7 ms·

Indoor air quality and learning: Evidence from large field study in schools [pdf]

144 points by elsewhen 4y ago

simonsarris 4y ago
These seem like crazy differences. Some classrooms have over 6x the CO2 concentration than others. Some classrooms have > 2000ppm every day. Panel A: Classroom Ventilation Mean St. Dev. Min. Max. Daily Peak of CO2 (in ppm) 1495 624 737 4665 Daily Average CO2 (in ppm) 988 336 485 2783 % of days w CO2 in classroom > 1000 ppm 77 29 0 100 % of days w CO2 in classroom > 2000 ppm 15 26 0 100 Note they claim there's no relationship observed between teacher quality and classroom ventilation Their conclusion: "An increase in classroom CO2 level during the school term by one standard deviation reduces subsequent test scores by 0.11 standard deviations. Our findings imply that exposure to poor indoor air quality directly interferes with learning, highlighting the role of physical school infrastructure in determining educational outcomes."
- culi 4y ago
  Agreed that's a huge Std Dev. I'm surprised they were able to achieve statistical significance with just 216 classrooms, but I guess the results are quite consistent: > The coefficient shows high stability in terms of its magnitude, sign, and statistical significance.
- antisthenes 4y ago
  > Some classrooms have over 6x the CO2 concentration than others. Some classrooms have > 2000ppm every day. That's basically the difference between having an open window or not. If your ventilation system is designed to get fresh air from the outside, you'll have <600 PPM, if not, you'll have 2000+ How do I know? I bought a CO2 meter and worked in an old office building that didn't get fresh air from the outside.
  - dzhiurgis 4y ago
    My dad has a shoddy heat recovery ventilation system which he throttled down to a minimum. I bought co2 meter and turns out it barely does anything, but he won’t believe me.
    - stuaxo 4y ago
      Sounds counter productive turning it to a minimum ? (I guess it could be shoddy in many other ways too!).
      - dzhiurgis 4y ago
        Over 60% it becomes quite audible, at 100% it can be annoying. It’s a ducted balanced system. If we have 4-5 adults in living room - it doesn’t keep up even at 100%. Ir I keep most doors open at night - it’s okay. Air quality is always good there, it’s mostly to manage humidity and it does it too well once it’s freezing outside.
- dahart 4y ago
  > These seem like crazy differences. Some classrooms have over 6x the CO2 concentration that others. 6x seems plausible just because some classrooms are more crowded than others, and kids are probably breathing harder at the start of class, during first class, during first class after lunch or breaks or P.E… “The variation in CO2 levels inside classrooms that we observe in our sample is almost fully caused by indoor sources, i.e. human breathing, with negligible variation from outdoor levels.” I wonder if peak rates could be easily misinterpreted? This chart doesn’t say how long peaks last or when they happen. Did they verify that a single sensor is a good proxy for distribution of CO2 in the room? It depends on where the sensor is located, for example. Near the door will see higher peaks as people come in and out than in the far corner, and air might flow toward the door. Looking at the average tells a more meaningful story, but even that may need more context, right?
- nomorewords 4y ago
  I'm not American, but when we were in up to the 9th grade, every break between classes we would play football (soccer) outside. Almost the whole class (our schools aren't like american HS where you go to a class with different people every period, we are like a "unit" and we do all our classes always together) would play football (soccer) every period. Most of the boys from other classes didn't do this. We always went sweaty into class, and I guess we breathed a lot at the beginning of every class.
- stuaxo 4y ago
  This tracks, I bought an Aranet 4 and just testing at home. With myself and one other person WFH it's easy to find r the room to go from 600 to 1800ppm if the door or window isn't open.
Spooky23 4y ago
I’d believe it. In my NYC public school, 4th grade in mid May circa 1988 was like 95 degrees, 90% humidity and no air movement. It was awful.
nwah1 4y ago
We are willing to spend endless trillions on administrators, elaborate facilities, tablet computers, tutoring, lowering student-teacher ratios... But not willing to spend any time or money figuring out how to provide kids with fresh air, nutritious food, sunlight, and adequate sleep. It almost seems like the lack of need to spend a lot of money on these effective interventions is precisely why they are given no attention. Advocates should pitch people on overpriced solutions to these.
