Center for Biological Diversity

For Immediate Release, April 13, 2022


Robert Ukeiley, Center for Biological Diversity, (720) 496-8568,
Kaya Allan Sugerman, Center for Environmental Health, (510) 740-9384,

Lawsuit Aims to Push EPA to Set New Limits on Soot, Sulfur, Nitrogen Pollution

OAKLAND, Calif.— Environmental groups filed a lawsuit today to force the Environmental Protection Agency to update limits on harmful soot, sulfur and nitrogen air pollution.

The agency last put new standards in place for the three pollutants in 2012 and 2013. Updates were due in 2017 and 2018.

“Since the EPA’s last review of these pollution standards, the science behind the ecological harm from soot, sulfur and nitrogen air pollution has become more certain,” said Robert Ukeiley, a senior environmental health attorney at the Center for Biological Diversity. “This new science can’t be used to protect the environment until the EPA follows the law and updates these important pollution standards.”

The Clean Air Act requires the EPA to set health- and welfare-based “national ambient air quality standards” for air pollutants like sulfur oxides, nitrogen oxides and particulate matter, commonly known as soot. Welfare-based standards address harmful impacts to wildlife, crops, soils, vegetation, climate and visibility.

The standards must be reviewed every five years to account for the latest science on the risks and threats to the environment.

The agency’s latest update and review of the welfare-based standards for sulfur oxides and nitrogen oxides was in June 2012; new standards were due in June 2017. The EPA last updated the particulate matter welfare-based standards in March 2013, so new updates to those standards were due in March 2018.

“EPA has a duty to listen to the science,” said Kaya Allan Sugerman, the Center for Environmental Health’s director of illegal toxic threats. “It is imperative that EPA uses new available research and findings to err on the side of protecting people’s health, welfare and the environment.”

Sulfur pollution is primarily released into the air by burning coal. It contributes to acid rain, threatening vulnerable aquatic plants and wildlife, and increases plant mortality and reproductive harm on land.

Acidification of aquatic ecosystems harms the endangered whooping crane by depleting its food resources. The whooping crane’s preferred prey, such as aquatic insects, crayfish and frogs, are vulnerable to acidic waters.

Nitrogen oxides are produced by burning fossil fuels and contribute to ozone formation, acid rain, nutrient pollution and poor visibility. Nutrient pollution increases harmful algae growth in aquatic ecosystems, which decreases life-sustaining levels of oxygen in waterbodies; nutrient pollution in groundwater can also contaminate drinking water.

Sources of soot include the burning of fossil fuels and fracking. Reduced visibility and haze are primarily caused by soot, which damages forests and crops by reducing nutrients in soil.

The lawsuit was filed in the U.S. District Court for the Northern District of California.

Whooping cranes/William R. Gates/USFWS Image is available for media use.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

The Center for Environmental Health works with parents, communities, businesses, workers, and government to protect children and families from toxic chemicals in homes, workplaces, schools and neighborhoods.

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