Benzene

Benzene is the simplest aromatic compound and the one that has received most attention by virtue of its known carcinogenic properties. Vehicles emit benzene through evaporation from their fuel systems and through exhaust emissions. While benzene content does not directly affect engine performance, it is a good source of octane. International practice in recent years has been to set lower limits on benzene in petrol in response to health and air quality concerns. Benzene levels have historically been regulated to control both evaporative emissions and exhaust emissions.