Press Release  AG Campbell Sues Trump Administration Over Failure to Implement Lifesaving Soot Standard

BOSTON — Massachusetts Attorney General Andrea Joy Campbell today joined a coalition of 11 states, the District of Columbia and two local governments in filing a lawsuit against the United States Environmental Protection Agency (EPA) over its failure to implement a lifesaving 2024 Clean Air Act rule that strengthens national ambient air quality standards (NAAQS) for fine particulate matter (PM2.5), commonly known as soot. 

“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,” said AG Campbell. “My office will continue its work to enforce critical federal environmental regulations that protect our residents’ health and wellbeing.”   

Soot is a deadly air pollutant emitted by combustion-engine vehicles, factories, and construction sites. These pollutants are typically 30 times smaller than the width of an average human hair. Because of the particles’ small size, once inhaled, soot can penetrate the lower parts of lungs, infect the bloodstream, and damage other organs, leading to myriad health problems including shortened lifespans, heart attacks, asthma attacks, and cancer. These health effects fall disproportionately on low-income communities and communities of color. 

Under the Clean Air Act, EPA is required to set NAAQS for several pollutants, including fine particulate matter, at a level that protects public health and welfare. When NAAQS are updated, the Clean Air Act gives EPA a specific deadline to identify areas of the country that are out of compliance, designating them as “nonattainment.” This designation provides key support for state programs focused on lowering dangerous air pollution levels. 

Reductions in soot exposure are directly linked to longer life expectancies and lower mortality risks. In 2024, EPA strengthened the soot NAAQS based on overwhelming scientific evidence. According to its own estimates, EPA has reported that the first year alone of full attainment of the 2024 NAAQS will avoid 4,500 premature deaths, 2,000 emergency room visits, 5,700 new cases of asthma, 800,000 cases of asthma symptoms, and 1,000 hospital admissions for Alzheimer’s/Parkinson’s diseases. The associated health benefits outweigh the estimated costs of implementation by $46 billion.  

In February 2025, EPA missed its deadline for designating areas with soot levels that exceed the 2024 standard, denying Massachusetts and other coalition states important access to resources that would reduce air pollution that crosses into their borders from upwind states. The coalition’s lawsuit alleges that EPA’s failure violates the Clean Air Act and undermines the ability of states and local governments to reduce levels of fine particulate pollution in the air—especially in low-income communities and communities of color, who are disproportionately impacted—and to achieve significant public health benefits including reduced premature deaths, mortality, and healthcare and administrative costs. 

While Massachusetts currently meets existing air quality standards and expects to remain in compliance with the updated 2024 ones, communities have not been spared from the harms of soot pollution—including pollution from upwind states. In 2019 alone, particulate matter exposure was responsible for approximately 2,780 adult deaths in Massachusetts, including more than 1,600 from cardiovascular disease and 2,185 from lung cancer. That same year, soot exposure contributed to more than 300 low-weight births, more than 15,000 new asthma cases, and a provisionally estimated loss of nearly 2 million Performance IQ points among children. In 2023, the Attorney General’s Office expanded the Pioneer Valley Healthy Air Network, a program that installs air quality monitors in the Pioneer Valley – a region that has been disproportionately impacted by environmental injustices like air pollution and asthma. 

The coalition is asking the Court to declare EPA’s failure to implement the 2024 standard unlawful and compel EPA to make attainment designations within 150 days of the court order.  

Joining AG Campbell in filing this lawsuit are the attorneys general of California, Connecticut, Hawaii, Maryland, Minnesota, New York, Oregon, Rhode Island, Vermont, Wisconsin, and the District of Columbia, as well as Harris County and the City of New York. 

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