This is the view of downtown Los Angeles from the Sam Merrill Trail yesterday. When you're down in the smog and you look directly up, the sky looks clear blue. You have to get some distance on it to see it.
Our air is markedly better now than it was when I moved to southern California 20 years ago, but there's still room for improvement. California tends to lead the nation in environmental protection and air quality legislation. Maybe this (undoctored) photo tells you why we keep trying so hard.