Considering you’re exposed to water during limited times (and need to actually ingest it) but exposed to air 24/7 (or else you die) that doesn’t seem like a reasonable comparison.
If someone standing in front of you sneezes, a filter in the HVAC isn’t doing anything to stop you from getting covid.
I mean, isn’t airborne transmission still uncertain for Covid?
We don't have to eliminate all transmission to stop Covid, we just need to bring the R value below 1 and keep it there. I don't think that direct transmission via sneezing is a significant cause of spread, but sneezed particles could remain in the air for a long time, long enough for a filter to make a difference.
>Recent investigations into the March 2003 outbreak of SARS in Hong Kong have concluded that environmental factors played an important role in the transmission of the disease. These studies have focused on a particular outbreak event, the rapid spread of SARS throughout Amoy Gardens, a large, private apartment complex. They have demonstrated that, unlike a typical viral outbreak that is spread through person-to-person contact, the SARS virus in this case was spread primarily through the air. High concentrations of viral aerosols in building plumbing were drawn into apartment bathrooms through floor drains. The initial exposures occurred in these bathrooms. The virus-laden air was then transported by prevailing winds to adjacent buildings at Amoy Gardens, where additional exposures occurred. This article reviews the results of the investigations and provides recommendations for maintenance and other measures that building owners can take to help prevent environmental transmission of SARS and other flulike viruses in their buildings.
I assume those floor drains lacked a functional p-trap because I've read with covid that disease would spread through drains without a proper p-trap, but otherwise the p-trap prevents drains like toilets and sinks from stinking and allowing contaminated air through.
P-traps can dry out though, but they stink if they do. Maybe that's what happened there?
Edit: yes, that's the theory - floor drains with dry u-bends allowed the poop air out.
It also had a cracked vent pipe. Sickness was correlated with floor level (the higher the floor level, the higher the infection rate).
The important takeaway is SARS 1 had significant fecal-oral transmission and not just respiratory.
And yet I'm supposed to believe that SARS 2 is respiratory only despite the fact that the government has detected SARS 2 in sewer systems, one of the early Covid symptoms is diarrhea, and SARS 1 had significant number of infections by fecal matter.
It seems to be a problem with older east Asian construction, I claim no specific expertise on the issue but I've observed poor p/u bend water barriers in even fairly nice buildings from the 70s and 80s in Taipei.
Fish tank filters are practically required for fish. I don't see why home air filters (HEPA) aren't more common especially in extreme environments with window opening not realistic.
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. Its for maybe hospitals that are on super covid lockdown that want a little more protection for their most vulnerable patients.
We get rid of covid through mass vaccination like any other virus. There's no shortcuts for those who refuse masks and vaccines.
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.
> but spending long periods with someone indoors in close proximity.
It's not obvious to me that in-room air filters wouldn't reduce the exposure in this case, as the original commenter claimed? If it reduces the virus in the air, as the OP study finds, it seems like it probably would reduce virus exposure and thus infection rate when spending long periods indoors in close proximity, no?
Sure, just because it reduces the virus in the air doesn't necessarily mean it reduces infection -- like hypothetically the virus could commonny be going right from someone's exhale to someone else's inhale without having a chance to be filtered -- which I think is what the original commenter was suggesting -- but that's not the "spending long periods" scenario at all. I think it's true that while you probably can get infected in as little as ~15 minutes (not necessarily in just a couple minutes), but also clear that the longer you are in the same room, the higher risk.
But sure, we don't know exactly everything. All we can do is build knowledge one brick at a time, AND all we can do is act on the bricks we already have (that we don't have the whole wall yet is not a reason to avoid acting on our best picture (mixed metaphor, sue me) form what we do have)... but reducing virus in the air is a pretty huge brick for a respiratory infection. Based on everything we do know, it is hard to believe what the original commenter asks us to, to believe that reducing viral concentration in the air would NOT significantly lower infection rate.
I think it's becoming increasingly clear we should be spending at least as much attention on HEPA air filtration as people have been on masks.
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?
What data are you referring to? The protests and marches last year seem to be hard to ignore example of things that should have had more spread by these standards.
