The Role of Sampling Conditions in Particle Size Distribution Measurements
Particle size distribution and particle number emissions rather than legislated particulate mass emissions from diesel engines are subject of rising concern especially in the US and several Western European countries *. Recently also particle number emissions from gasoline engines attracted much attention since these engines are supposed to emit very high numbers of ultrafine particles or even nano-sized particles . The work described in this paper focused on the impact of modern diesel exhaust gas aftertreatment systems like diesel oxidation catalysts (DOC) and diesel particulate filter (DPF) on particle number emission. Especially the effect that these aftertreatment systems are supposed to significantly increase ultrafine particle numbers (because they may act like “reactors” actively producing ultrafine solid particles) gave reason for investigating the effects and mechanisms more in detail.