UV-C lighting has the ability to kill viruses like Covid-19, although its inherent danger to humans has led industry groups to advise against its use. However, researchers have now shown that there is a way for UV-C lighting to be made safe for humans, while also killing harmful bacteria and viruses.
Two research groups, one from Vagelos College of Physicians and Surgeons at Columbia University Irving Medical Center and one from the Hiroshima University in Japan, have shown that a specific wavelength of UV light is capable of killing coronaviruses both in the air and on surfaces without posing any harm to humans.
This is a significant development, as one of the hurdles of using UV light for killing viruses is the fact that it also damages human DNA, causing all sorts of eye and skin problems, as well as increasing the risk of cancer. It’s those issues that led to the Lighting Industry Association to call for the technology to be avoided in domestic settings.
The specific wavelength that has been identified as being unable to penetrate the eye’s tear layer or the dead-cell layer of skin is 222 nanometres. More importantly than its inability to damage human DNA, was the fact that at 222 nanometres, the UV light was still able to kill coronaviruses – including Covid-19.
The study at Hiroshima University found that when a polystyrene plate covered with viral culture was exposed to a UV-C lamp from 24cm away, 99.7% of the virus was killed within 30 seconds. Meanwhile, Columbia University found that just eight minutes of UV-C light exposure killed 90% of airborne coronaviruses, while 25 minutes of exposure killed 99.9%.
While the early results of the studies are certainly promising, there’s no reason to rush out to buy UV-C lighting. In fact, we’d still encourage anyone in the electrical sector to follow the advice of the Lighting Industry Association. That’s because the team at Hiroshima University believes that more studies need to be conducted on UV-C lighting before their use in the real world.