水是大气气溶胶的重要组成部分，在痕量气体和气溶胶的转化与大气寿命、区域空气质量以及气候变化中均扮演重要角色，是我国大气重污染发生演变过程中起关键作用的重要因子。本研究拟基于气溶胶在热力学平衡过程中质量变化的原理为出发点，研发以石英晶体微天平为核心的可测定气溶胶中微量液态水含量以及气溶胶挥发性的技术手段，综合现有的多种技术方法，精确量化气溶胶的含水量；结合气溶胶化学、物理、气象参数等，进一步理清大气污染发生发展和消散过程中气溶胶含水量的变化规律，明确气溶胶含水量的决定因素；基于实验室研究和模式模拟，量化气溶胶含水量和相态对一次和二次有机气溶胶气-粒平衡的影响；结合研究小组已有的多年观测数据，综合评估我国大气污染控制措施实施过程中气溶胶化学组分和含水量的变化趋势以及气溶胶含水量变化对有机气溶胶生成的可能影响。

Condensed water is an important component of atmospheric particles and plays profound roles on atmospheric lifetime of trace gases and aerosols, air quality degradation, and climate change. Recent studies highlighted the importance of the aerosol liquid water content (ALWC) in secondary aerosol formation, and thus, in the generation of heavy haze events. The present study aims at developing a novel method to detect the trace condensed water in aerosols and gas-particle partitioning of organics on a basis of the mass changes during the aerosol thermodynamic equilibrium. By combining the current techniques, the ALWC will be quantified more precisely. The ALWC during the development of air pollution will be characterized to understand the roles of ALWC in the haze formation. The effects of ALWC and aerosol phase state on the gas-particle partitioning of primary and secondary organic aerosols will be focused. The changes in ALWC caused by the pollutants emissions reduction and its effects on secondary organic aerosol formation in the future will be assessed by integrating the long-term dataset and outcomes from this study.