Addressing Freight Pollution at the Source

Air Pollution, Freight Facility Clusters, and the Role of Indirect Source Rules

Sam Wilson

Published May 27, 2026

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Key Findings

The US freight system disproportionately exposes over 60 million nearby residents and workers to harmful air pollution.
In an uncertain political environment, indirect source rules offer a critical pathway for continued state and local actions that achieve measurable public health benefits.
Indirect source rules can help protect freight impacted communities today while reinforcing momentum toward a modern, sustainable freight system.

Nationwide, over 66 million people—nearly one in five people in the United States—live near freight facilities and corridors.

Growth in e-commerce has driven the construction of larger, increasingly clustered warehouses, and UCS research shows that higher concentrations of nearby warehouses are associated with greater environmental and health impacts in freight-adjacent areas. Because the US freight system largely runs on fossil fuels that pollute the air, people living around freight facilities and corridors are often exposed to elevated levels of harmful pollutants. Public health issues resulting from exposure include chronic and lethal illnesses that disproportionately affect people of color and people with lower incomes.

But indirect source rules (ISRs) for freight hubs can reduce emissions in the near term and direct investments to the people most burdened by freight pollution. This policy tool requires facilities that are pollution sources to begin to address pollution attracted by their operations.

Citation

Wilson, Sam. 2026. Addressing Freight Pollution at the Source: Air Pollution, Freight Facility Clusters, and the Role of Indirect Source Rules. Cambridge, MA: Union of Concerned Scientists. https://doi.org/10.47923/2026.16165

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