AGS-PRF: Triple Oxygen Isotope Investigations of Organic Aerosol Oxidation

This Postdoctoral Research Fellowship focuses on an investigation of the oxidation chemistry of organic aerosol in the atmosphere and how this chemistry can lead to compositional changes in the aerosol that alter its optical properties. This project will elucidate some of the mechanistic details of organic aerosol oxidation that have been previously inaccessible. Changes in aerosol optical properties can result in changes in aerosol-radiation interactions that influence climate. This research will address the following questions: (1) What organic aerosol (OA) oxidation pathways are the most important contributors to changes in aerosol composition in urban and rural environments? (2) Do these oxidant-specific contributions vary for different aerosol sources or with the seasons? (3) How do the extent and pathways of OA oxidation affect its optical properties? The postdoctoral scholar has developed an innovative methodology for the triple oxygen isotope measurement of organic matter that can be used to differentiate and quantify the specific oxidants contributing to atmospheric oxidation processes. The experimental plan includes utilizing carbon and nitrogen isotopes to distinguish OA sources and track (photo)chemical aging and characterizing the impact of different atmospheric oxidation pathways on OA light-absorbing properties. The project includes the support and mentorship of local high school students and summer 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.