The chemical composition of fogs and clouds in Southern California
The major inorganic species in cloud and fog water samples were NH{sub 4}{sup +}, H{sup +}, NO{sub 3}{sup {minus}}, and SO{sub 4}{sup 2{minus}}. Concentrations in fog water samples were 1 - 10 {times} 10{sup {minus}3} M; pH values ranged from {approx equal} 2 to 6. Nitrate usually exceeded sulfate. Acidity depended on the availability of NH{sub 3} from agricultural operations. Stratus cloudwater had somewhat lower concentrations; pH values were in the range 3-4. The major factors accounting for variation in fog- or cloudwater composition were the preexisting aerosol and gas concentrations and variations in liquid water content. Deposition and entrainment or advection of different air masses were also important during extended cloud or fog episodes. The droplet size dependence of cloudwater composition was investigated on one occasion in an intercepted coastal stratus clouds. Concentrations of S(IV) and CH{sub 2}O in the range 100-1000 {mu}M were observed in fogwater from urban sites in Southern California. Lower concentrations were observed in stratus clouds. The high levels of S(IV) and CH{sub 2}O were attributed to the formation of hydroxymethanesulfonate (HMSA), the S(IV) adduct of CH{sub 2}O. Direct measurements of HMSA in fogwater samples from Bakersfield, CA were made by ion-pairing chromatography. Glyoxal and methyglyoxal were observed at concentrations comparable to CH{sub 2}O in fogwater samples from Riverside, CA and in stratus cloudwater samples from sites along the Santa Barbara Channel.
- Research Organization:
- California Inst. of Tech., Pasadena, CA (USA)
- OSTI ID:
- 7065263
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kinetics, mechanism and thermodynamics of bisulfite-aldehyde adduct formation
Effects of hydroxymethanesulfonate on airway function in subjects with asthma. Final report
Related Subjects
020900 -- Petroleum-- Environmental Aspects
54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ACID RAIN
AIR POLLUTION
ALDEHYDES
AMMONIUM COMPOUNDS
ATMOSPHERIC PRECIPITATIONS
CALIFORNIA
CHEMICAL COMPOSITION
CLOUDS
ECOLOGICAL CONCENTRATION
FEDERAL REGION IX
FOG
FORMALDEHYDE
MONITORING
NITRATES
NITROGEN COMPOUNDS
NORTH AMERICA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PH VALUE
POLLUTION
RAIN
SULFATES
SULFUR COMPOUNDS
USA