AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Multiphase Oxidation Chemistry: Impacts on Both the Gas Phase and Aerosol
JONATHAN ABBATT, University of Toronto
Abstract Number: 173 Working Group: Invited by Conference Chair
Abstract Whereas gas phase oxidation mechanisms are comparatively well understood, considerable uncertainties remain with respect to the nature and potential importance of multiphase oxidation processes in which oxidative reactions occur either within a condensed phase or at a gas-particle interface. While such chemistry has long been recognized to be important in the oxidation of sulfur(IV) to sulfur(VI) in cloudwater and for promoting the Ozone Hole, its prevalence with tropospheric aerosol and at the Earth’s surface remains poorly quantified. As well, such reactions are likely to occur indoors, given the relatively slow gas-phase chemistry that prevails in these environments. In part, these uncertainties arise because of the complexity of the chemistry: oxidants may either form in-situ or be delivered from the gas phase, chemistry can occur at interfaces or in the bulk, and mass transport limitations can be important in both the gas and condensed phases. After an introduction to the general issues involved in multiphase oxidation chemistry, this talk will illustrate the complexity of the field by focusing on specific examples from across the realm of aerosol and atmospheric chemistry. Attention will be given to: i) organic aerosol oxidation, whereby the overall oxidation state and hygroscopicity of the particle may change, ii) transformations of trace, toxic species (such as polycyclic aromatic hydrocarbons) within particles, and iii) oxidation processes that occur within cloudwater. In addition, the potential for multiphase chemistry occurring at the Earth’s surface, such as at high latitudes with salty substrates or with the marine surface microlayer, will also be discussed.