  Bale et al. [1] perform a numerical study of droplet/aerosol transport in the
air to assess the probability of airborne transmission of COVID-19 from an
infected person to a nearby healthy person. In their numerical study, the air
flow field is solved by an implicit large eddy simulation model, and the
airborne transport of the droplets/aerosols exhaled from an infected person is
solved by a Lagrangian particle model which considers droplet/aerosol
evaporation. In the model used for droplets/aerosols, I found that an
unrealistic assumption is used which may have a significant impact on the
numerical accuracy: Droplet nuclei contained in real respiratory
droplets/aerosols are neglected.
