Bonneville Salt Flats

Bonneville Salt Flats

Jeremiah Bernau

The race to save Bonneville Salt Flats.

In the Utah desert, a treeless expanse of pristine white salt crystals has long lured daredevil speed racers, filmmakers and social media-obsessed tourists. It's so flat that on certain days, visitors swear they can see the curvature of the earth.

The glistening white terrain of the Bonneville Salt Flats, a remnant of a prehistoric lakebed that is one of the American West's many other-worldly landscapes, serves as a racetrack for land speed world records and backdrop for movies like "Independence Day" and "The World's Fastest Indian."

But it's growing thinner and thinner as those who cherish it clamor for changes to save it.

Research has time and again shown that the briny water in the aquifer below the flats is depleting faster than nature can replenish it. As nearby groundwater replaces the mineral-rich brine, evaporation yields less salt than historic cycles of flooding and evaporation left on the landscape.

It's thinned by roughly one-third in the last 60 years. The overall footprint has shrunk to about half of its peak size in 1994. The crust keeps tires cool at high speeds and provides an ideal surface for racing — unless seasonal flooding fails to recede or leaves behind an unstable layer of salt. Racers struggle to find a track long enough to reach record speeds with only 8 miles of track compared to 13 miles several decades ago.

Scientists largely agree that years of aquifer overdraws by nearby potash mining have driven the problem, yet insist that there's no hard evidence that simply paying the mining company to return water to the area will solve it amid detrimental human activity like extracting minerals or driving racecars.

Potash is potassium-based salt primarily used throughout the world as a fertilizer for crops such as corn, soy, rice and wheat. It's extracted in more than a dozen countries throughout the world, mainly from prehistoric lakebeds like Bonneville's.

It's mined from other iconic salt flats, including in Chile, where the thickness is not shrinking in a similar manner.

Collecting water samples near Wendover, Utah, Sept. 13, 2022. (AP Photo/Rick Bowmer)

In Utah, after three decades of studies examining the salt flats, nothing has slowed the deterioration. But officials are funding a new study as they try to find a solution. Researchers are seeking to pinpoint why the salt is fading and what can be done to stop it. Under a $1 million research project spearheaded by the Utah Geological Survey, scientists are gathering data to understand the effects climate change, racing, repaving the salt and operating the mine on leased federal land have on preserving the Salt Flats.

The salt is thinning as climate change drags the West into its third decade of drought, yet it's unclear how that affects the seasonal flood patterns the landscape relies on to maintain its size and footprint.

Frustration is boiling over for Dennis Sullivan, a car-builder and racer who set a land speed record in his 1927 Model T street roadster. His organization, the Salt Flats Racing Association, is convinced the potash mining company that extracts minerals from the flats is the primary reason that the aquifer is being depleted. But rather than point fingers that direction, he and other racers blame the U.S. Bureau of Land Management, which oversees the area and is required by federal law to balance multiple uses and preserve it now and into the future.

The Blue Flame at Bonneville Salt Flats on Nov. 4, 1970.

To save the landscape, Sullivan says, the U.S. government needs to find $50 million over 10 years to pay Intrepid Potash, the mining company, to pour briny water it's drawn from the land back on to the flats. He bristles at seeing more time and money spent on research when to him the solution is clear.

"In the world I came from, you study something, you figure out what changes you need to make, you make the changes and then you go back and study it again to see if your changes had an effect on it," said Sullivan. "It's ludicrous to just keep studying it until you do something."

The fragile landscape has become less reliable for racers, who had to cancel "Speed Week" events scheduled for this fall after the salt flats flooded and left them without enough space to drive on.

Though racers insist the answer is obvious, scientists contend that there's no hard evidence that simply returning briny water will reverse the effects of extraction and maintain the salt flats.

Sullivan doesn't blame Intrepid Potash; it has a leasing agreement with the federal government. He says land managers haven't invested in preserving the landscape or replenishing the salt taken off of it.

Intrepid Potash did not respond to questions from The Associated Press.

Jeremiah Bernau, a geologist working on the study with the Utah Geological Survey, said the mining company has already been pouring salt and it's unclear if that's the answer.

A 2016 study found that the areas most susceptible to thinning were places where races are organized. In simple terms, it changes how water can flow through the crust, Bernau said.

"Every use is going to have some sort of impact upon it. It's just trying to rank those, understand how much that impact is and what we can do to mitigate or understand it," Bernau said on a recent tour of the area, where reporters accompanied him as he measured the thickness of the salt and depth of the aquifer.

"My work is trying to understand how is that working and what are the actions that we can do in terms of helping to preserve this landscape," he said.

Backers of the study currently underway hope, if successful, the federal government will consider returning more salt in order to preempt conflict and allow the racers and miners to continue as they have been.

If the study shows salt laydown is effective, Utah state geologist Bill Keach said he expects racers will use the information to push for federal funding to keep up the project.

In 2019, when Utah lawmakers greenlit the initiative, they allocated $5 million, on the condition that the federal government would also provide funding, to return the briny water needed to preserve the salt crust.

Rep. Steve Handy, a Republican who spearheaded the effort, said the racers' lobbyists initially suggested the federal government would meet Utah's investment with an additional $45 million, giving the program the $50 million that Sullivan and other racers say is needed to maintain the status quo.

