Federal Court Rules EPA’s Fine Particulate Standards “Unsupported”

A federal court on Tuesday sided with 13 states that had challenged the U.S. Environment Protection Agency’s (EPA) annual air quality standard for microscopic pollutants known as particulate matter or soot, ruling that the government’s standards were “unsupported” by “reasoned decision-making.”

In a 2006 petition filed with the U.S. Court of Appeals for the District of Columbia Circuit, the states challenged a then-new rule adopted by the federal government, which set both daily and annual standards for airborne particulate matter.

The rule toughened the daily National Ambient Air Quality standard for particulate matter. However, it left the annual standard for the same pollutants—15 micrograms per cubic meter—unchanged, contrary to the advice of the EPA’s own Clean Air Scientific Advisory Committee. The Advisory Committee had recommended a standard of between 13 and 14 micrograms.

The states took issue with the EPA’s having ignored its own committee. They also contended that the EPA had failed to meet its legal obligation under the Clean Air Act to set limits on air pollutant concentrations that are adequate to protect public health with a margin of safety.

On Tuesday, the federal court said in a per curiam decision (PDF) that the government’s standards for fine particulate matter are “in several respects contrary to law and unsupported by adequately reasoned decision-making.” The court directed the EPA to revisit its standards to ensure they protect public health with a margin of safety, and to provide scientific support for its ultimate determination.

“This ruling validates our original contention that the EPA, under its former leadership, abdicated its legal responsibility under the Clean Air Act,” said New Jersey Attorney General Anne Milgram in a press release Tuesday. “The decision is important because it clears the way for EPA, under new leadership, to issue new, more stringent standards for fine particulate matter. Having adequate standards—with a margin of safety as required by federal law— is vital to our environment and, most importantly, to the health of New Jersey residents.”

Particulate matter is the general term used for a mixture of solid particles such as dust, ash and smoke in the air. Found in a variety of emissions, including those from power plants, automobiles, wood combustion, and diesel engines, particulate matter has been linked to debilitating lung and cardiovascular illnesses when breathed in high concentrations or inhaled consistently over extended periods of time.

The particulate matter regulated by the EPA is the smallest type—less than 2.5 microns in diameter (PM2.5).

Challenging the EPA’s standards were New Jersey, California, Connecticut, Delaware, Illinois, Maine, New Hampshire, New Jersey, New Mexico, New York, Oregon, the Pennsylvania Department of Environmental Protection, Rhode Island, Vermont, the District of Columbia, and the South Coast Air Quality Management District.

Sources: New Jersey Office of the Attorney General, U.S. Court of Appeals for the District of Columbia Circuit