Sangeetha Pulapaka

For decades, it's been known that broad-spectrum UVC light kills viruses and bacteria by destroying the molecular bonds that hold their DNA together. Unfortunately, it also causes skin cancer and cataracts in people. Now, however, scientists have discovered that a narrow spectrum of UVC – known as far-UVC – can eradicate airborne viruses without harming humans.

Led by Prof. David J. Brenner, researchers from Columbia University had previously demonstrated that far-UVC light could kill MRSA (methicillin-resistant Staphylococcus aureus) bacteria without damaging human skin. MRSA commonly causes surgical wound infections.

In their latest study, the team set out to see if overhead far-UVC lights could also kill airborne viruses. In order to do so, they released aerosolized H1N1 virus (which is a strain of the flu) into a test chamber, where it was exposed to very low doses of the light. As a control, they also released H1N1 into the chamber without the light exposure.

What the scientists found was that the far-UVC effectively eradicated the viruses, approximately as efficiently as a conventional broad-spectrum UVC germacidal light. Unlike such a light, though, the far-UVC isn't dangerous to people.

"Far-UVC light has a very limited range and cannot penetrate through the outer dead-cell layer of human skin or the tear layer in the eye, so it's not a human health hazard," says Brenner. "But because viruses and bacteria are much smaller than human cells, far-UVC light can reach their DNA and kill them."

If further studies support the team's findings, it is hoped that overhead far-UVC lights could ultimately be used to stop the spread of airborne viruses in public spaces such as hospitals, doctors' offices, schools, airports and airplanes. As an added bonus, unlike vaccinations, far-UVC should be effective against even newly-emerging strains of such viruses.

Source: Columbia University, Irvine Medical Center