RUI: Chemical phenomena of complex carbonyl-ammonium aqueous aerosol mimics

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This Research in Undergraduate Institutions (RUI) project is focused on improving the understanding of condensed-phase reactions that lead to the formation of brown carbon in the atmosphere. The proposed research effort will explore the mechanistic and kinetic changes that occur through the aqueous reactions of carbonyls and ammonium sulfate. This work includes a systematic study of light absorption as a function of composition and could lead to improved predictions of brown carbon formation in atmospheric particles.This effort involves research on the cross-reactions of ammonium sulfate with paired α-difunctional carbonyls (glycolaldehyde, glyoxal, and methylglyoxal) to determine the effects of carbonyl ratio and identity on product formation, brown carbon light absorption, and reaction rates. The proposed work aims to answer the following key scientific questions: (1) How do cross-reactions of carbonyl compounds with ammonium change product composition? (2) How do light absorption properties of the product mixtures change as a function of cross-reaction between carbonyls? (3) How do product formation and chromophoricity change as additional complexity is added to mixture? Supercritical fluid chromatography-mass spectrometry and UV-visible spectroscopy will be utilized for this study.Undergraduate research students will perform the laboratory experiments and will be involved in all aspects of the data workup and the presentation of the data.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.