I don't mean fog, I mean just the fact that air is blue, so things get smoothly bluer with distance (or rather, more sky-colored). Check out any mountain landscape, nearby trees are green and distant ones are blue: https://live.staticflickr.com/1009/531101849_a7d297e0cc_b.jp...
True, though in practice that's the way fog is applied in the shader. With the two-tone setup I can have a blue hue in the foreground transitioning into the hard white at the edge of the view dist.
