The California counties of San Bernardino, Fresno and Kern retained the top three positions as reported last year. The metro areas of Los Angeles-Riverside-Orange County, Bakersfield and Fresno also reprised their top rankings.
With its sunny skies, warm temperatures and reliance on the automobile, the Golden State has historically been the smoggiest place in America. While the air has gotten significantly cleaner — even as the population has swelled — haze continues to blanket large areas of the state in concentrations that violate federal standards.
"Even in the last few years, where they've made some large strides perhaps, it's just that again they have such a large hill to climb that it's hard for that to show up at this point," said Janice Nolen, director of national policy for the lung association.
Nationwide, nearly half of Americans are living in counties with unhealthy smog levels, the association reported. While 93 counties improved their marks from last year, 26 counties received lower grades this year.
Improvements in rankings, mostly in the Southeast, were attributed to weather patterns that brought cooler temperatures or winds that diverted pollution elsewhere.
The report gave 28 of California's 58 counties failing marks for air quality. Although nine counties improved their grades, the ALA said 33 million of the state's 35 million people are breathing dirty air. That number is up by nearly 4 million people from last year's report.
Some experts, however, cautioned that the report is based on deceptive methodology that can give failing grades for entire regions based on a few air monitoring stations that register violations, while others in the area record safe smog levels.
"It's incredibly misleading to tell people breathing clean air that they're in danger," said Joel Schwartz, a senior fellow at the nonpartisan Reason Public Policy Institute. "The report's been the same every year. It exaggerates air pollution levels and exaggerates risks each year."
The report is based on EPA data from 1999-2001.
The findings do not take into account a pollutant that's considered more dangerous than smog - tiny particles of soot that can lodge deep in the lungs and cause heart problems and even death.
By Brian Melley