A simplified model has been devised to estimate the falling dynamics of severe acute respiratory syndrome corona-virus 2 (SARS-CoV-2)-laden droplets in an indoor environment. Our estimations were compared to existing literature data. The spread of SARS-CoV-2 is closely coupled to its falling dynamics as a function of respiratory droplet diameter (1 to 2000 μm) of an infected person and droplet evaporation. The falling time of SARS-CoV-2 with a respiratory droplet diameter of about 300 μm from a height of 1.7 m remained almost the same among the Newtonian lift equation, Stokes’s law, and our simplified model derived from them so as to account for its evaporation. The evaporative demand peaked at midday which was ten times that at midnight. The evaporating droplets \(\le\) 6 μm lost their water content rapidly, making their lifetimes in the air shorter than their falling times. The droplets \(\le\) 6 μm were able to evaporate completely and remained in the air for about 5 min as droplet nuclei with SARS-CoV-2.

已经设计了一个简化模型来估计室内环境中载有严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 的飞沫的下降动态。我们的估计与现有的文献数据进行了比较。SARS-CoV-2 的传播与其下降动态密切相关，后者是感染者呼吸道飞沫直径（1 至 2000 μm）和飞沫蒸发的函数。在牛顿升力方程、斯托克斯定律和我们从它们推导出的简化模型中，呼吸液滴直径约 300 μm 的 SARS-CoV-2 从 1.7 m 的高度下降的时间几乎相同，以解释其蒸发。蒸发需求在中午达到峰值，是午夜的十倍。蒸发的液滴\(\le\)6 μm 迅速失去水分，使其在空气中的寿命比下降时间短。6 μm的液滴\(\le\)能够完全蒸发并作为液滴核与 SARS-CoV-2 一起在空气中停留约 5 分钟。