SALT LAKE CITY — Kevin Perry had just begun his morning routine, stepping outside to get the newspaper, when he noticed something was wrong with the sky.
“Within 30 seconds, I was coughing and my throat hurt,” Dr. Perry, an atmospheric scientist at the University of Utah, said of that morning in August. “It was the absolute worst air quality I’ve ever experienced in my life.”
Shrouded in smoke drifting from California’s colossal wildfires 500 miles away, Salt Lake City had on that morning edged past smog-choked megacities like New Delhi and Jakarta to register the most polluted air of any major city in the world.
The grim distinction alarmed both longtime residents and newcomers to Utah, where a red-hot economy and easy access to outdoor pursuits like skiing and mountain biking are fueling the fastest-growing population of any state.
But the consequences of the growth, including more vehicles on the road, and this summer’s wildfire smoke are aggravating an already bleak deterioration in air quality brought on by a prolonged drought.
Scientists say the drought, plus water diversions, has shriveled the Great Salt Lake, the country’s largest body of water after the Great Lakes, to its lowest levels in more than a century. The result is vast areas of parched lake bed, similar to the dried-up Aral Sea in the former Soviet Union, exposing millions of people in Utah to dust storms laced with arsenic and other toxic elements.
“Every time the wind blows, we’re subject to the dust from these dry lake beds being scattered all over,” said Dr. Brian Moench, president of Utah Physicians for a Healthy Environment. “There are residuals of pesticides and agricultural chemicals that migrated into the lake over many decades.”
For the moment, the slow-motion ecological disaster of the shrinking Great Salt Lake appears to stand in contrast to the vibrancy of Salt Lake City, a nerve center for a $1.5 billion skiing industry that is also home to outdoor clothing companies like Black Diamond, Cotopaxi and Kuhl.
But while the outdoor recreation industry relies on blue-sky imagery, scientists say that air quality around the Wasatch Front, the metropolitan region where about 80 percent of people in Utah live, is getting much worse than many residents realize.
The bowl-like topography of the valley that includes Salt Lake City creates an inversion that traps air pollution — generally during the wintertime — from sources like motor vehicle exhaust. It is much like the situation in Santiago, the Chilean capital cradled in mountains that is one of Latin America’s most polluted cities.
A newer problem throughout the year, amplified by the population boom, is ground-level ozone pollution from sources such as power plants and cars, which can increase the frequency of asthma attacks and aggravate lung diseases like emphysema and chronic bronchitis.
The Environmental Protection Agency in 2018 designated the northern Wasatch Front airshed, which includes part of the Salt Lake City area, as being in violation of federal ozone standards. The move spawned bitter political quarreling over whether Utah’s petroleum and mining industries were pushing ozone levels higher.
Expressing alarm over the deteriorating air quality, especially in the winter, the skiing magazine Powder warned, “We may start to see visitors in Salt Lake traveling with gas masks along with their ski gear.”
The wildfire smoke now blowing in from California, where several large blazes continue to burn, is also an extraordinarily toxic form of pollution. The particles can be much smaller than those from smokestacks, making them easier to inhale and get picked up by the bloodstream.
Then there is the shriveling of the Great Salt Lake. While the lake’s water level has fluctuated greatly over time, the U.S. Geological Survey found in July that it had reached its lowest mark since measurements began in 1875.
When at its average water elevation, the lake, which accumulates salt and other minerals because it has no outlet to the ocean, spreads over 1,700 square miles. But it spans only about 950 square miles today after losing 44 percent of its surface area, an area larger than the city of Houston.
The lake’s shrinkage makes for surreal scenes. On Antelope Island, near a once-bustling marina that is now idled and empty, dozens of microbialites, the reeflike mounds created by millions of microbes, stand exposed to the air.
Because the lake’s brine shrimp and brine flies rely on the microbialites as their primary food source, and because millions of birds feed on the shrimp and flies, falling water levels could trigger a collapse in the lake’s food chain if more microbialites are threatened, according to a study in July by the Utah Geological Survey.
Elsewhere around the Great Salt Lake, visitors who could once enjoy picnic tables at shore’s edge must now trek across a dry lake bed to dip their toes in the water; shipwrecks have begun emerging as the water recedes.
Julie Mattingly, commodore of the Great Salt Lake Yacht Club, which was founded in 1877, said dozens of boats at risk of being stuck in the lake bed were removed this year and placed in dry storage.
“There’s no yachting at the moment on the lake,” Ms. Mattingly said, adding that membership in the club had dwindled this year from about 100 members to 13. Now, she said, members do “land cruises,” where they drive around and look at historic sites along the lake.
The Great Salt Lake’s decline has drawn comparisons to the crisis around the Aral Sea, which was once the world’s fourth-largest body of inland water. It began drying up in the 1960s when the former Soviet Union built water diversion projects to irrigate parts of Kazakhstan, Uzbekistan and Turkmenistan.
Now much of the area is one of the world’s youngest deserts, which unleashes dust storms on almost a weekly basis and is known by some as the Aral Sands. Closer to Utah, scientists also compare the collapsing water levels to Owens Lake in California, which had its water diverted to Los Angeles about a century ago.
Since then, Owens Lake has also emerged as a site of huge dust storms, turning into the country’s largest single source of PM 10, a type of particle pollution that can irritate the eyes, nose and throat.
“We’ve seen this happen at terminal basin lakes around the world,” said Dr. Perry, the atmospheric scientist. He said the prolonged drought had resulted in disappointing snowfall in surrounding mountains; while the lake can gain up to two feet from spring runoff, the smaller snowpack over the winter raised its level by just six inches.
Another factor involves Utah’s policies of diverting fresh water from the sources that feed the lake. More than 60 percent of the redirected water goes to agriculture.
“We divert too much water from the Great Salt Lake,” Dr. Perry said.
As the lake continues to shrink, the consequences of such policies are raising alarm. A study by researchers at Brigham Young University, the University of Utah and Middlebury College in Vermont showed that 90 percent of dust in the Wasatch Front came from dry lake beds.
“There’s the potential there for a very large impact from that dust on our population,” said Bryce Bird, director of the Utah Division of Air Quality, referring to drying areas of the Great Salt Lake.
At the same time, demand for water is soaring in Utah as its population climbs higher. While the entire state is in severe drought, according to the National Drought Mitigation Center, many homeowners in Salt Lake City maintain lush lawns.
Utah stands in contrast to other parched states in the West that have moved more aggressively to limit water consumption, such as Nevada, which this year banned “nonfunctional” grass, including some lawns. Gov. Spencer Cox recently said he was exploring the possibility of similar measures in Utah.
Despite the concerns over water supplies and the Great Salt Lake, Utah’s water consumption dwarfs that of many other states, including in other arid climates. Sarah Null, a professor of watershed studies at Utah State University, said the state uses about 150 to 200 gallons a day per person.
Still, Jaimi Butler, coordinator of the Great Salt Lake Institute at Westminster College, said the already dire air quality readings were set to get worse. “All of this is happening while we aren’t really seeing the effects of climate change yet,” she said.