A new study has revealed that nearly 100% of seasonal coronaviruses present in airborne droplets are killed when exposed to a certain wavelength of ultraviolet light that is also safe for humans.
Far Ultraviolet C (UVC) light at its current environmental standard was found to wipe out 99.9% of seasonal coronaviruses, potentially reducing the level of airborne viruses in indoor environments. The study authors say that conventional germicidal UVC light can used to disinfect unoccupied indoor spaces such as empty subway cars and empty houses to eliminate coronaviruses. However, may not be possible in occupied indoor spaces because of the health risk.
To disinfect occupied indoor areas while eliminating or minimizing any health risks, the team of researchers investigated far-UVC light – this has a lower wavelength than conventional germicidal UVC light. Far-UVC light cannot penetrate the tear layer of the eye or the outer layer of the skin, hence cannot reach into the body to cause damage.
The researchers found that continuous exposure to far-UVC light at the current regulatory limit would kill 90% of airborne viruses in less than 8 minutes, 95% in about 11 minutes, 99% in about 16 minutes, and 99.9% in 25 minutes.