Role of nanostructure and adsorbed organic compounds on radical activity of flame formed soot

Combustion-derived soot is a polydispersion of carbon-based molecules/particles ranging from a molecular scale length to a particle scale length (1-100 nm). It is considered responsible of respiratory and heart disease (Kumfer et al., 2009), and its mechanisms of action is related to the composition and structure, in turn mainly depending on the fuel and temperature environment in which soot is generated. Soot particles present a structural variability at a mesoscopic scale (size, geometry, nanostructure, primary particle diameter) that can be responsible of a different lung deposition degree and particle translocation behaviour. The toxic effects of inhaled dusts are believed to be mainly driven by oxidative stress which is the result of reactive oxygen species (ROS) (i.e. hydrogen peroxide, superoxide anion, hydroxyl radical) either generated directly by the particles/molecules or by cells in response to the particle exposure (Donaldson et al., 2005). This work aims to gain insights about the radical activity measured by electron spin resonance of soot generated from different fuels, namely benzene and ethylene, in relation to the specific local chemistry and nanostructural features as inferred by FT-IR and Raman spectroscopy. This study was performed on soot washed by solvent in order to eliminate light PAH (< 300u) adsorbed on soot surface with the aim to study the specific soot activity independently from the well known role of PAH. Copyright © 2010 AIDIC servizi S.r.l.