Looking out the window as the plane pulls in to Beijing airport, there's definitely something mythical about the sky - the horizon is obscured in mists, and the light seems to catch in some kind of magic in the air. Then you get off the plane and realise that it really is "magic", in that sulfur and dark burning chemicals are often associated with witchcraft.
Beijing's air quality is a famous issue - it's kind of inevitable when you build a city on the edge of a desert and add three and a half million cars. But to really explain the texture of the air all ten million citizens would need to be burning plastic as a hobby. One of the first banners I saw in the airport - before even getting to the security checkpoint - was "SINOPEC: Petrochemical Partners of the Olympics" Which mean that either the Chinese have a secret and significantly more awesome internal-combustion competition going on, or the fact the air has more flavor than many meals isn't entirely natural.
Some days its like there's a fifty per-cent paint fill across the entire atmosphere. Those are the humid ones, and they're the worst. One day I couldn't see four blocks down the street. Other days it's marvellously clear, but since those are the days a cold air system has simply shoved everything out of the way you can't really appreciate it - any body part you expose to the fresh air won't feel it for longer than thirty seconds. Conversely, it can get worse in the summer - which is why I have never and will never come here in the summer. Something about sulfur combining with warm water then falling in the sky makes me not want to be there when it happens, and that something is "dissolving in goddamn acid rain."