Exposure generated by cough released droplets in the indoor environment - A comparison among four ventilation systems

Abstract

Respiratory secretions from an infected person can be aerosolized through expiratory activities and dispersed through indoor environment due to the airflow pattern generated with air delivery system. This study shows that Desktop Personalized Ventilation has the highest ability to provide protection of the users from the airborne transmission of infectious diseases. Among total volume systems Displacement ventilation shows the best performance for the supply flow rate of 6 ACH. When supply flow rate was 12 ACH Mixing Ventilation showed the best protective performance. At various distances between infected occupant and susceptible occupant (1 m, 2 m, 3 m and 4 m) ventilation systems have different performance but Desktop Personalized Ventilation showed the best protective ability from cough droplets released from sitting and standing height. Flow field analysis revealed that Desktop Personalized Ventilation flow provides additional protection by diluting cough released droplets in the breathing zone. Mixing Ventilation and Underfloor Ventilation systems dilute droplets in the total volume of room with airflow patterns generated while Displacement ventilation removes cough released droplets with convective boundary layer generated around the heated human body.