I agree that this is a stupid immersion killer. It's part of a problem with the horizon on ATi cards. The haze does not extend low enough and even at heights where the "blue line" isn't visible, there are still problems.
In the picture below, for example, the haze over land means that the land fades out of view into the distance - which is correctly realised. However, there is then a sharp horizon line above and beyond the land cutting through what should supposedly be a distant haze hiding both land and the actual sharp edge of the horizon.
