Using composite fingerprints to quantify the potential dust source contributions in northwest China.

Dust storms have a profound impact on the atmospheric environment, global climate change, and human health, so it is of great importance to strengthen related research. The main areas of occurrence and frequency of dust storms in northwestern China were distinguished by measuring the concentration of geochemical elements in the topsoil and atmospheric dust samples, combined with the HYSPLIT backward trajectory model, MODIS true-color satellite images, and PM real-time monitoring data. On this basis, the composite fingerprints method was used to establish an end-member model between the concentration of dust storm samples and topsoil samples, and then to trace the sand and dust sources in northwest China and quantify their source contributions. The results showed that the main potential source areas causing sandstorms were located in the Kumtag Desert, Hexi area, and the Gobi Desert in the central and western parts of Inner Mongolia. Overall, the contributions from natural sources were greater than those from anthropogenic sources, especially at Alxa League. In addition to natural sources, anthropogenic dust sources contributed highly to dust storms, with a contribution rate of approximately 40% in cities. The main dust source in Zhangye City was from agriculture areas. The contribution of the potential dust sources in the west of the study area showed a decreasing trend from west to east because of the distance effect. Because of the influence of the prevailing westerly winds in the east, the sources of dust were relatively extensive. The Badain Jaran Desert and Tengger Desert were not the main dust sources in the study area because of artificial sand control measures and the low amounts of fine-grained components in sandy deserts. These methods and results are of great importance for sustainable development in northwest China.