Mar. 8--New national standards for soot are not tough enough to protect Americans from microscopic air pollution linked to heart disease and respiratory ailments, said members of a federal scientific panel accusing the Bush administration of ignoring their advice.

The U.S. Environmental Protection Agency will hold hearings Wednesday in Chicago and two other cities on the proposed rules, which are tougher than current requirements but less stringent than those suggested by the scientists, EPA advisers on air pollution issues.

If the rules take effect, they say, thousands of Americans still will face too great of a risk of disease and early death from breathing soot from vehicles, power plants and factories. Chicago is considered one of the dirtiest regions in the nation for fine particles, commonly known as soot.

In a sign of how upset many scientists are with the EPA's proposal, the advisory panel is taking formal action to dispute it, a first in the committee's 35-year history.

Their frustration is prompted in part by records in the federal rulemaking docket, which show that the White House Budget Office edited the wording of the rules and deleted sections summarizing some of the latest research before the proposal was made public. Many of the changes softened scientific conclusions that soot pollution in the air is harmful at lower levels than previously thought.

"I'm frankly surprised and disappointed they didn't listen to our advice," said Rogene Henderson, chairwoman of the EPA's Clean Air Scientific Advisory Committee.

Henderson's concerns were echoed by a panel of scientists that advises the EPA on children's health issues and by more than 100 other scientists and physicians who sent a letter to EPA Administrator Stephen Johnson, urging him to set a more stringent standard.

The letter cites an agency risk assessment that concluded that more than 4,700 people in nine U.S. cities would die prematurely of soot-related causes each year even if those cities complied with the current standard.

Pollution controls already required under the Clean Air Act have steadily helped make the nation's air healthier to breathe. But the kind of air pollution that increasingly worries scientists is so small, thousands of soot particles could fit on the head of a pin.

Under the EPA's proposal, the daily standard for soot would drop to 35 micrograms per cubic meter of air from 65 micrograms. The acceptable annual average would remain unchanged at 15 micrograms.

By contrast, the advisory panel recommended setting a daily exposure limit between 30 and 35 micrograms per cubic meter and an annual limit of 13 or 14 micrograms.

The 100 scientists who signed the letter to the EPA said a growing body of science supports even stricter standards of 25 micrograms per cubic meter daily and an average of 12 micrograms annually. They contend that such limits would curb deaths related to soot pollution by 86 percent, or nearly four times more than the limits in the EPA's proposal.

In an interview Tuesday, a top EPA official said the agency will consider additional research before issuing a final rule in September. The hearing at the Hyatt Regency Chicago, 151 E. Wacker Drive, is one of three intended to solicit public comments, which will be accepted through April.

"This is a public process, and we will look very hard at that input before making a final decision," said Bill Wehrum, acting assistant EPA administrator for air and radiation.

Wehrum described changes made by the White House budget office before the new standard was released for comment as a routine part of the federal rulemaking process.

Among other things, the White House office deleted references to a study concluding that low-income people could be more vulnerable to soot. A sentence saying the new rules "may have a substantial impact on the life expectancy of the U.S. population" also was removed.

And although the EPA was prepared to consider a daily standard as low as 25 micrograms per cubic meter, the White House office said it would not accept discussion of anything below 30 micrograms.

By law, the EPA must review the science behind its air pollution standards every five years. The soot standards now in effect were proposed in 1997 but were delayed for years by a multimillion- dollar legal and lobbying campaign by business groups that went all the way to the U.S. Supreme Court. The rules did not take effect until 2004.

Nationwide, nearly 100 million people live in areas that fail to meet the current standards, most of them in California or the eastern third of the country. The standards give states until 2010 to comply.

State officials have said that to do so, they are counting on national rules requiring cleaner diesel engines and fuel and more dramatic reductions in power plant pollution. Many of those rules, however, are not expected to provide significant benefits for another decade.

Business groups argue that the EPA's newly proposed rules, which would give states until 2015 to comply, are too tough and could hurt the economy.

"Our general feeling is the agency should give us a chance to comply with the current standard," said Dan Riedinger, a spokesman for the Edison Electric Institute, a power industry trade group.

Meanwhile, the number of studies linking soot pollution to health problems continues to increase. The latest, published Tuesday in the Journal of the American Medical Association, found that hospital admissions for heart failure and respiratory illnesses increased on days when levels of soot pollution increased.

"This is strong evidence that current levels of fine particulate matter are causing damage," said Francesca Dominici, a professor of biostatistics at Johns Hopkins University and lead author of the study, funded by the EPA.

mhawthorne@tribune.com