基于SEM-EDS的大气降尘特征及来源解析——以荒漠草原区井工开采煤炭基地为例

利用场发射扫描电子显微镜-配能谱分析系统（SEM-EDS）于2019年3~5月对荒漠草原区煤炭基地及其周边5个功能区（煤炭工业区、煤炭运输道路、电力工业区、商住区和沙区）共计23个大气降尘样品的粒径特征、微观形貌、单颗粒能谱图进行检测分析.结果表明，各功能区大气降尘中颗粒物总体形貌基本相似，均包括近球状、类椭球状、颗粒状、块状和柱状/片状颗粒物以及烟尘集合体.此外，煤炭运输道路、电力工业区和商住区还存在球状颗粒物.各功能区大气降尘以>10μm颗粒物为主，其中，电力工业区、商住区、沙区和煤炭工业区大气降尘平均粒径均>100μm，且总量超过65%，煤炭运输道路大气降尘平均粒径为67.59μm，粒径>50μm的颗粒物量占53%.大气降尘主要由细粉砂、粗粉砂和细砂组成.大气降尘中颗粒物的类型包括存在于各功能区中的硅酸盐矿物（石英、钾长石和斜长石）、碳酸盐矿物（方解石和白云石）、硫酸盐矿物（石膏）和高岭石，存在于煤炭运输道路、煤炭工业区和电力工业区中的富铁颗粒，存在于煤炭工业区中的铁镁颗粒，存在于煤炭运输道路、煤炭工业区、电力工业区和商住区中的烟尘集合体和燃煤飞灰.大气降尘来源主要为本地源，包括各功能区中均存在的地表扬尘、工业扬尘、建筑扬尘和大气中二次化学反应产物，煤炭运输道路、煤炭工业区和电力工业区中存在的机动车零件磨损产物，以及煤炭运输道路、煤炭工业区、电力工业区和商住区中存在的机动车尾气排放和燃煤产物.

Characterization and the source appointment of atmospheric dustfall based on SEM-EDS——a case of well working coal mining base in desert grassland area

It was used methods of scanning electron microscopy coupled with energy dispersive spectrometer (SEM-EDS) to analyse the particle-size characteristics, morphology and elemental composition of individual particles for 23 samples of atmospheric dustfall which were collected in five kinds of tpyical area such as coal industrial area, coal road, electric power industrial area, commercial and residential area, desert area, from March to May in 2019. The results indicated that the overall morphology of atmospheric dustfall in each area was basically similar, incuding near-spheroidal, similar-ellipsoid, graininess, bulk, columnar/flake particle, and the aggregate. Furthermore, there was spherical particle in industrial area, commercial and residential area and the coal road area. The gain size >10μm particle was the main kind of dustfall in all areas, the average particle size of atmospheric dustfall in electric power industrial area, commercial and residential area, desert area and coal industrial area was >100μm which particle accounted for 65% in total dustfall amount, the average particle size in coal road area was 67.59μm in which >50μm size particle is accounted for 53%. Therefore, the atmospheric dustfall was mainly composed of fine silt, coarse silt and fine sand. The mineral type of atmospheric dustfall belong to silicate mineral (Quartz, Orthoclaseb and Plagioclase), carbonate mineral (Calcite and Dolomite), sulfate mineral (Gypsum) and Kaolinite in all areas. Besides, there are iron-rich particle which existed in coal road area, coal industrial area and electric power industrial area, magnesium-iron particle in coal industrial area, soot aggregate and fly ash in coal road area, coal industrial area, electric power industrial area, commercial and residential area. The dustfall source was mainly from local area, including soil dust, industrial dust, construction dust, secondary chemical product in all areas, there are wear of motor vehicle parts which existed in coal road area, coal industrial area and electric power industrial area, motor vehicle exhaust emissions and coal-burning products in coal road area, coal industrial area and electric power industrial area, commercial and residential area.