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. To this purpose an experimental apparatus made up of a Submicrometer Aerosol Generator TSI 3940, a Scanning Mobility Particle Sizer spectrometer (SMPS 3936, TSI), and a further Condensation Particle Counter (CPC TSI 3775) was used. Particle number distributions and total concentrations were found to change as a function of the molar concentration of the solution. Besides the molar concentration, an effect of the solution was also recognized. 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. Also the mode and the standard deviation of the distribution varied as the solution changed: therefore, salts able to provide number concentrations higher than the NaCl ones at low diameter ranges were found. As an example, the ammonium chloride (NH4Cl) provided particle number concentrations at 8 nm and 10 nm about 40-fold and twice the NaCl ones, respectively.