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As a high school teacher, I first noticed this effect when I started using a CO2 monitor in my classroom as a proxy for air freshness during COVID. The CO2 leve

As a high school teacher, I first noticed this effect when I started using a CO2 monitor in my classroom as a proxy for air freshness during COVID. The CO2 levels in our supposedly "no problem with the air" classrooms shot up to 2000 ppm within minutes of the start of school and stayed there all day. Kids weren't checked out ONLY because I teach mathematics. They were breathing bad air, too. Worse, when I brought the monitor home, I found the levels there were elevated even with no one home and surpassed 2000 with just two or three of us in a room. The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are.

tsss 3mo ago
Your comment is suspiciously missing the part where your students performed measurably better after decreasing CO2 concentration.
- wffurr 3mo ago
  Assuming they had any control over the ventilation in the room.
  - tsss 3mo ago
    No such assumption is necessary. If they didn't then that the entire comment is totally baseless speculation, no better than asking a horoscope.
- crypttales 3mo ago
  [dead]
weberer 3mo ago
>The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are. You could also install an energy recovery ventilation (ERV) system.
- Cthulhu_ 3mo ago
  Houses where I live were fitted with those. People turned them down to the lowest settings because they were loud. Then people developed health issues due to high CO2 and they had to refit the systems.
throw0101a 3mo ago
> The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are. The point of having "tight" houses is not (just) about energy efficiency but about air quality as well. The general mantra is build tight, ventilate right. It's why modern building codes mandate air tightness and having ERV/HRVs. By having a leaking house you do lose efficiency because in summer the air you paid to cool goes out and the hot-humid comes in, and in winter the air you paid to heat escapes and the cold comes in. But in addition to temperature (and humidity/moisture) you also get things like pollen, brake dust, (depending on your region) wildfire smoke, etc. By ventilating right with ERV/HRV, you remove stale air and bring in tempered fresh outside air that you filter before distributing throughout the building. Air quality is also why 'spot ventilation' is also generally mandated at certain locations like over a cooktop/range in the kitchen, and in bathrooms (where the primary purpose is not taking care of smells (though helpful), but rather moisture from showers/baths). * https://www.youtube.com/watch?v=CIcrXut_EFA https://www.youtube.com/watch?v=CIcrXut_EFA * https://www.youtube.com/watch?v=UTBNNhUH5V8 https://www.youtube.com/watch?v=UTBNNhUH5V8 * https://www.greenbuildingadvisor.com/app/uploads/sites/default/files/Houses%20Need%20to%20Breathe%20Right_FHB178.pdf https://www.greenbuildingadvisor.com/app/uploads/sites/defau... * https://www.youtube.com/watch?v=lFfH1ljQgN07&t=3m14s https://www.youtube.com/watch?v=lFfH1ljQgN07&t=3m14s
- cucumber3732842 3mo ago
  Not everywhere is LA. How much does implementing all that cost? What degree of benefit does it offer over simple window in situations where those concerns are negligible? What other benefits to human life could be procured with that money? It just boggles the mind that people feel emboldened to only look at one side of the equation.
  - throw0101a 3mo ago
    > Not everywhere is LA. > How much does implementing all that cost? What degree of benefit does it offer over simple window in situations where those concerns are negligible? What other benefits to human life could be procured with that money? Everywhere not being LA is actually an argument for ERVs/HRVs. The weather in LA (AIUI) is fairly even and consistent and it is probably fairly easy to just open a window. But if you're in Texas with high humidity, or Arizona with high heat, or north of the Mason-Dixon line where people get winter, it's kind of hard to open a window when it's 0 or -10 outside. If you have stale air (perhaps as measured by high CO2) what are you supposed to do? Over the July 4, 2026, weekend it's supposed to get >90F/>32C on the east coast of the US: do you want to open your windows and let all of that heat in? Especially if you already have an AC unit so paid to run it get your home's inside temperature down? If you have a place with ducts, you can purchase an ERV and tap into that for US$ 1000: * https://www.hvacquick.com/products/residential/HRVs-and-ERVs/Residential-ERV https://www.hvacquick.com/products/residential/HRVs-and-ERVs... or even less: * https://hvacdirect.com/air-cleaning/erv-air-exchangers.html https://hvacdirect.com/air-cleaning/erv-air-exchangers.html And even in milder climates (like LA), have the ERV suck in air from the outside through an MERV 13(+) carbon filter, and not only do you deal with things like wild fire smoke, but wild fire smell: * https://www.greenbuildermedia.com/blog/wildfires-make-indoor-air-quality-a-top-priority-for-homeowners https://www.greenbuildermedia.com/blog/wildfires-make-indoor... * https://shop.aprilaire.com/products/aprilaire-513cbn-odor-reduction-filter-replacement-for-whole-home-air-purifiers-merv-13-with-activated-carbon-removes-odors-from-pets-and-cooking-filters-vocs-and-particulates https://shop.aprilaire.com/products/aprilaire-513cbn-odor-re... It is possible to make your indoor air cleaner than the air outside.
crypttales 3mo ago
[dead]
Aurornis 3mo ago
Most studies don't register cognitive changes in the range of 2000ppm. A lot of the military and space studies used exposures multiple times higher than that without registering cognitive problems. It wasn't until you got to very high numbers that they registered any changes. Only a couple studies purport to show cognitive changes at levels around 2000ppm, and the ones I know of all involve one controversial researcher named Usha Satish. There are a lot of studies with CO2 levels at 10,000ppm or higher that have failed to find cognitive effect (an example https://pubmed.ncbi.nlm.nih.gov/29789085/ https://pubmed.ncbi.nlm.nih.gov/29789085/). Your 2000ppm classroom air would have been like fresh air relative to the concentrations these studies are looking at.

