The Wasatch Front’s seasonal inversion has returned — and this time, it might just linger through the holidays.

Air quality in the Salt Lake Valley began deteriorating over the weekend, but turned soupy and cough-inducing Monday morning, leaving driving conditions treacherous and views of the Wasatch Mountains swallowed up in the tainted fog.

The amount of small-particulate pollution in Salt Lake County’s air hovered between “orange” (unhealthy for sensitive groups), and “red” (unhealthy) levels throughout the day Monday, according to the Utah Division of Air Quality (DAQ). And the term “widespread haze” was included in the National Weather Service forecast for Salt Lake City every day through Friday.

Officials at DAQ also placed Davis County in the “orange” range Monday, with several additional counties — including Utah, Weber, Box Elder, Cache and Tooele — expected to face similar unhealthy air-quality levels as the week progresses.

Forecasts show Utah might not get a major storm for “a couple weeks or more,” allowing time for poor air quality to build up, said Bo Call, who oversees the DAQ’s air-monitoring section.

During a temperature inversion, warm air moving over valleys along Utah’s Wasatch Front valley traps cold air — and pollutants — beneath it, leading them to accumulate. The conditions usually persist until a storm front moves through the region to break up that weather pattern and cleanse the air.

Anticipating the murky air conditions, the DAQ last Wednesday enacted the season’s first “mandatory action” wood-burning ban across Box Elder, Cache, Davis, Salt Lake, Tooele, Utah and Weber counties. The agency has also raised its penalties this year for using a fireplace, wood stove or any other solid-fuel burning device on “no-burn” days — from $25 to $150 for a first offense.

The Utah Department of Health is ramping up outreach to schools around the state, informing them when children should stay inside for recess, said Brittany Guerra, with the department’s asthma program. (During “orange” air levels, kids with respiratory issues are urged to stay inside, while during “red” air, everyone is supposed to remain indoors.)

Meanwhile, area hospitals were bracing for visits to emergency rooms and urgent-care clinic from people suffering from seasonally related asthma and other respiratory problems. Children and the elderly are also especially at risk from high levels of airborne particulate.

Intermountain Healthcare spokesman Jess Gomez said Monday that emergency rooms and clinics already were reporting a “spike” in visits since the unhealthy air began over the weekend. He said patients often reported conditions ranging from mild asthma exacerbated by pollution to severe breathing problems.

One recent analysis found Utah ER visits for respiratory problems were as much as 40 percent higher on bad-air days.

Health officials recommend avoiding aerobic exercise outside, as it can force pollution deep into the lungs for a bigger dose of particulates, said Nicholas Rupp, a spokesman for the Salt Lake County Health Department. Experts also warn that exercising during an inversion can also hinder recovery time, increase heart attack risks and can even lead to developing asthma.

“Hit the treadmill for a couple days until the inversion moves on,” Gomez advised.

And it might be more than a couple days, if the National Weather Service’s long-term forecast is any indication, Call said, who added that he expects the inversion layer will worsen before an incoming weather front offers relief.