As the Great Salt Lake shrinks, dust from its lakebeds impacts the air that millions on the Wasatch Front breathe.
That dust contains fine particulate matter that can cause lung irritation, cardiovascular disease, gastrointestinal problems and cancer. But because of a gap in monitoring, researchers don’t yet know how bad the problem actually is — even though the state has provided funding to find out.
“People always ask me, ‘How often are these dust events?’ I don’t know,” said Kevin Perry, an expert on Great Salt Lake dust. “‘Are they getting worse?’ I don’t know. ‘Are they causing a health impact?’ I don’t know, because we don’t have the data.”
Perry said that the state isn’t monitoring enough for PM10, a type of particulate matter that makes up the majority of dust coming off of the Great Salt Lake, leaving him unable to answer questions about the dust’s danger.
He co-authored a recent study from the University of Utah, which found that Great Salt Lake dust is disproportionately harming communities of color. In that study, Perry had to use data about another type of particle — called PM2.5 — because of the lack of PM10 data.
Great Salt Lake dust consists of six times more PM10 than PM2.5. And while the state does have some monitors for PM10, it has three times the monitoring sites for PM2.5 — and existing PM10 monitors aren’t located near the people affected by dust events, Perry said.
The Legislature gave the Utah Division of Air Quality over $275,000 for five new PM10 samplers in communities around the Great Salt Lake in February 2023.
As of July 2024, the state hasn’t installed any.
“What we’re trying to do is use the funding in the best way possible,” said Chris Pennell, a technical analysis manager at the Division of Air Quality.
“We really just want to get it right and make sure that we’re purchasing the right instruments that are going to be able to answer the questions the best we can,” he added.
Dust poses a higher risk to disadvantaged communities
The recent University of Utah study, published in the journal OneEarth last month, found that Pacific Islanders and Hispanics tend to be most exposed to particulate pollution from the Great Salt Lake, while white people are generally the least exposed. People without a high school diploma also experience higher rates of exposure.
Exposure increases as the Great Salt Lake shrinks, baring more lakebed, the study said. Right now, 800 miles of the lake’s former lakebed are uncovered by water.
“If we can take better care of the lake, the dust for everyone goes down and the gap in exposure between these groups goes down too,” said Sara Grineski, the study’s lead author.
For the study, researchers looked at dust storms from April and May 2022, when increases in PM2.5 occurred simultaneously with strong wind. They used data from the Utah Department of Environmental Quality’s PM2.5 monitors.
PM2.5 particles are less than or equal to two and a half micrometers in diameter. Because they’re so small, they can travel deep into the lungs and other human tissues.
PM10 particles — less than or equal to 10 micrometers in diameter — are larger than PM2.5 particles. Though less penetrative than PM2.5, PM10 still poses a serious health risk; about half of inhaled PM10 ends up in the lungs.
“There’s no difference between PM10 an PM2.5 from a health perspective,” Perry said.
Great Salt Lake dust events — majority PM10 — occur about 15 times a year, experts currently estimate. But Perry added that they can’t be certain.
“Because we don’t have a robust PM10 network, I can’t tell you how many times a year these events happen,” he said.
Gaps in PM10 monitoring
Existing PM10 monitors are poorly placed to observe dust from the Great Salt Lake and far from the communities most impacted by its pollution, Perry said.
The Division of Air Quality operates PM10 monitors across northern Utah. Seven are located in Salt Lake, Utah and Weber counties, and there is one monitor in the Uinta Basin.
But Perry explained that most strong winds push dust into cities in Davis County, like Brigham City, Layton and Syracuse.
Pennell, with the Division of Air Quality, said that his agency monitors PM10 to ensure compliance with federal standards, which informs where they place monitors.
When the Division of Air Quality asked the Legislature for PM10 monitor funding in 2023, it acknowledged that exposure to arsenic and other toxic metals from Great Salt Lake dust remained unclear due to a lack of data.
“This request is to fund the testing for arsenic and other heavy metal in those filters,” the 2023 appropriations request read. “This data will fill in the gaps so we can better understand the extent to which communities have been exposed in the past and help inform mitigation efforts going forward.”
When asked about the delay in purchasing and installing the state-funded PM10 monitors, Pennell said that consulting with experts at federal agencies and universities has taken time. He added that it is also difficult to determine where to place the monitors.
“The monitors that we’re discussing are higher-grade monitors and we really want to get it right,” he said.
Pennell confirmed that the Division of Air Quality has placed an order for three new PM10 monitors using the 2023 funding from the Legislature. The division also already has two PM10 monitors that have not been installed, he said, but that it plans to deploy.
A Division of Air Quality spokesperson said that the division expects to have the new PM10 monitors operating by spring 2025 at the latest.
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