Evaluation of Respirator Filters for Asbestos Fibers. Final Performance Report

摘要

The effects of fiber dimensions, flow rate, and charge status of filtercartridges on the penetration of fiber aerosols were examined, using four types of test respirator filters (two for passive respirators, one for a powered respirator, and one disposal respirator). Some filters were charged to enhance the collection efficiency. Only high efficiency filters performed consistently for both spherical test aerosols and the three types of asbestos (1332214) fibers. The performance of these filters did not appear to be changed by the surface charge potential of filter cartridges and charge status of fibers. When the change potential on the filter was removed and/or fiber aerosols discharged, the performance of low efficiency filters and masks deteriorated for aerosols. The surface charges decreased in a high temperature, high humidity environment and disappeared after 1 week. Shorter fibers had higher penetration rates indicating the fiber interception is an important deposition mechanism.