tsss 3mo ago

Your comment is suspiciously missing the part where your students performed measurably better after decreasing CO2 concentration.

wffurr 3mo ago
Assuming they had any control over the ventilation in the room.
- tsss 3mo ago
  No such assumption is necessary. If they didn't then that the entire comment is totally baseless speculation, no better than asking a horoscope.
crypttales 3mo ago
[dead]

weberer 3mo ago

Cthulhu_ 3mo ago
Houses where I live were fitted with those. People turned them down to the lowest settings because they were loud. Then people developed health issues due to high CO2 and they had to refit the systems.

throw0101a 3mo ago

> The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are. The point of having "tight" houses is not (just) about energy efficiency but about air quality as well. The general mantra is build tight, ventilate right. It's why modern building codes mandate air tightness and having ERV/HRVs. By having a leaking house you do lose efficiency because in summer the air you paid to cool goes out and the hot-humid comes in, and in winter the air you paid to heat escapes and the cold comes in. But in addition to temperature (and humidity/moisture) you also get things like pollen, brake dust, (depending on your region) wildfire smoke, etc. By ventilating right with ERV/HRV, you remove stale air and bring in tempered fresh outside air that you filter before distributing throughout the building. Air quality is also why 'spot ventilation' is also generally mandated at certain locations like over a cooktop/range in the kitchen, and in bathrooms (where the primary purpose is not taking care of smells (though helpful), but rather moisture from showers/baths). * https://www.youtube.com/watch?v=CIcrXut_EFA https://www.youtube.com/watch?v=CIcrXut_EFA * https://www.youtube.com/watch?v=UTBNNhUH5V8 https://www.youtube.com/watch?v=UTBNNhUH5V8 * https://www.greenbuildingadvisor.com/app/uploads/sites/default/files/Houses%20Need%20to%20Breathe%20Right_FHB178.pdf https://www.greenbuildingadvisor.com/app/uploads/sites/defau... * https://www.youtube.com/watch?v=lFfH1ljQgN07&t=3m14s https://www.youtube.com/watch?v=lFfH1ljQgN07&t=3m14s

cucumber3732842 3mo ago
Not everywhere is LA. How much does implementing all that cost? What degree of benefit does it offer over simple window in situations where those concerns are negligible? What other benefits to human life could be procured with that money? It just boggles the mind that people feel emboldened to only look at one side of the equation.
- throw0101a 3mo ago
  > Not everywhere is LA. > How much does implementing all that cost? What degree of benefit does it offer over simple window in situations where those concerns are negligible? What other benefits to human life could be procured with that money? Everywhere not being LA is actually an argument for ERVs/HRVs. The weather in LA (AIUI) is fairly even and consistent and it is probably fairly easy to just open a window. But if you're in Texas with high humidity, or Arizona with high heat, or north of the Mason-Dixon line where people get winter, it's kind of hard to open a window when it's 0 or -10 outside. If you have stale air (perhaps as measured by high CO2) what are you supposed to do? Over the July 4, 2026, weekend it's supposed to get >90F/>32C on the east coast of the US: do you want to open your windows and let all of that heat in? Especially if you already have an AC unit so paid to run it get your home's inside temperature down? If you have a place with ducts, you can purchase an ERV and tap into that for US$ 1000: * https://www.hvacquick.com/products/residential/HRVs-and-ERVs/Residential-ERV https://www.hvacquick.com/products/residential/HRVs-and-ERVs... or even less: * https://hvacdirect.com/air-cleaning/erv-air-exchangers.html https://hvacdirect.com/air-cleaning/erv-air-exchangers.html And even in milder climates (like LA), have the ERV suck in air from the outside through an MERV 13(+) carbon filter, and not only do you deal with things like wild fire smoke, but wild fire smell: * https://www.greenbuildermedia.com/blog/wildfires-make-indoor-air-quality-a-top-priority-for-homeowners https://www.greenbuildermedia.com/blog/wildfires-make-indoor... * https://shop.aprilaire.com/products/aprilaire-513cbn-odor-reduction-filter-replacement-for-whole-home-air-purifiers-merv-13-with-activated-carbon-removes-odors-from-pets-and-cooking-filters-vocs-and-particulates https://shop.aprilaire.com/products/aprilaire-513cbn-odor-re... It is possible to make your indoor air cleaner than the air outside.

crypttales 3mo ago

[dead]

Aurornis 3mo ago

Most studies don't register cognitive changes in the range of 2000ppm. A lot of the military and space studies used exposures multiple times higher than that without registering cognitive problems. It wasn't until you got to very high numbers that they registered any changes. Only a couple studies purport to show cognitive changes at levels around 2000ppm, and the ones I know of all involve one controversial researcher named Usha Satish. There are a lot of studies with CO2 levels at 10,000ppm or higher that have failed to find cognitive effect (an example https://pubmed.ncbi.nlm.nih.gov/29789085/ https://pubmed.ncbi.nlm.nih.gov/29789085/). Your 2000ppm classroom air would have been like fresh air relative to the concentrations these studies are looking at.