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Redox chemistry of iron in fog and stratus clouds

Erel, Yigal and Pehkonen, Simo O. and Hoffmann, Michael R. (1993) Redox chemistry of iron in fog and stratus clouds. Journal of Geophysical Research D, 98 (D10). 18423-18,434. ISSN 0148-0227.

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The redox chemistry of Fe in fog and cloudwater has been investigated at coastal and inland locations in the Los Angeles basin, in Bakersfield California, and in Delaware Bay. Samples were collected and analyzed for Fe (Fe(II)), Fe(III), total(Fe), sulfur (S(IV), S(VI)), organic ligands (formate, acetate, oxalate), total organic carbon (TOC), pH, major cations (sodium, calcium, magnesium, potassium, ammonium), chloride, sulfate, nitrate, peroxides, and aldehydes (HCHO); the amount of sunlight was also measured. The ratio Fe(II)/Fe(total) varied between 0.02 and 0.55. The concentration of Fe(II) varied between 0.1 and 5 micromole, and the concentration of total Fe varied between 2 and 27 micromole. The atmospheric redox cycle of Fe involves both dissolved and aerosol surface species and appears to be related to the presence of organic compounds which act as electron donors for the reduction of Fe(III). Fe(III) reduction is enhanced by light but significant Fe(II) levels were observed in the dark. We suggest that reduction of Fe(III) species by organic electron donors may be an important pathway that affects the speciation of Fe in both urban and rural atmospheres. It is possible that reactions involving Fe and organic compounds might be an important source of carboxylic acids in the troposphere.

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Hoffmann, Michael R.0000-0001-6495-1946
Additional Information:© 1993 American Geophysical Union. Received November 3, 1992; revised June 7, 1993; accepted June 8, 1993. The authors wish to thank George Luther, Tom Church, Alan Veron, and the crew of RV Cape Henlopen the College of Marine studies at the University of Delaware, Cliff Weinman and his staff at the FAA radar facility in San Pedro, Ted Murphy and Mel Dutton of the California State University, Bakersfield, and the staff of LA county fire department at Henninger Flats for their help in sample collection. The authors also wish to thank J.J.Morgan, B. Faust, and J. Winchester for their helpful comments. Support for this work was provided by a grant from the National Science Foundation (ATM 9015775); additional support for the work in Delaware bay was provided by NSF gran OCE 8916804.
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NSFATM 9015775
NSFOCE 8916804
Issue or Number:D10
Record Number:CaltechAUTHORS:20150811-111819632
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Official Citation:Erel, Y., S. O. Pehkonen, and M. R. Hoffmann (1993), Redox chemistry of iron in fog and stratus clouds, J. Geophys. Res., 98(D10), 18423–18434, doi:10.1029/93JD01575.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59401
Deposited By: Ruth Sustaita
Deposited On:12 Aug 2015 18:34
Last Modified:03 Mar 2020 13:01

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