[Tiwaz]

If the map is meant to be foggy, e.g. Snowy Park, find a no-fog hack. Can't find it? Keep looking, it is out there.

Spearhead: If everything looks foggy, try switching to 32 bit colors (no need to change textures to 32 bit if you don't want to).
In Spearhead everything looks 'foggy' when using 16 bit colors. My guess is to improve performance. Frames per second, that is. You will find yourself performing much less, online.

In most AA maps there should be no fog present.