Characterization of reactants, reaction mechanisms, and reaction products in atmospheric water droplets: fog, cloud, dew, and rain water chemistry. Final report

Technical Report · Mon Apr 01 04:00:00 EST 1985

OSTI ID:6299937

Hoffmann, M R; Jacob, D J; Waldman, J M; Munger, J W; Flagan, R C

Analyses of ground-based fogwater collected by inertial impaction in the Los Angeles basin, the San Gabriel Mountains, and the San Joaquin Valley revealed very high concentrations of NO3 SO4 S, NH4 , and other ions, often coupled with very high acidities. Fogs and strata in the Los Angeles basin typically had pH values ranging from 2 to 4. Acidities were not as high in the San Joaquin Valley, mostly because of scavenging by the fogs of ammonia from agricultural sources. Deposition of fogwater was observed to be an important pollutant sink during stagnation episodes in the San Joaquin Valley, and may also be an important source of acid input to surfaces in some areas. Kinetic experiments showed that H2O2 is important in the oxidation of S(IV) to S(VI) at low pH. Metal-catalyzed autoxidation could also be an important source of sulfate. However, the extreme acidities observed in fogs (below pH 3) require condensation on preexistent acidic nuclei and scavenging of gaseous nitric acid. Stabilization of S(IV) in the fog was observed, and this was attributed to the formation of S(IV)-aldehyde adducts.

• Research Organization: California Inst. of Tech., Pasadena (USA). W.M. Keck Lab. of Environmental Engineering Science
• OSTI ID: 6299937
• Report Number(s): PB-86-107976/XAB
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACID RAIN
AEROSOLS
AIR POLLUTION
ALDEHYDES
ATMOSPHERIC CHEMISTRY
ATMOSPHERIC PRECIPITATIONS
CALIFORNIA
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
CLOUDS
COLLOIDS
DISPERSIONS
FEDERAL REGION IX
FOG
FORMALDEHYDE
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
INORGANIC ACIDS
IONS
KINETICS
MATHEMATICAL MODELS
NITRIC ACID
NORTH AMERICA
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PEROXIDES
POLLUTION
RAIN
RAIN WATER
REACTION KINETICS
SOLS
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
URBAN AREAS
USA
WATER
WATER CHEMISTRY