California is home to six of the 10 most polluted metropolitan areas in the U.S., according to national smog rankings released today by the American Lung Association. In fact, the top four areas were all in the Golden(Brown) State: Los Angeles-Riverside-Orange County, Fresno, Bakersfield, and Visalia-Tulare-Porterfield. Those rankings mask the fact that California’s air quality has actually improved on the whole, but the state faces “such a large hill to climb that it’s hard for that [improvement] to show at this point,” according to ALA National Policy Director Janice Nolen. Almost half of all U.S. residents live in counties with unhealthy smog levels, and 55 percent of all tested counties received a failing grade from the ALA. Conservative institutes decried the rankings, calling them exaggerated.