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From April 24 to 25, 2019, a characteristic floating dust event occured in Kashi, one of the most important cities in Xingjiang province, China. The Dust Aerosol Observation (DAO) field campaign captured this case and provided us with comprehensive ground-based observation to research this floating dust case. The instrument involved in DAO field campaign included particles monitors, gas analyzer, nephelometer, radiometers, and lidar, among others. Meanwhile, CALIPSO were used as a satellite remote sensing observation to perform auxiliary analysis. Furthermore, to give the case a further quantitative description and get a deeper insight of the interaction mechanisms, WRF-Chem which is a regional air quality model calculating meteorological and chemical field on line were adopt as well. According to comprehensive observation and simulation, we divided this floating dust case into two periods. Different periods have different aerosol sources. The first period is before 14 o 'clock on the 24th. The main aerosol source was dust transported from the edge of the Taklimakan Desert by east wind at a height of 3-5km. In this period, PM10 concentration increased to 4000μg·m-3 and PM2.5 concentration increased to 800μg·m-3 in a short time. In the second period, due to the diversion of wind direction, dust transfer reduced and stopped gradually. Because of the circulation background and weather condition, the combined effect of local accumulation and reaction of pollutants still maintained particles concentration at a high level. In this period, although PM2.5/PM10 more than the ratio in the first period, it still kept around 0.3. PM10 and PM2.5 concentration both maintained a slow decline.
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