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. 2021 Sep;25(9):976–980. doi: 10.5005/jp-journals-10071-23947

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Copyright © 2021; Jaypee Brothers Medical Publishers (P) Ltd.

© Jaypee Brothers Medical Publishers. 2021 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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Equation 1 — Overall fit factor (FF) calculation using quantitative fit test. ff1, fit factor normal breathing; ff2, deep breathing; ff3, head side to side; ff4, head up and down; ff5, reading aloud, ff6, bending over and ff7, normal breathing again.