Physicochemical And Light Extinction Characteristics In Atmospheric Particulates Of Shihezi,Xinjiang,China

Due to Shihezi unique climate and geographical location,haze and dust pollution become more serious.Few studies have been reported of haze and dust weather in Xinjiang area.Physical and chemical properties of atmospheric particles under different weather conditions were used IMPROVE?Interagency Monitoring of Protected Visual Environment?formula to analysis atmospheric particles extinction.The overall AQI?Air Quality Index?in Shihezi was grade two,and 2016 was grade one.The main pollutants in Shihezi city were PM₁₀,PM_2.5 and O₃₈ in both2015 and in 2016.The pollution was more serious than that in other seasons due to meteorological factors and human factors.Due to the influence of seasonal and pollution sources,fine part icles is mainly distributed in winter and heavy pollution days.PM_2.5/PM₁₀ is a low winter high trend,which is contrary to PM₁/PM_2.5 and PM_0.5/PM₁,indicating that the winter and heavy pollution days in Shihezi were mainly resulted by PM_2.5.WSI?Water-Soluble Ions?is mainly caused by seconed pollution,SNA?Sulfate,Nitrate and Ammonium?accounted for 69%of the total water-soluble ions.Haze and dust weather can promote the SO₄^2-and NO₃^-conversion and reduce alkalinity of atmospheric aerosols.In view of the high conversion rate of SOR?Sulfur O xidation Rate?and NOR?N itrogen O xidation Rate?and NO₃^-/SO₄^2-ratio,the pollution sources of Shihezi city are complex.Carbonaceous aerosols were analyzed by DRI-2001A and exhibited consistent trend with that of water soluble ions.Due to poor OC/EC correlation and high ratio of SOC/OC,Shihezi carbonaceous aerosols were mainly caused by second organic carbon,especially in winter and haze and dust days.The PCA?Principal Component Analysis?analysis showed that the main sources of pollution were biomass combustion,road dust,coal combustion and motor vehicle exhaust,and the main sources of pollution were diesel vehicles,road dust,coal and motor vehicle exhaust.This research was used to study the physicochemical properties of atmospheric particulates with IMPROVE formula.Visibility was mainly affected by PM_2.5,the chemical composition of ammonium sulfate and ammonium nitrate can determine the visibility in Shihezi.Based on the visibility analysis,the main reasons for the visibility reduction in Shihezi were controlled by coal burning and mobile sources.Visibility will be analyzed by IMPROVE equation according to the physicochemical property of atmospheric particles.PM_2.5 contributes 93%of the light extinction in pollution days and ammonium contributes nearly 80%.This study is expected to provide a basis for the study of air quality in Western China and the physicochemical properties and light extinction of atmospheric particles.