AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Evaluation of Glass Fiber Lengths Collected on a Screen Using a Periodic Purging Flow System
BON KI KU, G.J. Deye, Leonid Turkevich, Centers for Disease Control and Prevention, NIOSH
Abstract Number: 627 Working Group: Health Related Aerosols
Abstract Classification of airborne fibers by length is important to understand the effect of fiber length on toxicity because fiber length is believed to be an important variable in determining various toxicological responses to asbestos and other elongate mineral particles. Recent studies have shown that nylon mesh screens can be effective in classifying fibers by length and that a purging flow system for harvesting of long fibers collected on a screen may be useful in their recovery. In this study, we have further investigated the evaluation of glass fiber lengths collected on a screen, using the periodic purging flow system. Re-aerosolization of fibers collected on a screen would refine length classification for the fibers with that size range. Fibers aerosolized by vortex shaking were provided to different nylon mesh screens (10, 20, 30, and 41 µm mesh sizes) and the fibers collected on each screen were purged periodically using a computer-controlled purging flow system. The purged fibers were collected on a filter and their lengths were measured using a phase contrast microscope. These fiber length distributions were compared to those determined by washing the screen. It was found that the lengths of the fibers purged by this technique are smaller than those of the fibers from the washed screen. The mean fiber length from the screen are larger than the parent aerosol fibers and the fiber length was in the range of 35-54 µm. The results indicate that the screens have the effect of preferentially capturing the longer fibers, although our measurements have not determined any systematic variation with screen mesh size.