Trend And Correlation Analysis Of Main Pollutants In The Air Of Aksu City

As the economy of Aksu region enters a critical period of rapid development,the quality of urban ambient air has encountered unprecedented pressure.As an important economic development center in southern Xinjiang,the atmospheric environment pollution of Aksu is becoming very serious.The deterioration of ecological environment has become a main bottleneck problem for the sustainable development of urban society.This paper selected the Aksu as the research area,combined with the current situation of atmospheric environment in recent years,on the basis of a comprehensive and systematic collection of the natural environment and social and economic development in the research area,the environmental situation of Aksu was summarized,and analyzed.Based on the atmospheric environment data of Aksu from 2015 to 2018,this paper summarized the temporal trends of major atmospheric pollutants in Aksu region,and analyzed the correlation of each pollutant.The following conclusions are drawn:(1)From 2015～2018,the good and moderate air quality days accounted for 53.2%,37.0%,47.5%and 45.1%,respectively.Aksu is facing air pollution to some certain extent.When the sand dust days was excluded,the ratios of good and moderate air quality days in these years reached 59.9%,68.5%,71.5%and 71.0%,respectively.ADuring the study period,the number of days with O3 as the primary pollutant showed an increasing trend,the number of days with PM10 as the primary pollutant decreased first and then increased,the number of days with PM2.5 as the primary pollutant was decreasing gradually.(2)In the analysis of the daily,monthly,quarterly,and annual variations of various pollutants within four years,we found that the primary pollutants affecting the ambient air quality in Aksu were PM10,PM2.5 and O3.The average concentrations of PM10 and PM2.5 in the study period were 210.52 μg/m3 and 78.38 μg/m3,respectively.The annual mean concentrations of atmospheric particulates in each year exceeded the threshold of national standard level Ⅱ twofold.Although,there were differences between the variation trends of the annual mean concentrations of SO2,NO2,and CO in the study period,they were decreasing in the mass.The quarterly average concentrations of PM10 and PM2.5 in the study period were higher in spring and lower in summer.The monthly variations of SO2,NO2,and CO concentrations showed a "U-shaped"distribution,and they were both higher in winter and lower in summer.The distributions of the monthly average concentrations of O3 in these years were unimodal,and it was higher in summer and lower in winter(3)By establishing a multivariate linear regression model for six pollutants,it can be found that as the SO2 concentration decreased by one unit,the O3 concentration increased by 0.489 units;when the NO2 concentration decreased by one unit,the O3 concentration increased by 0.198 units;as the PM10 concentration decreased by one unit,the O3 concentration increased by 0.041 units on average;while the CO concentration decreased by one unit,the O3 concentration increased by 23.681 units on average,and as the PM2.5 concentration decreased by one unit,the O3 concentration increased 0.188 units.(4)Mining association rules for air quality monitoring data,a total of 894 strong association rules were mined.After screening these association rules,it was found that when the concentration of PM2.5 and CO decrease,the concentration of O3 will increase.