RUI: Photochemical and OH-initiated Processing of Aerosol Organic Coatings

化学系的环境化学科学计划和大气和地球空间科学部的大气化学计划共同资助这一奖项。胡安·纳维亚教授和他的本科生研究空气中悬浮的小颗粒，即所谓的大气气溶胶。其目的是提高我们对发生在大气气溶胶有机涂层上的化学反应的理解。覆盖在气溶胶上的有机化合物层会影响它们在空气质量、气候和健康方面的作用。尤其是涉及羟基自由基(OH)和太阳辐射的大气反应可以改变气溶胶的化学和物理性质。这影响了它们散射光线、播撒云层并诱导产生次生有机气溶胶的能力。该研究项目使用最先进的光谱系统独立地研究气溶胶有机涂层与太阳辐射、OH以及两者的组合的反应。这种方法提供了在反应发生时有机涂层中的化学变化的信息。可以对反应产物进行表征，并更好地了解导致大气颗粒物老化的机制。从事这个项目的本科生研究人员从事基础和应用化学研究，前往国家会议传播他们的发现，并接受指导和培训，这最终有助于扩大和保持学生对科学的参与。这项研究项目使用了一种新开发的非热等离子体系统，在受控的环境中，在没有光和存在光的情况下，产生和测量OH物种。Navea教授的实验室开发的多维光谱流动系统可以对矿物粉尘或燃烧颗粒成分上的表面有机物种进行时间分辨振动光谱。原位测量允许对OH反应、光解以及这些反应的组合进行动力学分析。非原位产品表征提供了对气雾剂涂层上氧化过程的机械理解。特别是，对光活性成分的研究，如半导体金属氧化物衬底和/或发色有机涂层，可以研究太阳辐射和羟基对表面结合物种的潜在协同效应。这个项目的结果提供了对大气颗粒物老化机制的更好的理解。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。

The Environmental Chemical Sciences Program in the Division of Chemistry and the Atmospheric Chemistry Program in the Division of Atmospheric and Geospace Sciences jointly fund this award. Professor Juan Navea and his undergraduate students study small particles suspended in air, known as atmospheric aerosols. The goal is to improve our understanding of chemical reactions that take place on the organic coatings of atmospheric aerosols. The layers of organic chemical compounds that that often cover aerosols affect their role in air quality, climate, and health. In particular, atmospheric reactions involving hydroxyl radical (OH) and solar radiation can change the chemical and physical properties of aerosols. This impacts their ability to scatter light, seed clouds, and induce the generation of secondary organic aerosol. The research project uses a state-of-the-art spectroscopy system to study, independently, reactions of aerosol organic coatings with solar radiation, OH, and the combination of both. This method provides information on the chemical changes in the organic coatings as the reaction takes place. Reaction products can be characterized and the mechanisms leading to atmospheric particle aging better understood. Undergraduate researchers working on this project engage in fundamental and applied chemistry research, travel to national conferences to disseminate their findings, and receive mentorship and training, which ultimately helps broaden and retain student participation in the sciences. Many of these students are historically underrepresented in the physical sciences.This research project uses a newly developed non-thermal plasma system to generate and measure OH species in a controlled environment in the absence and presence of light. A multi-dimensional spectroscopy flow system developed in Professor Navea’s lab allows time-resolved vibrational spectroscopy of surface organic species on components of mineral dust or combustion particles. In situ measurements allow for kinetic analysis of OH reactions, photolysis, and the combination of these reactions. Ex situ product characterization provides a mechanistic understanding of the oxidation process on aerosol coatings. In particular, studies of photoactive components, such as semiconductor metal oxide substrates and/or chromophoric organic coatings, allow the investigation of potential synergistic effects of solar radiation and OH on surface bound species. The results from this project provide a better understanding of atmospheric particle aging mechanisms.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.