A new type of ultraviolet light that is safe for people took less than five minutes to reduce the level of indoor airborne microbes by more than 98%, a joint study by scientists at Columbia University Vagelos College of Physicians and Surgeons and in the U.K. has found.
…Far-UVC light has a shorter wavelength than conventional germicidal UVC, so it can’t penetrate into living human skin cells or eye cells. But it is equally efficient at killing bacteria and viruses, which are much smaller than human cells.
In the past decade, many studies around the world have shown that far-UVC is both efficient at destroying airborne bacteria and viruses without causing damage to living tissue. But until now these studies had only been conducted in small experimental chambers, not in full-sized rooms mimicking real-world conditions.
…The efficacy of different approaches to reducing indoor virus levels is usually measured in terms of equivalent air changes per hour. In this study, far-UVC lamps produced the equivalent of 184 equivalent air exchanges per hour. This surpasses any other approach to disinfecting occupied indoor spaces, where five to 20 equivalent air changes per hour is the best that can be achieved practically.
“Our trials produced spectacular results, far exceeding what is possible with ventilation alone,” says Kenneth Wood, PhD, lecturer in the School of Physics and Astronomy at the University of St. Andrews and senior author of the study. “In terms of preventing airborne disease transmission, far-UVC lights could make indoor places as safe as being outside on the golf course on a breezy day at St. Andrews.”