The contribution of aqueous-phase radical chemistry to sulfate production in cloudy environments

Conference · Tue Apr 01 04:00:00 EST 1986 · Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States)

OSTI ID:5431761

Walcek, C J; Stockwell, W R

Some of the undesirable environmental consequences of acid deposition can be attributed to elevated levels of sulfuric and nitric acid in rain, cloudwater and air that is transported to a sensitive area. These sulfur and nitrogen compounds are usually emitted into the atmosphere from both natural and anthropogenic sources in reduced chemical forms which are subsequently transformed into acidic species through a complex series of interactions involving homogeneous and heterogeneous chemical processes in clear and cloudy environments. Emitted SO/sub 2/ is converted to sulfuric acid via both gas and aqueous phase reactions in the atmosphere. Gas-Phase oxidation of SO/sub 2/ is primarily a result of the interaction of HO radicals. This reaction can oxidize a few percent of the available SO/sub 2/ per hour under mid-day conditions with clear skies. Aqueous reactions converting SO/sub 2/ to sulfuric acid are much more rapid, with conversion rates on the order of a few hundred percent per hour being observed in both the laboratory and in field studies of cloudwater composition. The primary reactants responsible for this rapid oxidation rate have been identified as hydrogen peroxide and ozone, although numerous other reactants such as methylhydrogen peroxide, peroxyacetic acid, trace-metal catalyzed reactions, dissolved NO/sub x/, and carbonaceous soot have been suggested as possible oxidants in the atmosphere. Recent theoretical studies have suggested that dissolved radicals such as HO, HO/sub 2/ and NO/sub 3/ may be important contributions to the oxidation of SO/sub 2/ in solution. This paper presents a detailed gas and aqueous chemistry model which includes aqueous-phase radical chemistry has been applied to several cloudy environments typical of the northeastern U.S. to assess the contribution of radical chemistry to sulfate production in these areas.

• Research Organization: National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307
• OSTI ID: 5431761
• Report Number(s): CONF-860425-
• Conference Information: Journal Name: Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States) Journal Volume: 31:2
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACID RAIN
AQUEOUS SOLUTIONS
ATMOSPHERIC CHEMISTRY
ATMOSPHERIC PRECIPITATIONS
CHALCOGENIDES
CHEMICAL REACTION YIELD
CHEMISTRY
CLOUDS
DISPERSIONS
HYDROGEN COMPOUNDS
HYDROPEROXY RADICALS
HYDROXYL RADICALS
INORGANIC ACIDS
MIXTURES
NITRATES
NITRIC ACID
NITROGEN COMPOUNDS
NITROXYL RADICALS
OXIDES
OXYGEN COMPOUNDS
OZONE
PRODUCTION
RADICALS
RAIN
SOLUTIONS
SULFATES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SULFURIC ACID
YIELDS