Ultrafine particle generation through atomization technique: The influence of the solution

The present work is focused on the characterization of a sub-micrometer aerosol generation system (TSI 3940) in terms of particle number distributions and total concentrations as a function of the solution. Fourteen soluble salts were tested, and different solution molar concentrations were considered. The experimental apparatus was composed of a Submicrometer Aerosol Generator TSI 3940, a Scanning Mobility Particle Sizer spectrometer (SMPS 3936, TSI), and a Condensation Particle Counter (CPC TSI 3775). Particle number distributions and total concentrations were found to change as a function of the molar concentration of the solution. In addition, at a fixed molar concentration of the solution, different particle number distributions and total concentrations were measured as a function of the salt used in the solution preparation. The mode and standard deviation of the distribution also varied as the solution changed, and thus salts able to provide number concentrations higher than the NaCl ones at low diameter ranges were obtained. For example, ammonium chloride (NH4Cl) provided particle number concentrations at 8 nm and 10 nm about 40-fold and twice the NaCl ones, respectively.