There have been reports that using ethanol as fuels in cars has some drawbacks. The EU has decided to implement biofuels in 10% cars by 2020. In recent tests and studies showed that use of biofuel could increase the level of ozone in the atmosphere. Ozone being a pollutant is dangerous and harmful to the respiratory tracts.
A scientist suggested that if all cars where run on E85 ( a combination of 85% ethanol and 15% petrol) that significant parts of US where to have increased ozone presence. There are also some benefits in using ethanol cause it has been seen that it reduces levels of two atmosphere carcinogens but levels of others would increase which are linked to cancers. It would be same for petrol fumes.
A government report said that biofuels could reduce emissions by 50-60% when compared with fossil fuels.