"The international definition of fog consists of a suspended collection of water droplets or ice crystal near the Earth's surface ..." Fog and Boundary Layer Clouds: Fog Visibility and Forecasting. Gultepe, Ismail, ed. Reprint from Pure and Applied Geophysics Vol 164 (2007) No. 6-7. ISBN 978-3-7643-8418-0. p. 1126; see Google Books Accessed 2010-08-01.
