Scientists in Washington state say they've found a way to turn harmful nitrogen oxide emissions from diesel engines into harmless nitrogen.

According to a report by UPI, researchers at the Pacific Northwest National Laboratory in Richland, Wash., say they can cut nitrous oxides by more than half by combining electrically charged gas with a mineral catalyst. Scientists say they've developed a plasma reactor that works with minerals called zeolites to turn nitrogen oxides into nitrogen, a component of clean air.
Researcher Chuck Peden said a prototype reactor reduced nitrogen oxide emissions by half, but lab results show that greater than 90 percent reduction is possible. Lab tests also showed that the device has the potential to reduce soot particle levels.
Scientists hope to have a prototype vehicle that incorporates the plasma reactor by 2004.