Those were outdoors with plenty of room for viral particulate to disperse. there has been a lot written about this, its called the infectious dose which is the amount of virus particulate needed for someone to become ill with the virus. I recommend pubmed or google scholar if you want a deeper dive.
if you are having trouble visualizing how this works, imagine a perfume dispenser jetting out a fine mist, that's your covid positive person exhaling. In an enclosed small room, the concentration of that particulate mist is much higher than in a large room, and unable to disperse quickly without any ventilation. Over time, you will inhale more and more of this particulate in this room at this concentration, and you will hit the infectious dose level eventually. If you are outside, or in a larger or well ventilated room, concentration of the particulate is much smaller since its either dispersing into a greater volume of air or being removed from the area due to ventilation, and it might take you a long period of time to inhale enough particulate at this comparatively lower airborne concentration in order to become sick. Outside, even in a protest, the volume of air is so large in which to disperse particulate that the risk of getting an infectious dose is negligible even with someone yelling right next to you.
Some of the marches that I went to... were less than airy, to be honest. Easily comparable to any ballgame I have been to.
So, I have seen a lot of these papers, but too much feels like post hoc justification. I'm game for being cautious, so I'm not really saying to do anything different, but I do want to urge way more caution in messaging than I'm seeing. It is fair and ok to talk of the uncertainty.
In terms of safety, vaccines are much better then getting COVID.
One of the big factors of "better protection" of immunity gained after recovering from the virus is survivor bias. In data about mortality after reinfection there are no people who died after getting it for the 1st time. This leaves only ones who had body strong enough to recover.
There's no surprise that later that group fares better.
What if the air is being actively refreshed and filtered. I believe this is what needs to start happening in most indoor environments. This would definitely help with reducing the amount of cases.
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.
> 1x 20x20 MERV-13+ MPR-2400+ HVAC air filter ($20)
That's a MERV-13 filter, not a HEPA filter.
HEPA filters 99%+ of small (0.3um) particles per pass. A MERV-13 filter only filters like 60% per pass IIRC.
That means that a 1000 cu. feet of air through the HEPA filter will result in 990+ cu. feet of clean air. While the MERV-13 filter will only produce 600 cu. feet of clean air.
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A MERV13 filter would be good enough to improve most air, but its not HEPA and shouldn't be confused with it.
It’s worth noting that filter efficiency is a function of particulate size. A MERV13 and a HEPA filter are nearly equivalent for filtering pollen, but have drastically different performance for smoke and virus particles.
There’s a plot 1/3 of the way down the page that shows the curves:
MERV13 also needs less pressure, and a box fan is bad with pressure. If you stuck a HEPA filter on a box fan, it might only do 100cu feet of airflow. MERV13 is maybe 200.
HEPA is designed for higher pressure centrifugal fans. MERV13 is likely the best balance for home made designs
You're right, thanks for the clarification, this is a "DIY air purifier" not a "HEPA" filter. (Apparently products today even have to clarify if they are "true HEPA" due to misleading marketing)
According to this website (https://freshairaustralia.blogspot.com/2020/01/how-does-merv...) a study for underground mining filtration found a MERV-16 filter superior to HEPA in terms of airflow and cost, with a negligible difference in filtration efficiency.
According to the study, the MERV-16 filters have higher flow rates than a HEPA filter, which would both make the MERV filter a better fit for an inefficient fan, and increase the air filtration rate. The author of that site also finds that the airflow rate can be more important than a filter's rated efficiency: https://freshairaustralia.blogspot.com/2020/01/why-air-flow-...
After some web searching, it seems you can buy smaller replacement HEPA filters and MERV-16 filters starting at ~$40. So I guess you can spend less if you only need "air purifying", and more if you want the real deal.
note that phrase like "600ft³ of clean air" are misleading. filtration drops off rapidly with distance from the air purifier, so the fan would need to be quite oversized for a room to experience relatively even filtration. for most rooms, that wouldn't be comfortable, for both noise and draft reasons.
i'm down with air purifiers for indoor particulate matter (i.e., air pollution), but they're not really going to make a dent in covid transmission rates. transmission happens mainly during long face-to-face conversations, which mostly precedes/bypasses room air filtration.
it’s the appearance of doing something that’s more valuable to bureaucrats than solving real, underlying problems and providing genuine leadership (like quelling anxiety and fears rather than stoking them).
