However a compilation of existing data have been done and the results have been compiled into standard values for exhaust emissions from light vehicles run on different fuels.
These describes approximate emissions from passenger cars and light transport vehicles in environmental class 2005 during actual operation. (the report also covers values for older vehicles). The figures relate to vehicles approved by the manufacturer for running on the respective fuels.
Simple conversions, where for example the user converts a petrol-powered car to run on ethanol, can give much higher emissions, and the figures do not relate to such vehicles.
Conclusions:
Flexifuel vehicles run on ethanol E85 emit roughly 50 per cent less nitrogen oxides than when run on petrol. The amounts of hydrocarbons and particles are unchanged.
Diesel vehicles without particle filters or equivalent cleaning emit three to four times more nitrogen oxides and at least five times more particles than new ethanol vehicles. Emissions of hydrocarbons are 90-95 percent lower. If the vehicle has a particle filter, however, the particle emissionsare as low as from ethanol vehicles.
The work was financed by Vägverket (the Swedish Road Administration), the City of Stockholm, the City of Göteborg, Stockholm Transport (SL) and NTM.