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> Ultraviolet light can kill almost all the viruses in a room. Why isn’t it everywhere? Simple--cost. Specifically, UV lamps require maintenance and can be da

by bsder 3y ago

> Ultraviolet light can kill almost all the viruses in a room. Why isn’t it everywhere? Simple--cost. Specifically, UV lamps require maintenance and can be dangerous to those doing the maintenance since the flux is large and damaging to humans. UV LEDs change this calculus slightly as they can last a lot longer, but they are still dangerous to maintenance people. The interesting question is whether the Far UVC (222nm) LEDs can be made useful while not being harmful to people. That would change the calculus from "do a detailed cost/benefit analysis" to "what the hell--just throw it in".

nine_k 3y ago
Imagine UV-ing common spaces, like doorways, when people are not around. Sunlight has a fair amount of UV; I suspect that subjecting people indoors to an amount of UV radiation comparable with a day outside might be OK. (Ozone will likely be generated where the UV light is intensive; better ventilation would also help dispel dangerous microbial aerosols.)
- SECProto 3y ago
  > I suspect that subjecting people indoors to an amount of UV radiation comparable with a day outside might be OK And I suspect this is very incorrect. UV is beneficial at low quantities, but has serious negative impacts on human health at high quantities.[1] Your mention of using it in common areas (where individuals would only be for a few minutes a day) seems much more reasonable. [1] https://en.wikipedia.org/wiki/Ultraviolet#Human_health-related_effects https://en.wikipedia.org/wiki/Ultraviolet#Human_health-relat...
  - XorNot 3y ago
    The far UV spectrum being talked about here is not the same as conventional UVC germicidal lamps, nor the same as UVA/B from the sun. UV is only dangerous because at UVC wavelengths it penetrates cell nucleii and damages DNA. The interesting thing about far UV though is that while it will still damage DNA, it can't penetrate regular cells - it's blocked by the cell membrane/proteins. But viral particles don't have a cell membrane or a nucleus, so they have no protection against it. Basically, far UV can't damage cells, but can damage viruses.
    - SECProto 3y ago
      > The far UV spectrum being talked about here is not the same as conventional UVC germicidal lamps, nor the same as UVA/B from the sun. I was responding to someone suggesting outside-levels of UV exposure. If we're talking about a different wavelength, I am even more doubtful of the safety.
    - byb 3y ago
      Personally I feel the use of the term "far uv" is very misleading because the 220 nm wavelength is within UVC, and not too far away from 254 nm germicidal UVC. It is always helpful to consult a chart: http://www.drb-mattech.co.uk/uv%20spectrum.html http://www.drb-mattech.co.uk/uv%20spectrum.html So, from a public health/public education standpoint, I find it troubling that scientific research, which the article points out, is limited in this area. For decades, general advice has been that all UVC is dangerous to all life. We don't know below which wavelength does UVC no longer become harmful to animal (human) cells. Nor do we know if 220 nm wavelength light damage/weaken other materials. I'm not a chemist/engineer so I don't know if theoretical calculations can be made or if a massive scientific effort needs to be done to verify the impact of 220 nm UV light on lots of materials/life. If there is an animal/human cell safety region, perhaps a rebranding or subdivision of UVC into a "UV-D" is better than calling this "far uv". This has the added benefit of the "D" meaning "Death to germs/viruses". YouTuber Big Clive has had several videos on UVC lamps, I'd like to see someone get a 220 nm light into his hands to see if he smells like burnt meat. https://youtube.com/watch?v=1m0TQjBRcFo https://youtube.com/watch?v=1m0TQjBRcFo https://youtu.be/6DlfLthx89E?si=V4FD0DO4l09w2Wlr https://youtu.be/6DlfLthx89E?si=V4FD0DO4l09w2Wlr Edit: maybe I am a bit alarmist, some comments did share additional information about products offering this technology... I still hold that the branding/messaging is a problem by lumping it all together
      - bsder 3y ago
        As I understand it, the point of 222nm is NOT to sterilize organic tissue directly. The point of 222nm is to able to use it for sterilization in things like air return ducts, industrial cleaning equipment, etc. Since 222nm is relatively "safe", you don't have to worry some idiot opening up a system, giving himself a gigantic flux of UV in the face, and winding up in the ER for cornea burns. Consequently, your maintenance people don't need special equipment or extra training.
alexose 3y ago
I'd love to see the 222nm LEDs finding their way into sterilization products, but unfortunately that's still a long ways off. They're really only useful for sensing applications at this point (although that's still a very important use case). More here: https://www.lesswrong.com/posts/4Zjm8ycWhg6PzFwnF/far-uvc-light-update-no-leds-are-not-around-the-corner https://www.lesswrong.com/posts/4Zjm8ycWhg6PzFwnF/far-uvc-li...
Animats 3y ago
There are UV LEDs in the 225nm range now.[1] But look at the power rating. 2.2mW. Disinfection requires tens of watts of light output, at least. [1] https://www.suntechleds.com/regular-led-strip/uv-led-strip-light/far-uvc-led-light-207-220nm-222nm-far-uv-led.html https://www.suntechleds.com/regular-led-strip/uv-led-strip-l...

by bsder 3y ago

nine_k 3y ago

Imagine UV-ing common spaces, like doorways, when people are not around. Sunlight has a fair amount of UV; I suspect that subjecting people indoors to an amount of UV radiation comparable with a day outside might be OK. (Ozone will likely be generated where the UV light is intensive; better ventilation would also help dispel dangerous microbial aerosols.)

