Ultra-low sulfur diesel

From Freepedia

Ultra low sulfur diesel describes a new EPA standard for the sulfur content in diesel fuel sold in the United States beginning in 2006. This applies to all diesel fuel sold for use in roadgoing vehicles. The allowable sulfur content (15 ppm) is much lower than the previous U.S. standard (500 ppm), which not only reduces emissions of sulfur compounds (blamed for acid rain), but also allows advanced emission control systems to be fitted that would otherwise be poisoned by these compounds. These systems can greatly reduce emissions of oxides of nitrogen and particulates.

Because this grade of fuel is comparable to European grades, this standard may increase the availability of diesel-fueled passenger cars in the U.S., since engines will no longer have to be redesigned to cope with higher sulfur content. European diesels are both more advanced technologically and much more popular with buyers than those available in the U.S.