A new generation of clean diesel is fueling even greater environmental progress. As of 2007, exhaust from a clean diesel truck or bus is so clean that it would take 60 new trucks to equal the soot emissions of one truck sold in 1988. By 2010, truck and bus emissions levels will be near zero - a total reduction of 98 percent from 1988. The EPA predicts that these new trucks, once they fully replace the existing fleet, will reduce emissions of smog-forming gases by 2.6 million tons each year and cut soot emissions by 110,000 tons annually.

Ultra-Low Sulfur Diesel Fuel

Removing sulfur from diesel fuel is key to achieving these dramatic emissions reductions. Ultra-low sulfur diesel (ULSD) fuel with a sulfur content of less than 15 parts per million (15 ppm) is available nationwide. The primary purpose for ULSD is to enable or improve the performance of emissions reduction systems, but ULSD will also help reduce particulate (soot) emissions by approximately 10 percent when used without the addition of any exhaust-control devices.

Cleaner Engines

A pathway to clean diesel has been established for nearly every class of diesel engine, including:

Trucks and Buses

By 2010, it will take more than 53 new trucks to equal the emissions of nitrogen oxides (a smog-forming gas) from that same one truck sold in 1988. Read more.

Cars, Pickups and SUVs

Compared to the diesel engines of 10 years ago, today’s diesel automobiles have 80 percent lower particulate emissions, 70 percent lower nitrogen oxide emissions, 15 percent improved fuel consumption, 50 percent more power and 30 percent more torque. Modern diesel cars, trucks and SUVs are also much quieter than their predecessors, and by 2009, gasoline and diesel vehicles will be certified to the same stringent emissions standards. Read more.

Many of these same clean air technologies can be applied to existing diesel engines and equipment. Learn more about diesel retrofit.

Off-Road Equipment

Similar significant levels of emissions reduction will begin to phase-in for off-road equipment used in construction, agriculture and mining later this decade. Since 1996, when EPA first issued emissions regulations for off-road equipment, industry has made dramatic progress. For some categories of equipment – like backhoes and excavators – emissions levels have already been reduced by more than 80 percent. By 2010, sulfur levels in most non-road diesel fuel will be reduced to 15 parts per million, making it possible for engine manufacturers to use advanced exhaust control systems that significantly reduce emissions. For locomotive and marine fuel, this step will occur in 2012. Read more.

Many of the same clean diesel technologies developed for new engines can be applied to older vehicles and equipment. A number of cities and states struggling to meet strict federal clean air standards have found that clean diesel retrofits are a cost effective way to achieve real and immediate air quality progress. Learn more about clean diesel retrofits.