U.S. Rep Chris Stewart, who represents the area, assured Handy his office was working to secure the funds. Without hard evidence the salt laydown would restore the crust, the $45 million hasn't materialized but Stewart said in a statement that he "remains absolutely committed to finding science-based solutions" to save the crust.

Utah clawed back the majority of the funding after it got no matching federal funds.

"They're doing what they can with $1 million, which has not spread nearly far enough," Handy said, noting that it was ultimately the job of the federal government, not Utah, to manage the land.

But while solutions and the extent to which different parties are responsible is debatable, nobody disagrees that the landscape is a jewel worth preserving. Kneeling down, the crust of fused crystals looks like popcorn. From afar, the surface is moon-like, and draws hundreds of visitors daily, some coming in brightly colored dresses at sunset in search of the perfect picture.

"The fact that you can go out here and see this vast, white expanse with such a beautiful texture on the crust. It unleashes something, maybe more primal in yourself," Bernau said, looking off into the distance.


by Sam Metz and Brady McCombs, first published @

Wilkes Climate Prize

Wilkes Climate Prize

1.5 Million Dollar Wilkes Climate Prize.

The Wilkes Center Climate Prize at the University of Utah recognizes and supports innovative projects that have significant potential to help address the impact of climate change. 

In addition to $1.5 million prize money, the awardees will receive access to resources from the Master of Business Creation program at the University of Utah and mentorship by Utah-based business leaders.

What are the goals of the prize?

  • Incentivize
    To incentivize novel, feasible, and scalable climate solutions.
  • Support
    To support the development of these ideas from the early stages to the implementation phase.
  • Inspire
    To inspire and support the innovators behind these projects as they launch and scale their companies.

Nomination Details

  • Nominations will be open to individuals, groups, or entities worldwide.
  • The Wilkes Center for Climate Science and Policy at the University of Utah will administer the prize. A panel of distinguished judges with backgrounds in science and industry to review nominations.
    The prize will be announced at the Wilkes Center Climate Summit in May 2023.
  • Sign up to receive updates about the prize and the nomination process asz they are released over the next few months.
  • Sponsors

The prize is supported by a cross-section of Utah-based organizations and industries.

Contributors include:

For more information visit The Wilkes Center.

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Construction Updates

Construction Updates

Construction is about to begin on the University of Utah’s new Applied Science Project. The project will restore and renovate the historic William Stewart building and construct an addition to the building on the west side, adjacent to University Street. Construction will start in early October.

Construction Timeline

This important project will provide new and updated space to serve the University of Utah’s educational and research mission. It will serve as the new home for the Departments of Physics & Astronomy and Atmospheric Sciences, focusing on aerospace, semiconductor technology, biotechnology, data science, hazardous weather forecasting, and air quality. Together, the two departments teach more than 5,600 students. See why the University of Utah College of Science is so excited about launching this project.

New construction will provide a 56 percent increase in experimental and computer lab capacity. There will be 40,700 square feet of renovated space in the historic Stewart Building and a 100,00 square foot new addition. The project will preserve and restore the historic character of the William Stewart Building while introducing a modern yet complementary design for the new addition. The new building’s exterior finishes will resemble the latest addition to the Crocker Science building next door.

Tree protection plans are in place, and the project team has taken steps to ensure the safety and preservation of Cottams Gulch, which will remain open and accessible during construction. In addition, the project team is working with Simmons Pioneer Memorial Theater leadership to ensure construction does not affect theater activities.

Cottam's Gulch

What to Expect - Construction Impacts

  • Project construction timeline: October 2022 – August 2024
  • Construction hours are 7 am – 7 pm
  • The installation of six-foot-tall construction fencing around the project site will begin the second week of October
  • The existing rock wall near the University Avenue sidewalk will be dismantled for the duration of construction and restored when construction nears completion.
  • Construction traffic will enter and exit the project site via University Street; Full-time road flaggers will be in place to assist with traffic safety and flow
  • Sidewalks directly east of the Stewart building will be closed; signage will be in place to direct pedestrians east of the construction zone around the Life Sciences building
  • Visit the Applied Science Project construction website.


Traffic and Pedestrian Map

Construction Map


Story by Lisa Potter, first published in @theU.



Applied Science Video


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Toxic Dust Hot Spots

Toxic Dust Hot Spots

Kevin Perry

Where is Great Salt Lake's toxic dust most likely to originate?

Professor Kevin Perry believes there are many "trigger points" that indicate when there is something wrong with the Great Salt Lake.

For instance, anyone who has come to the lake for recreation has recently found an inability to launch watercraft as the lake levels continue to reach all-time lows. Struggles for the vital brine shrimp industry and a possible collapse of the lake's base food chain are other alarms on the horizon, says Perry, a professor of atmospheric science at the University of Utah.

Toxic dust from the drying lakebed ultimately became one of the first alarms that captivated researchers, though. The Great Salt Lake contains arsenic and other metals that are naturally occurring, while some researchers say could even be human-caused. And as the lake shrinks, it has exposed some 800 square miles of exposed lakebed, equivalent to the entire surface area of Maui.

