Transport of aerosol by coughing in an air-conditioned space

Aerosol generated from a human cough can be a major indoor health risk to surrounding individuals and even spread out via air-ventilation systems. This study aims to investigate the transport trajectory characteristics of coughed aerosols under the influence of ambient conditioned air ventilation as well as near-by humans. In this paper, a transient three-dimensional multiphase multi-component Eulerian-Lagrangian model has been established, which is numerically solved using commercial ANSYS Fluent code. The multi-component gas phase includes air and water vapor, while the multiphase is composed of a continuous phase of the gas mixture and a discrete phase of liquid aerosols. The coughed aerosols are modeled by defining its chemical components, size distribution, and evaporation property to mimic the actual situation. With this computational fluid dynamics (CFD) model, the indoor transport of coughed aerosols can be determined, particularly, the distributions of portions inhaled by individual person, deposited on surfaces of human body/wall/floor/ceiling, and re-circulated into the ventilation system. Results show that the coarse droplets affect most for human dummy in front of the coughing subject. Most fine aerosol droplets end up on the surface of four walls plus ceiling and floor. It also depicts that air circulation intensity could be a strong factor of influencing the aerosol transport.