We report that rates of I2(g) emissions, measured via cavity ring-down spectroscopy, during the heterogeneous ozonation of interfacial iodide: I-(surface, s) + O3(g) + H+(s) →→ I2(g), are enhanced several-fold, whereas those of IO · (g) are unaffected, by the presence of undissociated alkanoic acids on water. The amphiphilic weak carboxylic acids appear to promote I2(g) emissions by supplying the requisite interfacial protons H+(s) more efficiently than water itself, at pH values representative of submicrometer marine aerosol particles. We infer that the organic acids coating aerosol particles ejected from oceans topmost films should enhance I2(g) production in marine boundary layers.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry