Phenols and methoxyphenols represent common functional groups found in semivolatile organics released into the troposphere via biomass combustion, where they may readily adsorb onto aerosol surfaces. We use infrared spectroscopy (DRIFTS, transmission, and ATR-FTIR) to monitor the adsorption and subsequent ozonolysis of model organics � e.g., phenol, catechol, and eugenol � on sea salt and mineral aerosol substrates. Adsorption of gaseous organics on sodium halides is controlled by hydrogen bonding interactions and is readily reversible, especially at higher relative humidities, for all compounds studied except catechol. In comparison, dissociative adsorption of phenolic functional groups on Al2O3 produced surface bound phenolates even under humid conditions. Heterogeneous ozonolysis ([O3] = 400-900 ppb) of surface adsorbed aromatics resulted in ring cleavage forming carboxylic acids (e.g., catechol ? muconic acid). Reaction kinetics are measured as a function of substrate, ozone concentration, and relative humidity to assess the atmospheric impact of this chemistry.

Heterogeneous chemistry of phenols and methoxyphenols adsorbed on tropospheric aerosol substrates

244th National Meeting (2012)

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