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 00:00:00 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

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