SALT LAKE CITY — A thick layer of smog stubbornly lingering over parts of Utah has fouled the state’s air so badly this week that health officials warned people not to exercise outside, and some schools kept children inside for recess and sports.
The haze that has obscured Utah’s picture-perfect mountain views for the past several days is blamed on a weather phenomenon called an inversion that pins pollution to the valley floors and doesn’t relent until a major storm blows through.
The smog spell has made Utah’s air the dirtiest in the country for almost a week, and nearly eight of 10 Utah residents are living under health advisories. Residents are being urged to drive less and prohibited from burning wood, and even the most fit have been urged not to exercise outside.
“It’s a disgrace that we’ve got this,” said Richard Middleton, 72, a retired consultant who was out walking in Salt Lake City on Thursday to rehab his knee after surgery.
The haze lingering around the base of the Wasatch Mountains is a potent cocktail of tailpipe exhaust, industrial pollution, and emissions from homes and businesses.
The region’s geography makes matters worse: Much of Utah’s population resides in bowl-shaped valleys that cause the smog to get trapped.
The state issues daily health advisories on the region’s air quality between Nov. 1 and March 1. Already this season, 19 “red alerts” — the most severe ranking — have been issued for Salt Lake County, more than the previous two years combined and the third-most in the past decade, according to state records.
The state has made strides in cleaning up air pollution, including cracking down on large-scale polluters, limiting vehicle emissions, and making a huge investment in light rail and other mass transit.
Cheryl Heying, director of the Utah Division of Air Quality, said the state’s air is actually cleaner than it was just five years ago and nothing like the lung-clogging conditions from pollution heydays in the early 1990s.
What’s changed in recent years, she said, is that the Environmental Protection Agency tightened its standards, including for tiny particulates called PM2.5 that are linked to premature death in people with heart and lung disease. The pollutant is also particularly tough on people who already have pre-existing respiratory problems such as asthma.
The tighter standards mean more frequent exceedances, and more public health advisories, Heying said.
