Far-UVC light to reduce the risk of airborne viral transmission in occupied locations Physics and Astronomy Colloquium with Professor David J Brenner

Professor David J Brenner of the Center for Radiological Research at Columbia University presents ‘Far-UVC light to reduce the risk of airborne viral transmission in occupied locations' in this Physics and Astronomy Colloquium.

About Professor Brenner's work:

“A direct approach to limit airborne viral transmissions is to inactivate them within a short time of their production. Germicidal ultraviolet light is a proven tool in this context, and has the major advantage of killing mutant variants of a virus equally efficiently. However conventional germicidal UV light, at 254 nm wavelength, cannot be used directly in occupied spaces as it can be a potential health hazard to skin and eyes. By contrast, far-UVC light (~222 nm) efficiently kills pathogens potentially without harm to exposed human tissues, because these wavelengths are largely attenuated by the dead-cell layer on the surface of human skin, or the tear layer on the surface of human eyes.

We previously demonstrated that 222-nm far-UVC light efficiently kills airborne influenza virus and have extended those studies to explore far-UVC efficacy against airborne human coronaviruses. Low doses of < 2 mJ/cm2 inactivated 99.9% of aerosolized human coronaviruses 229E and OC43. The SARS-CoV-2 coronavirus virus responds similarly to far-UVC light.

Based on these results, continuous far-UVC exposure in occupied public locations at the current regulatory (ACGIH) exposure limit (~3 mJ/cm2/hour) would result in ~95% viral inactivation in ~11 minutes. The proposed revised ACGIH exposure limits would reduce this to under a minute. Thus while staying within regulatory dose limits, low-dose-rate far-UVC exposure can potentially safely provide a major reduction in the ambient level of airborne coronaviruses in occupied public locations, such as hospitals, nursing homes, buses, planes, trains, train stations, schools, restaurants, offices, theatres, gyms -- to name but a few.

In all these situations it would be beneficial to deploy overhead far-UVC lights that are continuously killing microbes, including the SARS-CoV-2 virus -- and so limiting the person-to-person spread of the virus.”