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RELATIVE IMPORTANCE TO SULFATE PRODUCTION OF OXIDATION PATHWAYS AND CLOUDS AS PREDICTED BY THE REGIONAL ACID DEPOSITION MODEL
Citation:
McHenry, J. AND R. Dennis. RELATIVE IMPORTANCE TO SULFATE PRODUCTION OF OXIDATION PATHWAYS AND CLOUDS AS PREDICTED BY THE REGIONAL ACID DEPOSITION MODEL. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/361.
Description:
Recent investigations into the oxidation of S(IV) to S(VI) in the aqueous phase have suggested that clouds play a major role in to production of sulfate in the troposphere (McHenry and Dennis, 1991; Hegg and Hobbs, 1981; Hegg, 1985; Shin and Carmichael, 1992). loud production of sulfate is accomplished through dissolution of S(IV) from polluted interstitial air and subsequent reaction by dissolved oxidants. ariety of oxidation pathways have been studied (Hegg, 1989; Walcek and Taylor, 1986; Pandis and Seinfeld, 1989; Carmichael et al., 1991). he Regional Acid Deposition Model (RADM) and associated RADM Engineering Model (RADM/EM) (Chang et al., 1990) incorporate a cloud/aqueous chemistry module that treats convective clouds in the troposphere as batch reactors, using modified Henry's law coefficients to determine aqueous- and gas-phase equilibria among ionic species in the cloud water and interstitial gases. oth precipitating and nonprecipitating clouds are treated. he aqueous mechanism (Welcok and Taylor, 1986) includes oxidation of S(IV) by H2O2, O3, O2 catalyzed by trace metals, methylhydrogen peroxide, and peroxyacetic acid.