Until recently, it was believed that 50-ppm sulfur would be the
main diesel specification. However, strong signs indicate that the
European Community will drop sulfur specifications to 10 ppm.
Equally important, other specifications, such as, PNA, density and
cetane may also change. New, proposed U.S. legislation is focused
on sulfur reductions. In December 2000, the U.S. EPA published
mandates for 15-ppm sulfur diesel by 2006. Some major oil companies
have adapted the policy to produce clean burning, so-called
"green", fuels. Consequently, strong drivers do exist for further
product quality improvement.