SECProto 3y ago
> I suspect that subjecting people indoors to an amount of UV radiation comparable with a day outside might be OK And I suspect this is very incorrect. UV is beneficial at low quantities, but has serious negative impacts on human health at high quantities.[1] Your mention of using it in common areas (where individuals would only be for a few minutes a day) seems much more reasonable. [1] https://en.wikipedia.org/wiki/Ultraviolet#Human_health-related_effects https://en.wikipedia.org/wiki/Ultraviolet#Human_health-relat...
- XorNot 3y ago
  The far UV spectrum being talked about here is not the same as conventional UVC germicidal lamps, nor the same as UVA/B from the sun. UV is only dangerous because at UVC wavelengths it penetrates cell nucleii and damages DNA. The interesting thing about far UV though is that while it will still damage DNA, it can't penetrate regular cells - it's blocked by the cell membrane/proteins. But viral particles don't have a cell membrane or a nucleus, so they have no protection against it. Basically, far UV can't damage cells, but can damage viruses.
  - SECProto 3y ago
    > The far UV spectrum being talked about here is not the same as conventional UVC germicidal lamps, nor the same as UVA/B from the sun. I was responding to someone suggesting outside-levels of UV exposure. If we're talking about a different wavelength, I am even more doubtful of the safety.
  - byb 3y ago
    Personally I feel the use of the term "far uv" is very misleading because the 220 nm wavelength is within UVC, and not too far away from 254 nm germicidal UVC. It is always helpful to consult a chart: http://www.drb-mattech.co.uk/uv%20spectrum.html http://www.drb-mattech.co.uk/uv%20spectrum.html So, from a public health/public education standpoint, I find it troubling that scientific research, which the article points out, is limited in this area. For decades, general advice has been that all UVC is dangerous to all life. We don't know below which wavelength does UVC no longer become harmful to animal (human) cells. Nor do we know if 220 nm wavelength light damage/weaken other materials. I'm not a chemist/engineer so I don't know if theoretical calculations can be made or if a massive scientific effort needs to be done to verify the impact of 220 nm UV light on lots of materials/life. If there is an animal/human cell safety region, perhaps a rebranding or subdivision of UVC into a "UV-D" is better than calling this "far uv". This has the added benefit of the "D" meaning "Death to germs/viruses". YouTuber Big Clive has had several videos on UVC lamps, I'd like to see someone get a 220 nm light into his hands to see if he smells like burnt meat. https://youtube.com/watch?v=1m0TQjBRcFo https://youtube.com/watch?v=1m0TQjBRcFo https://youtu.be/6DlfLthx89E?si=V4FD0DO4l09w2Wlr https://youtu.be/6DlfLthx89E?si=V4FD0DO4l09w2Wlr Edit: maybe I am a bit alarmist, some comments did share additional information about products offering this technology... I still hold that the branding/messaging is a problem by lumping it all together
    - bsder 3y ago
      As I understand it, the point of 222nm is NOT to sterilize organic tissue directly. The point of 222nm is to able to use it for sterilization in things like air return ducts, industrial cleaning equipment, etc. Since 222nm is relatively "safe", you don't have to worry some idiot opening up a system, giving himself a gigantic flux of UV in the face, and winding up in the ER for cornea burns. Consequently, your maintenance people don't need special equipment or extra training.

alexose 3y ago

I'd love to see the 222nm LEDs finding their way into sterilization products, but unfortunately that's still a long ways off. They're really only useful for sensing applications at this point (although that's still a very important use case). More here: https://www.lesswrong.com/posts/4Zjm8ycWhg6PzFwnF/far-uvc-light-update-no-leds-are-not-around-the-corner https://www.lesswrong.com/posts/4Zjm8ycWhg6PzFwnF/far-uvc-li...

Animats 3y ago

There are UV LEDs in the 225nm range now.[1] But look at the power rating. 2.2mW. Disinfection requires tens of watts of light output, at least. [1] https://www.suntechleds.com/regular-led-strip/uv-led-strip-light/far-uvc-led-light-207-220nm-222nm-far-uv-led.html https://www.suntechleds.com/regular-led-strip/uv-led-strip-l...