Bad air days on the rise: The nation's most polluted city is … usatoday.com

California's reign as the U.S. state with the worst air pollution continues, with Los Angeles again the nation's smoggiest metro area, according to a new report released Wednesday. And L.A. isn't alone when it comes to smog-choked cities in California: seven of the nation's top 10 smoggiest cities are in the Golden State, including other sprawling cities such as San Francisco, San Diego and Sacramento. Los Angeles has had the worst smog for 19 years of the 20-year history of the report. The bad news came from the American Lung Association's annual "State of the Air" report, which covers the years 2015-2017.