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

Work by others have evaluated the fit and function of masks after various disinfection treatments. These fit testing methods have utilized mannequin heads, and have used a small number of fit tests (usually 3) compared to the OSHA testing protocol for human fit testing (8 tests) . This is due to the fact that mannequin heads do not move. Humans model fit testing involves 8 tests, including: 1) normal breathing, 2) deep breathing, 3) turning the head left-to-right, 4) moving the head up-and-down, 5) talking, 6) grimacing, 7) bending over, and 8) normal breathing. Therefore, to our knowledge, there have not been any studies that have measured quantitative fit testing on heat-and UVGI-disinfected treated masks using a human model on the OSHA protocol. This would be the most accurate method to predict the fit performance of a mask on health care workers after disinfection. As authors of previous mannequin-based studies have stated as limitations of their studies, "These results should not be interpreted as being equivalent to a standard OSHAaccepted fit test method 11 Human subject testing is needed to truly assess respirator fit."