西安市分粒径大气颗粒物碳质气溶胶特性及析源研究

Study on the Characteristic and Source Apportionment of Carbonaceous Aerosol of Size-segregated Atmospheric Particulate Matter in Xi’an

本文采集了西安市冬春两季特征气象条件下分粒径段的大气颗粒物样品,使用热光碳分析仪测量了样品中的有机碳和元素碳,并凭借不同碳组分开展了颗粒物源解析研究。研究表明1.1~2.1μm粒径段的细颗粒是冬季大气污染物的主要组成部分,9~10μm处的粗颗粒是春季大气中的重要成分;冬季和春季有机碳质量浓度的最大值均出现在0.7~1.1μm处,元素碳浓度最大值分别出现在1.1~2.1μm和0~0.4μm处;结合前人研究结果,通过不同样品的碳组分即有机碳和元素碳与总碳的比值揭示了生物质燃烧和煤燃烧以及汽车尾气是西安市大气污染物的主要来源。

In this paper,size-segregated atmospheric particulate samples were collected under winter and spring certain meteorological conditions in Xi’an.The organic carbon and elemental carbon in samples were measured offline using the thermo-optic carbon analyzer,furthermore,the source apportionment of particles were analyzed through different carbon fractions.The results show that fine particles in the size range from 1.1~2.1 μm are the main components of winter air pollutants and coarse particles,while ones in the size range from 9~10 μm are important parts of spring atmospheric environment.The maximum mass concentrations of organic carbon almost appear in the particle size of 0.7~1.1 μm in winter and spring,and conversely the maximum ones of elemental carbon appear in the particle size ranges of 1.1~2.1 μm and 0~0.4 μm,respectively.Based on the results of previous studies,using the carbon fractions of different samples,namely the ratio of organic carbon and elemental carbon to total carbon,reveals that biomass burning,coal burning and motor vehicle exhaust are the main sources of pollutants in Xi’an.