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Real-world data show that filters clean Covid-causing virus from air

nature.com

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Re: Real-world data show that filters clean Covid-causing virus from air

#121

Post by overton »

dragonwriter wrote: post #119
overton wrote: post #117

Earlier quoted context omitted.

That's certainly the dominant narrative, but it flies in the face of superspreader events where it appears that one or a few people infected hundreds. Did they directly breathe on everybody they infected? https://montreal.ctvnews.ca/outbreak-at-quebec-city-gym-link... https://www.cdc.gov/mmwr/volumes/69/wr/mm6919e6.htm https://elpais.com/especiales/coronavirus-covid-19/a-room-a-...

> Did they directly breathe on everybody they infected? Maybe they coughed over shared food/drink trays.

The first case linked above was in a gym where patrons were supposed to be masked and two meters apart, and the second case had a CDC investigation which would have mentioned that as a factor if it were present.

Re: Real-world data show that filters clean Covid-causing virus from air

#122

Post by asdff »

notatoad wrote: post #112
drzaiusapelord wrote: post #101

Earlier quoted context omitted.

You won't often catch covid from stray particles but from the person breathing next to you, which these filters can't help. This study was in a hospital where everyone is wearing serious PPE, so its a super edge case to get rid of covid in the air because the main use case of catching covid has been handle by plain old PPE. This doesn't have sweeping applicability. It won't stop covid among the general population. It…

>You won't often catch covid from... how do you know? it seems like most cases are attributed to the nebulous "community spread" and nobody is really sure who they're coming from or how we're catching it. maybe we are getting it from the person breathing near us - if masks help, i don't see a reason that improved air filtration wouldn't.

All the data suggest that its not someone breathing on you in passing that's going to result in covid infection, but spending long periods with someone indoors in close proximity. Within a half hour in the massive grocery store? I would be shocked if you caught it. Drinking in someones living room, swapping stories within arms length, swapping spit flecks for 5 hours straight? Definitely going to spread everything you have in such a small enclosed space where the viral load is able to reach a much higher concentration over a long period of time.

Re: Real-world data show that filters clean Covid-causing virus from air

#123

Post by Vecr »

berberous wrote: post #58
overton wrote: post #36

Earlier quoted context omitted.

Early on in the pandemic, the Canadian IPAC (Infection Control and Prevention) establishment came down hard against theories of airborne COVID transmission, at first even going so far as to not recommend masking. Even now that the science of airborne transmission has been established, they're waging a rearguard battle to obfuscate/deny it and airborne protections such as better ventilation and masking. If you go to a…

N95s often have exhaust filters which make a surgical mask safer for everyone else around you.

You can put tape over the valve on the inside and the outside and that works fine.

Re: Real-world data show that filters clean Covid-causing virus from air

#124

Post by auslegung »

clairity wrote: post #91
Wowfunhappy wrote: post #35

Earlier quoted context omitted.

I'm student teaching in a third grade classroom, and I want to add a least a small counter: We are required to have two HEPA filters always running in the classroom. They are loud. Combined with the fact that (1) children mumble, (2) the children have masks on, and (3) everyone is supposed to stay 3+ feet apart, it's quite hard to hear what a lot of kids are saying! I don't know what the right answer is, but what we…

using air purifiers like that for corona is mostly theater anyway, since air purifiers don't filter the air evenly (despite the misnomer metric "air changes per hour") in a room. mostly, it filters really well near the purifiers and poorly everywhere else. this of course depends on the strength of the fan, but for most consumer air purifiers, it's likely a few feet radius at best. that's not to say that even that isn…

So much of what you’ve said is wrong. Not saying you’re a terrible human being, but what we know about these things is still, unfortunately, not settled. Can you give citations for

1. Air purifiers don’t filter the air evenly (commercial ones since that’s the context). 2. Social distancing indoors is doing most of the work (ie is almost all that’s needed to stop the spread). 3. The virus isn’t free-floating live in the classroom

Re: Real-world data show that filters clean Covid-causing virus from air

#125

Post by asdff »

throwaway984393 wrote: post #15

You can build your own high-flow HEPA filter for about $45: 1x 20-inch box fan ($20) 1x 20x20 MERV-13+ MPR-2400+ HVAC air filter ($20) 1x roll of duct tape ($2.50) Air particle meters and other testing show they work just as well as big expensive machines (it's just the filter doing all the work). This is indeed a dirt cheap way to improve overall health.

Chinesium HEPA air purifiers are pretty good in my experience too, and just as cheap. My Odec model was $35. It is striking how well they can eliminate even just general odors in the home. If I go on vacation and come back to my home, there is a smell (old building). When I started using these filters and come back after a long period away, there is no smell at all, its amazing. Cooking smells go away much faster too.

