Brown Carbon Formation by Aqueous Phase Reactions of Glycolaldehyde and Methylamine

Camille Carthy, Erin O'Leary, Swetha Tadisina, Daniel Griffith, Heidi Hendrickson, Joseph Woo, MELISSA GALLOWAY, Lafayette College

     Abstract Number: 738
     Working Group: Aerosol Chemistry

Abstract
Brown carbon in aerosol remains a significant source of error in global climate modeling due to its complex nature and limited product characterization. Though significant efforts have been made in the previous decade to identify the major light absorbing brown carbon chromophores formed through the reactions of small difunctional carbonyl-containing compounds with ammonium, substantial work is still required to identify the main absorbing species resulting from reactions of carbonyls with more complex amines. Using tandem mass spectrometry and isotopic substitution experiments to confirm proposed structures and support their mechanistic pathways, evidence is provided for the formation of N-containing oligomers and heterocycles in glycolaldehyde + methylamine reaction systems. Reaction kinetics and surface tension measurements provide evidence for changing physical properties as a function of reaction progress. These products contribute to brown carbon light absorption, thus holding significant relevance toward accurately predicting their effects on global climate.