Assessing the Filtration Effectiveness of a Portable Ultraviolet Air Cleaner on Airborne SARS-CoV-2 Laden Droplets in a Patient Room: A Numerical Study

Abstract

It has been confirmed that SARS-CoV-2 can infect humans via airborne transmission from person to person. Accordingly, there are two concerns about the exhaled airborne SARS-CoV-2 aerosol emitted from the coughs or sneezes of COVID-19 patients: (1) It might infect healthcare providers in the same confined patient rooms; (2) It might enter the main ventilation system and transmit to other patient room as a health threat. Therefore, a portable ultraviolet (UV) air cleaner is designed to mitigate the exposure risks to SARS-CoV-2 laden droplets in the patient room. Using the experimentally validated computational fluid-particle dynamics (CFPD) model, this study simulated the airborne transmission, deposition, and clearance of the COVID-19 virus-laden droplets emitted from a virtual patient in a virtual patient room with realistic ventilation conditions and various operating conditions of the portable UV air cleaner. Parameter analysis was performed to investigate how the ventilation conditions and the operation conditions of the sanitizer can influence the effectiveness of the filtration, which are quantified by the reduction of the concentration of virus-laden droplets suspended in the room and escaped from the room into the main ventilation system. Results indicate that the air cleaner is effective in virus-laden droplets clearance if placed in appropriate locations. In addition, maximizing the ventilation flow rate of the air cleaner will provide the best mitigation effect, with the highest filtration efficiency.