- A study has found that using ultraviolet C light with a wavelength of 222 nanometres (1 nanometre is a billionth part of 1 metre) effectively kills SARS-CoV-2, the virus that causes Covid-19.
- Ultraviolet light of wavelengths between 200 and 280 nm is known as ultraviolet C light, of UVC. Using 222 nm UVC light is safe around humans.
- As in vitro experiment by the researchers showed that 99.7 per cent of the SARS-CoV-2 viral culture was killed after a 30-second exposure to 222 nm UVC irradiation.
- Tests were conducted using a UVC lamp.
- A solution containing the virus was spread onto a plate.
- The researchers allowed it to dry before placing the UVC lamp 24 cm above the surface of the plates.
- A wavelength of 222 nm UVC cannot penetrate the outer layer of the human eye and skin, so it won’t harm the cells beneath.
- But 254 nm UVC germicidal lamps harm exposed human tissues, and can only be used to sanitise empty rooms.
