COVID-19 Fact Check: Can UV Light Kill Coronavirus?
By Divya Ramaswamy
04/07/20 AT 10:29 PM
As the whole world is dealing with the coronavirus pandemic, people throughout the world have been coming up with different strategies to combat the deadly virus. Ultraviolet light has been getting a lot of attention when it comes to disinfecting and reusing masks worn by healthcare workers to safely perform their duties.
But depending on the type of UV people are talking about, the idea that UV light could be used to disinfect hands, clothing or other objects could be either incorrect or dangerous.
The World Health Organization (WHO) has warned that ultraviolet light shouldn’t be used as a disinfectant against COVID-19. The agency also dismissed the idea that exposure to sun or temperatures above 25 degrees Celcius can prevent COVID-19.
“UV lamps should not be used to sterilize hands or other areas of skin as UV radiation can cause skin irritation. You can catch COVID-19, no matter how sunny or hot the weather is. Countries with hot weather have reported cases of COVID-19. To protect yourself, make sure you clean your hands frequently and thoroughly and avoid touching your eyes, mouth, and nose,” CTV News quoted WHO statement.
Here’s what you need to know about the three different types of UV rays:
• UVA, which makes up the vast majority of the UV radiation reaching the planet’s surface, is capable of penetrating deep into human skin. It is responsible for up to 80% of skin aging.
• UVB can damage the DNA in your skin and cause sunburn and even skin cancer.
• UVC, a relatively obscure part of the spectrum, is particularly good at destroying genetic material both in humans as well as viral particles. But, it hasn’t ever been encountered since the ozone filters it out before it can reach us.
Scientists found, in 1978, that the UVC light can be used to destroy microorganisms and, since then, it has been produced artificially and used to sterilize hospitals, offices, airplanes, and factories.
The use of UVC in medical settings is only about a couple of decades old. It hasn’t been used on personal protection equipment (PPE) such as gowns or masks because hidden cervices and folds make it hard for the UV light to work on pathogens. It is not completely understood how repeated exposure to these rays will affect the materials in PPEs.
The previous article was originally posted on https://www.ibtimes.com/covid-19-fact-check-can-uv-light-kill-coronavirus-2954177
Additional information to consider provided by https://en.wikipedia.org is as follows;
In a closed water or air filtration system the COVID-19 Virus can be reduced, redundancy in exposing microorganisms to UV is achieved by circulating the air or water repeatedly. These systems are closed to ensures multiple passes so that the UV is effective against the highest number of microorganisms and will irradiate resistant microorganisms more than once to break them down.
In UVGI system the lamps are shielded or are in environments that limit exposure, such as a closed water tank or closed air circulation system, often with interlocks that automatically shut off the UV lamps if the system is opened for access by humans.
For human beings, skin exposure to germicidal wavelengths of UV light can produce rapid sunburn and skin cancer. Exposure of the eyes to this UV radiation can produce extremely painful inflammation of the cornea and temporary or permanent vision impairment, up to and including blindness in some cases. UV can damage the retina of the eye.
“Sterilization” is often misquoted as being achievable. While it is theoretically possible in a controlled environment, it is very difficult to prove. The term “disinfection” is generally used by companies offering this service to avoid legal reprimand.
Light emitting diodes (LEDs)
Compact and versatile options with UVC LEDs. Recent developments in LED technology have led to commercially available UVC LEDs. UVC LEDs use semiconductors to emit light between 255 nm-280 nm. The wavelength emission is tuneable by adjusting the material of the semiconductor. As of 2019, the electrical-to-UVC conversion efficiency of LEDs was lower than that of mercury lamps. The reduced size of LEDs opens up options for small reactor systems allowing for point-of-use applications and integration into medical devices. Low power consumption of semiconductors introduce UV disinfection systems that utilized small solar cells in remote or Third World applications.
UVC LEDs don’t necessarily last longer than traditional germicidal lamps in terms of hours used, and instead have more-variable engineering characteristics and better tolerance for short-term operation. A UVC LED can achieve a longer installed time than a traditional germicidal lamp in intermittent use. Likewise, LED degradation increases with heat, while filament and HID lamp output wavelength is dependent on temperature, so engineers can design LEDs of particular size and cost to have higher output and faster degradation or lower output and a slower decline over time.
8.^ a b Messina, Gabriele (October 2015). “A new UV-LED device for automatic disinfection of stethoscope membranes”. American Journal of Infection Control. Elsevier. Retrieved 2016-08-15.
14. ^ a b “Ultraviolet germicidal irradiation” (PDF). University of Liverpool. p. 3. Archived from the original (PDF) on 2016-08-06.
25.^ a b Hessling, Martin; Gross, Andrej; Hoenes, Katharina; Rath, Monika; Stangl, Felix; Tritschler, Hanna; Sift, Michael (2016-01-27). “Efficient Disinfection of Tap and Surface Water with Single High Power 285 nm LED and Square Quartz Tube”. Photonics. 3 (1): 7. doi:10.3390/photonics3010007.