Newswise — New research from the University of Utah demonstrates how wind-carried dust from the exposed bed of Great Salt Lake is disproportionately affecting disadvantaged communities in the Salt Lake metro area.
The findings suggest restoring the lake to a healthy water level would reduce disparities in harmful dust exposure experienced by different racial/ethnic and socioeconomic groups, along with delivering other ecological and economic benefits.
Exposure to particulate pollution arising from dry portions of the lakebed is highest among Pacific Islanders and Hispanics and lowest among white people compared to other racial/ethnic groups, according to the findings reported June 21 in the journal One Earth.
This is likely because Salt Lake City’s lower-income neighborhoods are more likely to lie in the path of windblown dust from Great Salt Lake, which has shrunk to less than half its historical size, leaving about 800 square miles of lakebed exposed.
More than two decades of drought and unrelenting upstream diversions have contributed to the decline of the saline terminal lake located immediately west and north of Utah’s main population corridor along the Wasatch Front.
“People here in Utah are concerned about the lake for a variety of reasons—the ski industry, the brine shrimp, the migratory birds, recreation—and this study adds environmental justice and the equity implications of the drying lake to the conversation,” said lead author Sara Grineski, a professor of sociology and environmental studies.
Grineski led an interdisciplinary team of U faculty associated with the Wilkes Center for Climate Science and Policy.
The study analyzed data from the Utah Department of Environmental Quality’s air-quality monitoring network, which screens for fine particulate matter, or PM2.5. Comprised of ultra tiny particles that can penetrate lung tissue, this pollution is linked to myriad health problems, including cardiovascular disease and asthma.
During dust storms, current levels expose residents to 26 micrograms per cubic meter, or μg/m3, of PM2.5 on average, according to the study, significantly higher than the World Health Organization’s threshold of 15 μg/m3. Were the lake to dry up completely, exposure could rise to 32 μg/m3, while restoring the lake could reduce exposure to 24 μg/m3 during these wind events, according to the study.
The study examined four such events in 2022 on April 19, 20 and 21 and May 7, when spikes of recorded PM2.5 coincided with high winds.
For the study, Derek Mallia, a research assistant professor of atmospheric sciences, developed a model for predicting exposure levels for the three counties abutting the lake’s east and south shores—Salt Lake, Davis and Weber, home to 1.8 million residents—under four different lake level scenarios.
“We have to use weather models, since we cannot physically go out to the lake and remove/add water to see how much more/less dust it would emit,” Mallia said. “Models like the one that I developed let us run these hypothetical scenarios.”
The study’s scenarios range from a totally dry lakebed, to very low lake level, to current lake, to ‘healthy’ lake level designated as 4,200 feet above sea level. The lake’s South Arm currently sits at 4,194.4 feet, almost 6 feet higher than the historic low of 4,188.7 registered at the end of 2022.
According to the model, neighborhood disparities in exposure levels would increase when the lake level drops.
“We frame it the converse. Lake levels rise, overall levels of dust go down during the dust events and the gap, especially between Hispanic and Pacific Islander people, narrows with respect to the level of dust exposure for non-Hispanic white people,” Grineski said. “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.”
Her team’s prior research has previously documented disparities of PM2.5 exposure generally in the Salt Lake Valley
“There is a really strong pattern of inequality with respect to race and ethnicity,” she added. “It’s sort of a hopeful finding that if we can raise the lake to a ‘healthy’ level we can at least with respect to lake dust we can reduce some of that inequality.”
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