Wu Jialin, Weng Wenguo
Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, 100084, PR China; Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing, 100084, China.
Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, 100084, PR China; Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing, 100084, China.
Environ Res. 2021 Aug;199:111361. doi: 10.1016/j.envres.2021.111361. Epub 2021 May 21.
COVID-19 virus can replicate in the infected individual's larynx independently, which is different from other viruses that replicate in lungs only, e.g. SARS. It might contribute to the fast spread of COVID-19. However, there are few scientific reports about quantitative comparison of COVID-19 exposure dose (inhalation dose and adhesion dose) for the susceptible individual when the viruses were released from the larynx or lungs. In this paper, a typical numerical model was built based on a breathing human model with real respiratory tract. By using a computational fluid dynamics (CFD) method, two kinds of virus released sites in the infected individual's respiratory tract (larynx, lungs), seven kinds of particle sizes between 1 and 50 μm, three kinds of expiratory flow rates: calm (10 L/min), moderate (30 L/min) and intense (90 L/min) were used to compare the particle deposition proportion and escape proportion. The inhalation dose and the adhesion dose of the susceptible individual were quantified. The results showed that COVID-19 virus-containing droplets and aerosols might be released into the environment at higher proportions (39.1%-44.2%) than viruses that replicate in lungs only (15.3%-37.1%). The exposure doses (inhalation dose and adhesion dose) of the susceptible individual in different situations were discussed. The susceptible individual suffered a higher exposure dose when the viruses were released from the larynx rather than lungs (the difference for 1 μm particles was 1.2-2.2 times). This study provides a possible explanation for the higher transmission risk of COVID-19 virus compared to other viruses and some control advice of COVID-19 in typical indoor environments were also discussed.
新型冠状病毒肺炎（COVID-19）病毒可在受感染个体的喉部独立复制，这与仅在肺部复制的其他病毒（如严重急性呼吸综合征冠状病毒，SARS）不同。这可能有助于COVID-19的快速传播。然而，关于当病毒从喉部或肺部释放时，易感个体的COVID-19暴露剂量（吸入剂量和黏附剂量）的定量比较的科学报告很少。本文基于具有真实呼吸道的呼吸人体模型建立了一个典型的数值模型。通过使用计算流体动力学（CFD）方法，研究了受感染个体呼吸道中的两种病毒释放部位（喉部、肺部）、1至50μm之间的七种颗粒大小、三种呼气流量：平静（10L/min）、中等（30L/min）和剧烈（90L/min），以比较颗粒沉积比例和逃逸比例。对易感个体的吸入剂量和黏附剂量进行了量化。结果表明，与仅在肺部复制的病毒（15.3%-37.1%）相比，含COVID-19病毒的飞沫和气溶胶可能以更高的比例（39.1%-44.2%）释放到环境中。讨论了不同情况下易感个体的暴露剂量（吸入剂量和黏附剂量）。当病毒从喉部而非肺部释放时，易感个体遭受的暴露剂量更高（1μm颗粒的差异为1.2-2.2倍）。本研究为COVID-19病毒比其他病毒具有更高传播风险提供了一种可能的解释，并讨论了典型室内环境中COVID-19的一些控制建议。
