And weather watchers say that's not likely to happen before midweek — if then.
Cache County air quality on Friday was listed as "unhealthy for sensitive people." For everyone in Weber, Davis, Salt Lake and Utah counties, it's flat unhealthy.
"It's pretty bad out there," said Donna Kemp-Spangler, spokeswoman for the Department of Environmental Quality, who added that experts have told her they don't remember a longer stretch of unhealthy air.
Salt Lake City has had 22 days of smoggy or hazy conditions in January, according to KSL meteorologist Kevin Eubank. And the forecast for the coming week offers little hope for a break from the inversion affecting the Wasatch Front valleys, over which a high pressure has clamped a warm lid that's holding down a layer of cold, stagnant air.
With January winding to a close, it now seems likely the month will end up with only five days of clear skies, Eubank said.
As the inversion drags on, area hospitals are reporting increases in the number of patients they're seeing for respiratory and heart problems.
Dr. Linke Hebrew, an emergency-room physician at Pioneer Valley Hospital, says that whenever it's cold and the air's extremely dirty, as it is now, they treat more people who have lung disease or asthma. That's true throughout the affected areas.
"If you have respiratory problems, this haze is making it worse," says Christopher Nelson, spokesman for University of Utah Hospitals and Clinics. "It happens whenever the air in the valley gets this bad."
The respiratory-care department at St. Mark's Hospital has seen an increase in patients coming in with respiratory problems, says Pam Fogle, hospital spokeswoman, but they're also seeing patients inside the hospital whose pulmonary and heart problems are being worsened by the weather and bad air.
That's no surprise to C. Arden Pope, a leading expert on small particulate matter, which is the primary concern during an inversion. His research has shown increased respiratory symptoms, decreased lung function and rises in hospitalizations for both respiratory and cardiovascular disease, including an increased risk of death.
A recent study conducted with LDS Hospital found that greater exposure to fine particulates increases the risk of unstable angina and of heart attacks. On the breathing side, the pollution led to increased symptoms, reduced lung function, rises in absenteeism at work and school. Put bluntly, he says, more people are hospitalized and more people die.
Pope, a professor of economics at Brigham Young University, takes the effects of air quality seriously.
"I've made decisions about where I bought a home, how far away from major roads I live and where it's located in a valley. My decisions with regards to where and when to exercise are influenced by it. In these bad inversions, I go up the canyon to run. It's a nuisance, but get above the inversion layer."
Vehicle emissions are the primary source of the pollution, which is why officials are telling people to park their cars and use public transportation when possible during inversions. If the average person parked for just a day, it would keep a quarter-pound of pollution out of the air. If enough people did it, it would make a difference, says Kemp-Spangler.
A study released this week by the University of Southern California showed that children who grow up near a freeway have stunted breathing capacity for a lifetime and increased risk of serious lung and heart disease. Again, emissions are cited as a cause.
If you took the width of a human hair, which is about 60 micrometers in diameter, and cut off a slice, most of the particles that are so damaging, called PM2.5, would be just a speck on that slice of hair, Pope says. "They are incredibly tiny, tiny particles."
They're hard to escape for that reason. Pulling a sweater up over your nose or mouth won't do it. The particles even get indoors, although being inside helps some, he says. "Unless you have a very expensive filtration system in your office or home, even indoors you're breathing a lot of these particles."
Those who can't drive less need to drive smarter, says Kemp-Spangler. Starting the car emits a lot of pollution. So does starting and stopping in traffic and idling the engine. Driving at a steady speed emits less gunk.
Right now, those most likely to be impacted health-wise are those who are susceptible, including children, the elderly and people with existing chronic respiratory or heart conditions, says Dr. Dagmar Vitek, medical director of the Salt Lake Valley Health Department. But Royal DeLegge, director of SLVHD's Division of Environmental Health, notes that as concentrations of pollution rise — and the effect is cumulative until it gets blown away — even healthy people increasingly will feel the effects.
Geography doesn't help, he says. Surrounded by mountains, we live in a bowl.
"We're prone to inversions, but it is largely our activities that are creating it," DeLegge says. "Any moves we can make to correct it help."
E-mail: lois@desnews.com