Abstract
Infectious respiratory diseases such as the current COVID-19 have caused public health crises and interfered with social activity. Given the complexity of these novel infectious diseases, their dynamic nature, along with rapid changes in social and occupational environments, technology, and means of interpersonal interaction, respiratory protective devices (RPDs) play a crucial role in controlling infection, particularly for viruses like SARS-CoV-2 that have a high transmission rate, strong viability, multiple infection routes and mechanisms, and emerging new variants that could reduce the efficacy of existing vaccines. Evidence of asymptomatic and pre-symptomatic transmissions further highlights the importance of a universal adoption of RPDs. RPDs have substantially improved over the past 100 years due to advances in technology, materials, and medical knowledge. However, several issues still need to be addressed such as engineering performance, comfort, testing standards, compliance monitoring, and regulations, especially considering the recent emergence of pathogens with novel transmission characteristics. In this review, we summarize existing knowledge and understanding on respiratory infectious diseases and their protection, discuss the emerging issues that influence the resulting protective and comfort performance of the RPDs, and provide insights in the identified knowledge gaps and future directions with diverse perspectives.
Highlights
We have witnessed an increasing prevalence of infectious diseases, including SARS (2002–2003), H1N1 influenza (2009), and MERS (2012–2016) [1], that disrupt social activity and pose severe threats to human health and safety
Filtration efficiency ranged from 58% to 96%; for viral aerosol, filtration efficiency ranged from 51% to 90%
Double layer tea towel, and vacuum cleaner bag had similar filtration efficiencies (>94% for bacteria; >85% for viruses); double layer T-shirt did not offer any improvement over single layer [122]
Summary
We have witnessed an increasing prevalence of infectious diseases, including SARS (2002–2003), H1N1 influenza (2009), and MERS (2012–2016) [1], that disrupt social activity and pose severe threats to human health and safety. As of 21 November 2021, the ongoing COVID-19 pandemic has resulted in more than 257 million infections and 5.1 million deaths (Figure 1) [2,3,4,5]. The human-to-human transmission of the above diseases occurs through both indirect (e.g., via fomites) and direct contact. The latter includes droplets (aerodynamic particle sizes >5–10 μm) and airborne transmission by droplet nuclei (i.e., virus-laden aerosols; aerodynamic particle sizes
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