Translation Section Editors
Prof. Wan-Chen Lee, ScD
Take typical surgical masks for example. The proper way to wear one is described as the following steps:
If the mask is to be reused after being taken off, it is recommended to first fold the mask in half with the contaminated side (colored side) of the mask inwards. Then fold the mask further in half (a quarter of its original size) by taking one of the shorter sides and folding it to the other. Store the mask in a clean, airy container. The container used to keep the mask should also be discarded or cleaned regularly.
Face masks are classified into different types according to different filtration efficiency for particulate matters of different sizes. Generally, the masks commonly used by the public belongs to the air-purifying type and are disposable. They are designed mainly for protection from particulate pollutants. A face fit test is to check whether a respirator properly fits the face of someone who wears it. In addition to the filtration efficiency, the levels of the seal between the mask and the human face should also be understood. Therefore, a face fit test usually involves using a numeric result called a “fit factor” which refers to the average concentration of environmental pollutants divided by the average concentration of pollutants inside the protective equipment (e.g., a respirator). To put it simply, it is the ratio of the concentration of the pollutants inside and outside the mask. The face fit test is conducted in two ways: Qualitative Fit Test (QLFT) and Quantitative Fit Test (QNFT). The former relies on the user’s senses such as taste, smell, or stimulus-response to identify whether they could feel the relatively irritating particulate matters such as banana oil and saccharine when they are sprayed around the face mask. If the user feels that they can sense the test agents at any time during the testing process, it means that the mask fails to properly fit the face. While this test is simpler and more subjective, the quantitative test involves using an instrument to measure the particle concentration inside and outside the facepiece, rather than relying on the user’s sensory response to the test agent.
The protective effect of a mask relies on the tight fit and the use of materials with low resistance, and high filtration efficiency. A loose fit can lead to reduced protection of the mask. As a result, it is critical to pay attention to the fit of a mask while wearing it. For the general public, it is important to understand the procedure mask as stated above. For healthcare workers, a fit check must be performed when they wear N95 respirators before entering the negative pressure isolation room. A fit check has two types: negative pressure and positive pressure fit check. However, Professor Chih-Chieh Chen pointed out that a fit test cannot be replaced by a fit check. A more comprehensive respiratory protection program should be in place to protect health professionals from exposure to risks.
Take the disposable face mask for example. It is recommended that one choose a mask that best fit his or her face shape. If there are folds or openings between the mask and the face, the user should adjust the metal strip as previously mentioned. Furthermore, Professor Quan-Yu Lai suggested three alternative approaches to improve the mask fit, shown as follows.
Last but not least, remember to adjust the mask if there is any improper wearing of the mask. Only if one wears a mask appropriately to increase mask fit can one succeed in attaining respiratory protection from masks.
Press release by the Health Promotion Administration titled “HPA remind citizens of self-protection upon air pollution; proper steps to wear a mask are opening, wearing, pressing and sealing.” https://www.hpa.gov.tw/Pages/Detail.aspx?nodeid=1405&pid=10218
How to wear masks appropriately, a promotion film for disease control by Executive Yuan.
A Special Issue from Taiwan Occupational Hygiene Association on Apr 7, 2020. http://tohahost.reni.com.tw/ContentLibrary/host/TOHANewsletter/TOHANewsletter_specialissue_COVID19_NEW_20200410.pdf
Qualitative Fit Test of Respiratory Protective Equipment https://www.youtube.com/watch?v=-5gwVhOSvaI
Translation Associate Editor
Pei-Yi Chen, Yun-Chen Liu
Nan-Su Huang, Te-Chun Liu
Yi-Yun Cheng, Yao-Chung Chang