Study: Shrinking Salton Sea partially exacerbates air pollution, other issues impacting air pollution

OAKLAND — A study released by the Pacific Institute warns that the rapidly diminishing Salton Sea is unleashing a “breathing hazard,” with increasing dust and air pollution jeopardizing the health of approximately 560,000 residents in southeastern California’s Coachella and Imperial Valleys.

A shrinking lake, growing risk

The report indicates that over the past three decades, the Salton Sea—California’s largest lake—has shrunk by over 70 square miles (19%), driven largely by reduced irrigation runoff from the Colorado River, as water-saving agreements prioritize the protection of downstream reservoirs like Lake Mead and Lake Powell. Less agricultural runoff has led to more exposed lakebed—or “playa”—which is highly prone to dust emissions under wind action.

Strong prevailing winds funnel dust across a region already plagued by poor air quality and elevated respiratory hospitalization rates. The report notes that further reductions in water use could accelerate beach exposure and amplify health risks.

Complex pollution picture beyond the lake

While exposure of playa is a significant driver of airborne dust, the study underscores that the Salton Sea is only one part of a broader air pollution landscape. Surrounding desert terrain, unpaved roads, agricultural burning, diesel traffic, and confined animal feedlots all contribute to a toxic mix—particularly in a region already experiencing high poverty, limited healthcare access, and significant numbers of undocumented residents.

Notably, nearly 70% of particulate matter (PM) in the area comes from diffuse, “fugitive” sources such as wind-blown dust, with an additional 20% attributed to unpaved road emissions. Over 200 toxic air contaminants add to the complexity, including pesticides, black carbon, and hydrogen sulfide—a gas known for its rotten-egg smell that communities downwind of the lake have long reported.

Algal blooms—spurred by nutrient-rich runoff—have become a recurring hazard. A 2021 advisory warned locals to avoid contact with the Salton Sea due to toxic cyanobacteria, and recent research links these blooms to increased hospitalizations in downwind communities.

Health consequences and disparities

The health impacts are stark: ozone, fine dust, hydrogen sulfide, and chemical-laden particles contribute to respiratory distress and other ailments. Children in Imperial and Riverside counties suffer asthma-related emergency department visits at rates approximately 75% above the California average.

Action and attention

Efforts to combat dust include over 3,000 acres of playa stabilization projects initiated by the state—costing $49 million—and similar investments by Imperial Valley’s irrigation district, totaling about $55 million. These interventions reduce dust emissions by more than 75% at treated sites.

Public health improvements are emerging; childhood asthma hospitalization rates have recently dropped to near-state-average levels, though the causes remain unclear.

A dual strategy

Despite progress, the report warns that continuing shrinkage of the Salton Sea, combined with persistent sources of pollution and insufficient structural coordination, means that source-control strategies alone aren’t enough.

It recommends coupling dust suppression and regulatory action with exposure control measures—including weatherizing homes, installing air filters, and issuing dust alerts to guide outdoor behavior.

The authors also call for stronger institutional coordination. They urge the California Environmental Protection Agency to convene a coalition—including air districts, water boards, community representatives, and health experts—to revitalize the 2017 Salton Sea implementation timeline and align funding toward exposure mitigation efforts.

The assessment underscores a growing public health threat emerging from environmental and governance challenges—and the need for comprehensive, community-focused solutions.