Researchers are starting to identify places around the dried-up lake that are most likely to produce dust that is ultimately carried into Utah communities, Perry says. He pinpoints Farmington Bay in Davis County, Bear River Bay near Brigham City and Ogden, and the lake's northwest boundary in a remote part of Box Elder County as the three largest dust "hot spots."

Fragile eroding surface crust - Kevin Perry

These three locations have the highest potential of sourcing dust all over northern Utah for years to come unless there's a dramatic turnaround in the lake levels, Perry explained Tuesday evening in a presentation about dust concerns to the Utah Legislature's bipartisan Clean Air Caucus.

But before rushing into a panic, Perry told lawmakers there is still so much more research needed to fully understand the dust carried out of the dried Great Salt Lake, including if and how much of a role it plays in long-term health concerns.

Dust Hot Spots
There are certain spots within the 800 square miles of exposed lakebed with a higher potential to produce dust that is carried into Utah communities during storms. While winds typically impact areas east of the lake, like Wasatch Front communities, weather patterns can blow the dust into areas all over northern Utah.

"Everybody along the Wasatch Front (and Tooele Valley) is impacted at certain times," Perry said after Tuesday's meeting.

Perry's research over the years has focused on identifying the frequency that dust is exposed in the atmosphere and also the concentration levels of dust in the air that Utahns breathe to understand public health impacts. It's helped him figure out the areas where dust is more likely to be picked up.

Soil with higher amounts of erodible material like silt and clay are more likely to be picked up into the air. Farmington Bay, Bear River Bay and the "extreme" northwest quadrant of the lake have the highest levels of silt and clay of any exposed lakebeds, where the materials make up at least 10% of the soil samples. Most of it arrives from the lake's tributaries like the Jordan, Bear and Weber rivers.

Map of Dust Hot Spots - Kevin Perry

They are the same areas where the lake's surface crust is vulnerable. Perry explains that only about 9% of the lakebed is actively producing dust because three-fourths of the lake is currently protected by a crust, such as the natural salt pan that protects the lakebed from breaking.

The dust coming from the remaining quarter either doesn't have crust or the crust is considered erodible. Human activity from illegal motor vehicle riding on the exposed lakebed is one reason for this crust breaking, and dust can blow freely in the wind once the surface erodes.

Again, Farmington and Bear River bays emerge as hot spots, as well as Gilbert and Gunnison bays on the western corners of the lake. And while most of the lakebed is protected now, the amount of protection decreases every year it is exposed because of how fragile the crust is, Perry adds.

The Air Quality Threat
This dust is a problem just because of its ability to raise particulate matter levels, something Utahns are accustomed to hearing about from wildfires and during winter inversions that threaten Utah's air quality. But Perry cautions it is too early to know what the true human impact of the dust will be.

The lakebed contains levels of arsenic, lanthanum, lithium, zirconium, copper and other metals above the Environmental Protection Agency's residential and industrial standards. Of those, arsenic, which can increase the risk of a few diseases when there is chronic exposure, has the highest levels compared to EPA standards, according to Perry.

However, it is not very clear how much of it people are actually breathing in during a wind event. The dose levels, a calculation of concentration, frequency and bioavailability, are needed to fully understand the true human risk associated.

This data is collected by the Utah Division of Air Quality but Perry says it hasn't been analyzed to this point because of the cost: $27,500 per site annually. Until that is available, researchers don't really know any component in the dose level equation, including how many days of the year dust ends up in surrounding communities or if some communities have disparities compared to others.

This is why Perry emphasizes that what is in the dust should be considered a "potential concern." He likens this uncertainty to driving on an unfamiliar mountain road in the dark. Motorists are more likely to slow down and focus on the road ahead of them when they perceive a risk of driving off the roadway.

The same idea applies to the science of the Great Salt Lake.

"What we've done here is identify a risk," Perry says. "The risk is exposure to (the) heavy metal arsenic, and so what we need to do is step back and try and understand the significance of that risk. ... We need to do more research, we need to take more measurements but we need to be vigilant because there is a threat out there. We need to determine if that threat will be realized or not."

Representative Ray Ward

This is not a problem that might happen in the future, the lake is three-fourths of the way gone today and we really, really need to have a sustained focus on it over a longer period of time to make sure we put enough water into it.  - Rep. Ray Ward, R-Bountiful


Rep. Ray Ward, R-Bountiful, a member of the Clean Air Caucus, said after the meeting that the presentation didn't immediately spark any new bill ideas for the future; however, he said, it emphasizes the need for new state appropriations, which may include the cost of analyzing the air quality data for Great Salt Lake dust.

The Easiest Solution
But how does Utah avoid this potential concern? The easiest solution is refilling the lake, though, that's still a daunting task considering all the upstream water diversions that take water out of the lake and that Utah is in the middle of a two-decade-long megadrought. This says everything about how challenging it is to mitigate dust once a lakebed is exposed.

There are dozens of global examples of what can go wrong when a lake dries out but Owens Lake in California is the one that Perry pointed lawmakers to on Tuesday. The lake began to dry up when Los Angeles officials began diverting the lake's water sources into the Los Angeles Aqueduct.

