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One 4-stroke scooter and two 2-stroke scooters (50 cc bore) were run on dynamic test benches according to the EC47 driving cycle. Emissions from these scooters were continuously monitored, sampled and hot- diluted prior being driven to continuous flow through chambers containing organotypic cultures of lung tissue under bi-phasic Air/liquid culture conditions for three hours. Lung tissue was evaluated for viability (ATP), anti-oxidant defenses (intracellular GSH, Catalase, superoxide-dismutases, glutathione-S-Transferase, glutathione peroxidase, glutathione-reductase activity levels) and inflammatory reaction through the measurement of TNFalpha secretion in the culture medium. 4-stroke engine emissions had a moderate impact on lung tissue viability but induced a marked GSH depletion concomitant of increased GPx activity. 2-strokes engine emissions had variable impacts according to after-treatment technology and lube oil quality.

European regulations have made the use of diesel particulate filter (DPF) unavoidable because all future diesel vehicles have to comply with the Euro 5 regulation regarding particulate matter emissions. Indeed, DPF has an overall excellent filtering efficiency but should be periodically regenerated. We propose here an in vitro comparative toxicological study of diluted sampled exhaust, emitted during legislative NEDC (New European Driving Cycle) cycles with or without a DPF regeneration phase. Pollutants, particle sizing, ESR (Electron Spin Resonance) measurement and post-exposure biological evaluation were monitored. Only TNFα (Tumor Necrosis Factor alpha), a biological molecule produced during inflammatory processes, was slightly induced for the highest exhaust concentration including regeneration phase. In conclusion, it appears that regeneration process does not induce an acute toxicity.