The Division of Air Quality will conduct a public hearing (Docket #2026-R-A-0007) on a proposed State Implementation Plan (SIP) revision. Public comment period open through Nov. 12, 2026.

On February 7, 2024, and December 11, 2024, the Environmental Protection Agency (EPA) promulgated a revised annual primary fine particulate matter (PM_2.5) and secondary sulfur dioxide (SO₂) National Ambient Air Quality Standards (NAAQS), respectively. The EPA changed the annual primary PM_2.5 NAAQS from 12.0 micrograms per cubic meter (µg/m³) to 9.0 µg/m³ and the secondary SO₂ NAAQS from 0.5 parts per million as a 3-hour average, not to be exceeded more than once in a year, to an annual standard with a level of 10 parts per billion, averaged over 3 years.

The Clean Air Act requires states to submit an infrastructure plan within three years after the promulgation of a revised or new NAAQS. Infrastructure plans address how states will implement, maintain, and enforce the 2024 annual primary PM_2.5 and secondary SO₂ NAAQS. This proposed infrastructure plan demonstrates that Delaware has the legal and programmatic infrastructure in place to enforce the 2024 PM_2.5 and SO₂ standards.

To view the proposed SIP revisions visit regulations.delaware.gov/register/current_issue beginning Oct. 1, 2026. For any questions or to view the proposed SIP revisions in person, by appointment-only, contact Jasmine Steward, at Division of Air Quality, 100 W Water St, Dover, Delaware, 19904, or via phone 302-739-9402 or by email at Jasmine.Steward@delaware.gov.

Those wishing to offer verbal comments the hearing must pre-register no later than noon on Oct. 28, 2026, at de.gov/dnreccomments or by telephone at 302-739-9034.

The Department will accept public comment through Nov. 12, 2026. Comments will be accepted in written form via email to DNRECHearingComments@delaware.gov, using the online form at de.gov/dnreccomments, or by U.S. mail to the address on this page.

Public Hearing Officer: Theresa Smith
DNREC Office of the Secretary
89 Kings Highway
Dover, DE 19901

Proposed DNREC Exhibits

Exhibit 1: Environmental Protection Agency’s Final Rule. Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen, Oxides of Sulfur, and Particulate Matter.

Exhibit 2: Environmental Protection Agency’s Final Rule and Correction. Reconsideration of the National Ambient Air Quality Standards for Particulate Matter.

Exhibit 3: Register Notice for the proposed revision to Delaware’s State Implementation Plan, Implementation, Maintenance, and Enforcement of the 2024 Annual Primary Fine Particulate Matter (PM2.5) and Secondary Sulfur Dioxide (SO2) National Ambient Air Quality Standard, published in Delaware Register of Regulations on Oct. 1, 2026.

Exhibit 4: Affidavit and legal notice in the Sept. 23, 2026 Delaware State News.

Exhibit 5: Affidavit and legal notice in the Sept. 23, 2026 News Journal.

Exhibit 6: Hearing notice on the State of Delaware Public Meeting Calendar, Sept. 23, 2026.

Exhibit 7: Legal notice as posted on the website for DNREC Public Notices, dated Sept. 23, 2026.

Exhibit 8: Implementation, Maintenance, and Enforcement of the 2024 Annual Primary Fine Particulate Matter (PM2.5) and Secondary Sulfur Dioxide (SO2) National Ambient Air Quality Standard, as published in the Oct. 1, 2026 Delaware Register.

Exhibit 9: DNREC Presentation (Pending)