Is the fit of N95 facial masks effected by disinfection? A study of heat and UV disinfection methods using the OSHA protocol fit test.

Amy DPhil Price; Yi Cui; Lei Liao; Wang Xiao; Xuanze Yu; Haotian Wang; Mervin Zhao; Qiqi Wang; Steven Chu; Larry F Chu

1. The Portacount Pro + 8038 respiratory fit machine was first calibrated for testing using internal quality assurance checks, including particle check, classifier check, valve check, zero check, and max fit factor check. Testing did not proceed unless the machine passed all quality control checks ( Figure 3 ). 2. A test probe was inserted into disposable N95 respirators according to the make and model of the respirator. For proper fit testing, the probe was inserted into the "breathing zone" of the respirator where it would not be blocked by the person's nose or chin ( Figure 4 ). For the KN95 respirator (4C Air, Sunnyvale, CA) this was located to the left of the fold and for the 3M 8210 Plus respirator (3M, St. Paul, Minnesota) this was located above the fold ( Figure 5 -6). : Sample probes were placed in disposable N95 masks in the "breathing zone" of the respirator according to the specific make and model of the mask so that the probe would not be blocked by the person's chin or nose. The model is a co-author of this paper (LC) All rights reserved. No reuse allowed without permission.