5 ms·

FTA: >An in vitro experiment by HU researchers showed that 99.7% of the SARS-CoV-2 viral culture was killed after a 30-second exposure to 222 nm UVC irradiatio

by sauwan 6y ago

FTA: >An in vitro experiment by HU researchers showed that 99.7% of the SARS-CoV-2 viral culture was killed after a 30-second exposure to 222 nm UVC irradiation at 0.1 mW/cm2.

AstralStorm 6y ago
This is slightly long to effectively remove the virus from air with people in there breathing it. It's good for an airlock or surface disinfection though.
- Zancarius 6y ago
  30 seconds would be easy enough to fulfill for people queuing up at lines, such as at a point of sale though. Sure, if you're standing next to someone who's infected that's probably not enough time, but combined with other measures it might reduce the spread to others. One of the studies that was investigating the use of hydroxychloroquine came up with an interesting statistic that had nothing to do with HCQ: They found that individuals with no PPE interacting at less than 6' from someone infected with SARS-CoV-2 had about a 15% chance of contracting it after 10 minutes of exposure. I'd imagine UV would reduce this even further. This study was covered in Dr. Seheult's update 81[1] video. It's a bit ironic, because the study showed a failure of HCQ, but I'm not completely sure I'd suggest the study itself failed since there's valuable insight that came as a consequence of it! [1] https://www.youtube.com/watch?v=o5w7FiDJe1g&t=2m32s https://www.youtube.com/watch?v=o5w7FiDJe1g&t=2m32s
  - caseysoftware 6y ago
    Is UV-C dangerous to people? If so, after how long? It'd be interesting to consider this for doctor's waiting rooms, boarding areas for planes & trains, and waiting areas for restaurants. Just waiting for your table or appointment could sanitize you with zero additional effort. Not 100% but reducing the impact/risk in otherwise close quarter space would reduce the overall spread.
    - jimsmart 6y ago
      It's fairly well accepted that UV-C is carcinogenic to humans. https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation.html https://www.cancer.org/cancer/cancer-causes/radiation-exposu...
    - Zancarius 6y ago
      The sibling comment posted to a general overview of UV light, but I think it's a shame that it seems so dismissive. UVC, while higher frequency, can't penetrate the outer layer of skin[1]. At low energies, I'd imagine it'd be dangerous enough to virions and safe enough to humans for it to be a useful area disinfectant. Most of the studies I've seen use very low power sources that appear to be fairly safe, but I'd imagine there's long term exposure risk. Here's another article[2] worth reading. It appears to me that the specific wavelengths most of the research has focused on is far-UVC which is probably different from the frequencies of UVC currently more well studied. So, I think the answer is "it depends." [1] https://www.klaran.com/is-uvc-safe https://www.klaran.com/is-uvc-safe [2] https://www.discovermagazine.com/health/are-ultraviolet-sanitizing-lights-safe-for-humans https://www.discovermagazine.com/health/are-ultraviolet-sani...
- _ph_ 6y ago
  Higher intensities probably kill accordingly faster. 0.1mW/cm^2 isn't a very high intensity, so real time air cleaning would be feasible. Also, everything points towards that even if you cannot prevent infections, cutting down the virus count seems to make a huge difference in the disease severity.
gwittel 6y ago
Distance is important too: > ... placing the Far-UVC lamp 24 centimeters above the surface of the plates.

by sauwan 6y ago

FTA: >An in vitro experiment by HU researchers showed that 99.7% of the SARS-CoV-2 viral culture was killed after a 30-second exposure to 222 nm UVC irradiation at 0.1 mW/cm2.

AstralStorm 6y ago

This is slightly long to effectively remove the virus from air with people in there breathing it. It's good for an airlock or surface disinfection though.

Zancarius 6y ago
30 seconds would be easy enough to fulfill for people queuing up at lines, such as at a point of sale though. Sure, if you're standing next to someone who's infected that's probably not enough time, but combined with other measures it might reduce the spread to others. One of the studies that was investigating the use of hydroxychloroquine came up with an interesting statistic that had nothing to do with HCQ: They found that individuals with no PPE interacting at less than 6' from someone infected with SARS-CoV-2 had about a 15% chance of contracting it after 10 minutes of exposure. I'd imagine UV would reduce this even further. This study was covered in Dr. Seheult's update 81[1] video. It's a bit ironic, because the study showed a failure of HCQ, but I'm not completely sure I'd suggest the study itself failed since there's valuable insight that came as a consequence of it! [1] https://www.youtube.com/watch?v=o5w7FiDJe1g&t=2m32s https://www.youtube.com/watch?v=o5w7FiDJe1g&t=2m32s
- caseysoftware 6y ago
  Is UV-C dangerous to people? If so, after how long? It'd be interesting to consider this for doctor's waiting rooms, boarding areas for planes & trains, and waiting areas for restaurants. Just waiting for your table or appointment could sanitize you with zero additional effort. Not 100% but reducing the impact/risk in otherwise close quarter space would reduce the overall spread.
  - jimsmart 6y ago
    It's fairly well accepted that UV-C is carcinogenic to humans. https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation.html https://www.cancer.org/cancer/cancer-causes/radiation-exposu...
  - Zancarius 6y ago
    The sibling comment posted to a general overview of UV light, but I think it's a shame that it seems so dismissive. UVC, while higher frequency, can't penetrate the outer layer of skin[1]. At low energies, I'd imagine it'd be dangerous enough to virions and safe enough to humans for it to be a useful area disinfectant. Most of the studies I've seen use very low power sources that appear to be fairly safe, but I'd imagine there's long term exposure risk. Here's another article[2] worth reading. It appears to me that the specific wavelengths most of the research has focused on is far-UVC which is probably different from the frequencies of UVC currently more well studied. So, I think the answer is "it depends." [1] https://www.klaran.com/is-uvc-safe https://www.klaran.com/is-uvc-safe [2] https://www.discovermagazine.com/health/are-ultraviolet-sanitizing-lights-safe-for-humans https://www.discovermagazine.com/health/are-ultraviolet-sani...
_ph_ 6y ago
Higher intensities probably kill accordingly faster. 0.1mW/cm^2 isn't a very high intensity, so real time air cleaning would be feasible. Also, everything points towards that even if you cannot prevent infections, cutting down the virus count seems to make a huge difference in the disease severity.

gwittel 6y ago

Distance is important too: > ... placing the Far-UVC lamp 24 centimeters above the surface of the plates.