Environmental impacts of biofuels. The emissions issue. Apart from the security of supplies argument, the main reason for the push towards biofuels is their purported environmental benefits. The Df T(2007: 2), for instance, states that"evidence from lifecycle analysis suggests that sustainable biofuels can offer significant reductions in greenhouse gas emissions compared with fossil fuels and so represent an opportunity to address climate change. The EPA(2002) calculated that with a 40 per cent biodiesel mix, NOx would increase by around 4 per cent, particulate matter and CO would both decrease by around 22 per cent and hydrocarbons would decrease by about 36 per cent. If the biodiesel mix was increased to 80 per cent, the corresponding figures would be +9 per cent, 40 per cent and-60 per cent. Thus, emissions of most pollutants decrease with the use of biodiesel but emissions of nitrous oxides increase. The big gains are from a near-complete elimination sulphur emissions, with reductions in hydrocarbons and other local emis sions. Results of tests by the International Energy Agency support these findings; they conclude that'Biofuels(ethanol and FAME biodiesel)