Fog Color: This is the color of the fog.
Min Distance: Fog does not affect objects closer than this distance from the camera.
Max Distance: The distance from the camera which is needed for full fog effect. If saturation is 100, objects further than this distance are fully obscured by the fog.
Max Saturation: Defines how strongly the fog effect at its full level obscures objects. If the saturation is 100 %, the fog can fully hide objects. 50 % saturation blends maximally half of the fog color to the original image.