Is it true that you can use a lamp for the UVC light to disinfect an area of 1000 square feet?
July 1, 2020
Updated July 2, 2020 at 4h19
Verification: a UV lamp against the COVID-19?
The STATEMENT : “Is it true that you can use a lamp for the UVC light to disinfect an area of 1000 square feet?”, request Jacques Theriault from Gatineau.
The acronym UVC refers to a kind of ultraviolet (UV) light that some lamps disinfection” are designed to emit. UV rays are nothing more than a form of light, which cannot be perceived by the human eye and which is more energetic than the “visible light”. Those that it receives from the sun fall roughly into three categories : UVA, which make up 95% of ultraviolet rays that reach the ground, and who carry only a little more energy than visible light ; UVB, more energy, but are largely blocked by the atmosphere ; and the UVC, which are much more energy, but that do not cross the atmosphere.
In theory, you can disinfect a room with ultraviolet light. There is still no study on the survival of the COVID-19 UV, but it would be extremely surprising that this virus resists better than the others, said Pierre Talbot, a researcher at the Institut Armand-Frappier and a specialist of the coronavirus. “It is a principle common to all viruses : the UV rays destroy their [genetic material]. […] When we “push” a virus in the laboratory, once it has finished and that we need to, we turn on the UV lamp to destroy it,” he said.
In this game, the UVA and the UVB rays don’t kill the job in a very quick way. The UVC, are much more effective, we read in a study published in 2005 in the Journal of Virology. This is a method already used in some hospitals to sanitize operating rooms, and in some water treatment plants, for example, and this is why several manufacturers of lamps UVC have seen in the pandemic of COVID-19 (and the increased demand for all disinfectants) a beautiful business opportunity.
So yes, we can, in principle, sterilize a room with a lamp UVC. In practice, however, there are two other things you need to know about it, which may make this option somewhat less desirable. The first is that just like visible light, ultraviolet light can be blocked by matter. A virus can be “in the shadow” of something and escape the UV — and the size that they have, the less surface roughness can be used as a screen. Under conditions that are known and controlled, such as in hospitals or labs, and with instruments of high quality, UV can be highly effective to kill germs. But in other contexts and with lamps of variable quality available on the free web, their sterilizing effect is poorly demonstrated, warned recently, the national Academies of sciences, engineering and medicine in the United States.
Moreover, Health Canada has issued several warnings recently to “illegal advertising, false or misleading” against manufacturers of UV lamps [https://www.canada.ca/fr/sante-canada/services/medicaments-produits-sante/covid19-industrie/incidents-publicite-produits-sante.html]. Claims such as “should be in the bathroom, the living room, bedroom, hotel, influenza, and the COVID-19” had been deemed problematic.
The second thing to know, and it is probably the most serious one, is that if the UVC to kill germs, they are not good for humans either. Both the UVA as UVB rays can age the skin and damage the DNA of our cells, which comes with a risk of cancer of the skin. But because of their energy more strong, the UVC is even worse — it really is a chance that the ozone layer stops ! In addition to the danger of tumor, the UVC can also injure the retina of the eyes.
You should never try to disinfect the skin or any part of the body whatsoever with these lamps-there, warns the world health Organization on its website. The deleterious effects are not instantaneous, there is a consensus, but the instruments of UV disinfection are always handled with protective measures to avoid exposing humans to the rays.
It can work, but there are several “but”… The quality of the lamps UVC available on the web is variable and has not been well tested. Not to mention that the UVC is radiation harmful to human health.
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