dry fog

English

Noun

dry fog (plural dry fogs)

1. A fog or haze made up of dust or smoke particles, which consequently does not moisten exposed surfaces.
2. A fog of liquid droplets, occurring when the humidity or dew point would not normally allow fog, due to the droplets consisting of or being coated in an oil that prevents them from evaporating.
   • 1879, E. Frankland, Proceedings of the Royal Society of London, volume 28, page 240:

     This simple though important technical application suggested to me a condition of things under which the existence of so-called 'dry fog' would be possible. From our manufactories and domestic fires vast aggregate quantities of coal-tar and paraffin oil are daily distilled into the atmosphere, and, condensing upon, or attaching themselves to, the watery spherules of fog or cloud, must of necessity coat these latter with an oily film, which would in all probability, retard the evaporation of the water, [...]

   • 1919, Reprint and circular series of the National Research Council, page 50:

     (187) DRY FOG — Dense fogs have been noticed around London when the humidity was only 50 to 80 per cent. Frankland believes [...]. While this explanation is probably true, we do not know under what conditions a fog of oil and water gives drops of water coated with oil or drops of oil coated with water. [...] In view of the fact that lampblack enables us to emulsify water in oil, a smoky atmosphere might well be conducive to the production of dry fogs.

   • 1967 August, Popular Science, volume 1919, number 2, page 138:

     A thermal fogger is, in effect, a modern, updated version of the old Flit gun. You pull the trigger and a dry fog of vaporized insecticide billows out as you move around the outdoor area to be debugged. Key to the fogging phenomenon is the use of an oil-base liquid, such as deodorized kerosene; ...

Hyponyms

• qobar (“a dry fog, chiefly of the Upper Nile”)

See also

• dry haze; smog and various related phenomena listed there
• German Höhenrauch

Further reading

• “dry fog”, in Dictionary.com Unabridged, Dictionary.com, LLC, 1995–present. (sense 1)
• “dry fog”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present. (senses 1 and 2)