AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Influence of Soluble Surfactants on Heterogeneous Photooxidation of Aqueous Aerosol
JENNIFER FAUST, Jonathan Abbatt, University of Toronto, Canada
Abstract Number: 84 Working Group: Aerosol Chemistry
Abstract Oxidative aging alters the composition of organic aerosol in the atmosphere over time. Here we explore the heterogeneous photooxidation of aqueous-phase glyoxal by gas-phase OH radicals. Glyoxal (CHOCHO) is an abundant molecule in the atmosphere that is highly water-soluble. Homogeneous reactions of glyoxal and OH radicals have been extensively characterized in bulk liquid and bulk gas, but we report for the first time the reaction of OH(g) with glyoxal(aq) at the surface of aerosol droplets in the presence of UV light. Using a flow reactor and aerosol mass spectrometer (AMS), we determine the reaction rate and uptake coefficient, as well as monitor products in the particle phase. We also quantify changes in reaction rate upon addition of succinic acid (C4H6O4), a dicarboxylic acid that is known to exist in atmospheric aerosol. Succinic acid serves as a model soluble surfactant in our system; it should not directly interfere with glyoxal oxidation because OH reacts an order of magnitude more rapidly with glyoxal than with succinic acid in the aqueous phase. Finally, offline analysis, including electrospray ionization mass spectrometry (ESI-MS), is used for product identification.