Study On Temporal And Spatial Variation Characteristics For Pollution Source Regions Of PM_2.5 In Changchun

In recent years,with the development of industrial technology and national economy and the advancement of urbanization,people's living standards have been improved gradually.However,the increasing air pollution incidents represented by the haze also have affected people's normal life,human health and production activities seriously.At present,particulate matter in the atmosphere has become the main atmospheric pollutant in many major cities of China.How to control and reduce atmospheric particulate matter effectively is what many domestic and foreign scholars are concerned about at present.Compared to other atmospheric pollutants,fine particulate matter(PM_2.5)has more smaller size,larger specific surface area,easy to get more harmful substances adsorbed and can enter human body smoothly.In the air,fine particulate matter can hardly sedimentate,always affected by airflow with a long distance transportation.From the above,PM_2.5 has been the most respected matter of all particles in the air,and be a pollutant type whose concentration always been in the national long-term limit strictly at the same time.In this paper,on the basis of the concentration data of particulate matter from various atmospheric environmental monitoring sites in Changchun in 2016,by using the HYSPLIT backward tracking model and stepwise cluster analysis,the main average trajectory is obtained,and the time variation characteristics of PM_2.5.5 pollution source regions in Changchun city are studied.In the end,the main conclusions are as following:1?In the year 2016,the meteorological trajectory of the Changchun in the whole year of 2016 was analyzed by clustering analysis,as a result of 8784 at the each height of 50 meters,100 meters and 200 meters.The main tracking areas includes the eastern provinces of Inner Mongolia,Liaoning,Shandong,Heilongjiang,Bohai and Jilin provinces,as well as Russia and Mongolia.2?Changchun is mainly affected by pollutants from the northwest region in winter.Each year from November to march is the time when large-scale burning coal-fired come up to get central heating in northern cities,people burned fossil fuels,including coal,which increasing the concentration of fine particulate matter in the atmosphere.Particulate matter produced during in this this period from northwest area of Changchun in Jilin province?Songyuan,Baicheng?and the eastern city of Inner Mongolia province?Hulunbeir city,Hinggan league?,with the strong northwest wind through long-distance transported,and arriving in Changchun.Which aggravating Changchun winter air pollution with casing fog events.3?Changchun is mainly affected by pollutants from the southwest region in spring and summer.These areas mainly include Shandong province,Liaoning province,Bohai sea area and some cities in Jilin province?Gongzhuling,Siping?.Then,in the spring?from April to June?,the pollutants after long-distance transported from Liaoning,Shandong and Bohai were significantly affecting the air environment of Changchun.In the summer?from July to September?,in addition to the influence of pollution sources from southwest of Changchun where relatively close to Changchun area,air pollutants from the east of Changchun city in Jilin province area also has a significant contribution to the concentration of fine particulate matter at the height of 100 and 200meters4?Few pollutants from the southern and southeastern parts of Changchun can be transported by airflow to Changchun downtown area.Based on the geographical location of Changchun,it can be known that Changchun is hardly affected by the pollutants from the Korean peninsula,the southeastern city of Jilin province?Tonghua city,Yanbian Korean autonomous prefecture?.In contrast,the pollutants from the northern and northeastern regions of Changchun city had no significant seasonal differences,and the number of meteorological tracks transmitted to Changchun in each month was roughly the same.5?The winter of Changchun is long and the autumn is short.So all the cluster analysis results do not consider the changes of different sources area of pollution in autumn.6?Different heights of Changchun are affected by different sources of pollution.In the summer,the fine particulate matter at the height of 100 and 200 meters affected by pollutants from the eastern short distance transporting area,while the impact on the atmospheric environment of 50 meters from eastern area is small.