Understanding Great Salt Lake Dust and Air Quality

The Great Salt Lake is the largest saltwater lake in the Western Hemisphere, fed by the Bear, Jordan, and Weber rivers. The lake is a terminal lake, meaning pollutants build up within it rather than flushing downstream. Sediments in the lakebed contain elevated levels of natural and human-caused compounds, such as arsenic. As the lake dries, more of this sediment is exposed, which can be picked up by wind and affect communities nearby.

The Utah Division of Air Quality (UDAQ) is actively monitoring air quality and conducting research to understand dust from the lakebed and its potential impacts.

Dust and your health

• Dust, particularly small particles called PM₁₀, can affect the respiratory system.
• Larger dust storms can also reduce visibility, making driving and other outdoor activities hazardous. Fortunately, these large events can often be forecasted, giving people time to prepare.
• The exposed lakebed has a fairly solid crust that helps prevent dust from easily becoming airborne.

What we know: Monitoring and dust composition

We monitor dust by tracking particulate matter. We focus on:

• PM₁₀ (Particulate Matter 10 micrometers or less): These particles are 10 micrometers or less in diameter. The EPA’s air quality standard for PM₁₀ is 150 micrograms per cubic meter (μg/m3), measured over a 24-hour average. PM₁₀ primarily affects the upper respiratory system and can trigger conditions like asthma.
• PM_2.5 (Particulate Matter 2.5 micrometers or less): These are even finer particles, 2.5 micrometers or less in diameter. While PM_2.5 can enter the bloodstream, PM₁₀ is the main concern for upper respiratory impacts.

What’s in the dust? 

We analyze collected dust for heavy metals like arsenic. Here’s what our monitoring shows:

• We have been analyzing PM₁₀ for heavy metals at one of our stations for over a decade.
• Historical data shows no increase in airborne arsenic or other heavy metals as Great Salt Lake levels have decreased.
• Our highest recorded arsenic level is well below health thresholds set by California’s health standards – specifically, 100 times below these thresholds.
• Many elements in the dust are naturally occurring and not all are “bioavailable,” meaning they cannot be absorbed by the human body.

Environmental impacts

Dust from the Great Salt Lake and other sources in Utah can contribute to faster snowmelt in the spring. This happens when dust lands on mountain snow, making it darker and less reflective, which impacts Utah’s water supply.

What we’re doing 

We are actively working on several fronts to address Great Salt Lake dust concerns, in coordination with the Office of the Great Salt Lake Commissioner (a state government office dedicated to managing and protecting the lake) and other partners:

1. Expanding our dust monitoring network

• We continuously monitor PM₁₀ year-round at various monitoring stations across the state (including Bountiful Viewmont, Hawthorne, and the Utah Technical Center). The Roosevelt monitoring station (in the Uinta Basin, a region in northeastern Utah) includes both filter and continuous PM₁₀ monitoring.
• Thanks to recent legislative funding, we’ve added four new PM₁₀ filter monitors to stations closer to the Great Salt Lake. These include stations in specific areas near the Great Salt Lake (Lake Park, Prison, and Brigham City), with an additional monitor at Bountiful Viewmont to increase sampling frequency from every six days to daily.
• We collect samples from February 1 through September 30th to capture dust during the most likely periods (spring and fall). If these monitors capture dust events, the filters will be sent to a laboratory for compositional analysis. These monitors will aid in characterizing a Great Salt Lake dust signal, determining if the number of dust events or the severity of those events is increasing, and what the composition of the dust is. This information can help inform health exposure studies.

2. Supporting new research

• A state-led “Utah Dust group” was formed to guide research and ensure effective use of legislative funding appropriated for this topic. The group has been meeting regularly to design studies and discuss the best approaches for monitoring dust.
• Legislative funding also supports comprehensive research efforts. This includes analyzing daily filter samples from PM monitors and conducting a historic analysis of past filters to understand dust composition, especially during dust events.
• We fund dust-specific research through our Science for Solutions grant (a UDAQ research funding program).
  • Learn more about completed research projects like “Projecting the Impacts of a Shrinking Great Salt Lake on Dust Exposure along the Wasatch Front” (Mallia, University of Utah) and “Characterizing Air Quality Impacts from Exceptional Events along the Wasatch Front” (Carling, Adams, Brigham Young University).
• We support a project called WestSide AirSense, our local initiative, that has deployed low-cost PM sensors to provide real-time air quality data, particularly for communities near the Great Salt Lake, helping residents make informed decisions about outdoor activities.
• The Great Salt Lake Basin Integrated Plan (a state-led effort) is exploring ways to increase water levels and reduce dust and funds research annually.

