Abstract
Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as a serious threat to human health worldwide. The inactivation of SARS-CoV-2 on object surfaces and in the indoor air might help to halt the COVID-19 pandemic. Far-ultraviolet light (UVC) disinfection has been proven to be highly effective against viruses and bacteria. To understand the wavelength and duration of UVC radiation required for SARS-CoV-2 inactivation, we examined the efficacy of UVC light prototype devices with the wavelengths of 275, 254, and 222 nm. The disinfection effectiveness was determined by cell-based assays including the median tissue culture infectious dose (TCID50) and an immunofluorescent assay on African green monkey kidney epithelial Vero E6 cells. Among the three prototypes, the UVC LED (275 nm) had the best virucidal activity with a log-reduction value (LRV) >6 after 10 s of exposure. The mercury lamp (254 nm) reached similar virucidal activity after 20 s of exposure. However, the excimer lamp (222 nm) showed limited anti-SARS-CoV-2 activity with a LRV < 2 after 40 s of exposure. Overall, in comparison, the UVC LED (275 nm) exhibited superior SARS-CoV-2 disinfection activity than the mercury lamp (254 nm) and the excimer lamp (222 nm).
Highlights
UVC light air and surface disinfection have attracted considerable attention, and several products have been released in the market since the COVID-19 pandemic began
We further found that UVC LEDs (275 nm) exhibited a superior disinfection ability against SARS-CoV-2 compared to mercury lamps (254 nm) and excimer lamps (222 nm)
We found that there is more than a 99.9999% reduction in the virus count even after 20 s of exposure using a mercury lamp at 254 nm, which is more effective than the study mentioned above
Summary
The most effective way to halt the pandemic is to prevent the spread by disrupting the viral transmission routes. Pathogens, such as viruses, can transmit and spread through the atmosphere or contact with a contaminated surface. Many methodological approaches, such as heat sterilization, chemical disinfectant, ventilation, and ultraviolet (UV) irradiation can help to reduce the risk of viral infection [5]. UVC light air and surface disinfection have attracted considerable attention, and several products have been released in the market since the COVID-19 pandemic began
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
