E M Fisher1, R E Shaffer. 1. National Institute for Occupational Safety and Health, National Personal Protective, Technology Laboratory, Pittsburgh, PA 15236, USA.
Abstract
AIMS: To develop a method to assess model-specific parameters for ultraviolet-C (UV-C, 254 nm) decontamination of filtering facepiece respirators (FFRs). METHODS AND RESULTS: UV-C transmittance was quantified for the distinct composite layers of six N95 FFR models and used to calculate model-specific α-values, the percentage of the surface UV-C irradiance available for the internal filtering medium (IFM). Circular coupons, excised from the FFRs, were exposed to aerosolized particles containing MS2 coliphage and treated with IFM-specific UV-C doses ranging from 38 to 4707 J m(-2). Models exposed to a minimum IFM dose of 1000 J m(-2) demonstrated at least a 3 log reduction (LR) in viable MS2. Model-specific exposure times to achieve this IFM dose ranged from 2 to 266 min. CONCLUSIONS: UV-C transmits into and through FFR materials. LR of MS2 was a function of model-specific IFM UV-C doses. SIGNIFICANCE AND IMPACT OF THE STUDY: Filtering facepiece respirators are in high demand during infectious disease outbreaks, potentially leading to supply shortages. Reuse of disposable FFRs after decontamination has been discussed as a possible remediation strategy, but to date lacks supporting scientific evidence. The methods described here can be used to assess the likelihood that UV-C decontamination will be successful for specific FFR models. Journal of Applied Microbiology
AIMS: To develop a method to assess model-specific parameters for ultraviolet-C (UV-C, 254 nm) decontamination of filtering facepiece respirators (FFRs). METHODS AND RESULTS: UV-C transmittance was quantified for the distinct composite layers of six N95 FFR models and used to calculate model-specific α-values, the percentage of the surface UV-C irradiance available for the internal filtering medium (IFM). Circular coupons, excised from the FFRs, were exposed to aerosolized particles containing MS2 coliphage and treated with IFM-specific UV-C doses ranging from 38 to 4707 J m(-2). Models exposed to a minimum IFM dose of 1000 J m(-2) demonstrated at least a 3 log reduction (LR) in viable MS2. Model-specific exposure times to achieve this IFM dose ranged from 2 to 266 min. CONCLUSIONS: UV-C transmits into and through FFR materials. LR of MS2 was a function of model-specific IFM UV-C doses. SIGNIFICANCE AND IMPACT OF THE STUDY: Filtering facepiece respirators are in high demand during infectious disease outbreaks, potentially leading to supply shortages. Reuse of disposable FFRs after decontamination has been discussed as a possible remediation strategy, but to date lacks supporting scientific evidence. The methods described here can be used to assess the likelihood that UV-C decontamination will be successful for specific FFR models. Journal of Applied Microbiology
Authors: Edward M Fisher; John D Noti; William G Lindsley; Francoise M Blachere; Ronald E Shaffer Journal: Risk Anal Date: 2014-03-04 Impact factor: 4.000
Authors: Khaled Al-Hadyan; Ghazi Alsbeih; Ahmad Nobah; Jeffrey Lindstrom; Sawsan Falatah; Nawarh Faran; Salem Al-Ghamdi; Belal Moftah; Rashed Alhmaid Journal: Int J Environ Res Public Health Date: 2021-07-04 Impact factor: 3.390