Response of three instruments devoted to surface-area for monodisperse and polydisperse aerosols in molecular and transition regimes

Abstract

An increasing number of experimental and theoretical studies focus on airborne nanoparticles (NP) in relation with many aspects of risk assessment. Indeed, our understanding of the hazards, the actual exposures in the workplace and the limits of engineering controls and personal protective equipment with regard to NP are still under development. Several studies have already identified surface-area as an important determinant of low solubility nanoparticles toxicity. As a consequence, the concept that surface-area could be a relevant metric for characterizing exposure to low solubility airborne NP has been proposed [1]. To provide NP surface-area concentration, some direct-reading instruments have been designed, based on diffusion charging. The actual available instruments providing airborne NP surface-area concentration are studied in this work: LQ1-DC (Matter Engineering), AeroTrak™ 9000 (TSI) and NSAM (TSI model 3550). Their performances regarding monodisperse carbon NP have been investigated by Bau et al. [2]. This work aims at completing the instruments characterization regarding monodisperse NP of other chemical composition (aluminium, copper, silver) and studying their performances against polydisperse aerosols of NP.