What’s behind northern Utah’s ‘brown clouds’? New study pinpoints a major source

Jan 27, 2023, 9:46 AM | Updated: 9:52 am
A photo of the U.S. Magnesium refinery in Tooele County on Jan. 27, 2017. The plumes from the plant...
A photo of the U.S. Magnesium refinery in Tooele County on Jan. 27, 2017. The plumes from the plant had higher levels of chlorine and bromine, which boosted PM 2.5 levels in the area, according to a new study led by the National Oceanic and Atmospheric Administration. (National Oceanic and Atmospheric Administration)
(National Oceanic and Atmospheric Administration)

SALT LAKE CITY — A magnesium plant located near the Great Salt Lake is a major producer of chemical elements behind the “dense winter brown clouds” that sometimes hang over Salt Lake City and other parts of Utah’s northern half in the winter, a new federal study determines.

The study, led by the Cooperative Institute for Research in Environmental Sciences, finds that the US Magnesium plant in Tooele County produced high levels of chlorine and bromine during a study in 2017. Researchers say the chemicals were “significant contributors” to the clouds forming and boosting particulate matter levels by 10-25% in the Wasatch Front area during a winter inversion period.

“(The plant) is known to be a high emitter of chlorine issues but what was really interesting about this study was that we found a lot of bromine species,” Carrie Womack, a National Oceanic and Atmospheric Administration scientist, the study’s lead author, said in an interview with KSL NewsRadio on Thursday.

“The reason that’s interesting is that the (Environmental Protection Agency) requires facilities to report their chlorine emissions but they don’t require them to report their bromine emissions,” she added. “Bromine is playing a huge role in this build-up of PM 2.5.”

Womack also said that her team also found a “complete disappearance of all of the ozone” in the area, which is something that typically occurs in the Earth’s polar regions and had not been seen before “this far south.”

Her team’s findings were published in the Environmental Science and Technology on Wednesday.

Understanding the pollution within winter inversions

The study itself offers an analysis of plume samples collected via NOAA research flights in January and February 2017. Womack led a team of researchers in a study of winter air pollution in the Salt Lake, Utah and Cache valleys and other areas in between, including the Great Salt Lake.

Researchers wanted to study the area because a few Intermountain West valleys experience particulate matter levels that exceed federal standards more often than other areas of the country. For instance, the Salt Lake Valley averages 18 days of poor air quality days every year, especially during the winter inversion period.

“Our goal was to try and understand how those emissions turn into particulate matter,” Womack said.

High particulate matter levels can have lung and heart health consequences. A 2012 study led by the University of North Carolina Gillings School of Global Public Health found that there was a spike in asthma-related emergency room visits in the Salt Lake Valley during winter inversions, based on data collected from 2003 to 2007.

Womack and researchers at the University of Utah, the University of Toronto, the University of Washington and the EPA began sifting through the data and found many familiar particulate matter origins: pollution from industrial, agricultural and traffic sources. All of these are major factors in pollution production that have been warned about for years.

A previously unknown player

However, the US Magnesium plant also stuck out in the data, Womack said. Researchers had passed the plant as they flew across the Great Salt Lake on their first flight because it was already a “known source of pollutants in the area,” she said, adding that the air even smelled like bleach in the area.

The high bromine levels surprised them, though, as they had never been reported. While state and federal government agency track chlorine and nitrogen oxide emissions, they do not track bromine, an element naturally found in the earth’s crust and in seawater that can cause health problems if transmitted in high-enough doses.

The team’s modeling indicated that chlorine and bromine levels, which were high near the plant, were significantly boosting the region’s particular matter counts. Womack explained it is because the two chemicals are “very effective” at turning other pollutants into particulate matter, which residents see in the form of “brown clouds” during an inversion.

A diagram depicting the change in surface PM 2.5 levels because of halogen emissions, including chlorine and bromine, based on flights over the region in the winter of 2017. (Photo: Caroline Womack, National Oceanic and Atmospheric Administration)

“It was surprising to us how much this one facility was contributing to the PM 2.5 but there are a lot of other sources in the area,” Womack said, adding that the plant may be the largest chlorine emitter in the United States, but it’s unclear how it ranks in bromine because that chemical is not federally tracked.

