西安冬季棕碳气溶胶多相颗粒光吸收特性及源解析  

Light Absorption Characteristics and Source Apportionment of Brown Carbon Aerosol Multiphase Particles in Winter Over Xi’an

作　　者：王婷 李丹 薛树平 王跃社[1] WANG Ting;LI Dan;XUE Shu-Ping;WANG Yue-She(State Key Laboratory of Multiphase Flow in Power Engineering,Xiyan Jiaotong University,Xi'an 710049,China)

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,西安710049

出　　处：《工程热物理学报》2021年第8期2010-2016,共7页Journal of Engineering Thermophysics

基　　金：国家自然科学基金面上项目(No.51576160)。

摘　　要：棕碳(Brown Carbon,BrC)通过直接或间接效应对气候环境产生严重的危害。本文以西安地区冬季大气环境颗粒物PM_(2.5)为研究对象,采用液相萃取得到样品中的BrC,并对其光吸收特性以及潜在来源排放进行测量分析。使用甲醇溶液和水进行BrC萃取,发现甲醇萃取出的化合物占有机碳的79%左右。对光学参数计算评估发现,甲醇萃取液的吸光性对波长的依赖很强,在330~550 nm波长范围内其平均吸光指数为6.8,且在365 nm处甲醇萃取液的质量吸收效率((2.5±0.6)m^(2)·g^(-1))要高于水萃取液的质量吸收效率((2.0±0.6)m^(2)·g^(-1))。使用正矩阵因子分解(PMF)模型推测出采样期间生物质燃烧和机动车排放对于西安地区有机碳(Organic Carbon,OC)的贡献较大(约62%),对于BrC的进一步控制还需要从这两类主要排放源入手。Brown Carbon(BrC)causes serious harm to climate environment through direct or indirect effect.In this paper,taking PM2.5 in winter over Xi’an as the research object,the BrC was obtained by liquid phase extraction and its light absorption characteristics and potential source emissions were measured and analyzed.Using two kinds of extraction solvent for extraction(methanol and water),the compounds extracted from methanol accounted for about 79%of the organic carbon.Based on the calculation and evaluation of optical parameters,it was found that the absorbance of methanol extract is highly dependent on wavelength,with the average absorption Angstrom exponent of 6.8 in the wavelength range of 330550 nm.The mass absorption efficiency of methanol extract at365 nm((2.5±0.6)m^(2)·g^(-1))was higher than that of water extract((2.0±0.6)m^(2)·g^(-1)).The positive matrix factorization(PMF)model was used to obtain that the contributions of biomass combustion and vehicle emissions to the organic carbon were large(about 62%).Further control of the BrC needs to start with these two major emission sources.

关 键 词：大气气溶胶颗粒 棕碳 吸光特性 源解析 

分 类 号：X513[环境科学与工程—环境工程]