  Respiratory droplets exhaled during speaking, coughing or sneezing have been
responsible for the spread of the ongoing Covid-19 pandemic. The droplet
dynamics depend on the surrounding air velocity, temperature and relative
humidity. Droplets evaporate to form aerosols which contain the disease
spreading virus. In a confined space like an elevator, the risk of transmission
becomes higher when there is an infected person inside the elevator with other
individuals. In this work, a numerical study is carried out in a 3D domain
resembling an elevator using OpenFoam. Different modes of air circulation are
considered inside the elevator and the impact of these air circulations on
droplet dynamics is investigated. The scenario of the opening of elevator door
and the passenger leaving the elevator has also been considered in order to
simulate a real life condition. A pedantic analysis of certain risk assessment
factors and remedial measures to be adopted has been performed which include
the number of aerosols present in the zone of 0.8 to 1.8 m, the radial spread
of the suspended droplets around the mouth of the infected person. From these
factors, the safe condition can be understood. The time period up to which the
elevator will be risk prone has also been investigated in case the person
coughs just before leaving the elevator. After conducting these studies, the
quiescent environment has been found out to be the most dangerous whereas
ventilation with an exhaust fan is the safest.
