The impact of a typical dust weather on air quality and the source of the dust in Guanzhong region
Based on the ambient air quality monitoring data,the influence characteristics on urban ambient air quality of a typical sand blowing weather process in Guanzhong region and the source of dust were analyzed by applying HYSPLIT backward trajectory mode,potential source contribution factor(PSCF)and concentration weight trajectory(CWT).The results showed that on March 26,2020,Guanzhong region was affected by dust weather for 16 hours,and 5 cities in Guanzhong had severe and above pollution for 3～9 hours.The air quality in four cities except Weinan was 1～3 levels worse than that of the day before the dust,reaching light to heavy pollution.During the dust weather,the hourly concentration of PM10 and PM2.5 in the five cities of Guanzhong showed a"unimodal"variation,and the hourly concentration of PM10 was 1.2～13.5 times that of PM25.The decreasing period of PM2.5/PM10 concentration ratio was located in the early stage of dust weather,and its valley value laged behind the peak value of PM10 1～2 h.The hourly concentration of SO2,NO2 and CO decreased significantly,and the daily variation range of the hourly concentration of O3 decreased.The dust weather was caused by the Mongolian cyclone and the ground cold front system,and the main sources of dust were the Tengger desert,Kubuqi desert,Mu Us sandland and the Gobi desert in central and western Mongolia.The wind speed and direction of the cities near the sand source area had a sudden change before the arrival of dust,and the increasing of the PM10 concentration in the cities affected by the dust laged behind it by 1～5 h.The results of this study can provide a reference for forecasting and early warning of the influence of dust weather on ambient air quality in Guanzhong region.
万方数据
维普
