EPA Approves Delaware's Plan to Keep Philly Air Particle-Free Until 2046
Published Date: 11/20/2025
Proposed Rule
Summary
The EPA is proposing to approve Delaware’s plan to keep the air clean in New Castle County, part of the Philadelphia area, by maintaining safe levels of tiny pollution particles through 2046. This plan helps protect people’s health and supports local transportation projects without extra costs. Comments on this plan are open until December 22, 2025, so everyone has a chance to weigh in!
Analyzed Economic Effects
4 provisions identified: 3 benefits, 1 costs, 0 mixed.
EPA proposes approval of Delaware PM2.5 plan
The EPA is proposing to approve Delaware’s Limited Maintenance Plan (LMP) for the New Castle County portion of the Philadelphia-Wilmington area for the 2006 24-hour PM2.5 standard. If approved, the plan covers the second 10-year maintenance period through September 4, 2034 and is intended to keep short-term fine particle levels below the 2006 24-hour NAAQS.
Transportation projects may avoid regional analysis
If the LMP is approved and found adequate, transportation conformity in New Castle County can be shown without a regional motor vehicle emissions analysis under 40 CFR 93.109(e). That means federally supported transportation plans and TIPs in the area may not need the regional emissions analysis tied to the 2006 24-hour PM2.5 standard while the LMP is adequate.
Contingency measures could impose controls
Delaware’s LMP includes contingency triggers and a menu of possible measures that would be implemented if pollution or emissions rise. A single-year 98th percentile 24-hour PM2.5 reading of 35.5 micrograms per cubic meter or greater, or a total PM2.5/NOX/SO2 emissions increase more than 10% above 2008 levels, can trigger a ‘warning level’ response; a three-year average (design value) of 35.5 micrograms per cubic meter or greater triggers an ‘action level’ response. Potential measures include tightening offset or control requirements for new or modified sources, diesel retrofit programs, vehicle inspection improvements, and other controls; implementation timelines set some actions to be in place within 30 months of the triggering event and regulatory steps to be completed within 12 months after modeling.
State will keep PM2.5 monitors running
Delaware (DNREC) committed to continue operating the PM2.5 air monitoring network in New Castle County throughout the second 10-year maintenance period and to periodically update emissions inventories. Ongoing monitoring is meant to verify continued attainment and to trigger contingency responses if needed.
Your PRIA Score
Personalized for You
How does this regulation affect your finances?
Sign up for a PRIA Policy Scan to see your personalized alignment score for this federal register document and every other regulation we track. We analyze your financial profile against policy provisions to show you exactly what matters to your wallet.
Key Dates
Department and Agencies
Related Federal Register Documents
2026-06275 — Renewable Fuel Standard (RFS) Program: Standards for 2026 and 2027, Partial Waiver of 2025 Cellulosic Biofuel Volume Requirement, and Other Changes
The EPA just set new rules for renewable fuels in 2026 and 2027, including how much biofuel must be used. They’re also easing the 2025 cellulosic biofuel goals because production fell short and dropping renewable electricity as a qualifying fuel. These changes affect fuel producers and sellers, kick in mostly by mid-2026, and aim to keep America’s fuel cleaner and greener without breaking the bank.
2026-05167 — National Emission Standards for Hazardous Air Pollutants: Ethylene Oxide Emissions Standards for Sterilization Facilities Residual Risk and Technology Review Reconsideration
The EPA is proposing changes to rules for sterilization facilities that use ethylene oxide, a chemical that can be harmful if not controlled. They want to remove some strict risk-based limits, fix technical mistakes, and update how facilities prove they’re following the rules. If you run or work with these facilities, get ready for new deadlines and clearer standards by mid-2026, which could affect how you manage emissions and compliance costs.
2026-04646 — Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Large Municipal Waste Combustors Voluntary Remand Response and Five-Year Review
The EPA is updating pollution rules for big trash-burning plants to cut harmful emissions like lead, mercury, and dioxins. These changes affect both new and existing facilities, tighten limits, remove some loopholes, and improve reporting, all starting May 11, 2026. This update will help clean the air by reducing over 3,200 tons of pollution each year, making communities healthier and safer.
2025-21788 — Oil and Natural Gas Sector Climate Review: Extension of Deadlines in Standards of Performance for New, Reconstructed, and Modified Sources and Emissions Guidelines for Existing Sources
The EPA is giving oil and natural gas companies more time to meet new pollution control rules and report their emissions. Deadlines for fixing leaks, monitoring equipment, and submitting state plans are pushed back to help everyone get ready without rushing. These changes keep the climate goals on track while easing the financial and timing pressure on the industry.
2025-20402 — Updated Definition of “Waters of the United States”
The EPA and Army Corps are updating the rules that decide which waters are protected under the Clean Water Act, following a 2023 Supreme Court decision. This change helps everyone know exactly which waters are covered, making it easier to protect lakes, rivers, and wetlands while respecting state and tribal rights. People and businesses affected should share their thoughts by January 5, 2026, as this update could impact water projects and environmental protections.
2025-19882 — Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) Data Reporting and Recordkeeping Under the Toxic Substances Control Act (TSCA); Revision to Regulation
The EPA is updating rules for companies that make or import PFAS chemicals, asking them to report certain info about these substances from 2011-2022. The changes add some smart exceptions to ease reporting on things companies probably don’t know, saving time and hassle. Comments on the proposal are open until late December 2025, so affected businesses should get ready to weigh in!
Previous / Next Documents
Previous: 2025-20416 — Air Plan Approval; District of Columbia; Creation of Synthetic Minor Permit Program
The EPA is proposing to approve a new program in Washington, DC that lets certain polluters get special permits to keep their emissions just under federal limits. This change helps DC better control air pollution with clear, enforceable rules. If you want to share your thoughts, you have until December 22, 2025, to comment—no extra costs or fees involved!
Next: 2025-20419 — Approval and Promulgation of State Air Quality Plans (Negative Declarations) for Designated Facilities and Pollutants; District of Columbia
The EPA is proposing to approve the District of Columbia’s statement that it has no big waste burners, oil and gas plants, or power plants needing special air pollution rules. This means no new pollution controls are needed right now in D.C. If you want to share your thoughts, you have until December 22, 2025, to comment. No money changes hands, but this keeps things clear and simple for the city.
Take It Personal
Get Your Personalized Policy View
Start a Free Government Policy Watch to see how policy affects your household, then upgrade to PRIA Full Coverage for year-round monitoring.
Already have an account? Sign in