- culi 4y ago
  I think it's just that we try to be data-driven about what we spend on. Unfortunately the first set of variables you mentioned we already have good data on and can study easily. The latter set of variables can be more complex to measure the impact of and so the science lags behind
- jeff_carr 4y ago
  https://www.jamesgmartin.center/2022/11/administrators-have-seized-the-ivory-tower/ https://www.jamesgmartin.center/2022/11/administrators-have-...
- simonsarris 4y ago
  > figuring out how to provide kids with fresh air, nutritious food, sunlight, and adequate sleep Most of these are already known, which is the more frustrating thing. The 1001st paper on teenage sleep isn't going to suddenly make schools change their tune. They simply do not care. In the US it is illegal to offer whole milk in elementary school because the USDA says so because of completely insane rules from the 1980's when nutrition science was at its worst. The only way you can really fight these forces is by exiting (homeschooling, private schooling).
  - apocalypstyx 4y ago
    As a former home-schooled child, don't do this.
    - omginternets 4y ago
ummonk 4y ago
Note also that the spread of infectious diseases is likely also highly correlated with lack of ventilation.
graeme 4y ago
Tangentially related: management of these issues would be greatly improved by funding CO2 and AQI meters in relevant spaces Right now people’s attitude to indoor air quality is roughly: can’t see it, isn’t real But if you’re told: * Under 1,000 is good * This room is 2,200 ppm Many people would start asking why the air quality wasn’t good. Ventilation systems work, I’ve measured CO2 in an incredible crowded airport and found under 800 ppm. But without such monitoring there’s no visibility into which spaces are and aren’t ventilated
- nannal 4y ago
  I recently bought a PMSA003 sensor and started logging the results indoors in a capital city. Three big discoveries were that opening the windows made the air quality way worse, sometimes the air quality is bad indoors and out without any clear coloration with other weather events and finally deodorant is absolutely awful. We're about to start messing around with filters, I built a home brew one with a duct fan and an inline activated carbon filter, but we've bought a retail filter that will be here soon so that will be interesting. I do think more people should be aware of their air quality.
  - jackvalentine 4y ago
    I bought an air purifier a few years ago and if you use spray type deodorant in the same room as it the thing kicks in to hyper mode for a while. We’ve taken to saying ‘you made it angry’. Even farting directly in to it doesn’t make it do that.
    - nannal 4y ago
      Yeah, either I move to roll on or the world learns to live with my musk.
  - graeme 4y ago
    Yeah if you live in a place with pollution outdoors and no indoor HVAC there is a real severe trade off between co2 and aqi If a place is sub say 70-100 in AQI then usually indoors will be 4-13 AQI with windows open but above that you’ll see indoor increases with open windows.
bluecalm 4y ago
We still allow smoking in public and cars in cities including poisonous and carcinogenic diesel. No wonder we also don't care what kids breathe at school. It's just a result of convenience being valued higher than health even if the cost of convenience is ridiculous (like carrying a 2 ton metal box powered by a diesel engine everywhere you go in a city).
ck2 4y ago
Someday every smartphone is going to have an on-chip air quality meter and it will instantly become something people learn to monitor, it will change everything. Just imagine all the social media posts from every location. The problem is quality, apparently all consumer air quality chips are very poor and inconsistent. Some neat DIY hacks have appeared on HN though https://news.ycombinator.com/item?id=33025995 https://news.ycombinator.com/item?id=33025995 https://news.ycombinator.com/item?id=27124671 https://news.ycombinator.com/item?id=27124671 https://news.ycombinator.com/item?id=28457135 https://news.ycombinator.com/item?id=28457135
- a1371 4y ago
  Interesting vision
- dzhiurgis 4y ago
  Smart speakers and laptops especially - you already have a fan running all the time!
anonu 4y ago
Did they control for demographics of each school? A quick review of the paper seems like no... Maybe lower socioeconomic households live in places with poorer air quality?
- jeffbee 4y ago
