基于超高分辨率质谱研究大气棕碳气溶胶光学示踪物的化学组成与来源

Brown carbon is light-absorbing particulate organic matter. Its potential impact on climate was highlighted for the first time in the 5th assessment report of the IPCC in 2013. Since then, the optical properties, molecular composition, and sources of brown carbon have been recognized as one of the most active fields and are in the forefront of earth environment research. In this project, we plan to develop ultra-high resolution mass spectrometric and UV-Vis absorption methods to investigate the link between molecular composition and optical properties of brown carbon. This will include the study of primary brown carbon emitted directly from biomass burning and coal combustion and secondary brown carbon from aging of these direct emission exhausts in smog chamber. We will take field measurements at several typical regions in China. The concentrations and optical properties of bulk brown carbon will be quantified to investigate their spatial and temporal distribution. The molecular composition of brown carbon will be studied to get insights into the relationship between the chemical component and absorption of brown carbon. By combining the ambient and laboratory studies, the atmospheric evolution of chemical and optical properties of brown carbon will be investigated. The receptor model combined with fingerprint of brown carbon composition will be used to quantify the contributions of different sources and atmospheric processes to brown carbon in ambient air.

棕碳气溶胶是吸光性大气有机颗粒物。在2013年IPCC第五次评估报告中首次将棕碳的气候效应列为重点关注对象后，研究棕碳光学性质、化学组成和来源成为国际上地学研究的热点领域之一。本项目拟通过建立超高分辨率质谱和光谱分析方法，从分子水平上研究生物质燃烧和燃煤排放的一次棕碳和烟雾箱老化生成的二次棕碳的化学成分及吸光性质的定量关联,获得棕碳吸光示踪物的化学组成信息；通过在我国数个地区开展外场观测，获得不同地区、不同大气环境下棕碳气溶胶化学成分和光学性质的时空分布特征；结合外场观测数据和源排放与老化实验结果，探讨棕碳气溶胶化学成分和吸光能力的大气演化过程，定量各个主要排放源对实际大气棕碳气溶胶的贡献。

棕碳气溶胶是吸光性大气有机颗粒物。在2013年IPCC第五次评估报告中首次将棕碳的气候效应列为重点关注对象后，研究棕碳光学性质、化学组成和来源成为国际上地学研究的热点领域之一。本项目围绕大气棕碳气溶胶光学示踪物的化学组成与来源这一目标，建立以液相色谱-超高分辨率质谱-吸收光谱联用技术为核心的棕碳测量体系，通过开展燃烧源排放及烟雾箱老化实验，获得棕碳吸光示踪物的化学组成信息，及其与吸光性质间的定量关联；同时在西安、北京和石家庄地区开展外场观测，获得这些地区不同大气环境下棕碳气溶胶化学成分和光学性质的时空分布特征；结合外场观测数据和源排放与老化实验结果，揭示了棕碳气溶胶化学成分和吸光能力的大气演化过程，定量各个主要排放源对实际大气棕碳气溶胶的贡献。