Chin Yan Suen1†, Helen Hoi Ling Kwok 2†, Yuk Hang Tsui3,4†, Ka Hei Lui5,6, Hong Hang Leung1, Ka Wo Lam1, Karen Pik Shuen Hung1, Joseph Kai Cho Kwan This email address is being protected from spambots. You need JavaScript enabled to view it.1, Kin Fai Ho This email address is being protected from spambots. You need JavaScript enabled to view it.6 1 Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong † These authors contributed equally to this work
2 Institute for the Environment, Hong Kong University of Science and Technology, Hong Kong University of Science and Technology, Hong Kong
3 Department of Mathematics, The Hong Kong University of Science and Technology, Hong Kong
4 Department of Computer Science and Engineering, The Hong Kong University of Science and Technology, Hong Kong
5 Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong
6 The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong
Received:
June 19, 2023
Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.
Revised:
July 28, 2023
Accepted:
August 14, 2023
Download Citation:
||https://doi.org/10.4209/aaqr.230123
Suen, C.Y., Kwok, H.H.L., Tsui, Y.H., Lui, K.H., Leung, H.H., Lam, K.W., Hung, K.P.S., Kwan, J.K.C., Ho, K.F. (2023). Experimental and Computational Analysis of Surgical Mask Effectiveness Against COVID-19 in Indoor Environment. Aerosol Air Qual. Res. 23, 230123. https://doi.org/10.4209/aaqr.230123
Cite this article:
An experiment coupled with a computational analysis was conducted to investigate the effectiveness of surgical masks, which include KF94 and ASTM Level 1, in an indoor environment. The KF94 mask sample shows the highest filtration efficiency (99.9%) in the analysis. The simulation is consistent with the experimental results as the concentration of sodium chloride (NaCl) droplets is < 4% on average in the room. The ultraviolet-C (UVC) irradiation and dry heating samples are shown to retain the highest filtration efficiencies (> 97%) after 3 disinfection treatment cycles. All methods (boiling, steaming, ethanol treatment, and dry heating) effectively reduce the S. aureus load by 99.99%. The UVC irradiation shows exposure to 450 µW cm–2 for 10 minutes can effectively eliminate all S. aureus on the mask materials. Simulation shows the reduction in overall NaCl and carbon dioxide (CO2) levels is directly proportional to the filtration efficiency and the effectiveness of reused masks is also directly proportional to the filtration efficiency. The proxy indicator (CO2) for aerosol particles demonstrates that very fine respiratory droplets can penetrate the mask after reaching a steady state. The CO2 concentration increase shows that aerosol particles are accumulated under adequate ventilation and further pose the risk of infection. The NaCl droplets (2%) simulation shows that respiratory droplets have infiltrated the mask, but the mask demonstrates a higher ability to block the NaCl droplets and prevent their penetration. The findings suggest a need to revise the existing regulation of the control policy.HIGHLIGHTS
ABSTRACT
Keywords:
Surgical mask, Disinfection methods, COVID-19, Computational fluid dynamics, Indoor air quality
