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.