3. Planning and policy development

• We are charged with the responsibility of implementing the Clean Air Act in the state of Utah. The Clean Air Act requires agencies to develop long-term plans and rules for how to deal with poor air quality when the monitored air quality within a region does not meet the NAAQS for a specific criteria pollutant.
• The air quality in the Wasatch Front area (Utah’s primary metropolitan region) around the Great Salt Lake is currently in attainment for PM₁₀, which means it meets the federal standards set by the EPA. We also expect that areas currently classified as PM_2.5 nonattainment areas (where air quality does not yet meet federal standards) will soon be redesignated to attainment status, as we are actively working to meet and maintain those clean air goals.
• We are working together with state, federal, and local government agencies, non-profit organizations, academic institutions, industry representatives, and the public as part of the broader State effort to protect the Great Salt Lake. You can find more information about these Great Salt Lake management partners on the Great Salt Lake website.

Frequently Asked Questions (FAQs)

Why is Great Salt Lake dust a concern? 

Dust can negatively impact air quality and human health, particularly respiratory health. The dust can contain harmful substances and contribute to particulate matter pollution.

What is Great Salt Lake dust made of? 

Dust from the Great Salt Lake playa is composed of dried lakebed sediments, including various minerals and other particles.

How do we know what the dust is made of? 

Filters sample PM₁₀ and PM_2.5 particles in the air and are collected at a subset of our PM₁₀ and PM_2.5 regulatory air quality monitoring stations. The filters are regularly collected from these sites and analyzed for their mass and composition. This analysis helps to inform us on the makeup of the dust that may be blown into communities from the Great Salt Lake.

Is the dust from the Great Salt Lake toxic? 

While sediments from the Great Salt Lake have elevated levels of compounds like arsenic, historical data from over a decade of monitoring shows no increase in airborne arsenic or other heavy metals as lake levels have decreased. The highest arsenic levels detected are well below health thresholds, approximately 100 times below those set by California’s health standards. Research on the health impacts of dust is ongoing.

What is the difference between PM₁₀ and PM_2.5? 

PM₁₀ refers to particulate matter with a diameter of 10 micrometers or less. PM_2.5 refers to even finer particles, with a diameter of 2.5 micrometers or less. Both can be inhaled and pose health risks. PM₁₀ primarily affects the upper respiratory tract, while PM_2.5 can enter the bloodstream.

Where can I find real-time air quality data for my area? 

We support projects like West Side Air Sense, which provides real-time air quality data from low-cost sensors, particularly for communities near the Great Salt Lake. We encourage residents to check air quality forecasts and the Air Quality Index (AQI) at air.utah.gov before outdoor activities.

Technical information

• Our monitoring network:

• National Ambient Air Quality Standards (NAAQS) Details: We work to ensure air quality in the state meets the NAAQS set by the Environmental Protection Agency (EPA). This includes standards for particulate matter, specifically PM₁₀ and PM_2.5. The PM₁₀ standard of 150 μg/m3 over a 24-hour period, which cannot be exceeded more than once over a three-year period, is regularly reviewed by the EPA’s Clean Air Scientific Advisory Committee (CASAC). It was most recently reviewed in 2024, and the EPA decided to retain the current standard without revision.
• Specific research projects:
  • “Projecting the Impacts of a Shrinking Great Salt Lake on Dust Exposure along the Wasatch Front” (Mallia, University of Utah)
  • “Characterizing Air Quality Impacts from Exceptional Events along the Wasatch Front” (Carling, Adams, Brigham Young University)
• Research funding opportunities: Find information about our funding opportunities associated with Great Salt Lake dust research.
• Future information: We will add details from new dust studies as they become available.