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Published September 1984 | Published
Journal Article Open

A field investigation of physical and chemical mechanisms affecting pollutant concentrations in fog droplets


High ionic loadings were found in fogwater collected at Bakersfield. California during an extended stagnation episode. The major ions were NH_4^+, NO^-_3, and SO_4^(2-), with concentrations usually in the millimolar range. Droplet growth played an important r6le in determining fogwater concentrations. The amount of solute decreased substantially over the course of each fog event; this was attributed, at least in part, to deposition of fog droplets on surfaces. The occurrence of dense fogs thus seemed to limit particle build-up during stagnation episodes. The sulfate fraction in the aerosol increased appreciably over several days of stagnation, but no statistical evidence for in situ S(IV) aqueous-phase oxidation was found. The high ammonia concentrations present were sufficient to neutralize a large fraction of the ambient acidity. As a result, fogwater pH values rarely attained the extremely low values found in other polluted environments.

Additional Information

This journal is published under the terms of the Creative Commons Attribution 4.0 International (CC-BY 4.0) License. Manuscript received November 8. 1983: in final form February 15. 1984. This research was funded by the California Air Resources Board (CARB). We thank the staff of the CARB for their help and cooperation relating to our use of their facility at Bakersfield. We also acknowledge gratefully the CARB and the Western Oil and Gas Association for letting us use their data in this paper. Discussions with A. G. Russell were most helpful in the interpretation of some of the data.

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Published - j.1600-0889.1984.tb00247.x.pdf


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