How can air quality be ‘moderate’ while it’s so hazy?

SALT LAKE CITY ( ABC4 ) — When Sid Bhandari arrived in Salt Lake City for a work trip on Monday, one of the first things he noticed was the haze along the Wasatch Range.

“First time in Salt Lake City,” he said. “I would have wished we could have seen the mountains a little bit better.”

At least the haze didn’t come with nasty air quality. According to the Utah Department of Environmental Quality (DEQ), conditions were only in the “moderate” range Monday for small particulate matter pollution, which is associated with wildfire smoke.

But how can air quality be relatively healthy when the landscape looks so fuzzy?

Bryce Bird, air quality director at the DEQ, said that the worsening haze on the Wasatch Front is a product of recent weather changes. The high-pressure system that sat over the region last week has pushed east, allowing smoke from wildfires across the American West to blow in and mingle with the smoke from Utah’s own wildfires.

“With distant smoke, you start seeing the visual impacts before you see the impacts on the monitors,” Bird said.

Yet, when that pollution does fall into the valleys, people will be able to smell it and monitors will pick it up, Bird explained. He noted it’s at those times that his office begins sending out messages warning the public, particularly those with certain health conditions, to take precautions.

Another reason the wildfire smoke might be high in the sky but not on the ground level is because of pyrocumulonimbus clouds. Derek Mallia, a researcher at the University of Utah’s Department of Atmospheric Sciences , said that wildfires create these tall clouds, which act like chimneys, dispersing smoke high into the atmosphere.

He said people across the Wasatch Front might need to get used to the haze for the rest of the summer.

“Those clear days that we were seeing back in May and June … will probably be a little less common now that we have fires going on,” he said.

Looking ahead, the DEQ is expecting more wildfire smoke to come into the Beehive State. Depending on how the winds blow, this could potentially lead to elevated levels of particulate matter pollution. For Tuesday and Wednesday, forecasters are predicting pollution levels in Salt Lake County to be “unhealthy for sensitive groups.”

For Bird, however, pollution linked to wildfire smoke isn’t the biggest concern for the Wasatch Front this summer. Instead, it’s ozone , caused by a chemical reaction from car pollution and other emissions under intense sunshine and heat.

Indeed, last week, when skies were clear and temperatures rose into the triple digits, ozone levels exceeded federal standards on the Wasatch Front, Bird said. Unlike wildfire smoke, ozone can’t be smelled or seen, but it can still cause damage to people’s lungs when they breathe it in.

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