Regulated and non-regulated pollutants emitted during the regeneration of a diesel particulate filter

The emission of regulated and nonregulated pollutants [nanoparticle number and size distribution, soluble organic fraction (SOF), polycyclic aromatic hydrocarbons (PAHs), sulfates, cerium, individual hydrocarbons, and SO2] emitted during the regeneration of a diesel particulate filter (DPF) is studied on a Euro4 passenger car. The obtained results show that DPF regeneration increases significantly the emissions of HC and CO and slightly those of particulate matter. Regeneration increases also the number of nucleation nanoparticles; however, these nanoparticles are composed mainly from HC or sulfates. Cerium is effectively collected on the DPF, while SOF increases during regeneration. Total particulate PAHs increases during regeneration; however, PAH emission during regeneration is quite similar to PAH emissions upstream of the DPF. Methane is the major HC, and its percentage increases during regeneration. Particulate sulfates and SO2 emissions also increase during regeneration. Globally, even if DPF regeneration increases the emission of some pollutants, this increase is not very high compared to normal engine operation conditions.