Researchers also found a lack of ozone near the plant, as a result of the halogenated compounds. This is due to sunlight activating the halogenated compounds “into becoming these very reactive chemical species,” Womack said.

Updating pollution tracking?

It’s unclear what the finding means for health. The researchers say that could be something to study more in the future. They also believe more studies could be done to further understand what role bromine or the magnesium plant has on the region’s air quality.

Meanwhile, a Utah Department of Environmental Quality spokesman wrote in an email to KSL.com that the study could help the Utah Division of Air Quality improve its quality monitoring practices in the future.

“Halogen emissions, such as chlorine and bromine, could impact summertime ozone and wintertime PM2.5 pollution along the northern Wasatch Front. Being able to accurately estimate chlorine and bromine emissions in northern Utah could help (the division) refine their regulatory air quality modeling and better inform policy decisions,” the agency wrote.

US Magnesium LLC did not return KSL’s call for comment by press time. It is the largest producer of magnesium in North America. Magnesium is often used in all sorts of products like car seats, laptops, power tools and even fireworks, according to the Royal Society of Chemistry.

The company also made headlines last month after the Utah Division of Water Quality denied US Magnesium’s request for a canal continuation project by the Great Salt Lake, citing “insufficient information” provided by the company.

KSL 5 TV Live

Top Stories

Local News

Police lights...
Cassidy Wixom, KSL.com 

Utah man dies in small-airplane crash in rural Wyoming

A Cache County man has been identified as the person killed in a plane crash that happened outside of Casper, Wyoming, earlier this week.
1 day ago
Three people died in this Kane County crash...
Andrew Adams

Family remembers two loved ones killed in crash near Kanab

Family members on Thursday remembered loved ones killed in a triple-fatal crash in Kane County.
1 day ago
SNOTEL snow survey...
Lauren Steinbrecher

Utah will likely set historic snow record Friday

Thursday was on track to make history in Utah, with the snowpack ready to inch past a 40-year-old record. It all came down to a tenth of an inch.
1 day ago
Granite District K9...
Matt Rascon, Eliza Pace, and Lauren Steinbrecher

KSL+: Guns at schools and what’s being done about it?

Amid an increase in gun threats and incidents at some Utah schools, one school district is taking matters into its own hands to try and keep students safe.
1 day ago
Lamont Dorrity...
Ayanna Likens

How exercise helps with Parkinson’s disease

Parkinson's disease is affecting more and more people across the nation. While there is no cure, one thing is showing promise in improving symptoms.
1 day ago
Clearing Little Cottonwood Creek...
Jed Boal

Creek clearing is underway in Salt Lake to minimize threat of flooding

Many Utah communities are working proactively to minimize flooding that may happen when the snowmelt runoff really gets going in the next couple of months.
1 day ago

Sponsored Articles

Happy diverse college or university students are having fun on their graduation day...
BYU MBA at the Marriott School of Business

How to Choose What MBA Program is Right for You: Take this Quiz Before You Apply!

Wondering what MBA program is right for you? Take this quiz before you apply to see if it will help you meet your goals.
Close up of an offset printing machine during production...
Les Olson IT

Top 7 Reasons to Add a Production Printer to Your Business

Learn about the different digital production printers and how they can help your company save time and money.
vintage photo of lighting showroom featuring chandeliers, lamps, wall lights and mirrors...
Lighting Design

History of Lighting Design | Over 25 Years of Providing Utah With the Latest Trends and Styles

Read about the history of Lighting Design, a family-owned and operated business that paved the way for the lighting industry in Utah.
Fiber Optical cables connected to an optic ports and Network cables connected to ethernet ports...
Brian Huston, CE and Anthony Perkins, BICSI

Why Every Business Needs a Structured Cabling System

A structured cabling system benefits businesses by giving you faster processing speeds and making your network more efficient and reliable.
notebook with password notes highlighted...
PC Laptops

How to Create Strong Passwords You Can Actually Remember

Learn how you can create strong passwords that are actually easy to remember! In a short time you can create new ones in seconds.
house with for rent sign posted...
Chase Harrington, president and COO of Entrata

Top 5 Reasons You May Want to Consider Apartment Life Over Owning a Home

There are many benefits of renting that can be overshadowed by the allure of buying a home. Here are five reasons why renting might be right for you.
What’s behind northern Utah’s ‘brown clouds’? New study pinpoints a major source