A Physics Modeling Study of SARS-CoV-2 Transport in Air

Anchordoqui, Luis A.; Dent, James B.; Weiler, Thomas J.

Health threat from SARS-CoV-2 airborne infection has become a public emergency of international concern. During the ongoing coronavirus pandemic, people have been advised by the Centers for Disease Control and Prevention to maintain social distancing of at least 2 m to limit the risk of exposure to the coronavirus. We carry out a physics modeling study for SARS-CoV-2 transport in air. We show that if aerosols and droplets follow semi-ballistic emission trajectories, then their horizontal range is proportional to the particle's diameter. For standard ambient temperature and pressure conditions, the horizontal range of these aerosols remains safely below 2 m. We also show that aerosols and droplets can remain suspended for hours in the air, providing a health threat of airborne infection. The latter argues in favor of implementing additional precautions to the recommended 2~m social distancing, e.g. wearing a face mask when we are out in public.