Analysis on the temporal-spatial distribution character and effect factors of PM10 in the hinterland of Taklimakan Desert and surrounding area

摘要

In recent years, the physical and chemical properties of dust aerosols from the dust source area in northern China have attracted increased attention. In this paper, Thermo RP 1400a was used for online continuous observation and study of the hinterland of Taklimakan, Tazhong, and surrounding areas of Kumul and Hotan from 2004 to 2006. In combination with weather analysis during a sandstorm in the Tazhong area, basic characteristics and influencing factors of dust aerosol PM10 have been summarized as below: (1) The occurrence days of floating dust and blowing dust appeared with an increasing trend in Kumul, Tazhong and Hotan, while the number of dust storm days did not significantly change. The frequency and intensity of dust weather were major factors affecting the concentration of dust aerosol PM10 in the desert. (2) The mass concentration of PM10 had significant regional distribution characteristics, and the mass concentration at the eastern edge of Taklimakan, Kumul, was the lowest; second was the southern edge of the desert, Hotan; and the highest was in the hinterland of the desert, Tazhong. (3) High values of PM10 mass concentration in Kumul was from March to September each year; high values of PM10 mass concentration in Tazhong and Hotan were distributed from March to August and the average concentration changed from 500 to 1,000 μg/m3, respectively. (4) The average seasonal concentration changes of PM10 in Kumul, Tazhong and Hotan were: spring > summer > autumn > winter; the highest average concentration of PM10 in Tazhong, was about 1,000 μg/m3 in spring and between 400 and 900 μg/m3 in summer, and the average concentration was lower in autumn and winter, basically between 200 and 400 μg/m3. (5) PM10 concentration during the sandstorm season was just over two times the concentration of the non-sandstorm season in Kumul, Tazhong and Hotan. The average concentrations of sandstorm season in Tazhong were 6.2 and 3.6 times the average concentrations of non-sandstorm season in 2004 and 2008, respectively. (6) The mass concentration of PM10 had the following sequence during the dust weather: clear day < floating dust < floating and blowing dust < sandstorm. The wind speed directly affects the concentration of PM10 in the atmosphere, the higher the wind speed, the higher the mass concentration. Temperature, relative humidity and barometric pressure are important factors affecting the strength of storms, which could also indirectly affect the concentration change of PM10 in the atmosphere.