AQ Programs

The Clean Diesel Initiative was formed to work with fleet owners and operators to offer ways they can take advantage of the benefits of diesel engines, while reducing their impact. Fleets get help choosing the right mix of strategies for their business and in some cases, the fuel savings pays for the strategy, especially when combined with tax credits (and grants when available). Strategies for reducing diesel exhaust are categorized under three primary approaches: burning less fuel, burning cleaner fuel and burning fuel cleaner.

The easiest way to reduce diesel exhaust and to save money is to burn less fuel. Simple steps such as reducing unnecessary idling can result in significant savings in fuel costs, and reduced pollution.

  • Don't idle. Stopping unnecessary idling saves money in fuel and maintenance costs. One gallon of fuel is burned for every hour of idling.
  • Perform regular maintenance to improve efficiency and engine life. It can also prevent equipment failure.
  • Track fleet inventory. Tracking vehicle model year, usage, fuel consumption, average mileage and other baseline information allows fleet managers to make decisions about operational improvements.
  • Use auxiliary power units, which provide the utility of an engine idling with far less pollution and fuel use.
  • Driver training, which can include driver incentive programs, is often overlooked as a way to use less fuel, but is an important way to ensure fuel savings measures are being followed and to maximize vehicle efficiency.
  • Employ on-board diagnostic systems, which are getting more sophisticated at tracking fuel use and driver behavior.
  • Apply fuel savings measures such as low-rolling resistance tires, automatic tire inflation and other aerodynamic features are part of EPA's Smartway program for shippers and carriers.

There are an increasing number of cleaner fuels available for diesel engines, starting with ultra low sulfur diesel fuel. This fuel is required for highway trucks and nonroad applications such as construction equipment.

There are other fuels, such as biodiesel, compressed natural gas, ethanol, propane and electricity that provide environmental benefits on their own; however, exhaust from a diesel engine is most effectively reduced at the lowest cost when clean fuels are combined with exhaust controls.

These alternative fuels have operational advantages in specific circumstances and can be an excellent solution for a fleet to lower their emissions, and in some cases, offer operational savings. For fleets that remain committed to diesel, cleaner fuels like ultra low sulfur diesel and biodiesel can be combined with advanced exhaust controls to make the most environmentally cost effective solution.

This approach refers to installing advanced exhaust controls (retrofitting vehicles and equipment), or replacing (repowering) engines.

Of the three approaches (burn less fuel, burn cleaner fuel, burn fuels cleaner), retrofitting is the most cost-effective strategy on a cost per ton of pollutant reduced basis. Typically, diesel retrofits involve adding a device to remove emissions from the engine exhaust.Retrofits can be very effective, eliminating up to 90% of pollutants, depending on the device.Some examples of devices are diesel oxidation catalysts, diesel particulate filters, and closed crankcase ventilation systems.

DEQ offers technical assistance on these approaches and can refer fleets to vendors and other resources for more information. Grant monies may be available to help with costs.