outdoor bleu distance effect

I am wondering what is the easiest way of creating a blue-ish distance effect.
In real life things in the distance get a little blue because of atmospheric effects.

Is there some cycle setup perhaps to also have this effect ?

Use the mist pass as a mix between the render and a solid color, like this:

I’m glad someone asked this question, I’ve never used the mist pass in Cycles although I probably should have:) … you learn something new everyday.

I see you did what I suggested long ago is to make one node with comp and viewer with one input. Only makes sense.

I put it in my startup.blend. Only way I use the compositor.

But if my light color changes (raising sun), how to change the mist color with it ?

Just animate the color in the Alpha Over node and it will look like this: