基于单颗粒成分分析的气溶胶物理化学综合表征体系

This Project aims to establish a set of aerosol comprehensive measurement techniques (ACMT) for characterizing the particle size, mass density, chemistry, mixing state, hygroscopicity, light extinction and scattering. The ACMT is based on the single particle analysis of chemical composition, mainly by Single Particle Aerosol Mass Spectrometer (SPAMS) and Single Particle Soot Photometer (SP2). The Tandem Differential Mobility Analyzers (TDMA) coupled with thermal denuder or humidifier are employed to segregate the size-resolved chemical components or to promote the hygroscopic growth, and then the changed physical and chemical properties of the particles during the chemical segregation period or during the hygroscopic growth are characterized by the ACMT. The particle light extinction and scattering coefficients are measured by Cavity Attenuated Phase Shift Aldebo Monitors (CAPS-Alb) paralleled with the chemical analysis..The physical and chemical properties of various typical aerosol samples and ambient aerosols will be comprehensively analyzed by the ACMT. Based on the ACMT data, we will focus on the correspondence among the particle microphysics, chemical compositions, aerosol optical properties and hygroscopicity. By comparing the ACMT data for the typical samples and ambient aerosols, we will do source apportionment for the primary particles in ambient environment, and will investigate the formation pathways of the secondary components. This project will get a better understanding of the complex atmospheric particle pollution in China, and the ACMT will provide a new technique support for the research on the formation mechanism of the haze in China.

本项目旨在搭建一套基于单颗粒成分分析的综合表征体系，可在线分析大气气溶胶的颗粒物粒径、密度、化学组成、混合态以及光学性质、吸湿性等。体系核心为单颗粒气溶胶质谱仪和单颗粒黑碳光谱仪，用以单颗粒层面的成分分析。体系中使用了串联差分电迁移率分析仪，结合热解析仪对颗粒物复杂组分进行预分离，或结合加湿器使颗粒物吸湿增长，从而研究不同粒径和组分分离前后或者吸湿增长前后，颗粒物各理化性质的变化。气溶胶光学性质（吸光与散射）由与化学成分分析并行的腔衰减相移式单次散射反照率仪检测。使用该综合表征体系对几种典型气溶胶样品以及环境大气进行表征分析，精确构建出大气气溶胶的“微观结构与化学组分-吸湿性与光学性质”的对应关系。通过比较典型气溶胶样品和环境大气的表征结果，对环境大气中的主要一次颗粒物的来源进行解析，并对二次颗粒物的成因进行探讨，从而为深入认识中国大气复合污染（特别是重度灰霾的形成机制）提供新的技术支撑。

本项目完成搭建了一套基于单颗粒成分分析的气溶胶物理化学性质综合表征体系，可在线分析大气气溶胶的颗粒物粒径、有效密度、化学组成、混合状态态以及光学性质、吸湿性等。表征体系以单颗粒气溶胶质谱仪和单颗粒黑碳光谱仪为核心，进行单颗粒层面的化学组分和混合态分析。体系中使用了串联差分电迁移率分析仪，结合热解析仪对颗粒物复杂组分进行预分离，或结合加湿器使颗粒物吸湿增长，从而研究不同粒径和组分分离前后或者吸湿增长前后，颗粒物各理化性质的变化。气溶胶光学性质（吸光与散射）由与化学成分分析并行的腔衰减相移式单次散射反照率仪检测。.使用该综合表征体系，项目对船舶排放、生物质燃烧等典型一次源颗粒物的混合状态进行了深入研究；对一次颗粒物在大气中老化过程中发生的物理性质的变化实现了在单颗粒组分层面的解读；在线观测到重度污染过程中，黑碳颗粒物粒径的快速增长及其对光学性质的影响，并首次实现对黑碳颗粒物进行时间分辨的混合态与吸湿性联合观测；根据外场观测结果，开展了一系列半挥发性有机物液相反应形成二次有机气溶胶的机制研究。.研究成果精确构建出大气气溶胶的“微观结构与化学组分-吸湿性与光学性质”的对应关系。通过比较典型气溶胶样品和环境大气的表征结果，对环境大气中的主要一次颗粒物的来源进行解析，并对二次颗粒物的成因进行探讨，为深入认识中国大气颗粒物污染形成机制提供了新的技术支撑。