Effects of Ultraviolet C (Uvc) Light and Dry Heat on Filtration Performance of N95 Respirator Mask

Abstract

Background: The emergence of the Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) creates one of the most pressing issues with a severe shortage of personal protective equipment (PPE) particularly N95 respirators in healthcare settings worldwide. Recently, possible strategies to decontaminate disposable N95 respirators, including using ultraviolet C (UVC) irradiation and heat treatment, were reported to consider safely reusing the respirators. However, both methods create potential risks to reduce the ability of the respirator filter especially when exposed to these methods multiple times resulting in infectious agents passing through the filter.
 Objective: The study aimed to ensure the effectiveness of UVC and dry heat to decontaminate N95 respirators.
 Methods: N95 respirators were exposed continually to UVC and dry heat at 70°C. Then the ability of the aerosol penetration was assessed by introducing an aerosol containing a rotavirus used as a delegate for SARS-CoV2. The existence of the rotavirus at both external (front) and internal surfaces (back) of the N95 respirators was investigated using RT-PCR.
 Results: UVC and dry heat administered at a 30-minute cycle up to 5 cycles did not change the filtration performance of the N95 respirators. Our results suggested that the reuse of disposable N95 respirators decontaminated by either UVC or dry heat could be possible under the test conditions used.
 Conclusion: To reuse N95 respirators, UVC and dry heat were useful to apply amid the pandemic of respiratory diseases.