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I've heard similar claims for excimer lamps but I'd still prefer not to stand under one. It's still a great thing if it's even just safer than the usual 254nm

I've heard similar claims for excimer lamps but I'd still prefer not to stand under one. It's still a great thing if it's even just safer than the usual 254nm ones, if it allows for designs with brief incidental exposure.

gus_massa 4y ago
UV-B and UV-C are dangerous. As always, the dose makes the poison, so low exposure is safe. My guess is that they claim is safer for the environment or safer if they broke, but the language is confusing and they seam to claim they are safe in normal use. From https://en.wikipedia.org/wiki/Excimer_lamp https://en.wikipedia.org/wiki/Excimer_lamp > Mercury lamps are the most common source of UV radiation due to their high efficiency. However, the use of mercury in these lamps poses disposal and environmental problems. On the contrary, excimer lamps based on rare gases are absolutely non-hazardous and excimer lamps containing halogen are more environmentally benign than mercury ones.[citation needed]
- eternityforest 4y ago
  I assume they are referencing this, which claims it might be safe to directly expose people to: https://www.eurekalert.org/news-releases/477264#:~:text=Main%20Points-,Provided%20proof%20for%20the%20first%20time%20in%20the%20world%20that,for%20human%20skin%20and%20eyes https://www.eurekalert.org/news-releases/477264#:~:text=Main.... But I'd be worried about what it does to abraded or pre damaged skin, and whatever bacteria shows up when you kill the ones on your skin with it.
  - gus_massa 4y ago
    I replied to that in a sibling comment. It looks promising, but I'd wait to try it in my skin until other groups have reproduced it.
- Maursault 4y ago
  Mercury lamps just happen to emit light at 253.7 nm, very close to the wavelength of UVC that best kills microbes, 254nm. 185nm is also regarded as a wavelength that kills microbes, but this is by proxy of it being the wavelength best at producing ozone, which then kills microbes. It has been possible to purchase LEDs with a peak wavelength of 255nm (250-260nm) and other wavelengths of UVC and UVB for a decade at least, but they cost about $300/pc iirc, making them very expensive for building a one-off microbe-killer flashlight or disinfecting multi-LED array. Comparatively, Mercury lamps are cheap.
  - eternityforest 4y ago
    Not anymore, UVC LEDs are making it into consumer products like the LARQ water bottle(Which I have), and devices claiming to be 1W leds are in the $5 to $15 range.

gus_massa 4y ago

UV-B and UV-C are dangerous. As always, the dose makes the poison, so low exposure is safe. My guess is that they claim is safer for the environment or safer if they broke, but the language is confusing and they seam to claim they are safe in normal use. From https://en.wikipedia.org/wiki/Excimer_lamp https://en.wikipedia.org/wiki/Excimer_lamp > Mercury lamps are the most common source of UV radiation due to their high efficiency. However, the use of mercury in these lamps poses disposal and environmental problems. On the contrary, excimer lamps based on rare gases are absolutely non-hazardous and excimer lamps containing halogen are more environmentally benign than mercury ones.[citation needed]

eternityforest 4y ago
I assume they are referencing this, which claims it might be safe to directly expose people to: https://www.eurekalert.org/news-releases/477264#:~:text=Main%20Points-,Provided%20proof%20for%20the%20first%20time%20in%20the%20world%20that,for%20human%20skin%20and%20eyes https://www.eurekalert.org/news-releases/477264#:~:text=Main.... But I'd be worried about what it does to abraded or pre damaged skin, and whatever bacteria shows up when you kill the ones on your skin with it.
- gus_massa 4y ago
  I replied to that in a sibling comment. It looks promising, but I'd wait to try it in my skin until other groups have reproduced it.
Maursault 4y ago
Mercury lamps just happen to emit light at 253.7 nm, very close to the wavelength of UVC that best kills microbes, 254nm. 185nm is also regarded as a wavelength that kills microbes, but this is by proxy of it being the wavelength best at producing ozone, which then kills microbes. It has been possible to purchase LEDs with a peak wavelength of 255nm (250-260nm) and other wavelengths of UVC and UVB for a decade at least, but they cost about $300/pc iirc, making them very expensive for building a one-off microbe-killer flashlight or disinfecting multi-LED array. Comparatively, Mercury lamps are cheap.
- eternityforest 4y ago
  Not anymore, UVC LEDs are making it into consumer products like the LARQ water bottle(Which I have), and devices claiming to be 1W leds are in the $5 to $15 range.