The increasing prevalence of infectious diseases in recent decades has posed a serious threat to public health. Routes of transmission differ, but the respiratory droplet or airborne route has the greatest potential to disrupt social intercourse, while being amenable to prevention by the humble face mask. Different types of masks give different levels of protection to the user. The ongoing COVID-19 pandemic has even resulted in a global shortage of face masks and the raw materials that go into them, driving individuals to self-produce masks from household items. At the same time, research has been accelerated towards improving the quality and performance of face masks, e.g., by introducing properties such as antimicrobial activity and superhydrophobicity. This review will cover mask-wearing from the public health perspective, the technical details of commercial and home-made masks, and recent advances in mask engineering, disinfection, and materials and discuss the sustainability of mask-wearing and mask production into the future. 2020 https://creativecommons.org/licenses/by/4.0/ Exclusive Licensee Science and Technology Review Publishing House. Distributed under a Creative Commons Attribution License (CC BY 4.0). The increasing prevalence of infectious diseases in recent decades has posed a serious threat to public health. Routes of transmission differ, but the respiratory droplet or airborne route has the greatest potential to disrupt social intercourse, while being amenable to prevention by the humble face mask. Different types of masks give different levels of protection to the user. The number of particles generated varied greatly across individuals, raising the possibility of superspreaders who could be the primary spreaders of viruses by talking [ 31 ]. 2.2. Mechanistic Effect of Wearing a Mask Masks and other PPE items serve as a physical barrier to respiratory droplets. With imaging using laser light scattering, it was found that the number of flashes, which corresponds to the number of The rate of emission of particles correlates with voice loudness during speech or other vocal activities [ 38 ]. A physical obstruction that prevents the wearer from touching the face, a mask may lead to better hand hygiene [ 24 ]. The reverse is also true—an increased tendency for wearers to touch their faces, such as when adjusting their masks [ 39 ]. Even with the right mask, wearers can still be infected if droplets enter via the eyes, thus highlighting the importance of additional protection [ 40 ]. Masks also reduce the risk of environmental contamination by respiratory droplets [ 24 ]. As mentioned, SARS-CoV-2 transmission via fomites has been documented [ 24 ]. Unlike the BFE test, the agar plates in the Andersen sampler are first inoculated with E. coli , and areas in contact with the viral droplets become clear as the bacteria cells are lysed to form plaques. The VFE value is calculated by comparison with a control without the filter material as described above for BFE. 3.3.4. Fluid Resistance Fluid resistance evaluates the mask's ability to act as a barrier to the transfer of fluids from its outer to its inner layers due to spraying or splashing. Masks Made from Household Materials The surge in demand worldwide for commercial face masks during the COVID-19 pandemic has led to a global shortage of supplies for both physical products as well as raw materials [ 80 ]. In this circumstance, making a mask at home can be a life-guarding action [ 81 ]. Homemade masks may vary from the commercial ones in terms of structural integrity and effectiveness, but they are cheap and accessible. Wearing a simple cloth mask is far better than wearing no mask to safeguard the wearer and the others' health [ 81 , 82 ]. Using commonly available household materials, it is easy to fabricate simple masks that may block respiratory droplets from the wearer. Decontamination of Face Masks The worsening and prolonging of the COVID-19 pandemic have led to a surge in daily consumption and demand of PPE items, including face masks, by frontline healthcare workers, which resulted in a global shortage of face masks and raw materials. Unfortunately, the production of masks cannot be easily ramped up to meet this sudden surge in demand. further evaluated the viability of using microwave steam bags to perform MGS decontamination of FFRs, where the method yielded 99.9% efficiency in killing MS2 phage with a filtration efficiency of posttreated FFRs remaining above 95% [ 120 ]. More recently, Ma et al. subjected face masks made of melt-blown polypropylene to steam treatments of different durations (20–120 minutes) and found that they were still able to effectively block 98 to 99% of aerosolized H120 virus [ 121 ]. Likewise, Xiang et al. The Development of Masks with Antimicrobial Activity While face masks can offer some form of protection against airborne and droplet-borne pathogens entering our airway through the mouth and nose, contact with the outer layer of the mask, such as with hands during mask adjustment, removal, or even disposal, can nonetheless result in self-inoculation of pathogenic microbes. A recent study showed that the SARS-CoV-2 virus can remain infectious on the outer layer of the surgical mask even after 6 days [ 197 ]. As international travel bans gradually lift, airlines require passengers to don masks at all times. Experts are anticipating a prolonged period of such measures as the world battles the disease. Even when we leave the shadows of the COVID-19 pandemic, we prepare and anticipate future health crises, especially those of a respiratory and infectious nature. We could perhaps no longer treat mask-wearing as a temporary solution but to adapt to having face masks as part of our staple of accessories. With that comes an array of peripheral issues and problems to address, not necessarily medical in nature, in the “new norm.” The following paragraphs aim to highlight several of these.