This is not a problem that might happen in the future, the lake is three-fourths of the way gone today and we really, really need to have a sustained focus on it over a longer period of time to ... make sure we put enough water into it.  - Rep. Ray Ward, R-Bountiful

California leaders have since spent over $2 billion trying to mitigate the health concerns associated with the dried lake dust. They eventually determined the only feasible solution was to refill the lake, Perry explains.

This solution could take a long time to solve Utah's problems, though. Of the Great Salt Lake's four major concern areas, Perry considers Farmington Bay as the easiest to mitigate simply because it requires the least amount of water to help cover the surface area. The lake needs to gain about 10 feet of water to mitigate dust concerns in the bay, but that could take decades to happen, barring an unforeseen shift in trends.

"Which means that we're going to be plagued by dust coming off the Great Salt Lake not just for a few years but likely for decades," he said.

That said, he's more optimistic about this solution now than just three years ago. He's seen Utahns show more interest in reducing water waste and state leaders take larger steps toward water conservation compared to the past. Tuesday's meeting featured four experts explaining ways to improve water quantity and air quality around the lake.

Ward agrees that the state is going to need to more than just refill the lake once to resolve the lake's issue. The Utah Legislature directed $40 million toward getting more water to the lake in this year's legislative session. More money and projects are needed to ensure water is flowing to the Great Salt Lake, Ward acknowledges.

But it's time and money worth spending given the known and potential risks Utah faces as the lake dries up.

"The big picture is we're in trouble with the lake right now," he said. "This is not a problem that might happen in the future, the lake is three-fourths of the way gone today and we really, really need to have a sustained focus on it over a longer period of time to ... make sure we put enough water into it."


by Carter Williams, first published @

Wilkes Scholars

Wilkes Scholars

Apply to Become a Wilkes Scholar.

The Wilkes Scholars Program (WSP) enables outstanding undergraduate students to explore pressing climate challenges facing our state, region, and planet through transformative research. Wilkes Scholars will work with a mentor to advance research related to the mission of the Wilkes Center for Climate Science and Policy — catalyzing innovative science and solutions to address climate change.


To be eligible to receive this funding, applicants must:

  • Conduct research projects in the area of climate science and/or environmental studies. Examples of relevant research include, but are not limited to, drought and water issues, climate forecasting, climate justice, air quality, climate policy, fire and climate extremes, and environment and human health. 
  • Provide a tenure-line or career-line faculty contact who will submit a letter of support.
  • Be matriculated, degree seeking students at the University of Utah who have completed their first year of studies (sophomore+)

Wilkes Scholars are eligible for up $5,000 per semester and can receive two semesters of funding during the regular academic year (Fall and Spring). Students who receive funding are also eligible to apply for summer funding concurrently. Students who wish to receive funding through the summer must submit a new application before the March 1 deadline. Wilkes Scholars may be eligible for one subsequent renewal. Students may apply to become a Wilkes Scholar in any semester.

Wilkes Scholars awardees will be hired as temporary, part-time employees by the home department of their faculty mentor. Wilkes Scholars are paid $15/hour with a maximum Fall/Spring semester cap of 19hrs/week and a maximum Summer semester cap of 40hrs/week.

The Wilkes Center for Climate Science and Policy recognizes that a diverse student body benefits and enriches the educational experiences of all students, faculty, and staff. Thus, we strive to recruit students who will further enrich this diversity and make every attempt to support their academic and personal success while they are here.

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At-Risk Forests

At-Risk Forests

Global analysis identifies at-risk forests.

Forests are engaged in a delicate, deadly dance with climate change, hosting abundant biodiversity and sucking carbon dioxide out of the air with billions of leafy straws. They can be a part of the climate solution as long as global warming, with its droughts, wildfires and ecosystem shifts, doesn’t kill them first.

In a study published in Science, William Anderegg, the inaugural director of the University of Utah’s Wilkes Center for Climate Science and Policy, and colleagues quantify the risk to forests from climate change along three dimensions: carbon storage, biodiversity and forest loss from disturbance, such as fire or drought. The results show forests in some regions experiencing clear and consistent risks. In other regions, the risk profile is less clear, because different approaches that account for disparate aspects of climate risk yield diverging answers.


William Anderegg

“Large uncertainty in most regions highlights that there's a lot more scientific study that's urgently needed.”


An international team

Anderegg assembled a team including researchers from the United Kingdom, Germany, Portugal and Sweden.

“I had met some of these folks before,” he says, “and had read many of their papers. In undertaking a large, synthetic analysis like this, I contacted them to ask if they wanted to be involved in a global analysis and provide their expertise and data.”

Their task was formidable –assess climate risks to the world’s forests, which span continents and climes and host tremendous biodiversity while storing an immense amount of carbon. Researchers had previously attempted to quantify risks to forests using vegetation models, relationships between climate and forest attributes and climate effects on forest loss.

“These approaches have different inherent strengths and weaknesses,” the team writes, “but a synthesis of approaches at a global scale is lacking.” Each of the previous approaches investigated one dimension of climate risk: carbon storage, biodiversity, and risk of forest loss. For their new analysis, the team went after all three.

Three dimensions of risk

“These dimensions of risk are all important and, in many cases, complementary. They capture different aspects of forests resilience or vulnerability,” Anderegg says.

