类腐殖质（HULIS）具有吸水性和表面活性，是水溶性有机物的重要组成部分，显著影响大气气溶胶吸湿和活化。目前国内外对HULIS吸湿活化、表面活性及其与化学组成的关系认识非常有限，我国更是薄弱。因此，本研究计划使用双电迁移颗粒物吸湿测定仪和云凝结核计数仪测定生物质燃烧排放和实际大气颗粒物中HULIS的吸湿活化和表面张力等物理参数，使用先进的静电场轨道阱超高分辨率液质联用仪和高分辨率飞行时间气溶胶质谱获取HULIS的分子水平和宏观的化学信息，结合实验室测量和外场闭合实验，系统表征大气颗粒物中水溶性HULIS化学组分、吸湿活化能力和表面活性；基于有效吸湿参数和化学信息，建立新的表征HULIS吸湿性的参数化方法；从分子水平上理解HULIS表面活性；优化现有模型的输入参数，量化HULIS对大气气溶胶吸湿活化的影响，推进对雾霾形成机理和气溶胶气候效应的认识。

HUmic-LIke Substances (HULIS) play an important role in particle hygroscopicity and activation by taking up water and acting as surfactants. They account for large proportions of water soluble organic carbon. Currently, our knowledge on HULIS is still limited due to the lack of information on chemical composition, hygroscopicity and surface active properties of HULIS. Especially, studies on HULIS are very scarce in china. Therefore, we plan to investigate the hygroscopic growth and CCN activity of HULIS particles using Hygroscopicity Tandem Differential Mobility Analyzer and Condensation Cloud Nuclei counter. A novel ultrahigh mass spectrometer (Orbitrap) and High Resolution Time-of-Flight Aerosol Mass Spectrometer will be performed to provide molecular-level and bulk chemical information of HULIS. By integrating the laboratory investigation and field closure study, our study will obtain the parameters representing hygroscopicity and CCN activity, and surface active properties of HULIS in biomass burning particles and atmospheric particles. A parameterization scheme on a basis of the relationship between chemical information and effective hygroscopicity parameters will be evaluated. The surface active properties will be investigated in connection with molecular structure of HULIS. Based on the lab investigation, the parameters in the k-k?hler theory will be optimized. By using the new parameters, the effects of HULIS on hygroscopic growth and CCN activity of atmospheric particles will be quantified. The final goal of our study is to improve our understanding of the formation mechanism of haze in china, as well as aerosol climate effects.