Do biofuels help air quality?
Biodiesel is far cleaner than petroleum diesel, with significantly lower emissions of particulate matter, hydrocarbons, sulfates and cancer-causing air toxics. Biodiesel can emit more nitrous oxide, a smog-forming compound, but biodiesel’s lower hydrocarbon emissions mean that its overall smog-creating potential is 50% lower than petroleum diesel’s. Adding ethanol to gasoline decreases emissions of carbon monoxide and helps reduce carcinogenic substances in gasoline such as benzene, toluene, and xylene. According to the EPA, a 10% ethanol blend can reduce benzene by 25% compared to gasoline. However, ethanol does result in slightly higher emissions of acetaldehyde. Ethanol also has a mixed impact on ground-level smog – some studies show an increase, others a decrease.
