Mass-transport limitation to in-cloud reaction rates: Implications of new accommodation coefficient measurements

Conference · Sat Oct 01 00:00:00 EDT 1988

OSTI ID:7098606

Schwartz, S E

Although it has been recognized for some time that the rate of reactive uptake of gases in cloudwater can depend on the value of the mass-accommodation coefficient (..cap alpha..) describing interfacial mass transport (MT), definitive evaluation of such rates is only now becoming possible with the availability of measurements of ..cap alpha.. for gases of atmospheric interest at air-water interfaces. Examination of MT limitation to the rate of in-cloud aqueous-phase oxidation of SO/sub 2/ by O/sub 3/ and H/sub 2/O/sub 2/ shows that despite the low value of ..cap alpha../sub O3/ (5 /times/ 10/sup /minus/4/), interfacial MT of this species is not limiting under essentially all conditions of interest; the high values of ..cap alpha.. for SO/sub 2/ (greater than or equal to 0.2) and H/sub 2/O/sub 2/ (greater than or equal to 0.08) indicate no interfacial MT limitation for these species also. Although gas- and aqueous-phase MT can be limiting under certain extremes of conditions, treating the system as under chemical kinetic control is generally an excellent approximation. Interfacial MT limitation also is found not to hinder the rate of H/sub 2/O/sub 2/ formation by aqueous-phase disproportionation of HO/sub 2/. Finally, the rapid uptake of N/sub 2/O/sub 5/ by cloud droplets implies that the yield of aqueous HNO/sub 3/ from in-cloud gas-phase oxidation of NO/sub 2/by O/sub 3/ can be substantial even under daytime conditions. This report consists of copies of viewgraphs prepared for this presentation.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7098606
• Report Number(s): BNL-41219; CONF-880912-15; ON: DE89001607; TRN: 88-035724
• Resource Relation: Conference: 196. American Chemical Society national meeting, Los Angeles, CA, USA, 25 Sep 1988; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AQUEOUS SOLUTIONS
ATMOSPHERIC CHEMISTRY
GASES
SOLVATION
CHEMICAL REACTION KINETICS
CLOUDS
MASS
MATHEMATICAL MODELS
PRECIPITATION SCAVENGING
TRANSPORT
CHEMISTRY
DISPERSIONS
FLUIDS
KINETICS
MIXTURES
REACTION KINETICS
SEPARATION PROCESSES
SOLUTIONS
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)