Optimization of an ultraviolet LED radiation system for COVID‑19 disinfection and sterilization
Ultraviolet germicidal irradiation (UVGI, 254-nm) effectively inactivates or kills microorganisms. This has led to numerous applications, including disinfection of infectious airborne particles and sterilization of equipment and surfaces in healthcare settings. However, the effectiveness of UVGI is dependent upon types of microorganisms present, the contaminated surface or material, and culture environment (liquid or solid). As such, the efficacy of UVGI requires scenario-specific testing. Studies that have investigated UVGI sensitivities of different bacteria and viruses often determine the UV irradiance level required to decrease the bacterial cell number by one logarithmic order, and this value ranges from 13 to 73.3 W-m-2. Different irradiance levels need to be adjusted according to different environmental settings, such as decontamination of personal protective equipment (PPE), hand-held equipment, food preparation or vending premises and large surface areas. In response to the COVID‑19 pandemic, we aim to optimize an ultraviolet light emitting diode (LED) radiation (254 nm) system for disinfection or sterilization of different surfaces. This work adds a new and timely element to our ongoing collaborative research with our industry partner (U Technology) by using of our significant expertise in LED technology and modified LED configurations. Importantly, it is strengthened by an intra-institutional collaboration between the Departments of Bioresource Engineering and Microbiology and Immunology at McGill University. This in-depth study on UVGI dosage and coverage area will allow for improvements to a UV-LED irradiation system, better our understanding of the effectiveness of UVGI on pathogens, including SAR-CoV-2, and help mitigate the transmission of COVID‑19 in healthcare settings, long-term facility-based care or other indoor spaces.