(central) air filtration can be effective against harmful pollutants, but not really against infectious agents like corona.
This is fascinating! If MERV 13 filters 60% with each pass, can we put 9 in a room to increase the circulation/filtration and eventually get to 99.7% filtration? Does it even work like this?
Also, I found this article which I found informative. Judge it as you please:
This is fascinating! If MERV 13 filters 60% with each pass, can we put 5 in a room to increase the circulation/filtration and eventually get to 99% filtration?
Also, I found this article which I found informative. Judge it as you please:
I see people post this all the time, but I really don't think an axial fan can pull air through a HEPA-like filter. You need to spend $150 on a real solution. It's really not much, includes the filters, and looks a hell of a lot better to boot.
This Old House has a really good breakdown on filtration and air volume and have a pretty clever DIY box fan approach using multiple filters. Still costs under $100. The Wirecutter recommended Coway filter is $185 on Amazon.
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.
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 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.
> 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.
The sign I saw at a hospital in Toronto said no fabric masks, only surgical. It’s probably about uniform coverage not overall efficiency, a compromise of most big central systems.
My corner flower shop has a sign saying surgical or FFP2, just like most shops I’ve seen in my area of Germany. If they can manage it, so should a hospital.
> 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.
Wouldn't that just be because of protocol, ie. they don't know if you, a member of the public, actually have a legit N95 mask, or if you know how to correctly implement it, etc.
Incidentally, if you want to validate 3M N95 masks, 3M has a web site for that.[1] You type in the code on the bottom of the box and 3M checks it. You can only do this once per code; the site will tell you if a valid code has been used before. They suggest signing and dating the box after doing this, to indicate that check has been done.
How do they know that one is not wearing a fake surgical mask then? The obvious conclusion is that parts of the medical establishment are still being dumbasses about masks, two years into the pandemic.
Having some experience with hospitals and N95 they asked that we put a surgical mask over the one we came with. Pointless and unnecessary but I guess it’s easier than having staff validate the mask your wearing.
Airborne transmission and the usefulness of filters still doesn't seem that clearly established - this study didn't find that much virus in the air even without the filters, and most of the real-world transmission seems to involve people who were directly exposed to virus particles before they even had a chance to go through a filter, via standing next to someone or directly in an airflow path coming from their direction.
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?
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.
thanks for pointing this out. it gets lost in the fervor of trying to "fight the virus". most of our interventions are useless, and yet, we still insist on doing them. the virus just isn't aloft and active for very long. that's why the most dangerous activity is close conversation, something we tend to do around people we know well (friends & family), not strangers in public.
I suppose the cost of installation outweighed the minor inconvenience of colds and flus spreading in the past. Only now that we have a deadlier virus does it make sense.
Most likely. Canada also has a habit of under-spending on healthcare in general. The system is also hypersensitive to political whims and can end up getting neglected as a result. This is because the provinces have direct control over every aspect of the healthcare system, and set the budget for them directly.
Unlike other nations like Germany and Estonia, Canada's healthcare system is fully dependent on the provincial government to exist and be funded. If I'm not mistaken, in the two countries I mentioned, clinics can get private funding while providing universal access in most cases, which means they have a larger buffer between the political whims of the state, and their ability to provide service. If the state under-provides, the clinics can seek investors to cover the new costs, all the while maintaining universal coverage.
That's not something Canadians can do. Talk of any private involvement, or restructuring in general, in Canada's healthcare system is often very politically charged and not particularly honest, so change is not happening any time soon.
I suspect the issue here is that the hospitals know that having HEPA filters would be a good idea, but political will isn't there to give them what they need. Canadian politics on both sides lately has been more about the appearance of progress through large gestures, rather than careful consideration of long term solutions. It's very unfortunate.
