Court throws out US EPA’s ozone and particulate regulations

The decision means the EPA must develop new regulations for particulate matter, and cannot enforce its ozone standards under the Clean Air Act.

The court argued that the Clean Air Act does not give the EPA unlimited power to set air quality standards for ozone and particulate matter. The EPA’s actions were described by the court as an “unconstitutional delegation of legislative power,” because Congress had not awarded the Agency the authority to set regulations in this way.

The court’s decision prevents the EPA from implementing a more stringent ozone standard (0.085 parts per million (ppm) while the existing standard (0.12 ppm) has not been met.

The court also denounced as “arbitrary and capricious” the EPA’s use of the measure of particulate matter smaller than 10 microns in diameter (PM10) as a surrogate measure for all particles ranging from 2.5 to 10 micrometers (PM2.5 to PM 10).

In addition, the court declared that the EPA had only taken into account the detrimental health effects of ground-level ozone, while ignoring its beneficial effects.

The court therefore has ordered the EPA to review and revise the standards and took jurisdiction over the case to monitor the Agency’s ensuing actions.

An EPA statement pointed out that the ruling does not question the science underlying the standards, and that the panel had questioned the constitutionality of the primary public health provisions of the Clean Air Act.

The statement indicates that the EPA is recommending an appeal to the US Department of Justice. The EPA has 45 days to appeal.