Ultra Low Sulfur Diesel (ULSD) is defined as diesel fuel with 15 parts per million (ppm) or lower sulfur content. As of December, 2006, almost all of the petroleum-based diesel fuel available in Europe and North America is of a ULSD type replacing LSD diesel.
Lower sulfur content is expected to substantially lower emissions from diesel engines. Petroleum-based ULSD is not considered an alternative fuel under the Energy Policy Act of 1992 (EPAct), but most ULSD fuels produced from non-petroleum and renewable sources are considered EPAct alternative fuels.
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