Airborne Transmission Risk in Urban Buses: A Computational Fluid Dynamics Study

The Heat, Ventilation, Air Conditioning (HVAC) systems in urban buses promote high particle motion. In this paper the effect of centralized roof-top HVAC on virus transmission by droplets caused sneezing and coughing was studied with Lagrangian approach while through aerosols breathing talking modeled Eulerian tracer method. It found that large (> 200 μm) can travel more than 3 m without being affected airflow. On other hand, small (< 5 are easily dragged, dispersed, also captured HVAC. quickly spread reduces concentration central zone, but it is ineffective to renew air front rear sides. Wells-Riley risk model showed average across whole bus be reduced a half quarter renewing cabin 10 times per hour.