AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Investigation of Screen Collection Efficiency of Airborne Glass Fibers
BON KI KU, G.J. Deye, Leonid Turkevich, Centers for Disease Control and Prevention, NIOSH
Abstract Number: 264 Working Group: Health Related Aerosols
Abstract Collection efficiency of airborne fibers such as asbestos and elongated mineral particles on a screen is of interest from a health perspective because this information could be used to classify airborne fibers by length for toxicology studies. In this study, we investigated collection efficiency of airborne glass fibers using nylon mesh screens. A well-dispersed aerosol of glass fibers (a surrogate for asbestos) was generated by vortex shaking of a sample of glass fiber powder (mean length ~ 20 um and mean fiber diameter 0.88 um) provided by Japan Fibrous Material Research Association (JFMRA). With nylon mesh screens (10, 20, and 60 um mesh sizes), screen collection efficiency, defined as one minus a ratio of downstream to upstream concentrations of screens, was measured using an aerodynamic particle sizer under different screen configurations. These included screens with or without entrance length in a sampling cassette and a centrally blocked screen without entrance length. The results showed that screen collection efficiency increased as screen mesh size decreases from 60 to 10 um for both cases with and without entrance lengths. However, for the screen configuration without entrance length, higher collection efficiency was obtained than in the case with entrance length. The collection efficiency increased from 0.1 to 1.0 as aerodynamic diameter increased 0.5 to 10 um. The difference between the collection efficiencies for the different configurations was small in the aerodynamic size range below 3 um while it increased in the size range from 3 to about 7 um. Based on these results, it is believed that it will be possible to use a screen collection process with different configurations to prepare short fibrous aerosol controls free from longer fiber contaminants.