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Variability of the penetration of particles through facemasks

Pushpawela, Buddhi and Amanatidis, Stavros and Huang, Yuanlong and Flagan, Richard C. (2022) Variability of the penetration of particles through facemasks. Aerosol Science and Technology, 56 (2). pp. 186-203. ISSN 0278-6826. doi:10.1080/02786826.2021.2003291.

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COVID-19 is transmitted, at least in part, by airborne particles emitted by infected individuals. Wearing masks is one of the key actions that are required to prevent spreading COVID-19. To understand the variability in the performance, we evaluated the material performance of the whole mask, as manufactured, in terms of the penetration of particles, comfort and the quality factor of multiple copies of 29 different types. All masks were mounted to prevent leakage around the edges so the mask material and manufacture was tested, but the effects of the fit were not considered. The results of this study thus represent the upper bound of the performance of facemasks since leakage around the edges due to poor fit often overwhelms filtration through the mask material. The tests were performed at a steady flow rate of 30 L/min; mean values of the performance parameters were calculated for two different sizes; 0.12 µm and 0.3 µm. Of the masks tested, for 0.12 µm particles, N95 face filtering respirators consistently had the lowest peak penetration 1.7 ± 0.5%, while KN95 masks allowed 3.7 ± 2.6% penetration. In contrast, penetration through pleated procedure masks was 14.7 ± 16.9% due to one outlier - with that outlier removed, penetration decreased to 7.1 ± 4.3%; cloth masks allowed 26.4 ± 9.3% penetration. Tests on multiple copies of different masks demonstrated consistent performance of N95s, but considerably greater variability within the other classes of masks tested, leading to uncertainty in the degree of protection that they would provide.

Item Type:Article
Related URLs:
URLURL TypeDescription
Pushpawela, Buddhi0000-0002-3633-4104
Amanatidis, Stavros0000-0002-4924-8424
Huang, Yuanlong0000-0002-6726-8904
Flagan, Richard C.0000-0001-5690-770X
Additional Information:© 2021 American Association for Aerosol Research. Received 30 Jun 2021, Accepted 21 Oct 2021, Accepted author version posted online: 30 Nov 2021, Published online: 16 Dec 2021. The authors acknowledge Professor Niles Pierce and Caltech book store for supplying some samples. The authors also like to thank Ryan Ward and Benjamin Laccetti for useful discussions. The research was supported by the Jacobs Institute for Molecular Engineering for Medicine, California Institute of Technology, Pasadena, CA. Author contributions: RCF planned and designed the experiments. BP, SA and YH prepared the experimental setup. BP carried out the measurements, analyzed the data, and generated the figures. BP and RCF wrote and edited the manuscript. All authors reviewed the manuscript. No potential conflict of interest was reported by the authors.
Group:COVID-19, Jacobs Institute for Molecular Engineering for Medicine
Funding AgencyGrant Number
Jacobs Institute for Molecular Engineering for MedicineUNSPECIFIED
Issue or Number:2
Record Number:CaltechAUTHORS:20220127-913884200
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Official Citation:Buddhi Pushpawela, Stavros Amanatidis, Yuanlong Huang & Richard C. Flagan (2022) Variability of the penetration of particles through facemasks, Aerosol Science and Technology, 56:2, 186-203, DOI: 10.1080/02786826.2021.2003291
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113129
Deposited By: Tony Diaz
Deposited On:28 Jan 2022 19:15
Last Modified:28 Jan 2022 19:15

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