Human-safe UV light could be key in reopening indoor spaces, study shows

Ultraviolet light may be key in safely reopening indoor spaces amid the coronavirus pandemic.

A new study from Columbia University Irving Medical Center, published Wednesday in Scientific Reports, found more than 99.9 percent of coronaviruses in airborne droplets were killed when exposed to far-UVC light — a wavelength that is safe to use around humans — continuously, for around 25 minutes. A different wavelength has been used to disinfect empty public spaces, but was a health hazard to humans. Far-UVC "cannot reach or damage living cells in the body," per the study.

Since the COVID-19 coronavirus is largely spread via airborne droplets, "it's important to have a tool that can safely inactivate the virus while it's in the air, particularly while people are around," said the study's lead author David Brenner.

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The light is safe to use in places including hospitals, schools, offices, theaters, and various modes of public transportation. Far-UVC light safely kills other viruses, too, including airborne influenza.

"Anywhere that people gather indoors, far-UVC light could be used in combination with other measures, like wearing face masks and washing hands, to limit the transmission of SARS-CoV-2 and other viruses," Brenner said. Read more from Columbia.