But, he added, the report card's implementation is "uniformly despised" by air quality directors across the country "because of its unscientific criteria it uses."

The association counted days when PM-2.5 pollution reached a certain level. The EPA's scientific method is more nuanced, throwing out the six days per year with the highest peak pollution, and averaging the rest over three years.

Why average over three years? Because that shows if there's an actual problem or only a fluke event.

Sprott doesn't want to pull any punches about Utah's air pollution problems.

"We are close to violating the standard in Cache Valley," he said. "We have some pretty high values during the year along the Wasatch Front right now, but we are a ways from violating."

Scientists have suspected for years that the current standard is not stringent enough, he said.

The EPA is proposing new PM-2.5 rules. Most likely, the proposal will be changed before it is finalized in September, he said.

As written, the proposal would drop the 24-hour standard to 35 micrograms per cubic meter, instead of the present 65 micrograms. If that happens, he said, "they would have numerous counties from the Idaho border all the way down into Juab County" that would violate the standard.

But Utah wouldn't be alone.

If the new rules are put into place, Sprott said, the whole country "lights up like a Christmas tree" in nonattainment designations.

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E-mail: bau@desnews.com