Standard UVC is ultraviolet light with a wavelength of 250 nanometres.
This high frequency wavelength light kills bacteria and viruses and has been used extensively for more than 40 years in disinfecting drinking water, wastewater, air, hospitals, pharmaceutical products, and surfaces against a whole suite of human pathogens. All bacteria and viruses tested to date (many hundreds over the years, including other coronaviruses) respond to UV disinfection. Although, some organisms are more susceptible to UVC disinfection than others, all tested so far do respond at the appropriate doses.
What is FAR-UVC light?
Note: While FAR-UVC is very promising, it is still under peer review
Far-UVC is ultraviolet light with a wavelength of 220 nanometres
Far-UVC light, like standard UVC, also kills bacteria and viruses, however, unlike standard UVC which cannot be operated while people, plants, and pets are present, Far-UVC can be, requires no special training and is recommended for use by the general public. Note: While safer than standard UVC, prolonged human exposure to Far-UVC is not recommended.
How does UVC disinfection work?
As evident by multiple research studies and reports, when biological organisms are exposed to deep UV light in the range of 200 nm to 300 nm it is absorbed by DNA, RNA, and proteins.
Absorption by proteins can lead to rupture of cell walls and death of the organism. Absorption by DNA or RNA (specifically by thymine bases) is known to cause inactivation of the DNA or RNA double helix strands through the formation of thymine dimers. If enough of these dimers are created in DNA, the DNA replication process is disrupted, and the cell cannot replicate.
UVC Light Effect on Coronavirus and other Infectious Diseases
Can UVC help prevent COVID-19 transmission?
According Alex Berezow PhD, a microbiologist who has written on the topic, “UVC light is lethal to bacteria and viruses because of its high frequency that scrambles and damages their nuclear material. When it damages the DNA (or RNA) code of these pathogens, it also triggers lethal mutations that prevent them from reproducing properly.
As to whether the existing technology was effective against COVID-19, there haven’t been conclusive tests (it’s too new) showing that UVC light can kill the COVID-19. However, Berezow says “UVC light kills everything: bacteria, fungi, viruses, including other coronavirus, so it should kill COVID-19.” What we do know for sure, is that it is effective against other viruses like the flu, which is even more important now that we are fighting COVID-19.
On using UVC disinfecting light Technology
“Pretty much every public space -- restaurants, shopping malls, trains, subway stations, etc. -- could benefit from this non-chemical solution. Occasionally, the best answers to some of life's toughest problems are surprisingly simple”.
Alex Berezow, PhD — February 10, 2020
THE AMERICAN COUNCIL ON SCIENCE AND HEALTH