Investigation of airborne infection through coughing by using numerical analysis

In this paper, airborne infection caused by coughed airflow is investigated in a calm environment using transient CFD analysis on the dispersion of the coughed airflow. The dispersion phenomena of the airflows generated by coughing and exhaling in a calm room with two occupants were reproduced using the CFD analysis based on the unsteady models of coughing and breathing. The concentration simulation was coupled to reproduce the dispersion of the coughed air. The simulation results indicate that: 1) the indoor flow field is mainly determined by the air current from the air-conditioner, the rising warm stream due to the occupants' metabolic heat, and the expelled airflows of the occupants in a calm environment; 2) although the coughed airflow initially travels at high speed unaffected by the indoor airflow, it soon dissipates as its velocity drops sharply; 3) there is a less than 0.02% probability for the coughed air and aerosols to be inhaled by another occupant Moreover, according to the simulation results, airborne infection probably occurs within close proximity of the infector and is greatly influenced by the ventilation conditions.