Drying Inland Seas and Disparities in Dust Exposure: A Case Study of the Great Salt Lake

Inland seas globally are diminishing due to heightened human water consumption and the acceleration of climate change. This drying up is emitting harmful dust that contaminates nearby regions during dust storms. A new study, focusing on Utah's Great Salt Lake, uncovers notable differences in dust exposure among various racial, ethnic, and socioeconomic groups.

The research, published on June 21 in the journal One Earth, emphasizes that Pacific Islanders, Hispanic people, and individuals lacking a high school diploma are the most impacted by dust pollution.

Since the mid-1980s, the Great Salt Lake has been steadily drying, exposing its dry lakebed to weathering and wind. Previous studies have shown that dust emissions from drying salt lakes produce fine particulate matter (PM2.5), which is linked to numerous health issues and is the leading environmental cause of human mortality worldwide.

"We know that the dust from these drying lakes is very unhealthy for us, so the question becomes, what does that mean in terms of people's exposure to the dust, and what does it mean in terms of inequalities in exposure to that dust," says first author and sociologist Sara Grineski of the University of Utah. "Are some people more likely to have to suffer the consequences to a greater degree?"

Grineski worked with atmospheric scientists, geographers, and biologists to investigate dust pollution under various scenarios of the Great Salt Lake's water levels—whether the lake continues to dry or is restored to a healthy state. They utilized a model to predict the amount of dust generated by erosion and how it would be distributed by wind across three counties around the lake. These model results were then combined with demographic data from the 2020 U.S. Decennial Census and the American Community Survey to explore the link between dust exposure severity and racial, ethnic, or socioeconomic status.

The study found that during a typical dust storm, residents of the Great Salt Valley are currently exposed to an average of 26 μg/m3 of dust PM2.5. This level surpasses the World Health Organization's threshold of 15 μg/m3 but is below the U.S. National Ambient Air Quality Standards threshold of 35 μg/m3. If the lake were to dry up entirely, the average exposure would increase to 32 μg/m3. Conversely, restoring the lake to a healthy level would reduce average exposure to 24 μg/m3.

The research also revealed that dust exposure levels are not uniform across the population. Exposure was highest among Pacific Islanders, Hispanic people, and individuals without a high school diploma, a socioeconomic status indicator. However, there was no clear link between dust exposure and income level or home ownership.

Raising the lake's level would decrease disparities between groups, thus reducing one form of environmental injustice in the region. Grineski also noted that the valley has other social disparities in pollution exposure.

Looking ahead, the research team plans to investigate how future changes in the region's population size and demographics might influence dust exposure patterns. They hope their findings will guide local policymakers in prioritizing efforts to refill the Great Salt Lake.