Thanks to an air pollution monitor atop South Allegheny High School, Pittsburgh officially has the fourth-highest level of short-term particle pollution in the country, and the worst outside California.

		Most-polluted U.S. cities Based on short-term particle pollution 1. Los Angeles 2. Fresno, Calif. 3. Bakersfield, Calif. 4. PITTSBURGH 5. Eugene, Ore. 6. Salt Lake City 7. Sacramento, Calif. 8. Cleveland 9. Visalia, Calif. 10. Birmingham, Ala. Other Pa. cities 20. Philadelphia 22. Allentown-Bethlehem 24. Harrisburg Source: American Lung Association

The area also has the 17th worst ozone pollution in the country.

The rankings are part of the annual "State of the Air" report being released today by the American Lung Association. It warns that seven out of eight people in Pennsylvania, or 11 million people, live in areas that received a grade of "F" from the rankings. Four metropolitan areas in Pennsylvania are among the 25 worst in the country.

The high levels of air pollution are especially harmful to people with asthma, bronchitis and other respiratory problems, said Kevin Stewart, director of environmental health for the American Lung Association of Pennsylvania.

The pollution comes from industrial plants both in the area and in Ohio and West Virginia, and from such activities as using diesel engines and burning leaves and refuse, Stewart said.

But local officials counter that the pollution monitor atop the high school, which is near U.S. Steel's Clairton Coke Works, does not accurately depict the region's pollution levels, and that the state's pollution problem is actually improving.

"We get branded by that one monitor," said Roger Westman, manager of the Allegheny County Health Department's air quality program. "While we recognize the work that needs to be done out there, we are more typical of any urban area."

Four of the county's monitors show pollution levels above the regional standard, including those in North Braddock and Lawrenceville, but six monitors are in attainment of standards.

The county is working to clean up the Clairton area, where the worst pollution levels are recorded, and the state is putting together a plan so that the state can be in compliance with the Clean Air Act by 2010.

State ozone levels in 2004 were at their lowest level in the past 10 years, said Ana Gomez, a spokeswoman for the state Department of Environmental Protection. "Although air pollution is a problem," she said, "we're fighting it."

But while it's still around, the pollution is causing a wealth of medical problems. As ozone concentrations increase in the air, so do respiratory hospital admissions, said Dr. David Skoner, the director of allergy, asthma and immunology at Allegheny General Hospital. He's seen a lot of people with respiratory disease in the region, and says that ozone can make allergic reactions and asthma worse.

The report is based on both short-term and long-term particle pollution ---- soot-like specks in the air ---- as well as levels of ozone smog in hundreds of counties across the country. It uses national ozone and particle pollution data for 2001-03.