The radical-initiated oxidation of organic species plays an important role in the formation and aging of organic aerosol (OA). Oxidation reactions can either increase or decrease volatility, thereby controlling the partitioning between the gas and condensed phases. However, the effects and relative importance of key oxidative pathways are not well-constrained at present. Here, we estimate the effects of oxidation on the average carbon oxidation state (OSc) and vapor pressure of organics.  These are estimated for a number of important oxidation reactions as a function of carbon number, molecular structure, and site of radical attack, using structure-activity relationships. Fragmentation (C-C bond breaking) reactions are most efficient at forming highly oxidized carbon, but the products tend to be smaller and more volatile. Therefore the aging of atmospheric organic matter involves a balance between the formation of highly oxidized products and the loss of organics to the gas-phase.

Effects of oxidation on the volatility and carbon oxidation state of atmospheric organic species<i></i>

242nd National Meeting (2011)

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