Yep, I'd DEFINITELY say that fog option is what you should look at. I noticed in the most recent TMO that Ducimus added a lot more fog and well, a whole different look for it. It DOES get a little weird to look through, but I imagine its somewhat realistic. Or it makes playing more challenging anyway
Check out that Volumetic Fog option though! Turn it on and off and see what it does for you. ANOTHER one to look at might be Enviromental Effects, although that might remove other eye candy. But hey, whatever your eyes need to be happy