Soil-derived sulfate in atmospheric dust particles at Taklimakan desert

Authors

  • Feng Wu,

    Corresponding author
    1. Key Laboratory of Aerosol, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Science, Xi'an, China
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  • Daizhou Zhang,

    Corresponding author
    1. Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, Japan
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  • Junji Cao,

    1. Key Laboratory of Aerosol, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Science, Xi'an, China
    2. Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China
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  • Hongmei Xu,

    1. Key Laboratory of Aerosol, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Science, Xi'an, China
    2. Graduate School of Chinese Academy of Sciences, Beijing, China
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  • Zhisheng An

    1. Key Laboratory of Aerosol, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Science, Xi'an, China
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  • Corresponding author: F. Wu, Key Laboratory of Aerosol, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Science, Xi'an 710075, China. (kurt_wf@ieecas.cn)
  • D. Zhang, Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502, Japan. (dzzhang@pu-kumamoto.ac.jp)

Abstract

[1] Dust-associated sulfate is believed to be a key species which can alter the physical and chemical properties of dust particles in the atmosphere. Its occurrence in the particles has usually been considered to be the consequence of particles' aging in the air although it is present in some crustal minerals. Our observation at the north and south edge of Taklimakan desert, one of the largest dust sources in the Northern Hemisphere, during a dust episode in April 2008 revealed that sulfate in atmospheric dust samples most likely originated directly from surface soil. Its TSP, PM10 and PM2.5 content was proportional to samples' mass and comprised steadily about 4% in the differently sized samples, the ratio of elemental sulfur to iron was approximately constant 0.3, and no demonstrable influence of pollutants from fossil fuel combustion and biomass burning was detected. These results suggest that sulfate could be substantially derived from surface soil at the desert area and the lack of awareness of this origin may impede accurate results in any investigation of atmospheric sulfur chemistry associated with Taklimakan dust and its subsequent local, regional and global effects on the atmosphere.

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