At the risk of being too political, I saw this video on Youtube, and found it easy to follow and understand.

Needless to say, I do agree with the author. I do remember how bad the smog was in LA when I first visited there in 1968. It encouraged my decision to locate in the Bay Area. Fortunately, due to geography and weather, the Bay Area did not suffer from as heavy and frequent smog as the LA basin. Today, due in large part to California’s strong anti-pollution initiatives, the LA area is much improved. Currently, I live in an area that has little industrial pollution, but lots of blowing dust. Still, I find it sad that the US is abdicating its leadership in this area.