Chemical conversions in clouds

Conference · Mon Jul 01 04:00:00 EDT 1985

OSTI ID:5257497

Schwartz, S E

Clouds constitute an extreme atmospheric aerosol in terms of particle size and condensed-phase mass. The large amount of liquid water in clouds as well as the high state of dispersion make clouds a potentially important medium for atmospheric reactions, depending upon thermochemical driving force and chemical kinetics of particular reactions. This paper presents the formalism for evaluating the rates of in-cloud reactions making use of laboratory-determined physical-chemical properties and assumed or measured reagent concentrations and other situational variables. Accurate description of these rates is sensitive to the mass-accommodation coefficient ..cap alpha.. (fraction of gas kinetic collisions at the air-water interface effective in transfering gaseous species to cloud droplets) if ..cap alpha..< 0.01. Little information pertinent to ..cap alpha.. is available for relevant solute gases. Attention is directed to reaction of SO/sub 2/ and NO/sub 2/ to form sulfuric and nitric acids, respectively, and to reactions involving oxidants (O/sub 3/, H/sub 2/O/sub 2/) and free radicals (HO, HO/sub 2/). Important in-cloud reactions identified include aqueous-phase oxidation of SO/sub 2/ by H/sub 2/O/sub 2/ and O/sub 3/ and gas-phase oxidation of NO/sub 2/ by O/sub 3/ followed by uptake of N/sub 2/O/sub 5/ or NO/sub 3/ by cloudwater. 141 refs., 8 figs., 5 tabs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5257497
• Report Number(s): BNL-36923; CONF-8505106-1; ON: DE86000033
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring &amp; Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ATMOSPHERIC CHEMISTRY
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CLOUDS
KINETICS
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES