Research On The Characteristics Of Air Pollution In The Fenwei Plain

In recent years,the Fenwei Plain urban agglomeration has become a key area for the prevention and control of air pollution in my country.The accumulation process of PM_2.5 plays an important role in the occurrence and maintenance of heavily polluted weather.However,there are few studies on the accumulation process at present,and there are only researches on the accumulation process.It only focuses on the accumulation process of heavily polluted weather,and cannot measure the long-term accumulation level of the area.Therefore,analyzing the air pollution characteristics of the Fenwei Plain and quantifying the accumulation level of PM_2.5in the Fenwei Plain is a scientific and effective way to formulate air pollution prevention and control measures in the Fenwei Plain.It plays an important role in comprehensively improving regional air quality and promoting the coordinated and healthy development of the Fenwei Plain.This study analyzes the air pollution characteristics of the Fenwei Plain from the perspective of the temporal and spatial changes of pollutants and the characteristics of PM_2.5accumulation.From the perspective of the accumulation rate of PM_2.5,an evaluation index is established to evaluate the accumulation process and quantifies the different characteristics of the Fenwei Plain.The accumulation level of urban PM_2.5;and analyzed the pollution characteristics of a heavily polluted weather process in the Fenwei Plain;analyzed the PM_2.5pollution characteristics and the cause of the heavy pollution weather in Taiyuan from the perspective of accumulation characteristics.The results showed that:（1）Air pollution in the Fenwei Plain is dominated by particulate matter(PM_2.5and PM₁₀)and high concentrations of O₃;in terms of spatial distribution,cities with more mountains in the Fenwei Plain have lighter air pollution,while cities in the basin with relatively flat terrain The air pollution is more serious;the high concentration of SO₂ is mainly distributed in the cities of the Fenhe Plain.（2）The highest annual concentration of O₃ occurs from May to July,and the concentration of other air pollutants is higher in autumn and winter than in spring and summer.From the perspective of daily changes,the daily peak of O₃ appeared at around 16:00 in the afternoon,showing a"single peak and double valley"pattern,and the other five pollutants all showed a"double peak and double valley"pattern.（3）Among the 12 cities in the Fenwei Plain,the cities with strong PM_2.5 accumulation levels are Baoji,Linfen,Luliang,and Jinzhong;the cities with medium accumulation levels are Xianyang,Weinan,Tongchuan,Yuncheng,and Luoyang;The weak ones are Xi’an,Sanmenxia and Taiyuan.（4）The development stage of a heavy pollution process in the Fenwei Plain.The cities in the Fenhe Plain have characteristics of coal-smoky pollution,while the pollution characteristics of other cities are not significant;some cities in the maintenance stage will be transformed into a quadratic,dissipative stage There are more types of pollution in the sand-and-dust type and the partial-motor vehicle.（5）Under the slow accumulation state in autumn and winter in Taiyuan urban area,the formation of secondary pollutants helps increase the accumulation rate of PM_2.5;in the rapid accumulation state,the primary pollutant has a more obvious impact on the accumulation rate of PM_2.5;rapid accumulation At the time,air transport from the southeast direction increased significantly.（6）The formation process of heavily polluted weather in Taiyuan urban area is dominated by slow accumulation,accounting for 77%.In severely polluted weather,the urban area is dominated by the combined pollution of sulfate and nitrate,while the suburban area is dominated by nitrate pollution.