珠江三角洲大气PM2.5中二元羧酸来源的单体14C研究

Dicarboxylic acids in atmospheric fine particulate matter (PM2.5) are important components of water-insoluble organic compound, which have been widely studied due to their potential roles in affecting the global radioactive balance, climate change, human health and secondary organic aerosol formation. The composition and sources of dicarboxylic acids are largely variable and complicated, which have always been a concern in the atmospheric research. However, knowledge of their composition and sources is very limited. Identification of its source is the scientific basis for rational air pollution prevention and control policies. Radiocarbon (14C) measurement is a powerful tool that allows to quantitatively apportion between combustion and non-combustion products derived from fossil fuels (14C free or “dead”) and those formed from modern biomass (contemporary levels of 14C or “alive”). To better understand detailed information about source and formation mechanism of dicarboxylic acids, compound-specific radiocarbon analysis (CSRA) will be applied in this study. In this project, PM2.5 samples will be collected in three typical sites in the Pearl River Delta Region (PRD), and analyzed for dicarboxylic acids and their 14C content, water-insoluble organic carbon, and biomarkers. The main objectives of this project aims to 1) discuss the molecular composition and seasonal variation of dicarboxylic acids in PM2.5; 2) and identify the sources of dicarboxylic acids based on 14C results along with other source apportionment methods (correlation analysis and ratios of selected species, biomarkers and principle component analysis etc.), and to quantitatively apportion the sources of diacarboxylic acids; 3) and characterize the seasonal and spatial variations of the sources and the factors influencing the variation of dicarboxylic acids in PM2.5 in PRD region.

大气气溶胶中二元羧酸是水溶性有机物的重要组分，主要存在于细颗粒物（PM2.5）中，对地球辐射平衡、气候变化、人体健康和大气二次有机气溶胶形成机制等具有重要意义。其化学组成复杂，具有不同来源特征，识别其来源是制定有效大气污染防治对策的科学依据。放射性碳同位素（14C）是有效识别并定量化石碳和当代生物碳对颗粒态二元羧酸相对贡献的强有力工具。为获得更详细颗粒态二元羧酸来源及形成机制等信息，本申请项目将对其进行特定化合物14C分析（compound-specific radiocarbon analysis, CSRA）。本研究选择珠江三角洲为研究靶区，旨在1）掌握其大气PM2.5中二元羧酸污染水平与组成特征；2）基于14C示踪技术，联合其它示踪技术及源解析方法，查明该地区颗粒态二元羧酸的碳来源，定量估算当代生物质燃烧与化石燃料燃的相对贡献；3）探究二元羧酸来源的时空变化规律和影响因素。

大气气溶胶中二元羧酸是水溶性有机物的重要组分，主要存在于细颗粒物（PM2.5）中，对地球辐射平衡、气候变化、人体健康和大气二次有机气溶胶形成机制等具有重要意义。其化学组成复杂，具有不同来源特征，识别其来源是制定有效大气污染防治对策的科学依据。放射性碳同位素（14C）是有效识别并定量化石碳和当代生物碳对颗粒态二元羧酸相对贡献的强有力工具。为获得更详细颗粒态二元羧酸来源及形成机制等信息，本申请项目将对其进行特定化合物14C分析（compound-specific radiocarbon analysis, CSRA）。本研究首先建立了大气细颗粒物二元酸羧酸单体碳十四分析方法，使得我们环境碳十四实验室成为全球第二个能够独立分析二元羧酸单体碳十四实验室；其次，阐明珠江三角洲地区大气二元羧酸污染水平与组成特征； 来源的时空变化规律和影响因素；以及定量估算了珠三角当代生物质燃烧与化石燃料的相对贡献。在课题实施期间, 相关成果共发表SCI论文2篇，这2篇论文第一作者为课题负责人本人论文都发表在大气科学研究的主流期刊，包括1篇Atmospheric Chemistry，1篇 Scientific Reports, 依托本项目，共培养博士后1名，博士研究生1名。