  We predict and analyze the drying time of respiratory droplets from a
COVID-19 infected subject, which is a crucial time to infect another subject.
The drying of the droplet is predicted by diffusion-limited evaporation model
for a sessile droplet placed on a partially-wetted surface with a pinned
contact line. The variation of droplet volume, contact angle, ambient
temperature, and humidity are considered. We analyze the chances of the
survival of the viruses present in the droplet, based on the lifetime of the
droplets in several conditions, and find that the chances of survival of the
virus are strongly affected by each of these parameters. The magnitude of shear
stress inside the droplet computed using the model is not large enough to
obliterate the virus. We also explore the relationship between the drying time
of a droplet and the growth rate of the spread of COVID-19 for five different
cities, and find that they are weakly correlated.
