How many types of fog are there ?

There are many individual forms of fogs, all created by specific peculiarities of the region and/or local meteorological conditions. These are often named after the locality in which they occur or the whether condition under which they form. But most fall under one of three general processes: Adviction, where low levels of warm, moist air comes in contact with colder air; Radiation, where heat radiates into the atmosphere, lowering the air temperature and causing the air moisture to condense; Evaporation, where excess water vapor is pumped into the air saturating it above its holding capaticty. This is the same process that takes place when one can see the steam coming off a boiling pot or out of a steam kettle.

This is a a site that might prove uesful;

usatoday.com/weather/wcloud0 htm