According to a recent study published in the American Journal of Infection Control, Ultraviolet C (UVC) light emitted by the sun with a wavelength of 222 nanometers can destroy coronavirus.

The 222 nanometer UVC is also safe for humans, according to the scientists at Hiroshima University.

The researchers conducted an in-vitro experiment to show that 99.7 per cent of the SARS-CoV-2 viral culture can be effectively destroyed after a 30-second UVC exposure.

Study author Hiroki Kitagawa from Hiroshima University stated in the study: "This study shows the efficacy of 222-nm UVC irradiation against SARS-CoV-2 contamination in an in vitro experiment."

Study process

For the study, researchers used a UVC lamp, also called Far-UVC. Researchers analyzed the potential of the rays in killing seasonal coronaviruses who have the same structure as SARS-CoV-2. However, they did not use the original SARS-CoV-2 for the experiment.

The researchers developed a solution containing the virus and dried it before placing the UVC lamp 24 cm above the surface of the plates.

According to the researchers, a wavelength of 222 nm UVC cannot percolate the outer, non-living layer of the human eye and skin. Hence, it will not cause any harm to the living cells beneath. A nanometer is equivalent to one billionth of a meter.

Researchers believe that this makes it safer but an equally potent alternative to the more damaging 254 nm UVC germicidal lamps increasingly used in disinfecting healthcare facilities.

According to the study, since 254 nm UVC harms exposed human tissues, it can only be used to sanitize empty rooms.

But 222 nm UVC can be a promising disinfection system for occupied public spaces including hospitals where nosocomial infections are a possibility, the research team noted.

The researchers, however, maintained that further investigation is needed to corroborate their findings as their study only investigated its in-vitro efficacy.

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