ULTRAVIOLET RADIATION DISINFECTION FOR SARS-COV-2

INTRO: COVID-19 pandemic affected the entire globe and resulted in millions of deaths. Besides human-to-human respiratory droplets transmission, contact with aerosol-infected surfaces is an important way of transmitting this virus. The virus can be detected on many surfaces for a long time, in aerosols for at least 3 hours, and on plastic surfaces for up to 72 hours. Hence, it is crucial to determine how to disinfect the environment. Several biocidal agents have been used to clean the environment. Apart from biocidal agents, ultraviolet (UV) irradiation had also been used for environmental disinfection. However, there are several UV sources and systems with different wavelengths were used for disinfection and there was a wide range of effectiveness in disinfection with different modules. Thus, it was necessary to comprehensively review the current understanding of UV light used in disinfection to advise regarding UV light for environmental disinfection. METHODS: Using the keywords COVID-19, UV light, and disinfection from 2020 to 2022, we searched various databases for articles online. FINDINGS: We found various devices that had been studied for disinfection of SARS-CoV-2 with UV, such as monochromatic UV-C lamps, UV-LED light, broad- spectrum UV light devices, and excimer lamps. As a monochromatic UV source, different types of lamps were reported to have an excellent effect on disinfection, with the most common wavelength used for disinfection being 254 nm. As a broad-spectrum wavelength light, which is from 200 to 280 nm, one- minute exposure is enough to cause a 3 log10 reduction of viral load, which means 99.97% in disinfection. CONCLUSION: UV light are effective in coronavirus disinfection. Compared with the chemical agent, it is more environmentally friendly. To apply the UV light to environmental disinfection, five minutes is enough to reach 99.99% disinfection of the SARS-CoV-2 virus, for broad-spectrum wavelength light placed within one meter from the target surface.