  • Carbon storage: Forests absorb about a quarter of the carbon dioxide that’s emitted into the atmosphere, so they play a critically important role in buffering the planet from the effects of rising atmospheric carbon dioxide. The team leveraged output from dozens of different climate models and vegetation models simulating how different plant and tree types respond to different climates. They then compared the recent past climate (1995-2014) with the end of the 21st century (2081-2100) in scenarios of both high and low carbon emissions. On average, the models showed global gains in carbon storage by the end of the century, although with large disagreements and uncertainty across the different climate-vegetation models. But zooming in to regional forests and taking into account models that forecast carbon loss and changes in vegetation, the researchers found higher risk of carbon loss in southern boreal (just south of the Arctic) forests and the drier regions of the Amazon and African tropics.
  • Biodiversity: Unsurprisingly, the researchers found that the highest risk of ecosystems shifting from one “life zone” to another due to climate change could be found at the current boundaries of biomes – at the current transition between temperate and boreal forests, for example. The models the researchers worked from described changes in ecosystems as a whole and not species individually, but the results suggested that forests of the boreal regions and western North America faced the greatest risk of biodiversity loss.
  • Disturbance: Finally, the authors looked at the risk of “stand-replacing disturbances,” or events like drought, fire or insect damage that could wipe out swaths of forest. Using satellite data and observations of stand-replacing disturbances between 2002 and 2014, the researchers then forecast into the future using projected future temperatures and precipitation to see how much more frequent these events might become. The boreal forests, again, face high risk under these conditions, as well as the tropics.

“Forests store an immense amount of carbon and slow the pace of climate change,” Anderegg says. “They harbor the vast majority of Earth's biodiversity. And they can be quite vulnerable to disturbances like severe fire or drought. Thus, it's important to consider each of these aspects and dimensions when thinking about the future of Earth's forests in a rapidly changing climate.”

Future needs

Anderegg was surprised that the spatial patterns of high risk didn’t overlap more across the different dimensions.

“They capture different aspects of forests' responses,” he says, “so they wouldn't likely be identical, but I did expect some similar patterns and correlations.”

Models can only be as good as the basis of scientific understanding and data on which they’re built and this study, the researchers write, exposes significant understanding and data gaps that may contribute to the inconsistent results. Global models of biodiversity, for example, don’t incorporate dynamics of growth and mortality or include the effects of rising CO2 directly on species. And models of forest disturbance don’t include regrowth or species turnover.

“If forests are tapped to play an important role in climate mitigation,” the authors write, “an enormous scientific effort is needed to better shed light on when and where forests will be resilient to climate change in the 21st century.”

Key next steps, Anderegg says, are improving models of forest disturbance, studying the resilience of forests after disturbance, and improving large-scale ecosystem models.

The recently-launched Wilkes Center for Climate Science and Policy at the University of Utah aims to provide cutting-edge science and tools for decision-makers in the US and across the globe. For this study, the authors built a visualization tool of the results for stakeholders and decision-makers.

Despite uncertainty in the results, western North America seems to have a consistently high risk to forests. Preserving these forests, he says, requires action.

“First we have to realize that the quicker we tackle climate change, the lower the risks in the West will be,” Anderegg says. “Second, we can start to plan for increasing risk and manage forests to reduce risk, like fires.”

Find the full study here.


by Paul Gabrielsen, first published in @theU.

Air Pollution

Air Pollution

Smoke forecast, March 7, 1941.

Air you can chew: The history of Utah’s air quality

When Salt Lake City official George Snow said that the Wasatch Front’s air quality issues could not be solved “in a single day or year, not by a single group or group of persons . . . it will take a properly guided, united and continued effort to solve the problem”—it wasn’t in response to Utah’s torrential growth in recent years, nor was it during one of our recent inversions or smoke inundations from climate-driven Western wildfires. That quote is from 1917 and predates nearly everyone and everything that’s grown up in the Salt Lake Valley since then.

This quote shows that Utah’s air quality issues have been with us for a long time.

New research by Logan Mitchell, affiliated faculty in the U’s Department of Atmospheric Sciences, and Chris Zajchowski, who earned a Park, Recreation, and Tourism Ph.D. at the U in 2018 and is now at Old Dominion University, traces the history of air quality in Utah from the mid-19th century.

“It’s pretty clear that our air quality today is probably better than it has been at any time since about the 1880s,” Mitchell says. “We’ve been working on this for a long time, but we’re at a point in time when we really have an opportunity to make a big difference. And that’s really exciting.”

The research is published in the journal Sustainability.

The Wasatch Front shapes air quality—and vice versa
Yes, the Wasatch Front’s air today is sometimes gunky, gross and can be hazardous. But modern air problems pale in comparison to the noxiousness that poured out of smokestacks and chimneys a century ago when coal and wood burning was common and prevalent among homes and businesses.

Going back as far as the mid-1800s, early non-Indigenous explorers to the bowl-like valleys of the Wasatch Front noticed that wood smoke hung in the air, blue and hazy. Because the valleys of the Wasatch Front are shaped like mountain-ringed bowls, air pollution like smoke can settle in the valleys. In the winters, temperature inversions throw a cap of warm air on the cold valleys, trapping emissions and worsening air quality.

