AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Aqueous Photooxidation of Water-Soluble Compounds in Po Valley, Italy during PEGASOS: Chemical Insights and Modeling
YONG LIM, Jeffrey R. Kirkland, Ron Lauck, Barbara Turpin, Rutgers University
Abstract Number: 336 Working Group: Aerosol Chemistry
Abstract Aqueous chemistry is a potentially important atmospheric pathway to produce second organic aerosol (SOA). Moreover, SOA formed via aqueous chemistry in cloud droplets/wet aerosols helps to explain the high O/C of atmospheric organic aerosols. While aqueous SOA precursors have been proposed, it is not yet clear what the most important precursors are in the atmosphere. Recently, water-soluble organic compounds were scrubbed from the atmosphere using mist chambers in Po Valley, Italy during the PEGASOS campaign (June-July, 2013), and aqueous-phase OH radical reactions were conducted with these mixtures. Precursors and photochemical products were identified and quantified by using an electrospray ionization mass spectrometer (ESI-MS), ion chromatography (IC), and IC coupled with ESI-MS. Several ESI-MS positive mode ions decayed during these experiments (reactants). Subsequently, oxalate, pyruvate and mesoxalate formations were observed. These products are also formed in laboratory glyoxal/methylglyoxal photooxidation experiments. While we saw no evidence for the presence of glyoxal or methylglyoxal in the samples (experiment t = 0), there is some evidence that they may be intermediate products, forming and decaying during the reactions. Expected emission and gas-phase photochemistry were used to develop insights into potential precursors and kinetic modeling was used to link these precursors through glyoxal and methylglyoxal to pyruvate and oxalate. The underlying assumptions and implications will be discussed.