Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana, Slovenia.
J Biol Phys. 2021 Mar;47(1):1-29. doi: 10.1007/s10867-020-09562-5. Epub 2021 Feb 10.
A large number of infectious diseases are transmitted by respiratory droplets. How long these droplets persist in the air, how far they can travel, and how long the pathogens they might carry survive are all decisive factors for the spread of droplet-borne diseases. The subject is extremely multifaceted and its aspects range across different disciplines, yet most of them have only seldom been considered in the physics community. In this review, we discuss the physical principles that govern the fate of respiratory droplets and any viruses trapped inside them, with a focus on the role of relative humidity. Importantly, low relative humidity-as encountered, for instance, indoors during winter and inside aircraft-facilitates evaporation and keeps even initially large droplets suspended in air as aerosol for extended periods of time. What is more, relative humidity affects the stability of viruses in aerosol through several physical mechanisms such as efflorescence and inactivation at the air-water interface, whose role in virus inactivation nonetheless remains poorly understood. Elucidating the role of relative humidity in the droplet spread of disease would permit us to design preventive measures that could aid in reducing the chance of transmission, particularly in indoor environment.
大量传染病通过呼吸道飞沫传播。这些飞沫在空气中能持续存在多久，能传播多远，以及它们可能携带的病原体能存活多久，这些都是飞沫传播疾病传播的决定性因素。这个课题极其多面，涉及多个学科领域，但物理学界对此很少关注。在这篇综述中，我们讨论了控制呼吸道飞沫及其内部任何病毒命运的物理原理，重点关注相对湿度的作用。重要的是，低相对湿度——例如，在冬季的室内和飞机内——有助于蒸发，并使即使最初较大的飞沫也能作为气溶胶在空气中长时间悬浮。此外，相对湿度通过几种物理机制影响气溶胶中病毒的稳定性，例如在气-水界面处的开花和失活，尽管其在病毒失活中的作用仍了解甚少。阐明相对湿度在疾病飞沫传播中的作用，可以使我们设计预防措施，有助于降低传播的机会，特别是在室内环境中。