Early city planners understood the effect of the mountains on air pollution. If a smoky factory was built at the mouth of one of the Wasatch Mountain canyons, the canyon winds would blow the smoke through the valley. So, Mitchell found that in the 1890s factories were built on the valley’s west side. The legacy of that decision persists today: the west side of the Salt Lake Valley still bears much of the valley’s industrial activity and disproportionately exposes the majority-minority community to air pollution.

“We ought to be thinking, as we’re engaging in major development projects,” Mitchell says, “about what the environmental impacts and social impacts are, not just this year or next year or next quarter, but 50 or 100 years down the road.”

G. St. John Perrot and the sampling flasks used in the first aircraft sampling campaign to study SLC’s air pollution, 1919.

Learning about Utah’s air
Around the turn of the 20th century, Utahns spoke of the “smoke nuisance” which was also accompanied by soot. Measuring soot pollution was as easy as setting enamel jars outside that collected, in some parts of the city, 1000 tons of soot per square mile over the course of a winter. It’s an enormous amount of soot, Mitchell says. “That’s air that you can chew.”

Atmospheric scientists tried to learn all they could about the reasons for Utah’s air quality challenges. In 1919, “government smoke expert” G. St. John Perrot flew a biplane through Salt Lake’s “smoke bank” and gathered samples to test hypotheses about the temperature inversion phenomenon.

More than a century later, U atmospheric scientists are using similar methods. In an upcoming project called AQUARIUS, researchers will fly an airplane through the temperature inversion layer, studying the chemistry that forms aerosol particles from atmospheric gases. “The chemistry is not fully understood,” Mitchell says. “Somebody had that exact same study design literally a hundred years ago.”

Mitchell and Zajchowski found that throughout the state’s history, records indicated a preference for business and industry to address air pollution without a need for government intervention. But sometimes when citizens pushed against industry, the industry pushed back.

In 1899 the first copper smelter opened in Murray, beginning a smelting and refining industry connected to Utah’s mining industry. But the smelter facilities had no pollution controls and emitted sulfur, arsenic and lead. Farmers near the smelters sued when their crops began to die from the toxic emissions. Smelter owners responded by funding research into farming practices and accusing farmers of “smoke farming,” or suing smelters for money instead of tending to their crops.

“They’re trying to say that the farmers are just bad at farming trying to pass the blame off on something other than their emissions,” Mitchell says.

Restarting the Geneva steel mill after a 13-month closure caused an increase in pollution, 1987.

In 1986 the Geneva Steel plant in Utah County closed down operations for 13 months during a labor strike. The closure provided an opportunity for a natural experiment to compare health outcomes in the area during the closure with times when the plant’s smokestacks were in full operation. Studies published in peer-reviewed scientific journals showed that bronchitis and asthma hospital admissions for preschool-age children in Provo were halved during the idle year.

But a Geneva Steel-funded rebuttal study, not subjected to peer review before being released to the public, claimed that the difference in hospitalization rates was due to respiratory syncytial virus, or RSV. This claim was false since the original studies had controlled for RSV rates. But, the authors write, “the disinformation effort to create misleading news coverage had the desired effect of creating an artificial controversy that muddled public understanding of the health impacts of air quality in Utah for years.”

Environmental stewardship and economic growth
In 1893, a newspaper article foresaw that Utah’s economic and social growth would be closely linked with its air quality.

“Factories that blacken the city with smoke can be as much a detriment as they are an advantage,” wrote the Salt Lake Herald-Republican, “for Salt Lake has as much to expect from the increase she will receive from persons who will select it as their residence on account of its pure air and cleanliness as it has to gain from factories.”

That interplay between environment and economy has been a persistent theme in Utah’s history, Mitchell says.

“The two are paired,” he says. “Some people will say that we haven’t done a good enough job one way or the other, but that effort to balance those two things has been there throughout our history.”

Today, the OneUtah Roadmap from Governor Spencer Cox continues addressing that relationship between environment and economy by including air quality as a part of the state’s sustainable growth and economic advancement plan.

Where we are now
What will be written about today’s chapter in Utah’s air quality history?

“We’re better positioned than we’ve ever been before,” Mitchell says. “But the question of how fast we solve these issues is up to us.”

Although Utahns have long known that air quality is a problem and that action is needed to solve it, the missing piece that we now have in our hands, Mitchell says, is clean energy technology, including zero-emission technology. “And where we’re at today is that we’re starting to see those technologies become in many cases the best option, the cheapest option.”

Because of those emerging and advancing technologies, Mitchell says that Utah’s air quality will continue to improve, even if the state doesn’t take action.

“We also have a historic opportunity to lead that conversation,” Mitchell says, adding that Utah is well-positioned to lead as a conservative state with a sizable technology industry and support from elected officials.

“We have a choice,” said Representative John Curtis recently, as reported by the Daily Herald. “We can do it here in the United States, or we can sit back, ignore the climate movement and watch the next industrial revolution take place outside of the United States. The world has sent a signal that it will buy clean energy technology. Will we sell it, or will we watch it be sold?”

Our moment in time also comes with worsening air issues due to climate change, including wildfires and increased ozone formation.

