Is there a way to make 2.5 fog in AE?

I know that using 3d fog I can get the z-depth info from a sequence and add some fog.

But what if I want to put fog on my AE 2.5 scene instead? I'd like to control the level of (color) on a comp based on distance from the camera.

Is there a way to do this? Am I missing something?

Thanks in advance.

Cheers

Pablo