The start of 2021 is all about getting this COVID pandemic under control. Distributing vaccines as quickly as possible and continue to social distance, avoid large gatherings, wearing masks and washing our hands will be an essential part of developing herd immunity and getting our lives back to what was once normal.
Another part of reducing the presence of SARS-CoV-2 (the virus that causes COVID-19) is to find ways to destroy the virus in the environment before there is an opportunity for it to infect us. Much research has looked at the benefits behind good filtration systems and higher humidity to reduce the virulence of the virus. We are now re-visiting the benefits of ultraviolet light and its ability to kill viruses, bacteria and mold. Scientists have known about the disinfectant capabilities of ultraviolet light for decades. More than a century after Niels Finsen in 1903 won the Nobel prize for discovering that ultraviolet (UV) light could kill germs, UV light started being used in hospital rooms and other public places.
There are 3 types of ultraviolet light based on wavelength. The longest wavelengths are UV-A (315-400nm) and UV-B (280-315nm) which are found in ordinary sunlight. These rays can cause sunburn if you are outside too long without protection. They have limited germ-killing ability. But UV-C light (200-280nm) is part of the ultraviolet spectrum that can inactivate pathogens like bacteria and viruses. Because of their effectiveness, they are incredibly useful for hospitals, senior living centers, fire and police stations, schools, airports, hotels, office buildings and pretty much everywhere. So what’s the problem?
Similar to UV-A and UV-B rays from the sun, UV-C can damage the skin and eyes. You need to follow strict safety guidelines when the products are being operated. Basically, UV lamps should not be run when anyone is nearby. Trained workers should use the right personal protective equipment (PPE) and make sure products are turned off before performing maintenance. So this is maybe not as simple as screwing in a lightbulb. Disinfection with far-UVC lamps remains largely experimental but it may be safer in that it does not cause temporary skin burns and eye damage.
The other main problem is that if a surface is in shadow, it will not be disinfected. In a recently published study, a standard UV-C lamp was placed in the center of a typical hospital room and some places were partly or completely in shadow and did not receive the full dose needed to assure 99.99% disinfection. To address this problem, UVD Robots, a company based in Odense Denmark, developed a UV system that moves around the room autonomously. These robots are now available in 2000 Chinese hospitals and they are being used in more than 50 countries.
A company called Healthe has made progress on far UV-C lighting. They have developed systems that will be affordable for bars, restaurants, and other small businesses while close to eliminating the potential for spreading viruses. An LED version of UV-C may eventually be in our homes and offices. This can stop all viruses and bacteria. Can this finally be the cure for the common cold?? We will have to wait and see, but I can’t imagine a better time to push the technology envelope to help eliminate this pandemic and any future infections.
Mauldin, John. The Grip tightens. Jan 15, 2021. Mauldin Economics. https://www.mauldineconomics.com/frontlinethoughts/the-grip-tightens/
Tornberg, B. Using UV Light to kill Viruses Like COVID-19. Dec. 16, 2020. https://insights.regencylighting.com/can-uv-light-kill-viruses-like-covid-19
Mackenzie, D. Ultraviolet Light Fights New Virus. June 27, 2020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7319933/