Inversion

Ick. Living in a valley surrounded by mountains, is, for the most part, a beautiful and awe-inspiring thing. But in the winter, the combination of the closed in valley, too many vehicles and factories, and high pressure creates a wonderfully aweful sludge in the air. It's a soupy muck. These are the days I'm glad to work an hour from home, high up in the mountains, where I can escape this crud.

But alas, I didn't work today. So I was able to "enjoy" the worst air quality in the nation.