Utah does have problems with fine soot, but only with occasional daily spikes and not high levels that persist year-round.
In winter, when upper layers of warm air trap cold air and pollution in mountain basins for days and weeks at a time, the state does have difficulty meeting what are called the "eight-hour" federal standards. Utah is working on a long-term plan to reduce the spikes. On annual trends, McNeill said the three-year average for PM2.5 is generally around 8 to 10 micrograms soot per cubic meter of air, with the area around Zion National Park at around 4 micrograms soot per cubic meter of air. That's well below the U.S. Environmental Protection Agency's new standard limiting annual PM2.5 concentrations to no more than 12 or 13.
In a news release, the EPA said Friday the pollution reductions have direct health benefits, including decreased mortality rates and fewer incidents of heart attacks, strokes and childhood asthma.
In addition, the standards carry big economic benefits with comparatively small costs.
The EPA estimated benefits to range from $88 million to $5.9 billion a year. Meanwhile, estimated costs are between $2.9 million to $69 million. That translates into a return of between $30 and $86 for each dollar spent on pollution control.
The Obama administration tried to stall the new standards until after the November elections, but a federal court order forced the agency to move forward on the standard sooner under legal action brought by 11 states.
Virtually all U.S. counties would meet the proposed standard without added controls beyond those already in place and pending, according to an EPA official who spoke with The Associated Press.
PM2.5 is made up of microscopic particles that come from smokestacks, diesel trucks and buses, wood-burning stoves and other sources. At one-fortieth the width of a human hair, this fine soot creates haze and triggers a variety of health impacts, such as lung and heart trouble.
Albert Rizzo, chairman of the board of the American Lung Association, said soot, also known as fine particle pollution, is a known killer.
"The science is clear," he said, "and overwhelming evidence shows that particle pollution at levels currently labeled as officially 'safe' causes heart attacks, strokes and asthma attacks."
Earthjustice attorney Paul Cort, who represented the American Lung Association and the National Parks Conservation Association in the case, called Friday's announcement "an important first step in this process.
"But now the agency needs to set strong final standards to protect people from this deadly pollution," he said in a statement. "The law requires it, and the millions of Americans who live in areas made filthy by particle pollution desperately need it."
The Associated Press contributed to this report.