A friend just turned me on to this site where you can see animated maps of air quality for SoCal. It looks like it’s part of AIRnow, a cross-agency air pollution info site run by The Man. If you dig through, there’s lots of useful info about how they measure this kind of stuff, including explanations of particle pollution (which I wasn’t that familiar with), and good and bad ozone. Also, if you watch the animated map you can see how the air quality changes throughout the day. You would think living in L.A. would give you all kinds of knowledge about air pollution, but other than people complaining about it I never hear that much.