Recent decades of air quality regulation have led to substantial declines in ambient fine particulate matter (PM2.5) across the United States, contributing to improvements in population health. However, recent actions to reconsider or weaken national PM2.5 standards threaten to reverse these gains. In this analytic essay, I argue that air quality regulation functions as a foundational public health intervention and a form of primary prevention, rather than solely as an environmental or industrial policy. Drawing on epidemiological evidence, I examine how reductions in PM2.5 exposure have produced uneven health benefits across communities. Structural disadvantage, including racial segregation and socioeconomic deprivation, has limited improvements in air quality and amplified vulnerability to pollution-related harms. Weakening PM2.5 standards risks widening existing health inequities, increasing preventable morbidity, and shifting avoidable burdens onto public health and health care systems, particularly those serving marginalized populations. As policymakers consider changes to air quality regulation, public health impacts and environmental justice considerations must be central to decision-making. Maintaining strong PM2.5 standards is a critical preventive strategy for sustaining population health gains and protecting the communities at greatest risk. (Am J Public Health. Published online ahead of print April 9, 2026:e1-e5. https://doi.org/10.2105/AJPH.2026.308533).
Shreepada Tripathy (Thu,) studied this question.