The Division of Air Quality will conduct a public hearing (Docket #2025-R-A-0015) on a proposed State Implementation Plan (SIP) revision. Public comment period open through Oct. 7, 2026.

On June 4, 2018, the Environmental Protection Agency (EPA) designated 51 areas of the country as “non-attainment” under the 2015 8-hour ozone National Ambient Air Quality Standard (NAAQS) of 0.070 parts per million. Ground level ozone, one of the principal components of smog, is a serious air pollutant that harms human health and the environment. Among those non-attainment areas was the Philadelphia-Wilmington-Atlantic City (PA-NJ-MD-DE) Moderate Non-Attainment Area (Philadelphia NAA). This NAA included New Castle County in Delaware.

On October 7, 2022, the EPA published a final rule to reclassify certain ozone nonattainment areas from Marginal to Moderate for the 2015 ozone NAAQS. Under the Moderate non-attainment classification, the Philadelphia NAA did not meet the standard by the deadline of August 3, 2024.

On July 30, 2024, the EPA published a final rule to reclassify the Philadelphia NAA as Serious for the 2015 8-hour ozone NAAQS, with a new attainment date of August 3, 2027, and instructed states in the NAA to develop non-attainment plans. Subsequently, on June 4, 2026, the EPA issued a final rule creating a stand-alone NAA for New Castle County, Delaware; removing Delaware from the Philadelphia NAA. This hearing will address Delaware’s Serious Non-attainment Plan for New Castle County for the 2015 8-Hour Ozone NAAQS.

For additional information and to view the proposed SIP revisions visit the Delaware Register of Regulations, beginning Sept. 1, 2026. For more information, or to view the proposed SIP revisions in person, by appointment-only, contact Kelsey Schiliro, at the DNREC Division of Air Quality, 715 Grantham Lane, New Castle, Delaware, 19720, or via phone 302-323-4542 or by email at Kelsey.Schiliro@delaware.gov.

The Department will accept public comment through Oct. 7, 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

Relate Documents and Links

Delaware Public Meeting Calendar Notice