Study on the fit of nonwoven face masks on different face shapes

In the midst of the global COVID-19 pandemic, airborne infectious diseases, including contagious tuberculosis and illnesses transmitted through airborne droplets, such as influenza, SARS, and avian influenza, have emerged as some of the most severe pandemics in human history. Face masks have become an essential everyday item, despite their previous use primarily for the sick. Current mask designs come in various sizes; however, they may not be suitable for all face shapes, particularly for individuals with smaller or frequently moving facial features. Therefore, there is a need for research, especially focusing on women and individuals with smaller faces, to enhance the effectiveness of face masks in providing adequate protection. Accordingly, this study examined the current typical mask design 'normal mask' and four proposed mask designs for five face shapes (round, diamond, oval, square, or oblong) by using a quantitative fit test, as suggested in ISO 16975-3 and OSHA 29 CFR1910.134, to determine the masks' fit factor (FF). The FF of the normal mask was 80% on round faces, 66% on diamond faces, but only 41% on square and oblong faces. The FaceMe artificial intelligence program was used to modify the face mask design in accordance with each face shape, and the level of air leakage was evaluated. The results showed that modifying the mask edges could reduce air leakage, especially during movements. For square faces, the leakage level was reduced from 63% (normal mask) to 38% (line mask). For oblong faces, the normal mask had a leakage level of 63%, whereas wave masks reduced leaking to 34%, resulting in a reduction of almost 30%. Mask fit could also be improved by adjusting earloop tightness.