ULSD and Lower Sulfur Fuel

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Currently low sulfur fuel (500 ppm) is the national standard for on-road diesel fuel. Nonroad fuel is not currently regulated for sulfur.

Ultralow sulfur diesel fuel (15 ppm) will be required for use in on-road vehicles starting in 2006. Lower sulfur diesel fuel (500 ppm) will be required for nonroad diesel engines in 2007, followed by ultralow sulfur fuel in 2010, and for locomotives and marine engines in 2012. In California, ultralow will be required.

In addition to reducing emissions from the existing diesel fleet, these cleaner, lower sulfur fuels will enable the use of advanced aftertreatment technologies on engines. Technologies like particulate traps, capable of dramatic emission reductions, will be required under new standards set to begin phasing into the on-road sector in 2007, and into the nonroad sector in 2010. These programs will yield enormous long-term benefits for public health and the environment.

The full benefits of these changes will not be realized until the engine and vehicle fleet has been fully turned over, when PM and NOx will be reduced by 250,000 tons/year and 4 million tons/year, respectively. The West Coast Collaborative is working to encourage early voluntary use of lower sulfur diesel fuel and aftertreatment technologies, and early reductions in diesel emissions.

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