Comparisons of Aqueous SOA Products and Physical Properties in Methylglyoxal/Ammonium-Sulfate Solutions under Dark and Irradiated Conditions

ERIN O'LEARY, Maia Merriman, Katherine Pierre-Louis, Bruno Loyola San Martin, Joseph Woo, Lafayette College

     Abstract Number: 686
     Working Group: Aerosol Chemistry

Abstract
Methylglyoxal (MG) is a carbonyl-containing volatile organic compound that has been identified to be present in ambient aqueous aerosols under a variety of atmospherically relevant contexts. Recent work exploring the physical properties and aqueous-phase processing of aerosol mimics containing MG and ammonium sulfate (AS) have suggested the presence of multiple potential pathways for secondary organic aerosol (SOA) formation in the MG/AS reaction system under both dark (nighttime) and UV-irradiated (daytime) conditions. The surface-active nature of MG/AS reaction products have suggested that high surface/volume ratio systems, such as those in aerosols, may affect relative SOA yields due to locally-high reactants at the gas/liquid interface, resulting in higher-molecular-weight oligomers that would otherwise not be possible in bulk solution. This work compares the relative yields of irradiated MG/AS reaction products under bulk, µL-scale hanging-droplet, and aerosolized conditions. Surface tension, UV/visible absorbance, and ESI-MS data are reported. Reaction products of aged, aerosolized MG/AS solutions are compared without light exposure, with UV-A irradiation, and with UV-C irradiation.