Clean Air – Page 2 – Environmental and Energy Law Program

Regulatory Tracker

Ethylene Oxide (EtO) Emissions Standards for Commercial Sterilizers

The Biden EPA strengthened regulation of ethylene oxide (EtO) emissions from commercial sterilization facilities, which environmental groups and industry petitioners challenged in the D.C. Circuit. The Trump EPA plans to roll back the rule and invited industry to apply for exemptions.

March 27, 2025

Regulatory Tracker

Municipal Solid Waste Landfill Air Pollution Emission Standards for Methane and Other Pollutants

MSW landfills are currently subject to EPA’s 2016 New Source Performance Standards and Environmental Guidelines. In October 2024, EPA requested comments in advance of a rulemaking. Comments are due by May 23, 2025.

March 21, 2025

Regulatory Tracker

Regional Haze Rule

EPA is reviewing Regional Haze state implementation plans. The Trump administration announced that it plans to restructure the Regional Haze Program.

March 20, 2025

Regulatory Tracker

National Ambient Air Quality Standards (NAAQS) for Particulate Matter (PM)

The CAA requires EPA to review and set primary and secondary standards for PM NAAQS every 5 years. The Biden EPA strengthened the standard in March 2024, and on March 12, 2025, EPA slated this standard for rollback.

March 12, 2025

Regulatory Tracker

Implementation of 2015 Ozone National Ambient Air Quality Standards (NAAQS)

Under the Trump executive order Regulatory Freeze Pending Review, the Biden administration’s final rule setting deadlines for states to submit SIPs for nonattainment areas did not go into effect.

March 12, 2025

Regulatory Tracker

National Ambient Air Quality Standards (NAAQS) Review

EPA sets NAAQS for six common and harmful pollutants: carbon monoxide, lead, PM, ozone, nitrogen dioxide, and sulfur dioxide.

March 12, 2025

Regulatory Tracker

National Ambient Air Quality Standards (NAAQS) for Ozone

In 2024, EPA agreed in an unopposed motion in the D.C. Circuit to review the ozone NAAQS.

March 12, 2025

Regulatory Tracker

New Source Review

EPA establishes the baseline requirements for new source review permits, which are then issued by state and local air pollution agencies. The Trump EPA has announced it plans to change the NSR program.

March 12, 2025

Regulatory Tracker

Power Plant Startup, Shutdown, and Malfunction Rule

In early January 2025, the Biden EPA withdrew its direct final rule and indicated it would release a subsequent rule addressing the 13 states that failed to submit state implementation plan revisions.

March 4, 2025