长三角西部地区氧化态有机物来源及其对二次有机气溶胶的贡献研究

二次有机气溶胶是气溶胶的重要贡献者，但其形成机制尚不清楚。在我国，挥发性有机物的种类繁多，来源和氧化过程极其复杂，这使得针对其内在机制的理解和研究极具挑战性。本项目拟在南京大学SORPES观测站，综合运用多种先进技术，针对挥发性有机物、有机气溶胶及相关的气体/气溶胶参数进行两年的连续观测，并选择典型时间开展气态及气溶胶态（高）氧化态有机物的分季节观测，建立以“挥发性有机前体物→（高）氧化态有机物→二次有机气溶胶”为核心的参数数据集。利用新的质谱合并源解析技术（binPMF），提高（高）氧化态有机物的分子识别能力，建立其与挥发性有机前体物的定量关系；确认不同种类（高）氧化态有机物的挥发性，计算其在不同大气环境下向已有气溶胶的冷凝质量通量。最终实现从分子层次上理解挥发性有机物的氧化和凝结过程，并定量评估不同种类的挥发性有机前体物对二次有机气溶胶的贡献。

Secondary organic aerosol (SOA) dominate the aerosol budget globally, but its formation mechanism is so far poorly understood. In China, the speciation, sources and oxidation processes of volatile organic compounds (VOCs) are extremely complicated. This challenges the understanding of the underlying mechanism towards forming SOA. In this study, we propose a two-year continuous observation on VOCs, organic aerosol and related parameters (including particle size distribution, meteorological parameters, etc) at SORPES station. Several intensive campaigns will be conducted with gas-phase and aerosol-phase highly oxygenated / oxidized organic molecules (HOMs or OOMs) during typical months of different seasons. A data set will be set up with key parameters from VOCs to OOMs to SOA. A novel method, mass spectral binning combined with positive matrix factorization (binPMF), will be used to improve the peak identification of HOMs or OOMs from HR-Tof-CIMS. A VBS model will be used to estimate the saturation vapor pressure of the detected HOMs or OOMs. The mass flux of these organic condensable vapors can then be calculated under different conditions. The target of this study is to understand the oxidation of VOCs and their condensation to aerosols from molecular level, and connect the VOCs oxidation to SOA formation quantitatively.