Massachusetts Attorney General Andrea Joy Campbell announced on April 24 that she has joined a coalition of states, the District of Columbia, and two local governments in filing a lawsuit against the United States Environmental Protection Agency (EPA). The suit challenges the EPA’s failure to implement a 2024 Clean Air Act rule that strengthens national ambient air quality standards for fine particulate matter, also known as soot.
The issue is significant because fine particulate matter poses serious health risks. Soot particles are small enough to enter deep into the lungs and bloodstream, leading to health problems such as heart attacks, asthma attacks, cancer, and shortened lifespans. These effects disproportionately impact low-income communities and communities of color.
“Massachusetts residents deserve to breathe clean air. I am proud to be filing a lawsuit against the U.S. Environmental Protection Agency for its failure to implement its own lifesaving 2024 Clean Air Act rule strengthening national ambient air quality standards for fine particulate matter, commonly known as soot,” Campbell said. “My office will continue its work to enforce critical federal environmental regulations that protect our residents’ health and wellbeing.”
According to EPA estimates cited in the press release, full attainment of the updated standard could prevent thousands of premature deaths and new cases of asthma each year while saving billions in healthcare costs. In February 2025, however, EPA missed its deadline for designating areas out of compliance with these new standards—a step necessary for states like Massachusetts to access resources aimed at reducing cross-border pollution.
The coalition’s lawsuit alleges that this delay violates the Clean Air Act and undermines efforts by states and local governments—especially those serving vulnerable populations—to reduce dangerous air pollution levels. While Massachusetts currently meets existing air quality standards and expects continued compliance with updated rules, state data show significant harm from soot exposure: In 2019 alone it contributed to nearly 2,780 adult deaths from causes including cardiovascular disease and lung cancer.
The Massachusetts Supreme Judicial Court acts as the final authority on state law and handles appellate jurisdiction over lower court decisions according to the official website. The court is recognized as the oldest continuously functioning appellate court in the Western Hemisphere according to its official website, operates within the Commonwealth according to its official website, contributes educational outreach about judicial processes according to its official website, oversees regulation of legal practice while supporting public access to opinions according to its official website, and provides advisory opinions on key legal issues when requested by government leaders according to its official website.
The coalition is asking a federal court both to declare EPA’s actions unlawful and require designation decisions within 150 days if ordered by the court.