Have you lived any length of time in Canada? If so, where? While I have been fortunate enough to not have needed to go to hospital, my dental office reopened after the initial lockdown last year with a HEPA filter, doorway screen and other paraphernalia which made each workarea look like a clean room. And they shifted from water to air-driven cleaning and dressed like sci-fi actors. I would imagine the hospitals were similar due to the stress put upon them. Anecdotally, my wife had a breathing test in hospital a few days ago and they checked vaccination status and accepted the mask she walked in with.
Given that the federal government is responsible for funding much/most of the provincial health care system, they have some input into how things operate. Most provinces have a good handle on covid unless their government went too deep into the "covid is over" bit (Alberta, Saskatchewan). The covid response here was delayed due to the need to secure vaccines from others, but the end result has been quite good.
I have lived all over N America, and the freedom/flexibility of the Canadian health system has been better than anywhere except St. Louis, MO when I was there - and that required full-time employment.
Yes, I am a Canadian. I lived there for 25 years. I have Canadian citizenship. Most of my family still lives there. I also ended up stuck in Ontario for most of COVID. I have family in Ontario, in Quebec, and elsewhere in the country. I don't think Ontario had a very good handle on COVID. It's also no secret that Canada is suffering a major staffing, and funding shortage in the healthcare sector right now.
While most of your reply is about dentists (I'll get to that later), I see you're comparing Canada's healthcare system to the USA. I'm not. Compared to other systems in NA, yes, it's much better since it's free and somewhat fair. But that's the problem. Canadians should be looking to other developed nations with public healthcare. Not to the United States which operates on a completely different paradigm. My comment that you're replying to is entirely contrasting Canadian healthcare with EU systems, not Americans.
> dental office reopened
The majority of dentists are private entities, and are not subject to the same funding rules as hospitals. They're not licensed through the same entities, funded, or managed in the same way at all. Likely why they were able to adapt so quickly. See: https://www.cda-adc.ca/stateoforalhealth/servicescanada/
> [..] they checked vaccination status and accepted the mask she walked in with.
I'm not really sure what you're getting at here, this does not really relate to funding, or anything I'm talking about really. This is more about safety policy, not funding, which is what I'm trying to discuss.
Don't get me wrong, I've had some good experiences with the system as well, but that does not mean it shouldn't significantly improved.
The masks might have been after seeing a different comment, sorry. The problem with improving the system is that 1/3 of the country seems to want the US system in healthcare and probably (lots?) of other things. So it goes. Re: Ontario, I was looking at Ottawa specifically, the province generally and while it's "blessed" with a Conservative premier he's taken more medical advice (or indulged his populist leanings) more than other such premiers. Canadians, for the most part, are willing to play along which also helps.
I'm not really sure what you're trying to say here. I don't really think there's any real reason to think that 1/3 of Canada wants the American system. That's certainly never something I've seen any evidence for. My impression was always that it was a point of general pride that the Canadian system "wasn't' like the American's". Only a small fringe want otherwise from what I can tell. It's not even in the platform of any small fringe parties as far as I can tell. I would suspect if a niche issue like Albertan separatism finds political expression, this would too.
Could you be conflating talks about "privatization" (allowing private clinics to exist and take OHIP) with private healthcare payments (you don't get OHIP) by mistake? Those two are not really the same at all, but get conflated in the media often.
That last part there about Ottawa or Ontario, not sure which one, doesn't really make much sense, sorry. It's unclear what you're getting at. Nothing there really sounds related to what I'm talking about.
Not surprising? HEPA filters have been known to be able to filter viruses for some time; it's maybe the main reason they were invented? Not sure about that though.
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 negatively affect anyone, let’s shout it from the rooftops. If schools had been given funding to improve air circulation and filtration as well as a local gym now does after a $500,000 upgrade, I’m sure many would feel better about sending their children to school.
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.
The authorities have long since stopped recommending cloth masks and surface cleaning. Anyone still applying or recommending those methods isn’t up to date.
There’s nothing farcical about recommending cloth masks and surface cleaning during the first few months of the pandemic when nothing was known about how the virus spread and when masks needed to be reserved for those on the front lines.