  Perhaps you should "quickly scan" the paper again, since you obviously scanned it too quickly the first time. Their outcome variable correlates test scores to recent CO2 levels repeatedly for the same person.
- dtech 4y ago
  This is addressed in the abstract, it's individual student scores.
papito 4y ago
It's not only a problem in schools. I am shocked by how employers and employees do not care about stifled air and poor circulation in offices. I had to literally bring a CO2 meter in to show that the air in the office was not conducive of productivity and clear thinking. How many studies do we need that show people's basic thinking abilities starting to suffer as the CO2 ppm goes up? I have that CO2 meter at my home office. If it's above 700ppm, I open the window wider. There is a dollar amount attached to air quality, but most people just suffer through it like it's something that HAS to be suffered.
FriedPickles 4y ago
The paper doesn't discuss the physiological mechanism by which poor air quality impairs performance. Perhaps the idea just that a higher ppCO2 impairs CO2 excretion, creating back pressure against all aerobic metabolism. If so this raises some interesting questions: Could we achieve "superhuman" performance by breathing CO2 depleted air (below ~420 ppm)? Is the rising atmospheric CO2 level making us all stupider? Should teachers begin class with a breathing exercise?
- deleted 4y ago
  [deleted]
ahaucnx 4y ago
At AirGradient we are specialized in measuring indoor air quality in schools and monitor thousands of classrooms in real-time for CO2, PM2.5, temperature, humidity and TVOCs. We do see very similar CO2 ranges in our data as presented in this study and observe the best results in modern schools buildings with demand constrolled ventilation linked to specific indoor air quality targets [1]. The schools that we monitor that have the best indoor air quality often use positive pressure systems with high performance HEPA and carbon filters [2]. We encourage schools to be transparent about their data and share it with the community as this encourages discussion and lays the base for continous improvements. Some schools now publish real-time data on air quality on their website together with an explanation why healthy indoor air quality is so important for students. Here is a good example of a well done air quality webpage of a school with real-time data [3]. If you want to know more about the air you breath and build your own monitor - either yourself or with students- we maintain a popular open source air quality monitor project [4]. [1] https://www.airgradient.com/open-airgradient/blog/we-measured-the-co2-level-in-a-classrooms-this-is-what-we-found-out/ https://www.airgradient.com/open-airgradient/blog/we-measure... [2] https://www.airgradient.com/open-airgradient/blog/air-purifier-vs-positive-pressure-fresh-air-system-an-unfair-battle/ https://www.airgradient.com/open-airgradient/blog/air-purifi... [3] https://ptis.ac.th/aqi-at-prem/ https://ptis.ac.th/aqi-at-prem/ [4] https://www.airgradient.com/open-airgradient/kits/ https://www.airgradient.com/open-airgradient/kits/
- Siecje 4y ago
  Do you have plans to measure radon?
  - ahaucnx 4y ago
    Yes but so far we did not find suitable radon sensor modules available in the market that we could easily integrate into our monitor.
- amluto 4y ago
  Where were you that infiltration increased PM2.5 to over 50 ug/m3 in two hours? That seems rather extreme. I’m also interested in what PPS this was. The link for more information is broken: https://www.airgradient.com/blog/2020/01/08/positive-pressure-systems-for-clean-air/ https://www.airgradient.com/blog/2020/01/08/positive-pressur...
deleted 4y ago
[deleted]
londons_explore 4y ago
The usual caveat that this is correlation not causation applies. It seems entirely plausible that better teachers get assigned the more modern classrooms with better ventilation, while inexperienced/poor performing teachers end up in the unventilated storeroom converted into a classroom...
- londons_explore 4y ago
  I wonder how much an intervention study would cost? Ie. you enrol 200 classes into the study, then select 100 at random and fit a free ventilation system. Then look at test scores at the end of the year. School systems where the same students are assigned to the same room for the whole year would be a perfect fit for this. The study could be extended to various different air treatment options - eg. fresh air vs filtered room air. HEPA filters against particulates and viruses, vs carbon filters for volatile organics. Maybe even include CO2 scrubbing systems to see if you can get the CO2 levels in the classroom below 400ppm.

