Ever wonder?

Has anyone ever wondered how "clean" our city air is? I took these photos this morning on the MRRII.

Notice the film of grey hovering over the skyline. Clear blue skies above that.

The layer of polluted air is especially obvious in the mornings when the air is still cool. Towards the afternoon, the layer isn't visible anymore.

That's what we're breathing in every day. Jogging outdoors anyone?