Retrofitting today takes years
of emissions out of the air

EPA rules require that new diesel engines meet lower emission levels beginning in 2007 for on-road, heavy-duty engines and in 2011 for non-road equipment. The rules also require ultra-low sulfur diesel fuels for all on-road engines beginning in October 2006.  However, the million-mile lifecycle of some diesel engines means it will take years, even decades to fully benefit from EPA’s new rules.

Funding and technical assistance The Clean Air Agency has obtained about $1.7 million in annual funding for Diesel Solutions projects. Much of this money has been and is being allocated to participants in the program.  This includes special funding for a school bus retrofit program and transit retrofits, and additional funds for other public and private projects.

Retrofitting both on-road and non-road heavy-duty diesel engines now means the region can have cleaner, healthier air years before EPA’s national standards take effect, and for the older engine still on the road, for the years beyond.

Why retrofit?

The Puget Sound Clean Air Agency is encouraging fleet owners and operators to retrofit on-road and non-road heavy-duty diesel vehicles with emission-reduction equipment, usually called diesel retrofit devices, to reduce particulate matter and other diesel exhaust emissions.

• By retrofitting vehicles and operating them on ultra-low sulfur diesel fuel, emissions of carbon monoxide, hydrocarbons and particulates can be reduced by 90 percent or more, as well as smog-causing nitrogen oxides, depending on the retrofit device used.
• Installing retrofit devices can also significantly reduce the smoke and odor from diesel engines.
• In many cases, these devices can significantly improve the work environment of people who operate diesel engines.
• The public-health benefits from diesel retrofits are substantial.

About retrofit devices

The United States Environmental Protection Agency (EPA) defines a retrofit device as any device that reduces emissions below the levels required by law.

Most diesel retrofit devices are similar in appearance to the mufflers they replace. Using catalytic processes and/or filter technology, they reduce carbon monoxide, hydrocarbon emissions and particulate emissions.

Separately, crankcase filtration systems allow a diesel engine’s crankcase to be closed and use an air filter to trap unburned fuel and blow-by gases.  Crankcase filters help prevent engine emissions from entering the vehicle cab and are best used in conjunction with some type of exhaust retrofit.

Research and development is now under way on retrofit devices that will reduce other pollutants such as the oxides of nitrogen, commonly called NOx.

Diesel retrofit devices usually are not original equipment; they are installed on a vehicle just prior to or after it has been put in service.  New 2007 model year, heavy-duty engines will be built to meet lower emission levels and will not need retrofitting.

Are retrofit devices required?

No.  Diesel retrofit devices are not required by law in the Puget Sound region.   We encourage their use, however, because of their health and environmental benefits.

EPA regulations do require that new diesel engines used on heavy-duty trucks and buses meet lower emission standards beginning in 2007.

However, it will take years for our region to benefit fully from those regulations.  Benefits will be delayed because on-road diesel engines can operate for more than a million miles and go through multiple engine rebuilds.  Retrofitting diesel engine and exhaust systems now means the region can have cleaner, healthier air years before 2007 and beyond.

For more information:

If you have additional questions, including possible funding assistance, contact Air Resources department manager Dave Kircher.