Mobile Sources

Mobile sources include a variety of motor vehicles and mobile equipment that generate air emissions, and that autonomously move or can be moved from place to place. The DNREC Mobile Sources Control Program implements measures and programs to reduce motor vehicle-related pollution from both on-road vehicles and non-road vehicles.

State Mobile Sources Programs

Reducing Diesel Emissions

Delaware has anti-idling rules and helps fund diesel emissions reduction projects as part of the National Clean Diesel Campaign.

Inspection and Maintenance

Delaware requires that vehicles changing ownership be inspected to make sure their emission control systems are in good working order.

VW Mitigation Plan

DNREC has developed a proposed mitigation plan to use Delaware’s share of the VW Environmental Mitigation Trust fund.

Clean Vehicles and Fuels

Delaware has several programs designed to reduce air emissions by promoting clean fuels and alternative vehicle use.

Contact Us

Pamela Keeney
Division of Air Quality
302-739-9402

On-Road Vehicles Non-Road Vehicles

Fuel Rules and Regulations

The U.S. Environmental Protection Agency (EPA) regulates fuels and fuel additives used in both on-road and non-road motor vehicles and engines. These regulations are intended to prevent air and water pollution that could endanger public health and the environment. The EPA also regulates emission byproducts and fuel additives that may interfere with vehicles or engine emission control systems designed to reduce harmful emissions. (Federal Gasoline Regulations | US EPA)

In addition to federal regulations, the State of Delaware requires that all fuel sold within the state meet or exceed American Society for Testing and Material (ATSM) specifications, as codified in Delaware Code, Title 6, Chapter 29, §2913 (c)(1). These requirements are administered by the Delaware Department of Agriculture, Office of Weights and Measures. This rule is intended to protect the motoring public from fuel-related performance issues and ensure fuel quality consistency.

Federal Gasoline regulations are found under 40 CFR Part 1090, “Regulation of Fuels, Fuel Additives, and Regulated Blendstocks” and 40 CFR part 80, subpart M, “Renewable Fuel Standard.”

Federal Fuel Programs

Mobile Source Air Toxics Standard (see 40 CFR § 1090.210)

The Mobile Source Air Toxics Standard (MSATS) reduces hazardous air pollutants, also known as air toxics. Air toxics include benzene and other hydrocarbons such as 1,3-butadiene, formaldehyde, acetaldehyde, acrolein, and naphthalene. These are national requirements that require each refinery and importer to meet specific compliance baselines for conventional and reformulated gasoline. (Gasoline Mobile Source Air Toxics | US EPA)

Reformulated Gasoline (see 40 CFR § 1090.220 and 40 CFR § 1090.285)

Reformulated Gasoline (RFG) was mandated by Section 211(k) of the federal Clean Air Act (CAA) for metropolitan areas with the worst smog beginning in 1995. This includes New Castle and Kent County Delaware; and Sussex County which was opted in by the Governor in 1993. RFG is blended to burn more cleanly than conventional gasoline, reducing emissions of ozone-forming and toxic pollutants. About 30 percent of the gasoline sold in the U.S. is subject to RFG requirements. (Reformulated Gasoline | US EPA)

Reid Vapor Pressure (see 40 CFR § 1090.215)

Reid Vapor Pressure (RVP) requirements are designed to reduce the volatility of commercial gasoline during the summer ozone control season. Under Clean Air Act section 211(h), summer gasoline (e.g., gasoline that is sold to consumers from May 1 to September 15) must meet a maximum per-gallon RVP limit of 9.0 psi unless it is required to meet a lower RVP limit. Lower RVP limits apply in areas that are required to sell federal reformulated gasoline; therefore, Delaware has a lower RVP limit of 7.4 PSI. (Gasoline Reid Vapor Pressure | US EPA)

Renewable Fuels Standard (see 40 CFR Part 80, Subpart M)

The Renewable Fuels Standard (RFS) requires that transportation fuel sold in the U.S. contain a minimum volume of renewable fuel. The RFS applies to any refiner or importer of gasoline within the 48 contiguous states. Refiners have substantially met the RFS requirements to date by adding 10 percent ethanol to gasoline. (Overview of the Renewable Fuel Standard Program | US EPA)

Note: EPA gasoline regulations were reorganized from 40 CFR Part 80 to 40 CFR Part 1090 in 2021 apart from the RFS regulations. References have been updated accordingly.