“So as we’re making progress on air quality, the climate impacts exacerbating air quality issues are getting worse,” Mitchell says. “There will be a lot of work to change the technology and the energy types that we use to get around and heat our homes. But I feel it’s an enormous time of opportunity.”

Read Mitchell and Zajchowski’s paper here.

The research is published in the journal Sustainability.


by Paul Gabrielsen, first published in @theU.

Smoke Plumes

Smoke Plumes

Western wildfire smoke plumes are getting taller.

In recent years, the plumes of smoke crawling upward from Western wildfires have trended taller, with more smoke and aerosols lofted up where they can spread farther and impact air quality over a wider area. The likely cause is climate change, with decreased precipitation and increased aridity in the Western U.S. that intensifies wildfire activity.

“Should these trends persist into the future,” says Kai Wilmot, a postdoctoral researcher in the Department of Atmospheric Sciences at the University of Utah, “it would suggest that enhanced Western U.S. wildfire activity will likely correspond to increasingly frequent degradation of air quality at local to continental scales.”

The study is published in Scientific Reports and supported by the iNterdisciplinary EXchange for Utah Science, or NEXUS, at the University of Utah.


Kai Wilmot

“Given climate-driven trends towards increasing atmospheric aridity, declining snowpack, hotter temperatures, etc. We’re seeing larger and more intense wildfires throughout the Western U.S., and this is giving us larger burn areas and more intense fires.”


Smoke height

To assess trends in smoke plume height, Wilmot and U colleagues Derek Mallia, Gannet Haller and John Lin modeled plume activity for around 4.6 million smoke plumes within the Western U.S. and Canada between 2003 and 2020. Dividing the plume data according to EPA ecoregions (areas where ecosystems are similar, like the Great Basin, Colorado Plateau, and Wasatch and Uinta Mountains in Utah) the researchers looked for trends in the maximum smoke plume height measured during August and September in each region in each year.

In the Sierra Nevada ecoregion of California, the team found that the maximum plume height increased, on average, by 750 ft (230 m) per year. In four regions, maximum plume heights increased by an average of 320 ft (100 m) per year.

Why? Wilmot says that plume heights are a complex interaction between atmospheric conditions, fire size and the heat released by the fire.

“Given climate-driven trends towards increasing atmospheric aridity, declining snowpack, hotter temperatures, etc., we’re seeing larger and more intense wildfires throughout the Western U.S.,” he says. “And this is giving us larger burn areas and more intense fires.”

The researchers also employed a smoke plume simulation model to estimate the mass of the plumes and approximate the trends in the amount of aerosols being thrown into the atmosphere by wildfires . . . which are also increasing.

The smoke simulation model also estimated the occurrence of pyrocumulonimbus clouds—a phenomenon where smoke plumes start creating thunderstorms and their own weather systems. Between 2017 and 2020, six ecoregions experienced their first known pyrocumulonimbus clouds and the trend suggests increasingly frequent pyrocumulonimbus activity on the Colorado Plateau.

Taller plumes send more smoke up into higher elevations where it can spread farther, says John Lin, professor of atmospheric sciences.

“When smoke is lofted to higher altitudes, it has the potential to be transported over longer distances, degrading air quality over a wider region,” he says. “So wildfire smoke can go from a more localized issue to a regional to even continental problem.”

Are the trends accelerating?

Some of the most extreme fire seasons have occurred in recent years. So does that mean that the pace of the worsening fire trend is accelerating? It’s too early to tell, Wilmot says. Additional years of data will be needed to tell if something significant has changed.

“Many of the most extreme data points fall within the years 2017 -2020, with some of the 2020 values absolutely towering over the rest of the time series,” he says. “Further, given what we know of the 2021 fire season, it appears likely that analysis of 2021 data would further support this finding.”

In Utah’s Wasatch and Uinta Mountains ecoregion, trends of plume height and aerosol amounts are rising but the trends are not as strong as those in Colorado or California. Smoke from neighboring states, however, often spills into Utah’s mountain basins.

“In terms of the plume trends themselves, it does not appear that Utah is the epicenter of this issue,” Wilmot says. “However, given our position as generally downwind of California, trends in plume top heights and wildfire emissions in California suggest a growing risk to Utah air quality as a result of wildfire activity in the West.”

Wilmot says that while there are some things that people can do to help the situation, like preventing human-caused wildfires, climate change is a much bigger and stronger force driving the trends of less precipitation, higher aridity and riper fire conditions across the West.

“The reality is that some of these [climate change] impacts are already baked in, even if we cut emissions right now,” Wilmot adds. “It seems like largely we’re along for the ride at the moment.”

Find the full study at


by Paul Gabrielsen, first published in @theU.

Air Tracker

Air Tracker

New tool shows air pollution’s path.

On June 13, 2022, Environmental Defense Fund unveiled Air Tracker, a first-of-its-kind web-based tool that allows users to plot the likely path of air pollution. Run on real-time, trusted scientific models and coupled with air pollution and weather data and developed in partnership with the University of Utah and the CREATE Lab at Carnegie Mellon University, Air Tracker helps users learn more about the air they’re breathing, including pollution concentrations and its potential sources.

U professor John Lin, of the Department of Atmospheric Sciences, adapted his research group’s atmospheric model (the Stochastic Time-Inverted Lagrangian Transport model, or STILT) to run as part of Air Tracker.

John Lin

“Air Tracker is designed to trace our potential source regions for pollution. Users can make use of Air Tracker to investigate emission sources with a research-grade atmospheric model at their fingertips.”


“Air quality monitors can show us how polluted our air is, but they aren’t equipped to tell us what is causing the pollution,” says Tammy Thompson, Senior Air Quality Scientist and creator of the tool. “With Air Tracker, we’re able to see likely sources of pollution hotspots, which is especially helpful in cities where a variety of emitters contribute to overall air quality.”

Users can click anywhere on maps of Houston, Salt Lake City and Pittsburgh to create a “source area,” which shows the most likely origin of the air they’re breathing at any given time. They can also click on locations of individual air quality sensors to show real-time and historical fine particle (PM2.5) pollution readings, wind speed and direction.

Relying on STILT, Air Tracker incorporates a variety of weather forecasting models to show how particles move through the atmosphere, allowing the tool to map the probability of pollution’s path. Air Tracker goes beyond common source identification models–which are unable to capture fine-scale air pollution variability–to identify pollution sources at the city block level.

In Houston, for example, where a lack of zoning has allowed industrial sources to operate near communities with homes, schools, churches and hospitals, Air Tracker uses both real-time and historical data to show how different sources contribute to poor air quality at different dates and times.

“Breathing dirty air is bad for our health, and these health effects are not distributed equally,” said Sarah Vogel, EDF Senior Vice President, Healthy Communities. “The poorer and more disadvantaged groups disproportionately suffer the greater exposures and health impacts from air pollution. We hope community leaders and individuals will use this pollution data to hold polluters accountable and advocate for clean air policy change.”

In addition to learning more about the sources likely influencing the air they breathe, Air Tracker users can also use the real-time source area identification to help speed mitigation and help spot and control emissions resulting from accidents and unusual events. Through its “Share” feature, users can take screenshots of source areas to send to regulators and local officials.

Air Tracker is part of EDF’s ongoing work to better understand local air pollution, its behavior and its impacts. Air Tracker can be adapted to include additional pollutants and used in other cities around the world, including those that may not yet feature extensive, hyper-local air quality monitoring programs.

Learn more about Air Tracker, EDF’s Global Clean Air efforts and the project partners here.

One of the world’s leading international nonprofit organizations, Environmental Defense Fund creates transformational solutions to the most serious environmental problems. To do so, EDF links science, economics, law, and innovative private-sector partnerships. With more than 3 million members and offices in the United States, China, Mexico, Indonesia and the European Union, EDF’s scientists, economists, attorneys and policy experts are working in 28 countries to turn our solutions into action. Connect with us on Twitter @EnvDefenseFund.


by Paul Gabrielsen, first published in @theU. Adapted from a release by the Environmental Defense Fund


Interactive Forest Maps

Wildfire, Drought & Insects

Dying forests in the western U.S.

Threats impacting forests are increasing nationwide.

Planting a tree seems like a generally good thing to do for the environment. Trees, after all, take in carbon dioxide, offsetting some of the emissions that contribute to climate change.

But all of that carbon in trees and forests worldwide could be thrown back into the atmosphere again if the trees burn up in a forest fire. Trees also stop scrubbing carbon dioxide from the air if they die due to drought or insect damage.

The likelihood of those threats impacting forests is increasing nationwide, according to new research in Ecology Letters, making relying on forests to soak up carbon emissions a much riskier prospect.

“U.S. forests could look dramatically different by the end of the century,” says William Anderegg, study lead author and associate professor in the University of Utah School of Biological Sciences. “More severe and frequent fires and disturbances have huge impacts on our landscapes. We are likely to lose forests from some areas in the Western U.S. due to these disturbances, but much of this depends on how quickly we tackle climate change.”


William Anderegg

"We’ve seen devastating fire seasons with increasing severity in the past several years. Generally, we expect the western U.S. to be hit hardest."


The researchers modeled the risk of tree death from fire, climate stress (heat and/or drought) and insect damage for forests throughout the United States, projecting how those risks might increase over the course of the 21st century.

See their findings in an interactive map at

By 2099, the models found, that United States forest fire risks may increase by between four and 14 times, depending on different carbon emissions scenarios. The risks of climate stress-related tree death and insect mortality may roughly double over the same time.

But in those same models, human actions to tackle climate change mattered enormously—reducing the severity of climate change dramatically reduced the fire, drought and insect-driven forest die-off.

“Climate change is going to supercharge these three big disturbances in the U.S.,” Anderegg says. “We’ve seen devastating fire seasons with increasing severity in the past several years. Generally, we expect the western U.S. to be hit hardest by all three of these. And they’re somewhat interconnected too. Really hot and dry years, driven by climate change, tend to drive lots of fires, climate-driven tree mortality and insect outbreaks. But we have an opportunity here too. Addressing climate change quickly can help keep our forests and landscapes healthy.”

The study is published in Ecology Letters and was supported by the National Science Foundation, U.S. Department of Agriculture, David and Lucille Packard Foundation and Microsoft’s AI for Earth.

Find the full study at Ecology Letters.


by Paul Gabrielsen, first published at @TheU.