CHARACTERIZATION OF MODERN DUSTFALL IN THE LOESS PLATEAU: A CASE STUDY OF GUYUAN AND ANSAI

To investigate the characteristics of modern dustfall in the Loess Plateau, 12 dustfall samples were collected in May 2007 through April 2008 at Guyan in Ningxia Hui Autonomous Region, and 13 dustfall samples were collected from May through August 2007 and from March through November 2008 at Ansai in Shaanxi Province. In addition to the dustfall samples, 2 samples of undisturbed top soil were also collected around each sampling site. Analysis of total organic carbon, grain size and magnetic susceptibility suggests,the total organic matter content of the dust samples from both sites range from 1.029% to 6.634%, and grain-size distribution indicates that near-source transport of dust is dominant and anthropogenic PM10 accounts for only a small fraction of dustfall. Magnetic susceptibility for the dustfall samples appears to be markedly higher than that for the topsoil samples,but no seasonal characteristics could be found.