Calculation of diesel combustion particle deposition in the human respiratory tract

University of Salzburg, A-5020 Salzburg, Austria Keywords: diesel soot particles, ultrafine particles, nucleation mode, lung deposition. The primary particles generated during diesel fuel combustion are soot granules. As the exhaust fumes dilute and cool in the atmosphere the primary particles aggregate to form a well defined log-normal size distribution accumulation mode (AM). In addition, under certain conditions a nucleation mode (NM) is formed. The generation and the characteristics of the NM depend sensitively on engine operating conditions, on the sulfur content of the fuel, and on the presence of a diesel particulate filter (DPF) or oxidative catalyst. Although most authors agree that particle surface plays a key role in lung-particle interaction (Oberdorster, 2000), current legislation regulates only the total mass emissions. DPF reduces the emission of AM, and accordingly the total mass, but it does not affect the NM emission since it originates from SO