144 points by elsewhen 4y ago

These seem like crazy differences. Some classrooms have over 6x the CO2 concentration than others. Some classrooms have > 2000ppm every day. Panel A: Classroom Ventilation Mean St. Dev. Min. Max. Daily Peak of CO2 (in ppm) 1495 624 737 4665 Daily Average CO2 (in ppm) 988 336 485 2783 % of days w CO2 in classroom > 1000 ppm 77 29 0 100 % of days w CO2 in classroom > 2000 ppm 15 26 0 100 Note they claim there's no relationship observed between teacher quality and classroom ventilation Their conclusion: "An increase in classroom CO2 level during the school term by one standard deviation reduces subsequent test scores by 0.11 standard deviations. Our findings imply that exposure to poor indoor air quality directly interferes with learning, highlighting the role of physical school infrastructure in determining educational outcomes."

culi 4y ago
Agreed that's a huge Std Dev. I'm surprised they were able to achieve statistical significance with just 216 classrooms, but I guess the results are quite consistent: > The coefficient shows high stability in terms of its magnitude, sign, and statistical significance.
antisthenes 4y ago
> Some classrooms have over 6x the CO2 concentration than others. Some classrooms have > 2000ppm every day. That's basically the difference between having an open window or not. If your ventilation system is designed to get fresh air from the outside, you'll have <600 PPM, if not, you'll have 2000+ How do I know? I bought a CO2 meter and worked in an old office building that didn't get fresh air from the outside.
- dzhiurgis 4y ago
  My dad has a shoddy heat recovery ventilation system which he throttled down to a minimum. I bought co2 meter and turns out it barely does anything, but he won’t believe me.
  - stuaxo 4y ago
    Sounds counter productive turning it to a minimum ? (I guess it could be shoddy in many other ways too!).
    - dzhiurgis 4y ago
      Over 60% it becomes quite audible, at 100% it can be annoying. It’s a ducted balanced system. If we have 4-5 adults in living room - it doesn’t keep up even at 100%. Ir I keep most doors open at night - it’s okay. Air quality is always good there, it’s mostly to manage humidity and it does it too well once it’s freezing outside.
dahart 4y ago
> These seem like crazy differences. Some classrooms have over 6x the CO2 concentration that others. 6x seems plausible just because some classrooms are more crowded than others, and kids are probably breathing harder at the start of class, during first class, during first class after lunch or breaks or P.E… “The variation in CO2 levels inside classrooms that we observe in our sample is almost fully caused by indoor sources, i.e. human breathing, with negligible variation from outdoor levels.” I wonder if peak rates could be easily misinterpreted? This chart doesn’t say how long peaks last or when they happen. Did they verify that a single sensor is a good proxy for distribution of CO2 in the room? It depends on where the sensor is located, for example. Near the door will see higher peaks as people come in and out than in the far corner, and air might flow toward the door. Looking at the average tells a more meaningful story, but even that may need more context, right?
nomorewords 4y ago
I'm not American, but when we were in up to the 9th grade, every break between classes we would play football (soccer) outside. Almost the whole class (our schools aren't like american HS where you go to a class with different people every period, we are like a "unit" and we do all our classes always together) would play football (soccer) every period. Most of the boys from other classes didn't do this. We always went sweaty into class, and I guess we breathed a lot at the beginning of every class.
stuaxo 4y ago
This tracks, I bought an Aranet 4 and just testing at home. With myself and one other person WFH it's easy to find r the room to go from 600 to 1800ppm if the door or window isn't open.

Spooky23 4y ago

I’d believe it. In my NYC public school, 4th grade in mid May circa 1988 was like 95 degrees, 90% humidity and no air movement. It was awful.

nwah1 4y ago

We are willing to spend endless trillions on administrators, elaborate facilities, tablet computers, tutoring, lowering student-teacher ratios... But not willing to spend any time or money figuring out how to provide kids with fresh air, nutritious food, sunlight, and adequate sleep. It almost seems like the lack of need to spend a lot of money on these effective interventions is precisely why they are given no attention. Advocates should pitch people on overpriced solutions to these.

culi 4y ago
I think it's just that we try to be data-driven about what we spend on. Unfortunately the first set of variables you mentioned we already have good data on and can study easily. The latter set of variables can be more complex to measure the impact of and so the science lags behind
jeff_carr 4y ago
https://www.jamesgmartin.center/2022/11/administrators-have-seized-the-ivory-tower/ https://www.jamesgmartin.center/2022/11/administrators-have-...
simonsarris 4y ago
> figuring out how to provide kids with fresh air, nutritious food, sunlight, and adequate sleep Most of these are already known, which is the more frustrating thing. The 1001st paper on teenage sleep isn't going to suddenly make schools change their tune. They simply do not care. In the US it is illegal to offer whole milk in elementary school because the USDA says so because of completely insane rules from the 1980's when nutrition science was at its worst. The only way you can really fight these forces is by exiting (homeschooling, private schooling).
- apocalypstyx 4y ago
  As a former home-schooled child, don't do this.
  - omginternets 4y ago

ummonk 4y ago

Note also that the spread of infectious diseases is likely also highly correlated with lack of ventilation.

