Photolysis mechanism photodecomposition rates

Effects of microlayer constituents or other surface-active agents on photochemical reactions in aqueous media have not been widely studied. Zadelis and Simmons (1983) demonstrated that the photodecomposition of naphthalene in Lake Michigan microlayer material was slower by a factor of about 2 relative to that in lake water. Larson and Rounds (1987) also showed that a 30 mM concentration of a surface-active material (sodium dodecyl sulfate) significantly decreased the photolysis rate of 1-naphthol at pH 7. In contrast, Epling et al. (1988) showed that borohydride-promoted photodechlorination of polychlorinated biphenyls was significantly increased in the presence of ca. 100 mM concentrations of the surface-active agents Brij-58 (a polyethoxyethanol) and sodium dioctyl succinate. The mechanisms for these observed rate effects are unknown. 

Combining the rate coefficient values reported above and a diurnal average [OH] = 10 molecule cm provides an estimate of the atmospheric lifetime of carbonyl nitrates with respect to removal by reaction with OH in the range 3 to 30 days. Photolysis is also likely to be an important atmospheric loss mechanism. Wangberg et al. (1996) conclude that the photodecomposition in the troposphere is unimportant for tra 5 -2-hydroxy-cyclopentyl-1-nitrate (no significant absorption) but both 2-oxo-cyclohexyl-l-nitrate... 

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