AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Secondary Organic Aerosol Formation from Glyoxal: Salting Behavior and Kinetics of SOA Formation and its Dependence on Aerosol Seed Composition
ELEANOR WAXMAN, Jay Slowik, Christopher Kampf, Rupert Holzinger, Josef Dommen, Andre Prévôt, Urs Baltensperger, Rainer Volkamer, University of Colorado
Abstract Number: 410 Working Group: Aerosol Chemistry
Abstract Glyoxal forms secondary organic aerosol (SOA) by partitioning to the aerosol aqueous phase according to Henry’s law. Our recent simulation chamber experiments suggest that electrical forces, rather than vapor pressure, drive glyoxal partitioning to ammonium sulfate seed aerosols. The Henry’s law partitioning coefficient increases exponentially with salt concentration. A single “salting in” constant is found to bridge between dilute cloud water and concentrated aerosol water, providing a unifying concept for these very different chemical regimes. Through a series of experiments performed at the Paul Scherrer Institut in April/May 2011 and May/June 2013, we have studied the effect of these electrical forces on glyoxal partitioning by using a variety of aerosol seed chemical compositions, including ammonium sulfate, ammonium nitrate, and sodium nitrate. We have also varied the aerosol pH by including gas-phase ammonium. In this work, we present preliminary analyses of these experiments. We also briefly investigate the formation of irreversibly-formed and reversibly-formed SOA from glyoxal and the effect of seed chemical composition, and identify species that contribute to each of these SOA fractions.