Vertical distribution characteristics of dust aerosol mass concentration in the Taklimakan Desert hinterland

The different height mass concentrations of dust aerosol data from the atmosphere environment observation station(Tazhong Station)was continuously observed by instruments of Grimm 1.108,Thermo RP 1400a and TSP from January of2009 to February of 2010 in the Taklimakan Desert hinterland.Results show that:(1)The mass concentration value of 80m PM10was higher,but PM2.5and PM1.0concentrations at 80 m was obviously lower than 4 m PM10,and the value of 80 m PM1.0mass concentration was the lowest.(2)The PM mass concentrations gradually decreased from night to sunrise,with the lowest concentration at 08:00,with the mass concentration gradually increased,up to the highest concentration around18:00,and then decreased again.It was exactly the same with the changes of wind speed.(3)The high monthly average mass concentration of TSP mainly appeared from March to September,and the highest concentration was in April and May,subsequently gradually decreased.Also,March–September was a period with high value area of PM monthly average mass concentration,with the highest monthly average mass concentration of 846.0μg/m3for 4 m PM10appeared in May.The concentration of PM10was much higher than those of PM2.5and PM1.0at 80 m.There is a small difference between the concentration of PM2.5and PM1.0.Dust weather was the main factor which influenced the concentration content of the different diameter dust aerosol,and the more dust weather days,the higher content of coarse particle,conversely,fine particle was more.(4)The mass concentration of different diameter aerosols had the following sequence during dust weather:clear day<blowing dust<floating and blowing dust<sandstorm.In different dust weather,the value of PM10/TSP in fine weather was higher than that in floating weather,and much higher than those in blowing dust and sandstorm weather.(5)During the dust weather process,dust aerosol concentration gradually decreased with particle size decreasing.The dust aerosol mass concentration at different heights and diameter would have a peak value area every 3–4days according to the strengthening process of dust weather.