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. 2021 Sep 2;11(9):e045557. doi: 10.1136/bmjopen-2020-045557

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© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

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The six designs are displayed with an image of them on a user in the second column, and the filter material used in the third column. The last two columns present the respirators stratified by standardised face size of the user. Radial bar plots display overall fit factor from the OSHA 7-minute standardised fit test for each design as well as the 3M N95 for regular and small size standardised users. Green bars represent passing scores, 100 or greater, while red bars indicate failing scores. Areas noted by users to leak air were highlighted. OSHA, Occupational Safety and Health Administration.