AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Characterization of a Vortex Shaking Method for Aerosolizing Fibers
BON KI KU, Gregory Deye, Leonid Turkevich, Centers for Disease Control and Prevention, NIOSH
Abstract Number: 72 Working Group: Health Related Aerosols
Abstract Generation of well-dispersed, well-characterized fibers is important in toxicology studies. A vortex-tube shaking method is investigated using glass fibers to characterize the generated aerosol. Controlling parameters that were studied included initial batch amounts of glass fibers, preparation of the powder (e.g. pre-shaking), humidity, and aerosol flow rate. Total fiber number concentrations and aerodynamic size distributions were typically measured. The aerosol concentration is only stable for short times (t < 10 min) and then falls precipitously, with concomitant changes in the aerosol aerodynamic size distribution; the plateau concentration and its duration both increase with batch size. Pre-shaking enhances the initial aerosol concentration and enables the aerosolization of longer fibers. Humidity strongly affects both the number concentration and the particle size distribution, resulting in a higher number concentration but a smaller modal diameter. Running the vortex shaker at higher flow rates (Q > 0.3 lpm) yields an aerosol with a particle size distribution representative of the batch powder; running the vortex shaker at a lower aerosol flow rate (Q ~ 0.1 lpm) only aerosolizes the shorter fibers. These results have implications for the use of the vortex shaker as a standard aerosol generator for powders of polydisperse or asymmetric particles.