Measurements of peroxides in cloudwater and rain

摘要: Measurements of total peroxide content are reported for 190 cloudwater samples from nonsupercooled stratiform clouds, and 54 rain samples, collected at several nonurban sites in the eastern United States. Observed aqueous concentrations ranged less than 0.1 ..mu..M to over 100 ..mu..M, with precipitating nonprecipitating all exhibiting median values 10 similar concentration distributions. Specific analyses H/sub 2/O/sub 2/ on 48 showed that majority tested, was sole contributor concentration, but some substantial signal observed after selective destruction 2/, possibly indicating presence organic peroxides. Calculation potential partial pressure using measured cloud liquid water values, indicates a ppbv, maximum value approximately 1 ppbv. Gaseous SO/sub were rarely simultaneously present concentrations; generally one reactant great excess other, consistent occurrence themore » phase reaction S(IV) which or other species is limiting reagent. Evaluation rates oxidation by ozone, under conditions representative clouds sampled this study, former reaction, not latter, can produce acidification such clouds.« less