Toxic Potential of 2- and 4-stroke Scooter and Diesel Car Exhaust Emissions in Lung Cells In Vitro

Introduction A growing number of scooters (small two-wheeled vehicles, maximum speed of 45 km/h, engine capacity of 50 cm) produce an increasing amount of potentially harmful emissions. Comparisons between cars (Euro 3 standard) and various scooters show that two-stroke scooters can emit 10-23 times more carbon monoxide (CO), 10-171 times more total hydrocarbons (HC) and 3-8 times more nitrogen oxides (NOx), depending on the scooter type (Rudy and Weilenmann, 2006). Further high emissions of polycyclic aromatic HCs (PAH) and very high amounts of particulate matter (PM) in the nanoscale range are typical for scooter exhaust emissions (Czerwinski and Schramm, 2006; Rijkeboer et al, 2005). Therefore, scooters are significant contributors to air pollution (McDonald et al, 2005) and have to be considered as so-called super-polluters (McDonald et al, 2005; Siegmann et al, 2008).