They look a lot nicer than a big ugly box fan with a filter duct taped to it, are much smaller, and the lowest power setting runs imperceptibly quiet. The only issue is that the fans in these devices are cheaply made and can sometimes become unbalanced and start rattling over time. The low cost makes it easy to replace them, though.

Re: Real-world data show that filters clean Covid-causing virus from air

#126

Post by spaceisballer »

roughly wrote: post #25
auslegung wrote: post #20

Earlier quoted context omitted.

I have believed this for about a year, based on things I was reading at that time. I thought this was widely known because as you point out, that’s kinda their purpose. This article acknowledges that it was shown to be effective in lab settings and this is mainly about seeing those results in real life settings. But come on, if anyone finds something that’s probably effective based on science and isn’t going to negat…

With the added bonus that it would be better for the students’ health generally and would likely improve overall educational outcomes. An awful lot of our handling of COVID has been farcical (a year and a half in, we’re still relying on cloth masks and obsessively sanitizing surfaces), but in the case of schools it’s veered toward absurdist/tragic.

Maybe in some places. Thankfully in our school district they took the time while kids were doing school from home to upgrade ventilation and filtration (I believe a large part through federal grants). Also following CDC guidance for schools (masking, distancing, etc). Our county isn’t exactly highly populated but thankfully the school system has been great. It’s stressful with the kids back in school yet there have been no outbreaks at the school but we only seem to average one notification a week if someone who was sick (but we’ve gotten no close contact notifications). Sure seems like people are getting COVID elsewhere and potentially bringing it into school versus it spreading in school.

Re: Real-world data show that filters clean Covid-causing virus from air

#127

Post by notatoad »

asdff wrote: post #122
notatoad wrote: post #112

Earlier quoted context omitted.

>You won't often catch covid from... how do you know? it seems like most cases are attributed to the nebulous "community spread" and nobody is really sure who they're coming from or how we're catching it. maybe we are getting it from the person breathing near us - if masks help, i don't see a reason that improved air filtration wouldn't.

All the data suggest that its not someone breathing on you in passing that's going to result in covid infection, but spending long periods with someone indoors in close proximity. Within a half hour in the massive grocery store? I would be shocked if you caught it. Drinking in someones living room, swapping stories within arms length, swapping spit flecks for 5 hours straight? Definitely going to spread everything yo…

yes, that's pretty much exactly what i'm saying: all the data we have is that it spreads exactly as you say, sitting with somebody for an extended period of time. because that's the sort of thing that people remember, and tell the contact tracers about.

but at least in my region, the majority of cases still don't have a known source. maybe that's because people are catching it in scenarios where they're in close proximity to somebody for extended periods of time but forget about it when the contact tracers call them, and all cases are spread that way.

or maybe it's spreading in grocery stores and other casual contact scenarios but that's just impossible to measure or count. we keep hearing that there's no evidence of it spreading in schools, and yet as long as students are in school it spreads a lot more among students. is it not spreading there, or is it just really difficult to find the evidence of that?

Re: Real-world data show that filters clean Covid-causing virus from air

#128

Post by asdff »

gpm wrote: post #90
kadoban wrote: post #66

Earlier quoted context omitted.

The ones I have are HEPA and the fan speed is still variable, and very quiet on low.

Can you recommend the model you have? The one I have is loud enough on it's lowest setting that I don't like leaving it on in the background :(

If you go on Amazon they have many HEPA models that advertise their decibel levels explicitly. If its listed as going down to the low 20s in decibels it will be almost completely silent.

Re: Real-world data show that filters clean Covid-causing virus from air

#129

Post by asdff »

DantesKite wrote: post #63

Wouldn’t be a bad idea to start having air filters in confined spaces. Elevators, gyms, restaurants. Not saying it has to happen all at once, but it would help decrease most respiratory diseases from spreading.

So many public restrooms use some automated febreeze sprayer to deal with the feces particulate odor in the room. If they used actual HEPA they could actually cut down on the particulate and odors without having the bathroom smell like you are inside a scented candle, or an Abercrombie store. Ongoing costs would probably be similar, HEPA filters are cheap just like a can of febreeze.

Re: Real-world data show that filters clean Covid-causing virus from air

#130

Post by _3ddw »

jbay808 wrote: post #53
overton wrote: post #36

Earlier quoted context omitted.

Early on in the pandemic, the Canadian IPAC (Infection Control and Prevention) establishment came down hard against theories of airborne COVID transmission, at first even going so far as to not recommend masking. Even now that the science of airborne transmission has been established, they're waging a rearguard battle to obfuscate/deny it and airborne protections such as better ventilation and masking. If you go to a…

> If you go to a Canadian hospital wearing an N95 these days there's a good chance they will insist you to take it off in favour of a "clean" surgical mask with gaps around the sides and nose. Happened to me many times. Sometimes they let me wear it over my (certified) N95, sometimes they don't.

I am so confused… how do they think covid spreads, then? Why should you wear a surgical at all, then?
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