Dr. David Brenner is the Director of the Center of Radiological Research at the University of Columbia. At a General Hospital Panel Meeting regarding germicidal ultraviolet (UV) light personal use devices in December 2025, Dr. Brenner discusses the origin, uses, applications, and overall safety of 222 nanometer Far-UVC light when compared to conventional 254 nanometer UVC light. Brenner maintains that Far-UVC light, particularly at 222 nanometers, shows strong potential to reduce airborne pathogens in occupied spaces. He explains how it remains safer for skin and eyes than conventional 254-nanometer germicidal UVC even with prolonged exposure.
Conventional UVC has long been recognized as effective for inactivating airborne pathogens, including historical use in schools and operating rooms. One such example in the 1940s involved conventional UVC installation in Philadelphia public schools to control a measles epidemic. However, it was discovered conventional UVC can have detrimental effects on both skin and eyes. As a result, conventional UVC’s broader use in occupied environments has been limited by these known risks.
The aim now is to utilize a type of UVC light that is both efficient at inactivating airborne pathogens while also being safe for prolonged use and exposure. Brenner explains “for 222 nanometer light you see damage absolutely in the very top layer of the cornea, the superficial layer of cells, but you don't see any damage deeper down. Whereas with conventional germicidal 254 nanometer light you can see damage basically all the way through the cornea.” Therefore, Far-UVC, typically in the 222-nanometer range, is of interest because its shorter penetration depth appears sufficient to inactivate small pathogens while limiting penetration into living skin cells and deeper layers of the eye.
When describing the different between 254nm and 222nm UVC light, Brenner explains that for human skin the “222 nanometer light can’t really penetrate the stratum cornea, which is the layer of dead skin cells right at the very surface of our skin. It can’t reach living cells in the epidermis, in particular the basal cells at the bottom of the epidermis.” He further describes how “at the very surface of the cornea is the tear layer and again 222 nanometer light can’t penetrate the tear layer.” By using monochromatic wavelengths and looking for DNA damage in human skin and eye models, scientists have now been able to start gathering evidence supporting the use of Far-UV 222nm light for pathogen inactivation, which is no doubt an exciting development with countless applications.
Brenner’s discussion also highlighted potential applications in operating rooms and broader hospital environments. He explains that in the past the “need for cumbersome protective clothing when we're using conventional germicidal UVC really limited its use in in the operating room.” So, the substitution of 222nm Far-UVC instead of conventional UVC is “going to be equally effective at reducing surgical sight infections but without that need for cumbersome protective clothing.”
Brenner also shares an example of a reduction of more than 99% in airborne murine norovirus in an occupied mouse cage cleaning room after Far-UVC installation. He explains, “at Colombia we did a study where we basically exposed hairless mice to far UVC over a period total of 66 weeks. We didn't see any evidence of induced skin cancer or any other skin abnormalities after chronic exposure at any dose.” To summarize, the norovirus was 99% eliminated and there were no differences between the control animals and the exposed animals.
A question Brenner also investigates is whether Far-UVC is ultimately safe. He references updates to exposure guidance and equipment standards, including changes made in 2023 to threshold limit values in the Far-UVC range. Laboratory studies using skin models, corneal models, donated human corneas, short-term room studies, and chronic animal exposure studies were presented as supporting the view that Far-UVC can be used safely within current regulatory limits. There was a recent study at the University of Baltimore involving a hotel room with UVC lights installed. They looked at the change in indoor ozone concentrations for the far UVC lamps and found “an increase of about six parts per billion” and Brenner explains that’s “about typical in general for the far UVC lights. It’s a very slight increase of less than 10 parts per billion typically in most settings. They did not see an increase in ultrafine particles.”
Generally, Brenner believes studies conducted in real rooms, including a hotel room and a conference room, were described as showing only modest ozone increases and no meaningful increase in ultrafine particle concentrations under typical operating conditions. According to Brenner, more significant air-quality effects are most likely when devices are operated above current regulatory exposure limits or in unusually airtight spaces. This suggests that installation design, ventilation, and compliance with exposure guidance are important to safe and effective deployment. He maintains, “I'll just conclude that Far UVC is pretty promising as a practical option to safely reduce airborne viral loads in occupied indoor locations.”
Overall, Brenner’s discussion heralds Far-UVC as a promising option for reducing airborne viral and microbial burden in occupied indoor environments, including healthcare settings. His central message is that Far-UVC technology appears both effective and acceptably safe when used within current regulatory limits.
At Sterilray, the ongoing mission is to bring cutting-edge Far-UVC 222nm sterilization solutions that prioritize well-being to your own homes, workplaces, hospitals, and institutions. This hospital panel’s discussion only further validates the safety and efficacy of Sterilray’s vast range of germicidal Far-UV ray products.
Watch the video below to learn more about Dr. David Brenner’s research regarding 222nm Far-UVC and how it aligns with Sterilray’s vision for cleaner and healthier living spaces:
