ERI: Direct Photochemistry Effects on Carbonyl/Ammonium-derived Aqueous Secondary Organic Aerosol

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。气溶胶通过与阳光的相互作用和云的形成，对空气质量、人类健康和地球气候产生重大影响。大多数大气气溶胶是二次有机气溶胶(SOA)，由挥发性有机化合物氧化形成，然后在气溶胶凝聚相颗粒物中分配。含有羰基的挥发性有机化合物(CVOCs)是SOA值的重要贡献者。然而，CVOCs的光化学对SOA的大小、组成和物理性质的影响还不是很清楚。该ERI项目的首要目标是解决这一知识鸿沟。为了实现这一目标，首席调查员(PI)和他的团队将测量不同日照条件下COVC衍生的SOA水溶液的表面张力、光吸收和组成。该项目的成功完成将通过发展关于气雾剂对空气质量、云形成和气候变化的影响的新的基础知识来造福社会。将通过学生教育和培训，包括指导拉斐特学院的两名本科生，进一步造福社会。乙二醛和甲基乙二醛等含羰基挥发性有机化合物(CVOCs)及其反应产物是二次有机气溶胶(SOA)水溶液形成的重要因素。该ERI项目的主要目标是促进对CVOCs的体相和表面水相光化学及其对SOA水溶液的大小、组成和物理性质的影响的基本了解。为了推进这一目标，PI和他的团队提议实施一项围绕三项任务构建的综合实验计划。任务1将通过增加UV灯阵列来修改Lafayette连续流动大气室，使SOA水溶液能够在受控的相对湿度条件下暴露于不同数量的辐射中。任务2将使用CVOCs的气雾化含水混合物作为模型系统来测量SOA溶液的粒度分布、组成和表面张力的变化。任务3将分析收集的数据，并将任务2中测量的物理/化学性质的变化与类似的散装溶液和液滴样品的变化进行比较。这项研究的成功完成有可能促进我们对SOA水溶液的形成和物理/化学性质及其对空气质量、云形成、辐射强迫和气候变化的影响的基本了解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Aerosols have a significant impact on air quality, human health, and Earth’s climate via interactions with sunlight and in forming clouds. Most atmospheric aerosols are secondary organic aerosols(SOA), formed via the oxidation of volatile organic compounds followed by partitioning in the aerosol condensed phase particulate matter. Carbonyl-containing volatile organic compounds (CVOCs) are significant contributors to SOA. However, the impact of photochemistry of CVOCs on the size, composition and physical properties of SOA is not well understood. The overarching goal of this ERI project is to address this knowledge gap. To achieve this goal, the Principal Investigator (PI) and his team will measure the surface tension, light absorbance, and compositions of COVC-derived aqueous SOA solutions under varying amounts of sunlight. The successful completion of this project will benefit society through the development of new fundamental knowledge on the impact of aerosols on air quality, cloud formation, and climate change. Further benefits to society will be achieved through student education and training including the mentoring of two undergraduate students at Lafayette College. Carbonyl-containing volatile organic compounds (CVOCs) such as glyoxal and methylglyoxal and their reactive products are significant contributors to the formation of aqueous solutions of secondary organic aerosol (SOA). The overarching goal of this ERI project is to advance the fundamental understanding of the bulk and surface aqueous photochemistry of CVOCs and its impacts on the size, composition, and physical properties of aqueous solutions of SOA. To advance this goal, the PI and his team propose to carry out an integrated experimental program structured around three tasks. Task 1 will modify the Lafayette continuous-flow atmospheric chamber though the addition of UV lamp arrays to enable the exposure of aqueous SOA solutions to varying amounts of radiation under controlled relative humidity conditions. Task 2 will measure changes in the size distribution, composition, and surface tension of SOA solutions using aerosolized aqueous mixtures of CVOCs as model systems. Task 3 will analyze the collected data and compare the changes in the physical/chemical properties measured in Task 2 to those from analogous bulk solution and droplet samples. The successful completion of this research has the potential to advance our fundamental understanding of the formation and physical/chemical properties of aqueous SoA solutions and their impact on air quality, cloud formation, radiative forcing, and climate change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.