LOS ANGELES (CNS) – The Los Angeles-Long Beach- Riverside area still has the nation's worst smog but has dropped to No. 4 in short-term particle pollution and No 3 in annual particle pollution in the yearly air-quality report released by the American Lung Association.

"This report shows that air pollution remains a serious health threat to too many Californians," said Jane Warner, president and chief executive of the California chapter of the American Lung Association.

"State of the Air 2012 shows that we're making real and steady progress in the fight for clean air, but unhealthy levels of air pollution still exist, putting the health of millions Californians at risk. Much still needs to be done, and now is not the time to stop progress."

Thanks to reductions in smog and particulate pollution, the air quality statewide was the best it has been in 13 years, when the American Lung Association started Wednesday, April 25, its annual report.

The survey looked at ozone levels, or smog, short-term particle pollution – days when it reached unhealthy levels – and annual particle pollution average levels over the year. The Bakersfield-Delano area ranked No. 1 in both shortterm particle pollution and annual particle pollution on lists of the nation's 10 most polluted areas.

In the Los Angeles-Long Beach-Riverside area, annual levels of particle pollution have fallen about 40 percent and the number of days for short-term particle pollution has been reduced 53 percent since the American Lung Association started its annual report.

But the Los Angeles region remained No. 1 on the list for ozone pollution, or smog – a list that included only urban areas in California.

The Lung Association said that despite improvements in the state of the air in the Golden State, more than 90 percent of Californians live in counties with unhealthy air, particularly in the Central Valley, Los Angeles, Inland Empire, Sacramento, and San Diego.

"Ozone and particle pollution contribute to thousands of hospitalizations, emergency room visits, and deaths every year," said Dr. Kari Nadeau, a Stanford Medical School professor and American Lung Association researcher.

"Air pollution can stunt the lung development of children, and cause health emergencies, especially for people suffering from chronic lung disease, including asthma, chronic bronchitis, and emphysema. Both long-term and short-term exposures can result in serious health impacts."