After historic winter snowfalls, Utahans breathe a sigh of relief at the Great Salt Lake. But they’d better not take too deep a breath – there’s still an immense amount of hazardous dust pollution blowing along the Wasatch Front.
The lake sits at an elevation of 4,193.4 feet above sea level as of Thursday. That’s about 1.5 meters higher than its all-time low in November. However, the lake still has about two meters to swell before reaching a height that will allow it to rise and fall, as is the case with salty terminal lakes, without posing a hazard to industry, wildlife, and public health.
“It doesn’t matter what direction the wind is blowing, someone will get hit by dust from the Great Salt Lake,” said Derek Mallia, an assistant science professor in the University of Utah’s Department of Atmospheric Sciences.
And while the runoff has already been significant this spring, it won’t be enough to stop the dust.
Salt Lake City was devastated by an evening storm on Wednesday, as seen in an eerie time-lapse captured by the US’s MesoWest cameras.
“Dust was kicked up over the Great Salt Lake,” Mallia said. “It looked like it was probably Farmington Bay, which would make sense since most of that part of the Great Salt Lake is exposed.”
Downdrafts from the storm generated winds of up to 50 miles per hour near the Salt Lake airport.
“Unfortunately, it’s difficult to assess how much dust has been raised,” Mallia said. “You would have to run some kind of numerical model. Even so, the air quality looked pretty bad.”
Dust pollution is inherently harmful, damaging the lungs, triggering asthma and causing inflammation. The lake’s sediment also contains hazardous substances such as arsenic and other heavy metals. The impact of these pollutants on Wasatch Front residents remains unknown.
The lake must rise to about 4,200 feet for Farmington Bay to flood again.
Dust-producing winds typically occur in spring and fall, Mallia explained, and they can come from the north and south. Coming from the south and southwest, they blow dry Lake Sevier dust into the Salt Lake Valley while simultaneously blowing Great Salt Lake dust into Weber, Davis, and Box Elder counties.
When the storms come from the north and northwest, the Great Salt Lake dust blows across the Salt Lake Valley. U.S. scientists, including Mallia, have been running forecasts to find out where pollution from these particular storms is worst. They noted that it was having outsized impacts on the west side of the valley, and Wednesday’s storm fit into that pattern.
“If you look at the videos, it looks like this [dust] deposited over the West Valley,” said Mallia, “although it appears that the plume also invaded the eastern part of the valley.”
Communities in western Salt Lake County are already struggling with disproportionate environmental impacts, from mining activities to air pollution. It is a hub for airport, decommissioned train and truck traffic in the vast warehouse district surrounding the Utah Inland Port jurisdiction.
“Long story short, it seems like there is definitely an environmental justice issue here,” said Mallia, who is working on a report that further examines his dust projections and their impacts.
The U.S. Environmental Protection Agency is working on an environmental justice study of the west side of Salt Lake City, one of its first such investigations.
State air quality monitoring equipment recorded a rise in PM 2.5 particulate matter pollution as of 7 p.m. Wednesday when sensors recorded 30 micrograms per cubic meter over a period of about an hour. In comparison, air quality exceeds federal regulatory standards when PM 2.5 reaches 35 micrograms, but that’s an average over a 24-hour period.
“The daily average probably wasn’t that high,” said Chris Pennell, technical analysis manager for the Utah Division of Air Quality. “I think visibility was the most worrisome… Personally, I was driving at 7 o’clock.”
Still, dust levels are typically measured using the coarser PM 10 particles, which the state is not well equipped to track. And those larger particles likely contain harmful heavy metals, Pennell said.
“What we’re trying to do right now is figure out exactly what toxic compounds are in PM 10 and create a database that we can share with other researchers,” he said. “This is obviously an area of concern and we share that concern.”
In this latest session, Utah lawmakers have allocated $232,000 in one-time funds and $44,000 in ongoing funds to help state regulators monitor the dust blowing out of the lake and the hazards it poses .
DAQ scientists like Pennell study wind patterns to understand where to place instruments around the Great Salt Lake and to better map the exposed lake floor.
“We don’t set health standards here at DAQ, we monitor data,” Pennell said. “So what we’re trying to do here is monitor data so health effects can be identified later.”