Proposals to reduce the sulphur content in diesel fuel by 97% have been announced by the US Environmental Protection Agency. As part of a wider programme to lower air pollution caused by vehicles, the sulphur content is to be down from 500ppm to 15ppm by June 2006.

The EPA said that if pollution control technology on diesel vehicles, such as three way catalysts and soot traps, is to be effective the fuel would have to be significantly cleaner than it is now. To meet the new standards, diesel engine manufacturers will be able to phase in this technology between 2007 and 2010. Manufacturers of petrol engines will have to comply by 2007. Petrol will also have to have its sulphur content reduced by 90%.

The EPA said that the reduction was “the clean air equivalent of eliminating air pollution from 13m of today’s trucks.”