM2.5 in the two urban areas was significantly positively correlated with average air pressure,and significantly negatively correlated with average relative humidity,precipitation,average wind speed and sunshine hours.The average annual concentration of water-soluble ions in Daoli District was 19.92 μg/m3 from 2019 to 2020,and that in Xiangfang District was 19.84 μg/m3.The mass concentration ranked as NO3->SO42->NH4+>Cl-.The mass concentrations of four water-soluble ions in the two urban areas were higher in winter and lower in summer,and there were secondary transformations of SO2 and NO2 to SO42-and NO3-.The average air pressure in the two urban areas was significantly positively correlated with four water-soluble ions;the average temperature was significantly negatively correlated with water-soluble ions.The precipitation in Daoli District was significantly negatively correlated with NO3-,Cl-and NH4-.Precipitation in Xiangfang District was significantly negatively correlated with SO42-,Cl-and NH4+.The water-soluble ions can be divided into SO42-,NO3-,NH4+and Cl-.There were two categories SO42-and Cl-,NO3-and NH4+in Xiangfang District.The principal component analysis indicated that the main components of water-soluble ions in the two urban areas were NO3-and SO42-.The average annual mass concentration of PAHs in Daoli District was 31.52 ng/m3 from 2019 to 2020,and that in Xiangfang District was 30.37 ng/m3.The mass concentration ranked as Pyr>Fla>Chry>BaA>BkF>BbF>BaP>InP>BghiP>Phe>DahA>Acy>Ant>Nap>Ace>Flu.The variation of PAHs concentration in the two urban areas was higher in winter and lower in summer.The average pressure and temperature in the two urban areas were significantly positively correlated with Acy,Phe,Ant,Fla,Pyr,Chry,BaA,BbF,BkF,BaP,DahA,BghiP and InP.The precipitation in Daoli District was significantly negatively correlated with Chry,BbF,BkF,BaP,BghiP and InP.The precipitation was negatively correlated with BkF and BghiP.Polycyclic aromatic hydrocarbons are divided into NaP,Ace,Flu,Acy,Phe,Ant,Fla,Pyr and Chry,BaA,BaP,BbF,BKF,BghiP,DahA,InP.The main components of polycyclic aromatic hydrocarbons in the Daoli District were Chry,BbF,BKF,BaA and BaP,and Chry,InP,BKF,BaP,BbF,BaA,Pyr and Fla in Xiangfang District.The average annual concentrations of heavy metal ions in Daoli District and Xiangfang District were 253.62 ng/m3 and 284.69 ng/m3,respectively.The concentrations ranked as Al>Pb>Mn>As>Cr>Ni>Sb>Se>T1>Hg>Be>Cd.The concentrations of Cd,As,Se,Pb,Tl,and Sb were higher in winter.The mean air pressure in the Daoli District was significantly positively correlated with Sb,As,Cd,Pb,Se and Tl;the average temperature was significantly negatively correlated with Sb,As,Cd,Pb,Ni,Se and Tl;the average relative humidity was significantly negatively correlated with Cr;precipitation was significantly negatively correlated with Cd and Pb;the average wind speed was significantly positively correlated with Al and Mn.The average pressure in Xiangfang District was significantly positively correlated with As,Cd,Pb,Ni and Tl;the average temperature was significantly negatively correlated with As,Cd,Pb,Ni and Tl;precipitation was significantly negatively correlated with Cd,Pb and Ni;the sunshine hours were significantly negatively correlated with Cr.The heavy metals in Daoli district were divided into two Be,Al,Mn,Cr,Hg and Cd,Pb,As,Tl,Sb,Ni,Se.The heavy metals in Xiangfang district were divided into two categories Be,Al,Mn,Cr,Sb,Hg,Se and As,Tl,Cd,Pb,Ni,The main components of heavy metals and metalloid ions in the two urban areas was Al.