Face masks provide high outward protection despite peripheral leakage: Insights from a reduced-order model of face mask aerodynamics
Face masks provide high outward protection despite peripheral leakage: Insights from a reduced-order model of face mask aerodynamics
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DOI：
10.1063/5.0153513
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发表时间：
2023-06
影响因子：
4.6
通讯作者：
Tomas Solano;K. Shoele;R. Mittal
中科院分区：
文献类型：
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作者：
Tomas Solano;K. Shoele;R. Mittal
介绍了面罩空气动力学和气溶胶过滤的降阶模型。该模型结合了不同类型口罩过滤效率的现有经验数据，以及呼出气溶胶颗粒的尺寸分布。通过考虑实际的周边间隙轮廓，我们的模型估计了周边泄漏的程度以及口罩在外部防护方面的过滤效率。采用真实周边间隙轮廓的模拟表明，对于外科口罩，即使平均周边间隙仅为 0.65 毫米，呼出气流总量的 80% 或更多也可能通过面罩周边泄漏。然而，大多数呼出的气溶胶颗粒不会沿着流动路径穿过外围间隙，而是直接撞击面罩织物。因此，尽管周边泄漏量很大，这些口罩仍能过滤掉大约 70% 的呼出颗粒。为了验证我们的模型，我们将其预测与实验数据进行了比较，我们发现在估计外科口罩提供的外部保护方面存在合理的一致性。这一验证强调了我们的模型在评估外科口罩功效方面的可靠性。此外，利用从我们的模型中获得的见解，我们探讨了口罩的使用对社区内呼吸道病毒传播的影响。通过考虑各种情况，我们可以评估通过广泛采用口罩来减少病毒传播的潜力。
A reduced-order model of face mask aerodynamics and aerosol filtration is introduced. This model incorporates existing empirical data on filtration efficiency for different types of face masks, as well as the size distribution of exhaled aerosol particles. By considering realistic peripheral gap profiles, our model estimates both the extent of peripheral leakage and the fitted filtration efficiency of face masks in terms of outward protection. Simulations employing realistic peripheral gap profiles reveal that, for surgical masks, 80% or more of the total exhaled airflow could leak through the mask periphery, even when the average peripheral gap measures only 0.65 mm. However, the majority of exhaled aerosol particles do not follow the flow path through the peripheral gaps but, instead, impact directly on the mask fabric. As a result, these face masks can filter out approximately 70% of the exhaled particles despite the significant peripheral leakage. To validate our model, we compare its predictions with experimental data, and we find a reasonable agreement in estimating the outward protection provided by surgical masks. This validation underscores the reliability of our model in assessing the efficacy of surgical masks. Moreover, leveraging the insights gained from our model, we explore the impact of mask usage on the transmission of respiratory viruses within communities. By considering various scenarios, we can assess the potential reduction in viral spread achieved through widespread mask adoption.