CAREER: Toward an Understanding of Secondary Aerosol Formation, Particle Ageing in Droplets, and Cloud Processing

气溶胶在空气质量和地球辐射平衡中起着重要作用。气溶胶的有机成分普遍存在，但其形成性质尚不清楚。众所周知，水相过程会影响大气多相系统的组成，是二次气溶胶形成的重要途径。然而，由于有机气溶胶-水相互作用和云滴过程的非理想性是复杂的；目前的模型不能再现实验室或野外的观测结果。首席研究员（PI）将开发一种独特的测量能力，通过实验室和现场的云处理来研究二次气溶胶的形成和粒子老化。环境或人工产生的气溶胶将通过连续流动的流向热梯度室进行采样，并使用扫描迁移率颗粒分析仪和高分辨率气溶胶质谱仪对其进行采样和表征，以确定其数量大小分布和化学成分。将测量被活化成云凝聚核（CCN）的颗粒的组分，作为过饱和的函数，以及由云处理引起的气溶胶的挥发性、表面张力和其他性质的相应变化。将开发分离和表征间隙气溶胶和活化液滴以及通过CCN室回收处理过的气溶胶的方法。基于这种测量能力的结果将填补在理解云滴中清除的气溶胶的化学演化方面的关键空白。PI和她的学生将利用加州大学河滨伯恩斯工程学院最先进的空气污染实验室-环境研究与技术中心（CE-CERT）的现有设施。该设施还将为她的研究团队提供与更广泛的研究社区互动的机会。这项研究将解决空气质量、气候和健康方面的重要问题和推进知识。新的测量能力将被纳入早期职业PI的长期研究计划，该PI来自地球科学中代表性不足的群体。作为美国种族和经济最多样化的公共研究机构之一的教员，PI将为来自不同背景的学生树立榜样和导师。PI将针对研究生、本科生和K-12学生开发基于监督、情境和非正式指导技术的综合研究和教育计划。研究生将通过参与研究工作得到支持，并将通过科学会议和审查出版物传播研究结果。该项目还将资助两项本科生研究奖学金，其中一项将针对教育和/或经济背景较差的学生。PI将继续她目前与当地高中和代表性不足的学生的研究指导关系。最后，通过与加州科学项目的合作，PI将为K-12教师提供为期5天的夏季讲习班，重点关注气候变化。

Aerosols play an important role in air quality and Earth's radiative balance. Organic constituents of aerosols are ubiquitous but their formation properties are not well understood. Aqueous-phase processes are known to affect the composition of the atmospheric multiphase systems and are an important pathway for secondary aerosol formation. However non-idealities due to organic aerosol-water interactions and processes in cloud droplets are complex; current models do not reproduce observations in the laboratory or field. The principal investigator (PI) will develop a unique measurement capability to investigate secondary aerosol formation and particle ageing via cloud processing in both the laboratory and field. Ambient or artificially generated aerosols will be sampled and characterized for number size distributions with a scanning mobility particle analyzer and chemical composition with a high-resolution aerosol mass spectrometer both before and after processing through a continuous flow stream-wise thermal gradient chamber. The fractions of particles that are activated to cloud-condensation-nuclei (CCN) as a function of supersaturation and corresponding changes in volatility, surface tension, and other properties of aerosols that result from cloud processing will be measured. Methods to separate and characterize interstitial aerosol and activated droplets and to recycle processed aerosols through the CCN chamber will be developed. Results based on this measurement capability will fill critical gaps in understanding of the chemical evolution of aerosol scavenged in cloud droplets. The PI and her students will leverage existing facilities at a state-of-the art air pollution laboratory at the University of California, Riverside Bourns College of Engineering- Center for Environmental Research and Technology (CE-CERT). This facility will also provide opportunities for her research team to interact with the broader research community.The research will address important questions and advance knowledge in air quality, climate, and health. The new measurement capability will be incorporated into the long-term research plans of an early-career PI from an underrepresented group in the geosciences. As a faculty member at one of the most ethnically and economically diverse public research institutions in the United States, the PI will act as a role model and mentor to students from a broad range of backgrounds. The PI will develop an integrated research and education program based on supervisory, situational, and informal mentoring techniques targeting graduate, undergraduate, and K-12 students. Graduate students will be supported through participation in the research effort and will disseminate findings at scientific conferences and via reviewed publications. The project will also fund two undergraduate research fellowships, one of which would target students from educationally and/or economically disadvantaged backgrounds. The PI will continue her current research-mentoring relationships with local high school and underrepresented students. Finally, through collaboration with the California Science Project, the PI will offer 5-day summer workshops for K-12 teachers with a focus on climate change.