干旱区生态环境知识资源中心

Fine particulates less than 2.5 mu m (PM2.5) or 10 mu m (PM10) are often emitted from river bank or other alluvial lands to the atmosphere during dry and windy seasons worldwide, which contribute to land degradation and poor air quality. Investigation of PM2.5 and PM10 emission potential could contribute to the development of mitigation strategy and better land management practices. In the low-precipitation zone (<100 mm annual precipitation) of the Tarim Basin in western China, wind erosion and fugitive dust emission are recognized problems on the oasis. There is limited information, however, regarding wind erosion on river overflow areas, areas of temporal flooding, in the Tarim Basin. The objectives of this study were to characterize PM2.5 and PM10 emission potential and wind erosion potential of soils along the Tarim River. The results of particle analysis revealed that most soils (28 soils) were silt loam in the overflowing area of the Tarim River; few (12 soils) soils were sandy loam. The soils had low clay and high silt contents. Soil particles greater than 840 mu m (nonerodible soil particles) were not found by sieving all soil samples. Contents of PM2.5 and PM10 ranged from 1.6 to 30.4% and 4.5 to 78.6%. These high percentages of fine soil particulates suggest that mitigation of soil wind erosion and fine-particle emission is important in protecting air quality in the region. The highest content (44.9%) of saltation-size particles (100- to 500-mu m diameter) was found in the lower reaches of the river, followed by the middle reaches (14.6%) and then the upper reaches (11.7%) of the river. The highest content of suspension particles (<100-mu m diameter) was observed for soils in the middle reaches (13.1%), followed by the upper reaches (11.2%) and the lower reaches (7.1%).