UVC Light Technology
What is Standard UVC light?
Standard UVC is ultraviolet light that has a wavelength of 250 nanometres.
This high frequency wavelength UV light kills microorganisms, including bacteria and viruses. All known bacteria and viruses that have been tested are susceptible to UV sanitization, including coronaviruses. While some organisms respond more readily to UVC disinfection, all tested organisms (many hundreds to date) are susceptible at the right doses. Standard UVC light has been widely used for more than 40 years to disinfect drinking water, wastewater, air, surfaces, hospitals, and pharmaceutical products to eliminate human pathogens.
What is FAR-UVC light?
Far-UVC is ultraviolet light that has a wavelength of 220 nanometres
Far-UVC light also kills microorganisms, including bacteria and viruses, however, it requires no special training to operate and is therefore recommended for use by the general public. Unlike standard UVC light, Far-UVC light can be operated while people, plants, and pets are present. However, while it is safer than standard UVC light, prolonged exposure to Far-UVC light is not recommended.
Note: While FAR-UVC is a very promising option, it is still under peer review
How does UVC disinfection work?
As demonstrated by multiple research studies and reports, when biological organisms are exposed to germicidal UV light (in the range of 200 nm to 300 nm), the waves are absorbed by DNA, RNA, and proteins, rendering the organisms incapable of reproducing.
Absorption by DNA or RNA causes the formation of thymine dimers, which leads to inactivation of the DNA or RNA double helix strands. If enough thymine dimers are created, the DNA replication process is disrupted and the cells can no longer replicate. Absorption by cell proteins can lead to rupture of the cell walls and the death of the organism
UVC Light Effect on Coronavirus and other Infectious Microorganisms
Can UVC light help prevent COVID-19 transmission?
Alex Berezow, PhD is a microbiologist who has written about the topic, states that “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 existing UVC technology is effective against COVID-19, there have not yet been conclusive tests showing specifically that UVC light can kill COVID-19. However, Berezow says “UVC light kills everything: bacteria, fungi, viruses, including other coronavirus, so it should kill COVID-19.” We do know for sure that it is effective against other viruses, such as the flu, which is even more imperative now that we are fighting the COVID-19 pandemic.
Why use 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
Ultraviolet Germicidal Irradiation: Current Best Practices
"Ultraviolet germicidal irradiation (UVGI) is the use of ultraviolet (UV) energy (electromagnetic radiation with a wavelength shorter than that of visible light) to kill or inactivate viral, bacterial, and fungal species. The UV spectrum is commonly divided into UVA (wavelengths of 400 nm to 315 nm), UVB (315 nm to 280 nm), and UVC (280 nm to 200 nm). The entire UV spectrum can kill or inactivate many microorganisms, but UVC energy provides the most germicidal effect, with 265 nm being the optimum wavelength."
"Scenario: Workers using ultraviolet (UV) lamps may have skin or eye exposure to stray ultraviolet light emissions. Such workers need to know acceptable levels of irradiance (measured in milliwatts per square centimeter (mW/cm2)) and how to monitor for stray radiation. The exposed UV dose would be in units of millijoules per square centimeter (mJ/cm2). [In most cases, the UV lamp would be a low pressure mercury lamp, so almost all the UV light is at 253.7 nanometers (nm).]"
"The ionizing radiation standard covers alpha, beta, gamma, and X-rays; neutrons; high-speed electrons and protons; and other atomic particles; but does not include sound or radio waves, or visible, infrared, or ultraviolet light. Therefore, there are no OSHA-mandated employee exposure limits to ultraviolet radiation."