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Went to a donut shop in Japan today. They had a CO2 monitor on the counter and a UV light on, plus circulating air through the ventilation system. Also all the staff and most of the customers were masked. ๐ท It's really not that hard and if a donut shop can do it we can certainly do it at least in schools and hospitals. This is more what I'd think "Live with the virus" looks like. What we're doing feels more like "Pretend there is no virus". Edit: UV light is a bug zapper. 48 comments
@libroraptor @pezmico I didn't know UV lights would be effective. Unless it's designed extremely well and positioned correctly I feel like it would do very little. Do you know more? @dean @libroraptor I also know little about it, but I remember them being part of the #DavosSafe protocols. I've read they're helpful although probably need a more strategic placement. I wonder about the effectiveness of this one lamp just standing in the corner of the room, but I guess it can't be worse than not having it. UV-C light is pretty high energy light, which breaks down molecules and thus kills off germs. But breaking down molecules also means it creates free radicals - highly reactive short-lifetime chemical compounds, that seek to react with other things they come into contact with. This might mean combining with one another in the air and creating entirely new chemicals that have very little with their original source chemicals. This might also mean damaging your tissue if you come into contact with them, most likely by inhaling. That smell of freshly baked bread and sweets has a lot of chemicals in it, disassembling those chemicals and re-assembling them in a random way is quite a chemical experiment. On the other hand, fine enough filters (think HEPA) can remove viruses, and a carbon filter after particle filter can also serve as reactant to safely react with reactive chemicals in air and remove free radicals and VOC.  Naomi Wu is a Cantonese Maker who has covered this extensively in a series of very thorough videos. How it works, how it is safely done and how to install, how to do it cheaply. You want a very specific kind of UV light source, 222 nm, https://twitter.com/realsexycyborg/status/1436691276921860099?lang=en, and install it in air ducts or filters to deactivate virus material,  @isotopp @pezmico @dean For the school contexts that I'm thinking about, home-made won't do โ it'd have to be a commercially supplied one from the HVAC company. These things have been around for years; what I'm wondering is whether there is an important reason why they're not being promoted while filtration is. @libroraptor @isotopp @pezmico @dean @mmlvx @isotopp @pezmico @dean I didn't think to check Wikipedia before, but it turns out that they have a broad-and-thin, inconclusive, but at least reasonably current, summary https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation#Air_disinfection  I am not an expert, but the impression I get is that this is new technology using very specific kinds of UV light, called "Deep UV": @FediThing @dean @pezmico It's been in commercial production for years, and is available for home installation. It's used both for sterilising the air and for sterilising internal coils (microbe habitat surfaces). I don't know how well regulated it is, though, notably on the ozone concentration front. HVAC sizing is something that people often get wrong so it wouldn't surprise me if people often choose excessively powerful UV bulbs and end up with far more ozone than is healthy. @dean @pezmico UV-C is typical for sterilising HVAC air. What I'm thinking about here is situations with ducted air โ we could sterilise the entire supply rather than trying to filter and recycle what's already inside the room, especially since we still need to remove stale air. How much energy the UV irradiator consumes depends on how big a bulb (or bulbs) the HVAC system needs.  @libroraptor @pezmico UV lamps also attract insects, which is why many restaurant kitchens have them in fly zappers. The wavelengths might differ slightly between the bug-attracting bulbs and the germicidal bulbs, but I can see UV in the ducts without also having a physical barrier being a real problem. https://www.bhg.com/home-improvement/porch/outdoor-rooms/best-bug-zappers/ @LinuxAndYarn @libroraptor This may be the actual reason they had an UV light. A lot of dead bugs were inside the shield. @pezmico @LinuxAndYarn My parents used to have a low-wavelength one for generating ozone when they had a motel. They used to to clean out units when people had sneakily smoked inside. The ozone would eat the tobacco stench out of the wallpaper and carpets. @pezmico @libroraptor Yeah, if it was one that sat on the wall in a big bowl-shaped sconce that was a bug zapper. @kotaro lol no worries, there's a lot I love about Japan. There's also things I'm critical of, but I don't live here so I focus on what I love. @pezmico What kind of "UV light" might that be? I have a hard time to find reliable info about UV/ UVC / Far-UVC. That is maybe helpful technology, but it is potentially dangerous, too. Which solution/ product has usability for the "normal" user? #UV #UVC #DavosStandard #CleanAir #Ventilation #Filtration #CovidIsNotOver @fihu @pezmico Thanks, i will look into it. I already have a Philips Aircleaner working with UV, but in the end it is not what i am looking for, because it is a closed system. The other Philips consumer products are not suitable with lifeforms around, as i understand. I am searching for a solution where you can still be in the room (safely). @better_tomorrow @pezmico I guess the ceiling lamp Naomi built is okay - and Philips has professional versions of that too. Basically, it generates an UVC "field" beneath the ceiling which then does its job on viruses and other organics stupid enough to rise up to the ceiling. Just make sure there are no reflecting objects inside the fieldโฆ ๐ชฉ @better_tomorrow @pezmico  @jeffsamsonow @pezmico It's very low for indoors. My living room is at 680 ppm ๐   Peer pressure is disheartening. Don't let yourself get infected, or infected again. Dont pass on an infection you didnt notice or worry about. @pezmico Mister Donut is far more dangerous for calories than for covid thankfully.  @pezmico Well, not everything with all these budget cuts. Especially when you have to buy CO2 monitors and UV lights. @pezmico The non-democratic aspect of that phenomenon is basically there has not been a law which demands you to do such things. It's not like "we make the rule, we live together by following it." Instead, it's like "I follow the herd, so that I won't be blamed by anyone." Wearing a mask, taking a vaccine, and everything is essentially based on the same mentality; not for the sake of us living together, but to dodge unknown third party's negative judgement. Just my two cents.  @pezmico  @pezmico @RussSharek @pezmico all good, but do we have a reliable assessment of the effectiveness of this UV measures in real word cases? And the negative effects? Don't get me wrong, I strongly supported COVID related measures and still do, but there should be real advantages to any measure, otherwise pushing them will inevitably backfire. @pezmico @pezmico @donmelton the deaths are nearing the flu which has been with us sinceโฆ1918. COVID isnโt going away. Thereโs nothing stopping you from wearing a mask if youโre concerned but itโs a bit silly to expect permanent mask requirements. |
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@pezmico I've been unable to understand why people have been putting up mechanical filters and not sticking UV lamps into the HVAC ducts. Maybe it's because the filter industry is supporting future sales?