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Scott G Winterton, Deseret News
Fog and an inversion obscure the Salt Lake skyline on Monday, Dec. 11, 2017.

SALT LAKE CITY — With the possible exception of Friday, northern Utah residents can expect an absence of storms and the continual accumulation of pollution as a temperature inversion settles in through at least the end of the year — or even longer.

That grim forecast, according to air quality officials, means very little holiday cheer for ski resorts yearning for more snow and for residents with respiratory problems affected by the buildup of fine particulate pollution, or PM2.5.

The PM2.5 air pollution monitor at Salt Lake City's Hawthorne Elementary hit 58.2 micrograms per cubic meter at midday Monday, but then started to fall. The U.S. Environmental Protection Agency's 24-hour standard is 35 micrograms per cubic meter.

Mary Archbold
Sources of air pollution

Bo Call, who oversees air monitoring for the state Division of Air Quality, said in some ways the fog is making air quality conditions seem worse than they are — Utah and Cache counties had pollution measurements far below the standard — but at the same time, those conditions are just going to get worse as the inversion hangs on.

"There's nothing out there storm wise on the horizon for weeks," he said.

Lack of snow on the ground and temperatures climbing into the 40s — for now — are keeping the worst effects of the inversion at bay.

It's just cold enough, however, and the high pressure strong enough, to set up a protracted inversion that will keep pollutants trapped in the valleys.

"The inversion sets up, everyone who makes pollution continues to generate pollution and it continues to go up," he said.

The worsening air quality conditions are spurring the agency to ask residents to curtail travel by telecommuting, carpooling or consolidating trips. Residents under mandatory restrictions should not use solid fuel burning devices such as fireplaces or wood burning stoves.

Vehicle emissions make up the majority of pollutants in the Salt Lake Valley at 48 percent.

Brian McInerney, hydrologist with the National Weather Service in Salt Lake City, said the persistent dry pattern is in stark contrast to what forecasters had hoped would play out this water year.

Utah, he said, endured a dry weather pattern from the fall of 2011 to November of 2015.

"It put us in a drought, drained our reservoirs and put us in long periods of bad air quality," he said.

That changed in the following year, which flipped to an active weather pattern in which December of 2016 and January of 2017 had 200 percent of normal precipitation.

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"We had a progressive weather pattern, really good air quality, copious amounts of snow and we filled up the reservoirs, most of them. … It was a nice change."

McInerney said such a weather shift — jumping headlong into a wet year after a dry spell — typically signals a pattern that will continue for a couple of years.

Friday is expected to have a weather shift that might stir things up a bit, but McInerney said it will not be enough to overcome the strength of the high pressure ridge.

The options, now, are to look to 2018 for some relief, he added.