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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.

The reduction of Particulate emission from diesel engines is one of the most important diesel exhaust emission problems and the use of Diesel Particulate Filter (DPF) appears essential for meeting future legislation. The Direct Injection turbo-charged diesel engine is characterized by low exhaust gas temperature and requires the use of an additive catalyst to allow soot combustion in the DPF. Diesel particulate filter combined with additive are now commonly studied by car manufacturers. Presently suppliers propose different additives which are not easy to evaluate. The aim of this work is to propose a new evaluation method of the capability of different additives. Usually the additive performance for trap regeneration is assessed through the measurement of a single criterion: ignition temperature. This temperature depends on different parameters linked to exhaust gas and particulate filter properties.