Adding another blow to the state is the reports finding that each of the nation's 10 smoggiest counties are in California, with San Bernardino, Riverside, Kern, Tulare and Los Angeles in the top five.
Though a a great deal of the report seems cloudy, California has made some progress. The number of high-ozone days has dropped by 25% in metropolitan Los Angeles and by 57% in metropolitan San Francisco, which includes Oakland and San Jose, since 2000.
Annually, California's dirty air is estimated to cause 19,000 premature deaths, 9,400 hospitalizations and 300,000 respiratory illnesses.
Only two cities appear on all three of the lung association's lists of cleanest cities — for ozone, for year-round particles and for short-term measures of particles: metropolitan Fargo, N.D.; North Dakota, which also includes Wahpeton, Minn.; and Lincoln, Nebraska.