Ten southwestern Pennsylvania counties are among 211 counties and 23 Native American reservations across the nation designated by the U.S. Environmental Protection Agency yesterday as not meeting tighter federal health standards for fine particle soot pollution.

Parts of Allegheny, Armstrong, Lawrence, Greene and Indiana, and all of Beaver, Butler, Washington, Westmoreland and Cambria counties were declared in "nonattainment" of the daily federal pollution standards for fine particulates.

Also in nonattainment are seven counties around Philadelphia in the southeastern corner of the state, three around Harrisburg, two around Allentown and Lancaster County.

Because of those designations, Pennsylvania and 24 other states containing counties not meeting the health standard must submit plans to the EPA detailing how they will reduce fine particle pollution or risk losing federal highway funding.

Allegheny County and most of the other southwestern Pennsylvania counties struggled to meet less stringent health-based soot standards set in 1997. What's different for the fine particle standard set in 2006 is that the more polluted areas of some counties -- like Liberty-Clairton in Allegheny County -- have been carved out as nonattainment areas, while the remainder of the counties, where soot pollution readings are lower, can avoid the negative designation.

"I think it's a good idea to back off the whole county designation. It allows us to concentrate our pollution reduction efforts in those areas where they are needed most," said Dr. Bruce Dixon, Allegheny County Health Department director.

"From a health perspective, for many living in our county, airborne particulates are not the foremost pollutant," he said.

"But in some areas of the Mon Valley where industry is concentrated, we need to recognize that it is."

Dr. Dixon said U.S. Steel Corp.'s ongoing $1.2 billion coke oven replacement project at its Clairton Works will help the Liberty-Clairton area reduce soot levels and move that part of the Monongahela River Valley toward attainment of the federal standard.

"It may even achieve the standard," he said. "But if not, we will look at reductions from other industry. We want every industry to make improvements to their processes that reduce pollution. Our first target date is 2010, so we have some time."

The federal standard measures soot particles that are 2.5 micrometers in size, called PM 2.5 -- so small that several hundred could fit on the period at the end of this sentence.

The fine particle pollution can be emitted directly from coal-burning power plants, other industrial sources or vehicles, or form in the atmosphere from chemical reactions involving sulfur dioxides and nitrogen oxides.

Exposure to higher levels of such soot pollution can cause a number of serious health problems, including asthma, heart attacks and premature death, as well as increased hospital admissions and emergency room visits for respiratory and cardiovascular problems.

The EPA designations culminate a two-year process that identified counties that failed to meet the 2006 standards and allowed states, tribal leaders, environmental groups and business and industry lobbyists to comment on the agency's proposed designations.

The American Lung Association faulted the EPA for leaving five metropolitan areas and several counties with high air pollution off its nonattainment list for fine particles, saying it puts populations in those areas at risk.

The five cities -- Houston, Texas; Augusta and Columbus, Ga.; Greenville, S.C.; and Fairmont, W.Va. -- all showed unhealthy year-round levels of soot pollution. In two of those cities, Columbus and Houston, fine particulate levels have worsened.

"The Clean Air Act plainly requires the EPA to identify all the places where air pollution poses a threat to public health," said Paul Billings, American Lung Association vice president for national policy and advocacy.

"The EPA has a responsibility to do more to protect public health when it comes to air pollution."

The EPA said it "closely reviewed" recommendations from states and public comments before making its nonattainment designations.