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This is awesome and I'm glad companies are doing things like this. It made me interested if face shields are something I should add to my own PPE collection. V

This is awesome and I'm glad companies are doing things like this. It made me interested if face shields are something I should add to my own PPE collection. Very interesting summary of the effectiveness of face shields [1] "Utilizing a cough aerosol simulator loaded with influenza virus (aerosol volume mean diameter of 8.5 μm) and a breathing simulator, Lindsley et al.[16] reported 96% and 92% reductions in the risk of inhalational exposure immediately after a cough for a face shield at distances of 18 in (46 cm) and 72 in (183 cm), respectively. Decreasing the aerosol size to 3.4 μm resulted in the face shield blocking 68% of the inhalational exposure at 18 in (46 cm) immediately after the cough and 23% over 1–30 min post-cough (during which time the larger aerosol particles had settled out and droplet nuclei had formed and remained airborne so that flow occurred more easily around the edges of the face shield)" Seems like a face shield may be very good protection for a short term exposure - especially combined with a mask. e.g. walking by someone who coughs. It also makes me wonder about a face shield fixed with something to blow filtered air in from the top of the shield. I assume that would make it less likely for air to come around the edges of the mask and possibly be more comfortable than a mask. You could have a shield blowing a constant cool breeze on you. Although this would have the disadvantage of needing batteries and replacing filters. 1 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015006/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015006/

seventytwo 7y ago
There are things called PAPRs which are an enclosed version of what you’re taking about.
- ALittleLight 7y ago
  I was imagining more of a face shield with a filtered blower at the top blowing air onto the shield. I imagine this would reduce the amount of air coming around the edges of the shield and hopefully increase the effectiveness of the shield. The PAPR definitely looks interesting, and surely more effective, but it has the drawback of probably being less comfortable. I find masks uncomfortable. My face or nose itches. My glasses fog up. I feel like a face shield might be more comfortable.
  - brodie 7y ago
    If you’re looking at shields with fans you should just wear a mask. Take some anti-itch medication or ointment beforehand. Based on what medical professionals are saying, regular shields aren’t going to protect you from normal aerosols. Social distancing is probably better for people coughing near you. And buying shields is only going to increase mortality for hospital workers. Also, mild discomfort is a small price to pay compared to not infecting and killing people around you.
    - ALittleLight 7y ago
      I don't think any of those things are true. Shields have fairly promising results without fans. I cited some research to that effect above. The problem with the shield is that air flows around it, and that might be mitigated by fans blowing filtered air. Social distancing is, axiomatically, not better for people coughing near me. If someone is coughing near me then social distancing has already failed. If I need to go to a grocery store, why shouldn't I consider wearing a shield? Shields are made out of a sheet of plastic, which is not in short supply. If I needed to buy any it would not "increase the mortality for hospital workers". Regarding mild discomfort being a small price to pay, you've misunderstood. The choice is not between mild discomfort and infecting people, but between mild discomfort and comfort. Obviously the latter is preferable, hence my curiosity about the shield and fans.
      - DanBC 7y ago
        PPE worn by members of the public going about their everyday life is a premature optimisation, and it risks causing harm. People wear PPE to protect them from specific things. The specific thing you are protecting yourself from with Covid-19 is droplets that have been coughed from infected people into the air, and the droplets that then fall onto other surfaces. So far we think these droplets are fairly large. There's a lot of talk in this thread about aerosolised, and that's tricky because there's no real definition of what that means. It's unlikely the drops caused by normal covid-19 coughing meet that definition though. So, these large drops don't travel far (maybe three metres), and they don't hang in the air for long before falling. The most important thing you can do to protect yourself is stay at home. If you must travel outside you need to carefully and frequently wash your hands and maintain 2 metres distance from other people. Do not touch your face. If you're doing that you'll get at best marginal protection from wearing PPE. But you only get that protection if you're wearing PPE correctly, and more importantly if you're taking it off correctly. If you're not wearing PPE correctly you lose those marginal benefits. If you take it off incorrectly you not only lose the benefits but you increase your risk. If PPE is causing you to take risky action, such as leaving your home when you'd otherwise stay in, then again you're increasing your risk.

seventytwo 7y ago

There are things called PAPRs which are an enclosed version of what you’re taking about.

ALittleLight 7y ago
I was imagining more of a face shield with a filtered blower at the top blowing air onto the shield. I imagine this would reduce the amount of air coming around the edges of the shield and hopefully increase the effectiveness of the shield. The PAPR definitely looks interesting, and surely more effective, but it has the drawback of probably being less comfortable. I find masks uncomfortable. My face or nose itches. My glasses fog up. I feel like a face shield might be more comfortable.
- brodie 7y ago
  If you’re looking at shields with fans you should just wear a mask. Take some anti-itch medication or ointment beforehand. Based on what medical professionals are saying, regular shields aren’t going to protect you from normal aerosols. Social distancing is probably better for people coughing near you. And buying shields is only going to increase mortality for hospital workers. Also, mild discomfort is a small price to pay compared to not infecting and killing people around you.
  - ALittleLight 7y ago
    I don't think any of those things are true. Shields have fairly promising results without fans. I cited some research to that effect above. The problem with the shield is that air flows around it, and that might be mitigated by fans blowing filtered air. Social distancing is, axiomatically, not better for people coughing near me. If someone is coughing near me then social distancing has already failed. If I need to go to a grocery store, why shouldn't I consider wearing a shield? Shields are made out of a sheet of plastic, which is not in short supply. If I needed to buy any it would not "increase the mortality for hospital workers". Regarding mild discomfort being a small price to pay, you've misunderstood. The choice is not between mild discomfort and infecting people, but between mild discomfort and comfort. Obviously the latter is preferable, hence my curiosity about the shield and fans.
    - DanBC 7y ago
      PPE worn by members of the public going about their everyday life is a premature optimisation, and it risks causing harm. People wear PPE to protect them from specific things. The specific thing you are protecting yourself from with Covid-19 is droplets that have been coughed from infected people into the air, and the droplets that then fall onto other surfaces. So far we think these droplets are fairly large. There's a lot of talk in this thread about aerosolised, and that's tricky because there's no real definition of what that means. It's unlikely the drops caused by normal covid-19 coughing meet that definition though. So, these large drops don't travel far (maybe three metres), and they don't hang in the air for long before falling. The most important thing you can do to protect yourself is stay at home. If you must travel outside you need to carefully and frequently wash your hands and maintain 2 metres distance from other people. Do not touch your face. If you're doing that you'll get at best marginal protection from wearing PPE. But you only get that protection if you're wearing PPE correctly, and more importantly if you're taking it off correctly. If you're not wearing PPE correctly you lose those marginal benefits. If you take it off incorrectly you not only lose the benefits but you increase your risk. If PPE is causing you to take risky action, such as leaving your home when you'd otherwise stay in, then again you're increasing your risk.