The Hibbards already have ruled out a backyard swing set this spring because of the choking dust from the gravel pit next to their neighborhood. Now, the federal government plans to exempt some big dust-makers like the pit from new air-pollution controls.

"I give up," said Jackie Hibbard, who has helped organize a government-industry-citizens group to deal with the gravel pit in Cottonwood Heights. "To me, the flaw is at the federal level."

Other Utahns share her exasperation. Environmental groups, a University of Utah pollution researcher and regulators plan to raise their concerns with the U.S. Environmental Protection Agency (EPA) during a public comment period that ends April 17.

The regulations cover a new category of pollutant, called Particulate Matter Coarse or PMC, which would replace standards for PM10. And PMC, unlike PM10, would not apply to the most urban parts of the nation, probably including Wasatch Front counties. The new rules would cover microscopic particles of dust and soot between one-fortieth and one-tenth the width of a human hair.

Growing evidence suggests particles, breathed in, wreak havoc with the heart and lungs. A growing body of research traces particle pollution to tens of thousands of hospitalizations and premature deaths each year.

Opponents have two main gripes with the EPA's proposal: It does not apply to rural areas; and it exempts dust from farms and mining, like gravel pits, in both rural and urban areas.

And in Utah, gravel pits have been a sore spot. State air regulators fielded 103 complaints about them last year.

Air-quality activist Kathy Van Dame has been rallying health and environmental groups to fight it.

"When Congress passed the Clean Air Act, it did not discriminate against rural citizens," said Van Dame, policy coordinator for the Wasatch Clean Air Coalition. "Everyone is entitled to clean air, not just folks who live in cities."

John Veranth, a toxicologist at the University of Utah and Utah Air Quality Board chairman, plans to submit a letter to the EPA outlining his concerns. He agrees there are far fewer studies about the tiniest particles, PM2.5 and smaller, than there are about the larger-sized particles covered under the new PMC standard, but he notes there is enough known to apply the new controls broadly.

Veranth points out that silica, a lung-damaging component of dust, is found in rural dust just as it is in urban dust. And studies he's done show no significant differences in the defensive response of lung cells exposed to rural or urban dust.

"From a health standpoint," he said, "there is no evidence these dust spots are safe."

Meanwhile agriculture and mining groups have vowed to lobby to protect the exemptions.

At a March 8 hearing in Washington, Tamara Thies, environmental director for the National Cattlemen's Beef Association, called the health-based evidence to apply the new coarse-particle standard in rural America "weak, limited [and] uncertain."

"Coarse particulate matter is fugitive dust, or basically dust in the wind," she said, "and has never been demonstrated to have adverse impacts on health at ambient levels."

In Wyoming, according to the Casper Star-Tribune, mining companies breathed a sigh of relief when EPA regulation writers dropped the suggestion of a coarse-particle standard in rural areas.

"We have more coarse particulates than other areas of the U.S.," Greg Schaefer of Arch Coal Inc. told the newspaper. "If it were applied in Wyoming, we'd be in severe non-attainment."

Rick Sprott, director of the Utah Division of Air Quality, said the EPA's proposal is "a bad idea" and will be tough to implement. He also expects a court fight over them.

Given that his agency gets more complaints about dust than anything else, he's sensitive to people like the Hibbards and those who live near gravel pits from St. George to Brigham City. But he is confident that state regulations will, for the most part, continue to provide adequate controls for Utahns worried about dust.

"We already have pretty strict rules on this statewide," he said.

Hibbard has set to work on the problem at the local level. She has helped organize a committee that includes the gravel pit operators, city government and citizens to do what they can to limit the pollution.

It's going well, but she still won't allow that playset.

"Dusty. It's very dusty," she said, "so we are worried about the particulate matter and the long-term health effects, especially with the children."

fahys@sltrib.com