Which of the following is NOT a type of fog?

Pressure fog is indeed not recognized as a distinct type of fog. Fog typically forms when water vapor condenses in the air, and various environmental conditions contribute to this process. Radiation fog occurs when the ground cools rapidly at night, causing moisture in the air near the surface to condense. Advection fog forms when warm, moist air moves over a cooler surface, resulting in the cooling of the air to its dew point. Ice fog is a type of fog that forms in freezing temperatures when water vapor condenses and directly freezes into ice crystals in the air.

While pressure can influence weather conditions and visibility, it does not classify as a specific type of fog formation. Thus, in the context of the question, pressure fog is not recognized in meteorological terms, which makes it the correct response for identifying what is not a type of fog.