Pollution Characteristics And Transportation Pathways Of Air Pollutants In The Main Urban Area Of Harbin

With the rapid development of urbanization and industrialization in China,the urban pollution of sulfur dioxide,nitrogen oxides and particulate pollutants is becoming more and more serious.Based on the monitoring data of air quality in Harbin in 2017,this paper analyzes the mass concentration of six kinds of air pollutants(SO₂?NO₂?O₃?CO?PM₁₀?PM_2.5)The air quality state is described intuitively by means of AQI?Air Quality Index?evaluation system,and the variation of pollutant concentration is discussed.The relationship between chemistry and meteorological factors.The transmission path of air pollution in Harbin is analyzed by using backward trajectory model and potential source contribution algorithm.It provides scientific data support for the current situation and control of air pollution in Harbin,and provides a reasonable direction for the formulation and implementation of pollution control policies.According to the analysis of pollution characteristics of six pollutants in Harbin,the rate of air quality reaching the standard in Harbin has steadily increased in the past five years.Pollutants have obvious seasonal variation characteristics,and the correlation between particulate matter and gaseous pollutants is high.Fine particulate matter is the main pollutant in Harbin in 2017.Automobile exhaust is an important cause of air pollution in Harbin.According to the spatial distribution of PM_2.5.5 concentration in 2017,the concentration of control sites in all countries decreased.In the AQI assessment system,about 13%of the cases were light pollution in mid-2017,and about 14%were moderately polluted or above.Among the four seasons of spring,summer,autumn and winter,the compliance rates were 66.30%,92.39%,82.32%and 48.39%respectively.In2017,the number of days of pollution in Harbin became the number of pollutants PM_2.5>PM₁₀>NO₂.Meteorological factors have different degrees of correlation with pollutant concentration by affecting the stability of the atmosphere.Besides the correlation between O₃ and meteorological factors,the correlation between air pressure,air temperature and pollutant concentration is greater than that between wind speed and relative humidity.According to the analysis of the transmission path of air pollution in Harbin,the air flow from western Russia accounts for 30.15%of the total height of 500 m.In addition to the summer in Heilongjiang Province and Jilin Province,the largest proportion of air flow in spring,autumn and winter came from western Russia,Mongolia,Inner Mongolia Hulunbeier and Xingan League.For the 20 m high layer,the air flow comes from the South and west of Harbin.The air flow from Jilin Province is the largest,the air flow from Inner Mongolia is the smallest,and the transmission speed is the slowest.Except for a small amount of air from the eastern part of Harbin in summer,there is no eastern air inflow in spring,autumn and winter.In autumn and winter,Harbin is mainly affected by the Hulunbeier and Xingan League in Inner Mongolia.According to the analysis of PSCF pollution source area,the pollution of SO₂,CO and NO₂ in six kinds of pollutants is relatively light,and the pollution mainly comes from Hulunbeier,Qiqihar and Daqing.O₃ pollution in Harbin may mainly come from the Bohai Sea,Liaoning and Jilin provinces in the southwest of Shandong Province.For PM₁₀0 and PM_2.5.5 pollution,the pollution of Harbin by the two kinds of pollutants is more serious,and the sources are closer,mainly from the Northwest Hulunbeier,Qiqihar and Daqing,as well as the southwest of Jilin and Liaoning Province.