Determination of airborne nanoparticle mass concentration from number concentration using their effective density - Application to ELPI data

Nanoparticles are generated by numerous industrial processes like arc welding, thermal metal spraying, combustions. Effective density (e) is among the key characteristics of airborne nanoparticles due to its role in particle deposition in the human respiratory tract and in the conversion of number distributions to mass distributions. The measuring method of e is based on the tandem measurement of airborne nanoparticles electrical mobility (with a DMA) and mass (with an APM). The methodology was first applied to spherical model particles to validate the associated data treatment and protocol. The method was afterwards applied to an aerosol of ultrafine metal particles produced by an electric arc spraying process. Results show a good agreement between particle number and mass concentrations determined from the different instruments, corrected from the diameters established from the effective density.