The light at the end of the tunnel for the COVID-19 pandemic might just be overhead.
A new study shows a hands-off approach using ultraviolet light, called far-UVC light, reduced transmission of indoor airborne pathogens by more than 98% in less than five minutes, according to a recent statement.
“Far-UVC rapidly reduces the amount of active microbes in the indoor air to almost zero, making indoor air essentially as safe as outdoor air,” said co-author Dr. David Brenner, director of the Center for Radiological Research at Columbia University Vagelos College of Physicians and Surgeons.
But the statement notes that far-UVC is a relatively new technology.
Although it’s been known for years that ultraviolet C light (UVC) has properties to destroy germs, its use has been largely limited because it can cause sunburns, skin cancers as well as harm people’s eyes, so its usage has been limited primarily to sterilizing medical equipment, the statement said.
But almost 10 years ago, scientists at Columbia University proposed that a different type of UVC light, called far-UVC light, could destroy germs as efficiently as conventional UVC light without the harmful side effects, because the light’s shorter wavelength does not allow it to penetrate human skin or eye cells, per the statement.
Studies over the past decade confirmed far-UVC kills airborne bacteria and viruses without damaging living tissue as the germs are much smaller than human cells, but the studies up to this point were confided in experimental chambers that never mimicked the real-world setting, according to the press release.
The current study tested the efficacy of far-UVC light in a chamber the size of a large indoor room that had an equivalent ventilation rate as a typical home or office, which is approximately three air changes per hour.
Researchers continuously sprayed a bacteria called Staphylococcus aureus until the concentration of the microbes stabilized, then turned on overhead far-UVC lamps.
They choose this particular bacteria versus coronavirus, because it is slightly less sensitive to far-UVC light, so the researchers could create a conservative model.
The study discovered not only the light inactivated more than 98% of the airborne bacteria in only five minutes, but also was able to keep the level of bacteria in the air low over time as microbes continued to be sprayed in the room.
“Far-UVC light is simple to install, it’s inexpensive, it doesn’t need people to change their behavior, and evidence from multiple studies suggests it may be a safe way to prevent the transmission of any virus, including the COVID virus and its variants, as well as influenza and also any potential future pandemic viruses,” Brenner said.