A new study conducted by researchers at Columbia University’s Irving Medical Center and published in the journal Scientific Reports has found that a specific wavelength of ultraviolet light kills over 99.9% of seasonal coronaviruses without causing any harm to humans.
“Based on our results, continuous airborne disinfection with far-UVC light at the current regulatory limit could greatly reduce the level of airborne virus in indoor environments occupied by people,” said lead author on the study David Brenner from Columbia.
Given that, unlike conventional germicidal UVC light (254 nm wavelength,) far-UVC light (222 nm wavelength) cannot reach or damage living cells in the body, the research team wanted to see if it could be successfully used for disinfection purposes in areas occupied by people.
In the study, Brenner and colleagues Manuela Buonanno, David Welch and Igor Shuryak used a misting device to aerosolise two common coronaviruses and then exposed them to a far-UVC lamp, finding that even low exposure at the current regulatory limit is highly effective at killing airborne viruses.
More specifically, the researchers found that continuous exposure to far-UVC light would kill 90% of airborne viruses in about 8 minutes, 95% in about 11 minutes, 99% in about 16 minutes, and 99.9% in about 25 minutes. This could be achieved by installing overhead far-UVC lamps in places where people gather in substantial numbers indoors.
Preliminary results of a separate on-going study – also conducted by Brenner’s team – indicate that far-UVC light is every bit as effective against SARS-CoV-2 which causes COVID-19, thereby making it, at least potentially, a powerful tool in reducing the worst impacts of the current pandemic.
“Because it’s safe to use in occupied spaces like hospitals, buses, planes, trains, train stations, schools, restaurants, offices, theatres, gyms, and 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 transmissions of SARS-CoV-2 and other viruses,” Brenner said.