The only farcical piece is how our society reacted to the recommendations of the experts.
> Anyone still applying or recommending those methods isn’t up to date.
That's why it's farcical. In my area, you're required to wear your mask when you enter a restaurant and keep it on until you reach your table. Employees spend 8 hours breathing in the building through a cloth mask. Many places are still serving using single-use dishware to "stop the spread". Many people are still walking around with gloves on.
I'm not saying these were bad recommendations at the time, but they've turned into talismans and rituals we do to ward off the evil spirit of COVID while people broadly go about their lives as before.
Meanwhile, things like updating and repairing HVAC systems or restructuring buildings to maximize airflow, which both actually address COVID and have actual positive effects on health and wellbeing get short shrift, because we're wearing masks, so we're safe, and doing real work is expensive.
> The authorities have long since stopped recommending cloth masks
That depends completely on where you live, there are plenty of places that still have indoor or outdoor mask mandates, despite them being completely useless.
If one looks at a typical FFP2 or FFP3 mask, they have two years written on them - 2001 and 2009 - which reference the years the standards for such masks were published.
Now this pandemic started around 2020, which is more than decade later.
So recommending cloth masks was and is indeed farcical. Doing it after recommending against mask usage is idiocy. And no, the world’s collective scientific understanding of masks didn’t change between 2020 and 2021.
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 have now really sucks!
The point would be to have the central HVAC system be renovated to boost circulation with HEPA filters in the loop precisely so that you don't have to have two noisy things doing a middling job of a similar task in the classroom itself.
Speaking for many schools in heating dominated climates: renovate the what? (Many schools have forced water radiators, which are obviously not able to be retrofitted for effective air filtration.)
There's quiet filters. I can barely hear the one(s) in my house, and they're just cheapo ones. Typically the key is to keep the fan speed reasonable, if you crank it up all the way almost any fan is going to be loud.
Sure, ya it's the Winix 5300. Bit confused on the price though, I remember it being significantly cheaper than the prices I see for it now. I do like it though (one note: I never use the "plasma wave" or whatever that is, just the filtering).
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.
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't worth having in an average bedroom, but in a classroom, it's likely not doing much at all.
also, you're already distancing (which is doing nearly all the work there) and wearing masks (which is mostly theater in a distanced classroom as well). the virus isn't free-floating live in the classroom. most virus falls to the ground directly. of what's aloft, it becomes inactivated pretty quickly for all sorts of reasons (dessication, ph, temperature, radiation, etc.) and most likely won't land anywhere near a viable infection spot. so almost no active virus is filtered out before it has a chance to reach a moist, viable passageway in another person.
even huge central commercial systems likely wouldn't filter out coronavirus before they die off or land somewhere harmlessly. it's another potential intervention that sounds plausible on the surface, but is mostly useless against covid.
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
no, but you’re welcome to present your own perspective and rationale for discussion. research is ongoing, but we certainly have enough time and information to form and debate hypotheses by now.
for instance, this study did not link air filtration to a reduction in transmission, only that a hepa+uv filter can reduce sars-cov-2 from known aerosolized air, basically an expected result in a controlled study (not “real-world”, as claimed).
We have the Austin Air Healhmates at work. They are quiet.
That said the real failure was the FDA not making getting the vaccine approved for your 3rd graders by the start of the school year. Frankly I don't know how those guys can look themselves in the mirror while they are shaving in the morning.
I think vaccine approval for 5-11 year olds is coming in early November.
Ending the pandemic is in everyone's interests, as it would help repair the economy. Kids would be included in that as the economy changes how adults are able to care for kids.
Kids have been separated from their parents due to increased evictions, their parents may not be able to work which means less money for food/clothing/services/healthcare, their parents & extended family are dying, their education has been impacted, and everyone has been going crazy from being cooped up with their families & not being able to play with friends or do extracurriculars.
What bothers me is about 7-10 years ago there was a high quality paper linking transmission of flu to temperature, humidity, and air turn over. Depressingly the response was 'oh well nothing we can do cause too expensive'
We'd be in a lot better shape if we'd decided to actually do something instead of falling back on the usual learned helplessness.
