AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Screen Collection and Harvesting of Airborne Glass Fibers
BON KI KU, G.J. Deye, Leonid Turkevich, Centers for Disease Control and Prevention, NIOSH
Abstract Number: 55 Working Group: Health Related Aerosols
Abstract Fiber length is believed to be an important variable in determining various toxicological responses to asbestos and other elongate mineral particles. In order to prepare samples for toxicology studies, it is necessary to develop and evaluate methods for separating fibers by length. Recent studies have shown that the collection of airborne glass fibers on a screen is useful for classifying fibers by length. We have extended these studies to harvest the screens, using a periodic back-flushing purge flow. Regeneration of a selected size would refine length selection for that size range. In a second set of experiments, a well-dispersed aerosol of glass fibers (mean length ~ 20 µm), generated by vortex shaking, was fed directly into the Baron Fiber Length Classifier, in order to produce monodisperse length fibers. With nylon mesh screens (10, 20, 30, 40 and 60 µm mesh sizes), the screen collection efficiency was measured using an aerodynamic particle sizer. As the screen mesh size decreases, the screen collection efficiency increases for the longest fibers (~ 53 µm) tested in the study. Also, the collection efficiency for fibers with a given physical length was found to be nearly constant for aerodynamic diameters 1-4 µm for screen 20 and 30 µm, but to rise significantly at higher aerodynamic diameters. These results indicate that it will be possible to use a screen collection process to prepare short fibrous aerosol controls free from longer fiber contaminants as well as long fibers if we would harvest the screens.