Everything you need know
WHAT IS ULTRA VIOLET LIGHT?
The human eye can detect light that has a wavelength anywhere between 400 and 700nm. UV-light, on the other hand, has a spectrum of 100-400nm, is divided into categories of UVA (315-400nm), UVB (280-315nm) and UVC (100-280nm) and is invisible to the human eye. The sun radiates UVA and UVB light onto Earth and we are used to protect ourselves from it using sunglasses and sunscreen. The UVC waves coming from the sun, however, never reach Earth do its ozone layer which protects it from it. If UVC reached Earth’s surface, life here as we know it wouldn’t exist, because it kills essentially all pathogens that have RNA or DNA.
Far-UVC 222nm
After years of comprehensive research, the results of several groundbreaking studies were recently published by prestigious international science publications, with many others to follow quickly*. The big discovery was that, within the spectrum of UVC light lies a wavelength that effectively inactivates pathogens and, as opposed to the conventional 254nm UVC light, doesn’t penetrate the outermost layer of our eyes nor the outer layer of our skin.
This new discovery, the wavelength of 222nm, was eventually titled Far-UVC.
Conventional UVC
The germicidal effects of UVC light on pathogens has been known already for as long as approximately four decades, and been used for disinfecting air, water, and surfaces for almost as long.
At the time of discovering the technology, however, it was thought that the most effective wavelengths for the job were above 230nm, and more specifically 254nm, and therefore most commercially manufactured UVC lamps emit exactly that. Its harmfulness towards human skin and eyes, however, has limited its scalability and utilization from a commercial and societal perspective.
THE TECHNOLOGY
Far-UVC 222nm lamps are excimer lamps, which means they operate on a gas called Krypton Chloride. Here’s how: The lamps contain a chamber filled with noble gas that doesn’t use inner electrodes and is completely mercury-free. High voltage applied across the outside of the glass excites the gas inside, causing Far-UVC 222nm light to be emitted. And their construction allows them to instantly turn on or off without warm-up time or decreased lifetime, unlike other similar lamps. In addition, and perhaps most importantly, the lamps contain an optical filter, which ensures that no secondary emissions (other, potentially harmful, and dangerous UVC wavelengths) are let through.
IS FAR-UVC 222NM LIGHT EFFECTIVE AGAINST
AIRBORNE CORONAVIRUSES?
A study conducted in June 2020 by researchers at Columbia University Irving Medical Centre* reported that 99.9% of aerosolized seasonal coronaviruses (that cause the common cold) were inactivated when exposed to Far-UVC 222nm light for 25 minutes. The study found that even with exposures as low as 1.2-1.7mJ/cm2, Far-UVC light neutralized 99.99% of coronaviruses present in airborne droplets.
HOW DOES UVC LIGHT INACTIVATE PATHOGENS?
UVC-light penetrates through a pathogen’s cell wall disrupting its RNA/DNA structure, thus inactivating and neutralizing it, making it unable to reproduce. In fact, it is believed that 222nm light is even more effective in killing pathogens than the conventional 254nm, since it is highly absorbed by proteins, thus affecting the pathogen’s surface proteins resulting in its inactivation even before disrupting its RNA/DNA.
Can Far-UVC 222nm light inactivate SARS-CoV-2 (COVID-19)?
A study conducted by researchers at Hiroshima University* found that Far-UVC 222nm light effectively reduced more than 99.7% of surface contamination of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19.