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.”

Pushback
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.

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.

Is Utah’s great lake turning to dust?

The flat dry lakebed (also called a playa) surrounding Utah’s Great Salt Lake is more than 750 square miles—an area bigger than Houston. The wide-open landscape is surprisingly varied and is the realm of coyotes, bison, and a few hardy plants. It’s probably safe to say that no one knows the Great Salt Lake playa better than University of Utah atmospheric scientist Kevin Perry.

From June 2016 to August 2018, Perry traversed the playa by bike, researching how it contributes to dust in the Salt Lake Valley’s air. In a report prepared for the Utah Department of Natural Resources and Utah Division of Facilities Construction and Management, Perry details the current dust source regions on the playa and explains how declining lake levels, as well as damage to the playa, could make the problem worse.

“A lot of the lake is being protected by a relatively fragile crust,” Perry says. “Only 9% of the lake right now is blowing dust. If the crust were to erode or be destroyed, then a maximum of 22% of the lake would actually have enough silt and clay particles to become dust sources. We know where those sources are. We know what needs to be protected.”

photo: Kevin Perry

A solitary journey
Perry has decades of experience studying how dust is transported through the air. He first delved into the topic as a postdoctoral researcher at the University of California at Davis where he used National Park Service measurements of particle composition to prove that high concentrations of mineral dust in the air over the eastern United States during summer originated from Africa. Later, he used these same techniques to track Asian dust originating in the Gobi and Taklamakan deserts as it traversed the Pacific Ocean. “As I’ve lived here in Utah longer,” he says, “I eventually became more interested in the local dust sources.” As the Great Salt Lake water level has declined from its historic high in the 1980s, more and more of the playa is exposed to wind, and dust storms in the Salt Lake Valley have become more frequent. Perry secured funding to study the playa, determine where the dust was coming from and analyze the sources to see if elements present in the dust might pose a health hazard to Wasatch Front residents.

Perry decided he would traverse the playa on a preset grid system, to make sure he wasn’t biased in selecting sampling locations, and to ensure he captured the different kinds of terrain present on the lakebed. He also decided that he would do the survey by himself and do it on a bicycle.

Biking had practical advantages—it was far less costly than operating an ATV, and was much less likely to damage the playa surface. Also, bicycles don’t get stuck in the mud as much as ATVs—Perry says it took him all of 20 minutes to free the bike in his worst incidence of getting stuck.

But Perry also had personal reasons for choosing a bicycle. “I turned 50 during the experiment,” he says, and biking allowed him to revisit his preferred mode of transit for many years when he was younger. “I felt like this was probably my last chance to go do something to really push myself physically,” he says.

photo: Kevin Perry

Surprising variation
So, on days that he wasn’t teaching, including weekends and summers, Perry set off on his bike, trailer in tow, to survey the playa. His colleagues were a bit skeptical. “They thought I was crazy,” Perry says. “They said, ‘Why would you spend two years of your life doing this?’”

But once he got past the edges of the playa, everything, including the bugs, went quiet and he found a terrain full of surprising variation. “You could look 15 yards off to the right and it would look very different than where you’re standing,” he says.

He used a classification system to describe each location. Was there vegetation? How thick was the surface crust and how erodible was it? Were there any other features, such as mineral crystals, sand dunes or, cryptically, rocks with long trails in the playa suggesting they had moved over time? He also took samples to take back to the lab and analyze for percentages of silt and clay.

Perry saw wildlife too: porcupines, pelicans, coyotes, bison—even the tracks of a cougar. “They come out onto the lake bed looking for things,” he says, “I don’t know what they’re looking for, but I was just amazed by the variety in the wildlife that I saw.”

Dust sources
Only about a quarter of the lakebed could potentially generate dust, Perry found. That’s because most of it is covered with a crust that prevents the wind from lofting the dust and carrying it into the Salt Lake Valley. Vegetation, when it is present, can also help to anchor the dust.

How did Perry determine if a location was generating dust? Active dust sources were identified as areas with little or no vegetation, no crust or an erodible shallow crust, and high silt and clay fractions. The “boot test” —kicking the ground several times to see if the surface was susceptible to wind erosion—was a great way to identify these spots in the field. Four dust-generating hotspots were identified: the extreme northwest corner of the playa, the northern Bear River Bay area, Farmington Bay east of Antelope Island and Carrington Bay, on the west shore.

“We now know the elevation of all of those dust sources,” Perry says. “In Farmington Bay, if the lake level were increased to 4,200 feet, it would cover up 75% of the dust hotspots.” Conversely, further reductions in lake levels will likely expose more dust-generating regions. And the destruction of the crust—by ATV activity, for example, would further expand the dust sources.

Perry also analyzed the soil samples for elemental composition to see if dust from the playa might possibly be carrying toxic heavy metals. For most elements, the soil contained too little to be of any health concern. Perry did find elevated levels of arsenic in the soil, but it’s not clear yet how frequently Salt Lake Valley residents are exposed to the dust.

Becoming an advocate
The expansive data set Perry brought off the playa has other applications as well. Researchers studying the effects of dust on snowpack in Utah’s mountains can use the chemical signatures in soil samples to determine where the dust comes from. Ecologists can assess the effects of both nutrients and toxic elements in the dust on near and distant ecosystems. And dust can now become part of the conversation about conserving and protecting the Great Salt Lake.

“I started off as a scientist and I’m starting to feel more like an advocate for the preservation of the lake,” Perry says. “Most people think that any water that goes into the lake is wasted water because it turns salty and we can’t drink it or use it through irrigation. So, there’s this mindset locally that we should use all the water before it gets to the lake because once it gets to the lake, it’s useless.” But each drop, he says, adds to the unique interconnected environment supported by the waters of the Great Salt Lake.

“I’ll look back on this project with fondness,” Perry says. “While you’re actually doing it, it’s hot, it’s unpleasant, it’s a lot of physical work. But just knowing that there’s this resource out there that we need to protect—I’m glad I’ve done it.”

Find the full report, “Results of the Great Salt Lake Dust Plume Study,” here.