Condensed-Phase Organic Photochemistry in Aerosol Particles and in Aerosol Liquid Water

该项目包括一些实验室实验，以研究大气中暴露在阳光下的小颗粒的命运。暴露在阳光下会导致颗粒中的化学变化，从而缩短它们在大气中的寿命。这项研究将为预测老化的有机颗粒物的去向提供有价值的信息，并与了解大气中细颗粒物对健康的影响有关。本研究的目的是：(1)系统地探讨二次有机气溶胶(SOA光)降解速率与SOA光降解类型和形成条件的关系；(2)模拟气溶胶液态水中的条件，研究SOA光化学在高浓度无机电解质溶液中的光化学；(3)研究直接和间接光化学过程在辐照SOA光化学过程中的相对重要性；以及(4)研究燃烧生物质的有机气溶胶中的光降解和光敏化过程。这些实验的结果将被用来模拟大气有机颗粒内部和含有溶解有机物的云滴内发生的光化学反应对全球大气有机气溶胶负荷的影响。这一努力将直接支持至少两名研究生和至少六名本科生的培养。这一奖项反映了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 project includes a number of laboratory experiments to study the fate of small particles exposed to sunlight in the atmosphere. Exposure to sunlight can cause chemical changes in the particles that reduces their atmospheric lifetimes. This research will provide valuable information for predicting the fate of aged organic particulate matter and is relevant to understanding the health effects of fine particles in the atmosphere.The objectives of this research are to: (1) systematically explore the dependence of secondary organic aerosol (SOA) photodegradation rates on the type of SOA and on the conditions of SOA formation; (2) investigate photochemistry of SOA in highly concentrated solutions of inorganic electrolytes mimicking the conditions found in aerosol liquid water; (3) investigate the relative importance of direct and indirect photochemical processes in irradiated SOA; and (4) investigate photodegradation and photosensitization processes in biomass-burning organic aerosols.The results of these experiments will be used to model the effects of photochemical reactions occurring inside atmospheric organic particles and inside cloud droplets containing dissolved organics on the global atmospheric burden of organic aerosol. This effort will directly support the training of at least two graduate students and at least six undergraduate students.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.