4 ms·

I'm pretty aware of this space (I work in healthcare and did my Masters in contamination of hospital environments). There are a number of companies that sell t

by giarc 6y ago

I'm pretty aware of this space (I work in healthcare and did my Masters in contamination of hospital environments). There are a number of companies that sell these units specifically for patient rooms. There was one that include 4 sensors that you placed in the corners of the room. They would detect the amount of UVC light reaching them and adjust the 'clean time' to allow enough UVC to reach all corners. As for the effectiveness of UVC light on pathogens, that's pretty well known. I suspect you are looking further, and asking if using a tool like this actually reduces infections in a place like this food bank. I suspect no. For one, coronavirus (and other resp viruses) don't live well on surfaces, especially when going from varying environments (refrigerated storage, delivery truck, someones house). Additionally our environment is covered with a lot of (mostly) harmless bacteria, such as Bacillus sp. Bacillus can be worrisome for people with no immune system, but for general population it won't do anything. I personally think UVC equipment has utility in specific use cases, such as patient rooms, but in grocery stores, food banks etc it won't do much. In those situations, its mostly about close person to person contact.

sailfast 6y ago
Would this have an impact on transmission rates if a virus did allow for airborne transmission?
- giarc 6y ago
  I wouldn't put a ton of weigh to the recent reports of 300 physicians asking the WHO to categorize it as an airborne virus. If it were truly an airborne virus it wouldn't be a very good one. The main source of transmission is close contact with positive patients. If it were airborne we would see a ton more cases (or atleast a ton more unknown source cases). For example, in my province, Alberta, we have 8300 confirmed cases. Only 800 or so are from unknown sources, all the other cases have known links to previous cases [1]. If this were airborne, you would expect many more unknown cases since people would pick it up in grocery stores etc and we wouldn't be able to track it back to the known case. 1. alberta.ca/covid-19-alberta-data.aspx?utm_source=google&utm_medium=sem&utm_campaign=Covid19&utm_term=data&utm_content=v1&gclid=Cj0KCQjwupD4BRD4ARIsABJMmZ8cO5v1TFH7D0uHfjhcZ9aNdMhvWcOdJLqY5_hude3dLqrE1V_HgToaAi_KEALw_wcB Back to your question though, if it were airborne, vapourize products or UVC would work against it but you would have to disinfect after a positive person were present. Given air currents, and air exchange rates in most buildings, a positive person wouldn't leave behind enough of a viral load to affect someone that far past their presence.
tensor 6y ago
Disinfecting any airborne particles would seem the bigger advantage no?
wittyreference 6y ago
Coronavirus stays suspended in the air for hours. UVC disinfection affects those suspended articles, which surface cleaning does not.
- giarc 6y ago
  >Coronavirus stays suspended in the air for hours. In controlled lab environments. Also, it likely doesn't stay in loads high enough to cause infection. Any airborne virus will be affected by volume displacement, air currents, air exchanges in addition to things like UV light from the sun, humidity and temperature changes. If I were asked to pick a disinfection method, I would not take disinfecting the air into my consideration.
  - elliekelly 6y ago
    There’s some evidence it happens in the real world too. In the very early days of the pandemic first there was a case in China where an infected but asymptomatic person went to church and sat in a pew. That person left the church and a different person who later sat in the same spot became infected.
    - giarc 6y ago
      That case was mentioned in a popular paper with about 8 others I recall. One big issue is that they all occured pretty early on when testing wasn't so wide spread. So there's also a good chance it was just a concidence and they were actually exposed to someone else. This is one issue with the media. That paper, with less than 10 case reports of asymptomatic and potential airborne spread was spread much more rapidly than the WHO report which reviewed ~70k Chinese cases and most spread within household contacts.

by giarc 6y ago

sailfast 6y ago

Would this have an impact on transmission rates if a virus did allow for airborne transmission?

giarc 6y ago
I wouldn't put a ton of weigh to the recent reports of 300 physicians asking the WHO to categorize it as an airborne virus. If it were truly an airborne virus it wouldn't be a very good one. The main source of transmission is close contact with positive patients. If it were airborne we would see a ton more cases (or atleast a ton more unknown source cases). For example, in my province, Alberta, we have 8300 confirmed cases. Only 800 or so are from unknown sources, all the other cases have known links to previous cases [1]. If this were airborne, you would expect many more unknown cases since people would pick it up in grocery stores etc and we wouldn't be able to track it back to the known case. 1. alberta.ca/covid-19-alberta-data.aspx?utm_source=google&utm_medium=sem&utm_campaign=Covid19&utm_term=data&utm_content=v1&gclid=Cj0KCQjwupD4BRD4ARIsABJMmZ8cO5v1TFH7D0uHfjhcZ9aNdMhvWcOdJLqY5_hude3dLqrE1V_HgToaAi_KEALw_wcB Back to your question though, if it were airborne, vapourize products or UVC would work against it but you would have to disinfect after a positive person were present. Given air currents, and air exchange rates in most buildings, a positive person wouldn't leave behind enough of a viral load to affect someone that far past their presence.

tensor 6y ago

Disinfecting any airborne particles would seem the bigger advantage no?

wittyreference 6y ago

Coronavirus stays suspended in the air for hours. UVC disinfection affects those suspended articles, which surface cleaning does not.

giarc 6y ago
>Coronavirus stays suspended in the air for hours. In controlled lab environments. Also, it likely doesn't stay in loads high enough to cause infection. Any airborne virus will be affected by volume displacement, air currents, air exchanges in addition to things like UV light from the sun, humidity and temperature changes. If I were asked to pick a disinfection method, I would not take disinfecting the air into my consideration.
- elliekelly 6y ago
  There’s some evidence it happens in the real world too. In the very early days of the pandemic first there was a case in China where an infected but asymptomatic person went to church and sat in a pew. That person left the church and a different person who later sat in the same spot became infected.
  - giarc 6y ago
    That case was mentioned in a popular paper with about 8 others I recall. One big issue is that they all occured pretty early on when testing wasn't so wide spread. So there's also a good chance it was just a concidence and they were actually exposed to someone else. This is one issue with the media. That paper, with less than 10 case reports of asymptomatic and potential airborne spread was spread much more rapidly than the WHO report which reviewed ~70k Chinese cases and most spread within household contacts.