Validated computational modeling to evaluate spatial inactivation of airborne pathogens by Far‐ UVC irradiation

Recent experimental studies have indicated the potential for ultraviolet C irradiation at 222 nm (Far-UVC) to be used in occupied rooms to safely reduce exposure to airborne pathogens. We present simulations coupling Monte Carlo radiation transfer with computational fluid dynamics to predict the spatial variation in airborne microorganism inactivation. Our simulations effectively reproduce data from steady-state experiments in a room-sized bioaerosol chamber for the reduction of aerosolized Staphylococcus aureus. Application of the validated model suggests that germicidal Far-UVC lamps could reduce levels of airborne human coronavirus by more than 90% in rooms with low ventilation rates. Depending on the UVC susceptibility of the aerosolized pathogen, Far-UVC lamps have the potential to provide in excess of 100 equivalent air changes per hour, much greater than is possible with mechanical ventilation or filtration devices. The success of our simulations at reproducing the experimental data provides confidence that we can simulate larger environments where steady-state airflow is appropriate and inform best practices for installations of germicidal Far-UVC lamps.