Clean Air – Environmental and Energy Law Program

Regulatory Tracker

New Source Review

EPA establishes the baseline requirements for new source review (NSR) permits, which are then issued by state and local air pollution agencies. In 2025 and 2026, EPA made changes to the NSR program easing permitting requirements.

July 6, 2026

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.

June 26, 2026

Regulatory Tracker

Clean Car Rules — Corporate Average Fuel Economy Standards/Greenhouse Gas Standards

The EPA rescinded the Endangerment Finding and all GHG vehicle standards.

June 22, 2026

Quick Takes

A Legal Challenge with Major Implications for Citizen Suits

DOJ intervenes in and moves for dismissal of citizen suit, citing primacy of its own enforcement discretion

June 16, 2026

Legal Analysis

EPA Proposes to Limit Its Responsibility to Revise Hazardous Air Pollution Standards

Analysis of the proposal regarding previously unregulated hazardous air pollutant emission points, the agency’s legal rationale, and the implications for EPA’s broader obligations under the Clean Air Act.

June 9, 2026

Regulatory Tracker

National Ambient Air Quality Standards (NAAQS) for Ozone

On March 12, 2025, EPA announced a reconsideration of the NAAQS.

June 9, 2026

Regulatory Tracker

EPA VOC and Methane Standards for Oil and Gas Facilities

The Biden EPA finalized three rules regulating methane emissions from the oil and gas sector. One of the rules, the Waste Emission Charge, was repealed using the Congressional Review Act. In Sept. 2025, EPA proposed to delay the GHG reporting rules until 2034. In Nov. 2025, EPA finalized the deadline exemptions for certain provisions regulating methane emissions from new and existing oil and gas sources.

June 8, 2026

Regulatory Tracker

Regional Haze Rule

Through two state plan approvals, EPA finalized a new policy that eases all states’ Regional Haze planning obligations. Environmental groups are challenging the approvals.

June 5, 2026

Regulatory Tracker

Hydrofluorocarbons and the Kigali Amendment to the Montreal Protocol

In 2022, the U.S. Senate ratified the Kigali Amendment, which committed the U.S. to reducing the use of HFCs. EPA issued multiple rules to implement the mandate. In Oct. 2025, EPA issued a proposed rule to loosen requirements and compliance deadlines for air conditioning, retail food refrigeration, and other sectors.

May 26, 2026