Don’t put your faith in the many advertisements for ultraviolet light machines making claims that they destroy SARS-CoV-2, the virus that causes COVID-19. They have not been shown to be effective, and UV rays strong enough to kill a virus may also damage your skin and eyes. Rays from most of these lamps cover such a small area that they have not yet been shown to disinfect large areas. Pulsed xenon lamps can disinfect hospital rooms, but these strong light rays can harm you, so that they can be used only when nobody is in the room. I do not recommend any ultraviolet lights for home use.

Especially beware of ultraviolet lights that emit UVC rays, the strongest and most damaging ultraviolet rays. The FDA reports that, “The effectiveness of UVC lamps in inactivating the SARS-CoV-2 virus is unknown because there is limited published data about the wavelength, dose, and duration of UVC radiation required to inactivate the SARS-CoV-2 virus” (Aug 21, 2020). Ultraviolet rays are classified by wavelength into UVA, UVB, and UVC. Only UVA and UVB pass from the sun to reach you. You are not normally exposed to UVC because UVC from the sun is absorbed by the ozone in the earth’s atmosphere and does not reach the earth. If it did reach the earth, it could cause severe sunburns and skin cancers. Never look directly at a UVC lamp:
• Some UVC lamps generate ozone, which can damage your lungs and increase risk for infections
• UVC can degrade plastic, polymers, and dyed textiles
• Some UVC lamps contain harmful amounts of mercury