Legal strategies to minimize subway air pollution in the United States

Air pollution in U.S. subway systems poses a major threat to public health. People in subway stations breathe in dangerously high levels of dusts, called particulate matter. Current legislation does not effectively address this problem; in fact, the United States does not have a comprehensive indoor air quality law at all. Left unregulated, people regularly exposed to subway air pollution could suffer respiratory and cardiovascular issues and even premature death. To mitigate these health effects, some countries have imposed PM standards in subway systems and underground spaces. Others have standards covering all indoor spaces. In the United States, many subway systems have begun exploring technologies to filter subway air in the wake of the coronavirus pandemic. To support their efforts and innovation, the United States should enact legislation establishing a grant and loan program for subway systems' air-purifying initiatives. Modeled after the successful Diesel Emissions Reduction Act, this law would adopt a carrot-based approach to effectively reduce subway air pollution, allowing each system to tailor initiatives to their unique characteristics. While the United States should explore a mandatory standards-based approach long term, it should prioritize this legislation to protect the public more quickly from this ongoing threat.