Department of Engineering Physics, Tsinghua University, Beijing, China; Beijing Key Laboratory of City Integrated Emergency Response Science, Beijing, China.
Department of Engineering Physics, Tsinghua University, Beijing, China.
Environ Res. 2021 Sep;200:111751. doi: 10.1016/j.envres.2021.111751. Epub 2021 Jul 22.
A numerical study was conducted on the effects of ambient temperature and humidity on the transportation of sodium chloride particles (100 nm-1 μm) in a human airway model ranging from the nasal cavity to bronchi. A mucus-tissue structure was adopted to model the mass and heat transfer on the airway surface boundary. The temperature and humidity distributions of the respiratory flow were calculated and then the interaction between the particle and water vapor was further analyzed. It was predicted that the particle size grew to the ratio of 5-6 under subsaturation conditions because of hygroscopicity, which shifted the deposition efficiency in opposite directions on dependence of the initial particle size. However, the particles could be drastically raised to 40 times of the initial 100 nm diameter if the supersaturation-induced condensation was established, that was prone to occur under the cold-dry condition, and consequently promoted the deposition significantly. Such behavior might effectively contribute to the revitalized coronavirus disease 2019 (COVID-19) pandemic in addition to the more active virus itself in winter.
针对氯化钠颗粒（100nm-1μm）在人体气道模型（从鼻腔到支气管）中传输的情况，进行了一项环境温度和湿度影响的数值研究。采用黏液-组织结构对气道表面边界的质量和传热进行建模。计算了呼吸流的温度和湿度分布，然后进一步分析了颗粒与水蒸气之间的相互作用。预测在亚饱和条件下，由于吸湿性，颗粒尺寸会增长到 5-6 倍，这会根据初始颗粒尺寸的不同，使沉积效率朝相反的方向变化。然而，如果建立过饱和诱导凝结，颗粒的直径可能会急剧增加到初始的 100nm 直径的 40 倍，这在寒冷干燥的条件下更容易发生，从而显著促进了颗粒的沉积。这种行为可能会有效地促成 2019 年冠状病毒病（COVID-19）大流行的复苏，除了冬季病毒本身更加活跃之外。
