There has been a number of these studies in schools and hospitals showing HEPA filters reduce up to about 2/3rd of infections. We now know many viruses are airborne including Covid and Al Hubbard's studies on how long virus is viable has shown it can be hours and it's helped by high CO2. Air circulation and reducing CO2 makes a big difference as well.
<a href="https://youtu.be/gaQTYrisieA" rel="nofollow">https://youtu.be/gaQTYrisieA</a><p>This is an extremely well researched and presented video that exposes the fact that HEPA purifier marketing is a bit of a scam. The most important factor in air purifiers is not the filter but Clean Air Delivery Rate. You can only make a difference if you are moving air through the filters faster than particulate is introduced into the air.<p>I just returned a Medify filter because their advertised square footage is way higher than what the purifier should support based on the info in the video; it is inadequate. No idea how they are calculating their numbers - not to mention it's probably at the max speed setting - but it doesn't align with the sources from the video.<p>On top of that, smaller air purifiers must move air faster, be noisier, and the smallest sizes of particulate are captured most effectively at low velocities.<p>Use something like this to make a nicer version of a CR box:
<a href="https://acinfinity.com/component-cooling/cabinet-fan-systems/airplate-s7-home-theater-and-av-quiet-cabinet-cooling-fan-system-12-inch/" rel="nofollow">https://acinfinity.com/component-cooling/cabinet-fan-systems...</a><p>Or buy one of these:
<a href="https://www.cleanairkits.com/" rel="nofollow">https://www.cleanairkits.com/</a><p>Those seem to be the best options that ACTUALLY work.
If borne out this is pretty big. A huge amount of productivity is lost by parents taking care of sick kids or who get sick from their kids. Further it might even lessen the overall spread of seasonal diseases.
This is one of the three educational interventions with solid evidence of it working. The other two are air conditioning and free school lunches. People don't get excited over them though, because they have nothing to do with teachers or curriculum or educational theory.
I installed a Zehnder ComfoAir Q ventilation system in my home. It has heat and moisture recuperation capabilities. It's currently refreshing the air at around 100m³/hour. It has an F7 (aka "ISO Fine" or "MERV 13") filter. Since installing it, my asthma has improved a fair bit, and I'm sneezing a lot less. Added benefit, virtually no mosquitoes have been able to enter my home. I'm still considering getting an extra filter addon to filter out more fine soot from car exhaust etc, but even without that option I've been very happy with the results.<p>Edit: hit reply too soon. Wanted to add: are air purifiers as effective as increased ventilation? Should we combine the two?
With my experience around poorer schools in the USA I would worry that the filter wouldn’t get replaced for decades and itself become a breeding ground for molds.
There was a great deal of interest in how to remove airborne viruses during Covid.<p>One of the biggest takeaways seemed to be that UV light destroys viruses in seconds.<p>Seems like there a lot of things we could do
Anecdotally can vouch for air purifiers. I bought an old earth bermed home. I suspected radon may be an issue. Purchased 2 AirThings and they were off the government charts so to confirm Radon Daughters were being produced I bought more air purifiers and an Alpha Geiger Counter. I can hold it 2 inches from any of my filters and the alarm sounds. 640 CPM alpha radiation. That changed my project priorities. The filters only bought me some time as the air away from the filters is the same level of radiation as outdoor background noise but obviously the source is still emitting gas. I will probably just bulldoze this place.
Can anyone provide or link to some solid guidelines on what kind/brand of air purifiers actually do real effective filtration vs. garbage products? I have found that a great many of these "air purifiers" have great marketing and make amazing claims.
Even better (where weather allows) is fully outdoor daycare. We were fortunate to have only the briefest of shut downs during COVID.<p>Obviously impractical in many areas but it's part of the California dividend
So from 10-13 down to 7-9? Nice.<p>Will be neat to see if the kids were still carriers, but managed to keep the viral loads down such that they weren't "sick" during that time. I recall a study a few years back that said kids at that age were basically always sick, just not often symptomatic.
Any HVAC professionals or plumbers know if a mini-split A/C system can be outfitted with UV bulbs?<p>Have a few Levoit air purifiers that sit flush against the wall. But would be nice to have an extra layer at the source.
I wouldn't call this a statistically significant result, and the fact that the buildings in question had good mechanical air ventilation could very well explain the results:<p>> "Utilizing the model, we used portable air cleaners in two day care units (A and B, number of children participating in the study n = 43) and compared infection incidents between the two intervention units to the rest of the units in city of Helsinki (n = 607). The intervention buildings had mechanical supply and exhaust air ventilation."<p><a href="https://www.sciencedirect.com/science/article/pii/S2950362024000043" rel="nofollow">https://www.sciencedirect.com/science/article/pii/S295036202...</a><p>You also have to consider external air quality, as ventilating a building with polluted air would have negative effects like increased asthma. In that case perhaps a sealed building with air purifiers is a better option, but then CO2 buildup is a concern, so you'd need CO2 scrubbers, which are expensive.<p>That's why clean air regulations matter, and getting off fossil fuel combustion as an energy source (and limiting pesticide/herbicide use in agricultural zones) is the easiest route forward.
Given that air purifiers could increase airborne endotoxin levels [0], that instead better ventilation should be prioritized as it also solves the higher CO2 problem, where we know cognitive function slows down due to higher CO2 levels [1]. Given that OSHA sets an upper limit on CO2 in the workplace, I wonder whether daycare centers have such norms enforced too.<p>[0] <a href="https://www.sciencedirect.com/science/article/pii/S016041202031833X" rel="nofollow">https://www.sciencedirect.com/science/article/pii/S016041202...</a><p>[1] <a href="https://www.ucl.ac.uk/bartlett/energy/news/2018/dec/study-mitigating-effects-higher-co2-levels-productivity-receives-widespread-coverage" rel="nofollow">https://www.ucl.ac.uk/bartlett/energy/news/2018/dec/study-mi...</a>
Yes, please. My colleagues, who are parents, are constantly sick whenever their children are at daycare, and I have no interest in the constant coughing and/or getting sick myself.
I actually hope building codes eventually include some kind of positive pressure system in the future where incoming air is hepa'd. PPSystems tend to clean the air the most.
I'd like to see the study first, how can we know that this year's flu variant wasn't just less infectious ? What was the sample size ? What's the p-value ?
It's amazing that this seems surprising to people after COVID.<p>Next up:<p>* Air purifiers in schools cut parent's sick days too (not just "I need to care for my kid" days - "parent is sick" and "childless coworker of parent is sick" sick days)<p>* Air purifiers in strategic locations (high density offices, public transit, schools, ...) cut sick days across the population.<p>I think this will be our generations "realizing that washing your hands before surgery makes patients die less", and it's quite embarrassing that with all the knowledge about viral transmission we couldn't figure this out <i>before</i> the pandemic, and even more embarrassing that we couldn't figure it out immediately after we tested many of these things at a large scale.
As much as I hate the amount of illnesses my kids get from daycare - maybe this shouldn't be a goal? In workplaces, hospitals, etc. we definitely want to reduce illness. In daycares, the kids are all building their immune systems and the contact with germs is a vital part of that.<p>I definitely understand the teachers don’t want to be sick, and it’s a hardship on parents to keep kids home, so it’s not all about the kids’ health. But the kids’ health might be better served by letting them get more minor illnesses, not less.