Biofuels are being investigated as a potential renewable energy source to replace fossil fuels in the transportation industry. They can reduce harmful emissions like particulate matter and carbon monoxide, but may increase nitrogen oxides and other pollutants. Advanced biofuels made from inedible biomass are preferred, but more research is needed for commercial use. Biofuel blends are being tested as alternatives to conventional aviation fuels, with potential cost reductions. However, using i-butanol as a biofuel may increase ozone levels in the upper atmosphere. Further studies are required to determine the practicality, cost, and impact of biofuels on existing vehicles, engine infrastructure, climate, and human health.