"Right now, it's a visibility issue," said Cheryl Heying, an air-quality specialist with the Utah Department of Environmental Quality.

Pollution monitors throughout the state showed soot levels well within the "healthy" range, she said.

Greg Zschaechner (pronouced ZEK-ner) estimated that Nevada wildfires were responsible for 80 percent of the smoke and southern Utah blazes accounted for the rest.

Hundreds of firefighters battled the flames over hundreds of thousands of acres on Friday.

The Interagency Smoke Program, which involves state and federal fire and air-quality agencies, predicted that the smoke will clear as firefighters bring the flames under control over the weekend and as cooler weather sets in next week.

Heying added that evening wind, storms and lower temperatures helped disperse the haze. Though ozone pollution also might be a problem with hotter temperatures and more stagnant weather, ozone was not reaching worrisome levels, she said.

"It's not building, which is good," she said.

Air-quality and fire officials can't help but feel wary going into the summer season this year. Wildfires have started earlier than usual and tall wildland grasses offer added fuel for fires going into the drier weather that is expected in coming months.