generally produce lower tailpipe emissions of carbon monoxide, hydrocarbons sulphur dioxide and particulate matter than gasoline or conventional diesel fuel. They state, however, that ethanol-blended gasoline produces more volatile organic compounds(VOCs). They also point out that the hydrocarbons that are produced are different from those in conventional fuels and that the health effects of these hydrocarbons are not yet fully known. Most research suggests that there will be slight increases in the emissions of nitrous oxides(NOx) as a result of the use of biofuels. However tests also indicate that once sulphur has been eliminated from fuel(which seems entirely possible in the near term), this will enable the use of powerful NOx-breaking catalysts that cannot be used when sulphur is present. So, in the future, it is possible that the NOx gases can be reduced too, thereby improving the environmental credentials of biofuels. The change in the level of emissions of carbon dioxide(co resulting rom a switch towards biofuels is much more debatable. The EPA(2002: ated that they were not able to identi an unambiguous difference n CO, emissions between conventional fuel and biodiesel. exhaust 10 percent increase in the tailpipe Other research suggests that there is a emissions of CO, when using biodiesel, but that the sequestration effect the plans to start with is calculated to offset this increase