What is the ideal time for sterilization by UV light and are humans affected by exposure to the UV light?
Hi
It produce cancer and simultaneously it is good for sterilization for all puropse
Tk
Hi Hamzah, I am going to answer your question from a "food processing" point of view:
UV is usually effective for sterilization, but you need to consider that its use is affected for some factors, especially concerning:
- When the object produces "shades" on its own surface, where UV can not reach, its global effect is lower.
- If you are working with water, and its turbidity is considerable, UV's is not much effective, and you should use complementary treatments.
- Its application time depends on many factors. In general, to affect DNA of microorganisms in water, it takes at least 20-30 minutes, depending on the lamp capacity, turbidity, water flow, etc.
- UV applied directly in humans is not advisable, generally.
In short:
- Make sure that the whole surface is (regularly or constantly) irradiated by UV, consider the different factors affecting this UV irradiation (is it by air, water?), and avoid exposure for humans.
Greetings!
In disinfection by UV there is no ideal treatment time. The disinfection depends on the delivered dose which is the radiation (flux of photons) times the exposure time.
UV damages human skin and tissue. It breaks down chemical bonds and produces free radicals. The effect is like a very bad sunburn.
It depends on what you want to sterilize and your wavelength. For the viruses, for example, 230-260 nm would be sufficient. and 260 nm do not give harm humans. However, if you exceed over 280 nm, UV will give harm to humans like sarcomas.
Serena Özabrahamyan Can you provide some literature on this. Can we make use of UV lights to disinfect peoples or their clothes (in case we do not want their skins to be exposed)? Or Any other types of gates which can help to disinfect public before entering to colleges, offices, shopping malls etc, ?
I was wondering if anyone has looked into the use of Far UVC light as a way of treating Covid-19. Far UVC light has a strong antiviral effect but has minimal effect on mammalian cells compared to UVC light. By use of a Thoracosopy technique a fiber optic Far UVC light source could be introduced into a patients lungs and target the Covid-19 cells. Combining this with Ultraviolet Blood Irradiation (UBI) may be a therapeutic treatment that in some critical cases could be applied until such time as a true drug therapy can be applied.
Please let me know your thoughts
It is completely unsafe to use far UV inside the lungs. VUV produces radicals and ozone as well as damage proteins. This is a s wrong as Trump's idea to drink bleach.
Far UVC light is a very narrow spectrum and wavelength of UVC light that based on a study by Columbia university has no effect on mammalian cells due to the characteristics of their cell wall versus that of virus or bacteria cell walls. In addition on April 20th Cedar Sinai medical center in Los Angeles announced a clinical study to bring this technology to use.
If far UV cannot penetrate human cells it cannot reach the virus which are inside the lung cells of infected persons.
Besides it is correct far UV doesn't penetrate skin the protection comes from that skin have a top layer above the living cells. Inside our lungs the living cells are directly in contact with air. It seems you didn't refer the study by Columbia so I cannot see which types of cell the study is about and it the tolerable far UV doses are relevant to inactivate virus even on a surface.
As far as I know, as Henrik Rasmus Andersen suggests, the use of Far UV is for sterilization use outside the human body. It can be used on cuts and wounds, on medical equipment, and for treating airborne viruses (see, Welch, D., Buonanno, M., Grilj, V., Shuryak, I., Crickmore, C., Bigelow, A.W., Randers-Pehrson, G., Johnson, G.W. and Brenner, D.J., 2018. Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases. Scientific Reports, 8(1), pp.1-7.)
The following is from an interview with David Brenner, a leading medical researcher on UV sterilization:
" Theoretically, it would be possible to snake a tube with a UV light into a person’s airway, but that would be a very bad idea. “That would be damaging to all the cells inside the body,” says Brenner. And in any case, the light wouldn’t reach all areas of the lungs. “The UV light can’t go around corners,” he says. “I don’t think you’d be killing all the viruses by any means.” Any remaining viruses would simply multiply, leaving the person still trying to fight off a Covid-19 infection—but now with potential cellular damage from the UV light.
Brenner has been studying far-UVC, a wavelength that can kill viruses but can’t penetrate beyond the top layer of human skin, which is made up of dead cells. Brenner says that kind of light could be used to safely kill germs in the air, not just in hospitals, but in airports, transit stations, and other places where people gather. Still, he points out, the idea would be to use far-UVC for environmental surface decontamination, not internally to treat patients."
(https://www.wired.com/story/heres-what-disinfectants-and-uv-light-really-do-to-your-body/)