Intercomparison in the laboratory of various Condensation Particle Counters challenged by nanoaerosols in the range 6-460 nm

This study aim is to compare the number concentration of airborne nanoparticles reported by 13 different Condensation Particle Counters (CPC) with regards to a reference CPC, for a set of aerosols of interest. Among the models investigated, 5 are handheld CPC, while the 8 others are stationary CPC. The latter include butanol-based CPC as well as water-based CPC. Polydisperse test aerosols with modal diameters between 6 and 460 nm were produced in the CAIMAN experimental facility. Non-hydrophobic aerosols consisted of metal-based particles (Ti, C, Al, Cu, Ag), as well as nebulized suspensions (SiO2). Hydrophobic particles consisted of DEHS as well as alkanes (n-C-13 to n-C-20). Overall, about 400 different conditions were investigated to represent a wide range of aerosols potentially encountered in workplaces. The range of number concentrations provided by the reference CPC was 500-400 000 cm(-3). To highlight the possible effect of particle counting efficiency on the total concentration reported by the different CPCs, 40% of the test aerosols presented a modal diameter below 40 nm. The influence of particle material for water-based CPCs was investigated through the generation of about 100 hydrophobic test aerosols. CPC response was found to be sensitive to the mode of the aerosols measured, depending on the counting efficiency curve of the CPC investigated. An effect of particle hydrophobicity on the response of some water-based CPC models was demonstrated, while one water-based CPC did not show any material dependence.