Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Institute of Environmental Engineering, Zurich, Switzerland.
Laboratory for Advanced Analytical Technologies, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, Switzerland.
Indoor Air. 2022 Oct;32(10):e13127. doi: 10.1111/ina.13127.
The protection provided by facemasks has been extensively investigated since the beginning of the SARS-CoV-2 outbreak, focusing mostly on the filtration efficiency of filter media for filtering face pieces (FFP), surgical masks, and cloth masks. However, faceseal leakage is a major contributor to the number of potentially infectious airborne droplets entering the respiratory system of a susceptible individual. The identification of leaking spots and the quantification of leaking flows are crucial to estimate the protection provided by facemasks. This study presents a critical review on the measurement and calculation of facemask leakages and a quantitative analysis of their role in the risk of SARS-CoV-2 infection. It shows that the pairing between the mask dimensions and the wearer's face is essential to improve protection efficiency, especially for FFP2 masks, and summarizes the most common leaking spots at the interface between the mask and the wearer's face. Leakage is a crucial factor in the calculation of the protection provided by facemasks and outweighs the filtration performances. The fit factors measured among mask users were summarized for different types of face protection. The reviewed data were integrated into a computational model to compare the mitigation impact of facemasks with vaccination with consideration of new variants of SARS-CoV-2. Combining a high adoption rate of facemasks and a high vaccination rate is crucial to efficiently control the spread of highly infectious variants.
自 SARS-CoV-2 爆发以来，人们广泛研究了口罩的防护作用，主要集中在过滤式面罩（FFP）、外科口罩和布口罩的过滤介质的过滤效率上。然而，面罩贴合不紧密是导致大量潜在传染性飞沫进入易感个体呼吸系统的主要原因之一。确定泄漏点并量化泄漏流量对于估计口罩的防护作用至关重要。本研究对口罩泄漏的测量和计算进行了批判性评估，并对其在 SARS-CoV-2 感染风险中的作用进行了定量分析。结果表明，口罩尺寸与佩戴者面部的匹配对于提高防护效率至关重要，尤其是对于 FFP2 口罩，并且总结了口罩与佩戴者面部之间最常见的泄漏点。泄漏是计算口罩防护作用的关键因素，比过滤性能更为重要。不同类型的面部防护口罩的使用者的适配因子测量值进行了总结。对已审查的数据进行了整合，并纳入计算模型中，比较了在考虑 SARS-CoV-2 新变体的情况下，口罩和疫苗接种对减轻感染的影响。因此，要有效控制高传染性变异的传播，提高口罩的采用率和高疫苗接种率至关重要。