It's not surprising if you understand how HEPA filters work, the particulate sizes that they're effective for, and the particulate sizes of viruses. Most people are not familiar with one or more of those things, so these stories are worth amplifying to the end of the earth and back, so that we can be better prepared to deal with this pandemic and the next.
HEPA filters were developed for radioactive dust during the Manhattan Project. Only several years later did the technology get declassified and started being used in biology and medicine.
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.
HEPA filters do not remove odors. Bad smell is caused by extremely small particles that cannot be removed by HEPA filters. To remove odor, you will need other filters, such as an activated carbon filter. Some air purifiers come with both a HEPA filter and a filter to remove odors.
Classrooms where already an issue before Covid. Concentration goes way down when the air starts to get thick and same goes for meeting rooms. How many times have you entered a meeting room where the air was so thick you felt it as soon as you stepped in?
I'm skeptical that would be good for overall long term health. There are only a limited number of endemic respiratory viruses. Most of us will be exposed to them at multiple times in our lives regardless of what protective steps we take. So I'd rather get them while I'm still relatively young and healthy because the resulting immunity will give me at least partial protection later in life.
Of course ideally it would be better to have effective sterilizing vaccines for all those various respiratory viruses, and perhaps someday we will. But those generally don't exist today for the vast majority of viruses.
There are significant health benefits to cleaner air, not just from infectious disease, but also from particulate pollution and various other harmful substances. I strongly suspect that on the balance it would be a significant net positive from that aspect alone, though I don’t have possession of any hard evidence to back that up.
I bought a air filter which takes a rectangular panel filter like a Filtrete FAP series. Then I replace the filter regularly by cutting HEPA panel filters sold at Walmart to size. It's a cheap way to keep air clean at home. The amount of gunk and black soot and dust stuck within and to the filters is amazing. I also tend to run the device at full speed, the noise helps me tune out disturbances and leads to peaceful sleep.
> Hospitals have turned to portable air filters as an attractive solution when their isolation facilities are full.
Woah! I knew that isolation rooms where full-on filtered and with positive pressure. But I genuinely believed that all hospital HVAC units and major circulation ducts had HEPA filter stages.
Is this true? Is it not mandatory for hospitals to add these filtering stages on all HVAC units or circulation ducts?
Do they really just keep rotating the same contaminated air throughout the whole hospital?
So what would’ve happened if we had created a zillion jobs installing air filtration to create healthier workplaces across many dimensions (not just Covid) instead of paying people to stay home?
Why didn't they research this earlier? "oops, we forgot?" Or "oops, nobody thought about it?"
There have been videos going around many months ago of people in the business saying this is what should be doing instead of wearing masks. But hey, let's not doubt or question, that's bad!
I recently posted a description of a powerful cooling fan I set up for my MacBook Pro that I'm thinking of adding a filter to. I wonder if the inline duct fan I got is strong enough for HEPA filters. It's a lot stronger than a box fan. It runs off of AC and has a speed adjustment control. The TD-500/150-160 moves 550 m^3/hour at 2480 rpm.
Here are some centrifugaal high pressure tube fans, but I don't know how noisy they are compared to the S&P "TD-SILENT" silent series (with noisy sounding names like "Cyclone").
The overheating problem on my MBP was so bad and so pathetically common, that I had to take drastic and expensive measures, which work pretty well.
I tried various laptop cooling stands, and they were cheap and plastic and had shitty fans that hardly pushed any air, and didn't help.
So I got a solid aluminum laptop stand without a fan, which conducts heat much better than plastic, and I bought four sets of stick-on heat sinks (some large and some small), and stuck them all over the back of the aluminum laptop stand on the surface that touches the bottom of the laptop.
Then I bought a very powerful and quiet inline ventilation fan (the kind you use to pump air out of the bathroom), and analog speed dial (make sure you get an AC speed control for an AC fan, or a DC control if you get a DC fan) and some big wide round air tubing, and I set the fan in the opposite corner of the room (or outside the room with the door open) where the noise it generates is harder to hear, and ran the tube up to the cooling-fin encrusted back of the laptop stand, where it quietly blows lots of air on the back, and cools the stand and laptop quite effectively.
