Ultraviolet Light (UV C or X) is one of the top 3 biggest offenders when it comes to promoting a solution to exterminating COVID. Yet many consumers persuaded perhaps by misleading advertising claims, are being persuaded to use it.
Listening to the professionals
“There’s only one type of UV that can reliably inactivate Covid-19 – and it’s extremely dangerous. You would literally be frying people,” says Dan Arnold, laughing in disbelief. (April 2020- https://www.bbc.com/future/article/20200327-can-you-kill-coronavirus-with-uv-light UV Light Technology) The article quoted above addresses the use of UV-C and while both UV-A and UV-B damage the skin – nothing in the UV options is as damaging as UV-C. The author goes on to explain that ‘the highest exposure of UVC is needed to possibly kill the virus, but the amount of ultraviolet required varies widely, depending on factors such as the shape and type of material the virus is on’. There is a good reason WHO issued a warning to people to not use UV light to sterilize their hands or skin anywhere.
The scientific community agrees that using this technology to supply continuous air disinfection that would disrupt micro-droplets is not effective and can be dangerous. In addition, UV-C is being promoted as an integrated solution to add within the HVAC system in stream of the airflow, advertising that this will “immediately” kill any virus that passes through the wavelength released. This is a contradictory claim at best considering average inactivation takes up to 8 minutes. While good in a controlled setting such as induct for coils and filter deactivation, or a Biosafety cabinet, these are not ideal for open areas, and they do not provide room level mitigation which is the real concern when discussing mitigation strategies from bioaerosols and improving general indoor air quality (IAQ).
Using technology that is dangerous or not fully verified
For example, UV is supposed to be a benefit that was recently promoted online by a company that sells UV to schools for disinfection: Ultraviolet light can disinfect air and surfaces – anywhere the light touches! That is exactly the point ‘anywhere the light touches,’ which begs the question how about the places in shadow, under objects, etc. as we do not live in a 2-dimensional world. Let’s not forget to mention that any UV light that is meant to deactivate pathogen on the surface should never be done in an occupied room and therefore leads to the discussion as to the true value. After all, if we aren’t addressing the air we breathe and the limitation of the total dose, frequency, and shadowing exist, then how is UV seen as a truly viable solution for improving the air we breathe?
In addition, UV light—particularly the shortest wavelength, known as UVC—kills viruses by damaging their DNA or RNA, crippling their ability to make copies of themselves. As you may know, hospitals have been using UVC lamps and even UVC robots to disinfect the air in patient and operating rooms. However, just as with disinfectants, UVC light doesn’t discriminate what it kills. “This light can also damage human cells, potentially harming the cornea, causing sunburn, and raising the risk of skin cancer,” says physicist David Brenner, who is director of the Center for Radiological Research at Columbia University. “That’s why hospital staff turn on the lamps only when the rooms are empty.”
There is now what is known as far-UV which releases a wavelength of 222 nm and is promoted as safe for human exposure and sold as a room purifier. Unfortunately, the promotion of such devices is premature, to say the least, and studies are ongoing for both effectiveness and safety. Preliminary tests show that this form of UV will kill 99.9% of airborne viruses but it will take 25 minutes to do so, and once again far-UV cannot reach shadowed areas. Something being ‘safe to use’, even if the data supports it, does not qualify it as effective.
Drawing conclusions based on science
So, to recap and following this train of thought, expert opinion says the UVC concentration must be strong enough to kill germs and viruses so it should only be used in a human-free area. To learn that some people are using it in their classrooms where children are subjected to it all day is either totally appalling to the point of being criminal, or as one might suspect, indicative of the weak, ineffective strength of the UV being employed. We must conclude that UVC lamps used for disinfection purposes may pose potential health and safety risks depending on the UVC wavelength, dose, and duration of radiation exposure. The risk may also increase if the unit is not installed properly or used by untrained individuals.
While UV is a recognized ‘no-touch’ technology and scientifically proven to be effective at deactivating pathogens and bacteria, it must be applied in the appropriate settings and the risks must be understood and supported by test data. If not used properly and without an understanding of the effectiveness you risk harm to humans and a false sense of security. A safe, no-touch technology solution will have the advantages of not requiring changes in a room’s ventilation, not leaving residue or harmful byproducts after treatment, and having a broad spectrum of action and rapid exposure times. Most importantly it will pull up aerosolized contaminated air ‘everywhere’ from the room occupants breathing zone, working with the thermal heat load generated naturally from the human body reducing harmful pollutants and bioaerosols from the air we breathe. The reality is that nothing is 100% effective, and a proper mitigation plan should be implemented as a multi-layered approach. However, the efficacy of the technology put in place as part of the strategy should be carefully analyzed to determine if you are truly implementing a solution rather than a false sense of security and equally as concerning potentially unintentional harm to occupants.
A complete air filtration system to promote quality indoor air
As there are many health hazards lurking in our air, in addition to viruses, it would be wise to consider filtration technology that will also remove pollution from bad inside air that is now so prevalent it has been categorized as Sick Building Syndrome and is the cause of many respiratory and cardiovascular diseases. The last time we looked UV disinfecting does not fix bad indoor air quality and as you have just read, may do more harm than good.
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