I usually run it at the lowest quietest setting "1", but can turn it up to "10" to cool it down quicker when it's overheating.
If anyone's interested I can provide links to the actual products I bought. Desktop and laptop fans were just not powerful enough, and very loud and clumsy, and it sucks to have the fan itself right next to you instead of in the next room. But the inline room ventilation fans are much more powerful and quieter and adjustable, but more expensive, and the flexible air tube lets you position the fan far away from the computer.
I was losing so many hours of work due to overheating that it was well worth investing in all the equipment to really cool it down.
Here are the small and large adhesive heat sinks, which are sold for 3d printers (I got two packs of each size: 16 eur total for 40 small ones, 16 eur total for 8 big ones):
CTRICALVER Aluminium Heatsink, Black Heatsink, Thermal Adhesive Pad Cooler, for 3D Printer, Pack of 10 (20pcs)
CTRICALVER Thermal conductivity of the radiator, heat conduction measures L40 mm x W40 mm x H11 mm, pack of 4
The fan was 185 eur, and the AC speed control was 35 eur or so, and I wired it myself with a switched plug for a couple euros. There are many models of fan, some AC and some DC, that move various amounts of air per minute, with fixed or three or variable speeds, that make different amounts of noise, but I shopped around and am pretty happy with the mid-range one I got. (S&P is a European brand so YYMV.)
Soler & Palau TD-500/150-160 Silent 580/430m3 Air Conditioning Fan + REB-1N AC speed control
The aluminum stand was 36 eur:
NULAXY Laptop Ständer, Einstellbar Notebook Ständer, Ausblendbar laptopständer Kompatibel für alle 11-17 inches Notebooks: MacBook Pro/Air, Dell
The next step I'm planning is making an air filteration system by taping together some filters like this DIY box fan air purifier, but using the powerful inline fan instead of a weak box fan:
I haven't decided what kind of filters to use yet: cheap high flow central air conditioner filters, or more expensive HEPA filters, that restrict the air flow more. The fan is quite powerful so I'm pretty sure it can handle the HEPA filters, but I haven't tried yet. Maybe that's overkill. But after wasting so many hours on overheating, overkill is kind of the point.
A heavy duty Blue Air? I’d stay away from the 605 unless your problem is really bad, they are just too loud. The newer ones are nice and quiet, though the ones they target at the western markets are much so than the ones that sell well in China (where air pollution is much more of a problem). You might want to start with measuring your indoor air quality.
The disease that develops after being infected is called COVID-19 which means Corona Virus Disease (first seen in 20)19. The virus that causes it is SARS-CoV-2, the Severe Acute Respiratory Syndrom Corona Virus 2, which is one of many coronaviruses. The 2 is there because there was an earlier coronavirus caused disease (SARS) in 2002 for which the pathogen was called SARS-CoV(-1).
I mean you are dropping the whole colds are coronaviruses too part though. though, the "cold" has a bunch of possible viruses that cause it (something like 200 different viruses) with the rhinovirus being one of the larger ways since it's so resistant to being inactivated comparatively to sars2 which only lasts for a day to three as a fomite vector, is neutralized by soap and water or 70% IPA. If covid had a viral vector like a rhinovirus that can last for months on surfaces in wide variety of conditions on surfaces and also spread via aerosolized particles it would have been a completely different pandemic that would have been far more deadly.
Only 4 known coronaviruses that cause a cold, anyway. While it'd be a bit surprising if there were more, HCoV-HKU1 was only discovered surprisingly recently.
Not entirely. AIDS is only the name for the final stage of the disease, when your immune system is rendered totally unable to defend your body. It usually takes years from an HIV infection until AIDS develops. In the first viremic phase of HIV you can even have fever but often people don't notice it or put it off as some innocent cold. COVID-19 however is used however to refer to all stages and forms of the disease.
The machine is mostly just a question of convenience, as long as the flow rate is right it's the filter that does all the work, and those are relatively much cheaper.