graeme 4y ago

Tangentially related: management of these issues would be greatly improved by funding CO2 and AQI meters in relevant spaces Right now people’s attitude to indoor air quality is roughly: can’t see it, isn’t real But if you’re told: * Under 1,000 is good * This room is 2,200 ppm Many people would start asking why the air quality wasn’t good. Ventilation systems work, I’ve measured CO2 in an incredible crowded airport and found under 800 ppm. But without such monitoring there’s no visibility into which spaces are and aren’t ventilated

nannal 4y ago
I recently bought a PMSA003 sensor and started logging the results indoors in a capital city. Three big discoveries were that opening the windows made the air quality way worse, sometimes the air quality is bad indoors and out without any clear coloration with other weather events and finally deodorant is absolutely awful. We're about to start messing around with filters, I built a home brew one with a duct fan and an inline activated carbon filter, but we've bought a retail filter that will be here soon so that will be interesting. I do think more people should be aware of their air quality.
- jackvalentine 4y ago
  I bought an air purifier a few years ago and if you use spray type deodorant in the same room as it the thing kicks in to hyper mode for a while. We’ve taken to saying ‘you made it angry’. Even farting directly in to it doesn’t make it do that.
  - nannal 4y ago
    Yeah, either I move to roll on or the world learns to live with my musk.
- graeme 4y ago
  Yeah if you live in a place with pollution outdoors and no indoor HVAC there is a real severe trade off between co2 and aqi If a place is sub say 70-100 in AQI then usually indoors will be 4-13 AQI with windows open but above that you’ll see indoor increases with open windows.

bluecalm 4y ago

We still allow smoking in public and cars in cities including poisonous and carcinogenic diesel. No wonder we also don't care what kids breathe at school. It's just a result of convenience being valued higher than health even if the cost of convenience is ridiculous (like carrying a 2 ton metal box powered by a diesel engine everywhere you go in a city).

ck2 4y ago

Someday every smartphone is going to have an on-chip air quality meter and it will instantly become something people learn to monitor, it will change everything. Just imagine all the social media posts from every location. The problem is quality, apparently all consumer air quality chips are very poor and inconsistent. Some neat DIY hacks have appeared on HN though https://news.ycombinator.com/item?id=33025995 https://news.ycombinator.com/item?id=33025995 https://news.ycombinator.com/item?id=27124671 https://news.ycombinator.com/item?id=27124671 https://news.ycombinator.com/item?id=28457135 https://news.ycombinator.com/item?id=28457135

a1371 4y ago
Interesting vision
dzhiurgis 4y ago
Smart speakers and laptops especially - you already have a fan running all the time!

anonu 4y ago

Did they control for demographics of each school? A quick review of the paper seems like no... Maybe lower socioeconomic households live in places with poorer air quality?

jeffbee 4y ago
Perhaps you should "quickly scan" the paper again, since you obviously scanned it too quickly the first time. Their outcome variable correlates test scores to recent CO2 levels repeatedly for the same person.
dtech 4y ago
This is addressed in the abstract, it's individual student scores.

papito 4y ago

It's not only a problem in schools. I am shocked by how employers and employees do not care about stifled air and poor circulation in offices. I had to literally bring a CO2 meter in to show that the air in the office was not conducive of productivity and clear thinking. How many studies do we need that show people's basic thinking abilities starting to suffer as the CO2 ppm goes up? I have that CO2 meter at my home office. If it's above 700ppm, I open the window wider. There is a dollar amount attached to air quality, but most people just suffer through it like it's something that HAS to be suffered.

FriedPickles 4y ago

The paper doesn't discuss the physiological mechanism by which poor air quality impairs performance. Perhaps the idea just that a higher ppCO2 impairs CO2 excretion, creating back pressure against all aerobic metabolism. If so this raises some interesting questions: Could we achieve "superhuman" performance by breathing CO2 depleted air (below ~420 ppm)? Is the rising atmospheric CO2 level making us all stupider? Should teachers begin class with a breathing exercise?

deleted 4y ago
[deleted]

ahaucnx 4y ago

At AirGradient we are specialized in measuring indoor air quality in schools and monitor thousands of classrooms in real-time for CO2, PM2.5, temperature, humidity and TVOCs. We do see very similar CO2 ranges in our data as presented in this study and observe the best results in modern schools buildings with demand constrolled ventilation linked to specific indoor air quality targets [1]. The schools that we monitor that have the best indoor air quality often use positive pressure systems with high performance HEPA and carbon filters [2]. We encourage schools to be transparent about their data and share it with the community as this encourages discussion and lays the base for continous improvements. Some schools now publish real-time data on air quality on their website together with an explanation why healthy indoor air quality is so important for students. Here is a good example of a well done air quality webpage of a school with real-time data [3]. If you want to know more about the air you breath and build your own monitor - either yourself or with students- we maintain a popular open source air quality monitor project [4]. [1] https://www.airgradient.com/open-airgradient/blog/we-measured-the-co2-level-in-a-classrooms-this-is-what-we-found-out/ https://www.airgradient.com/open-airgradient/blog/we-measure... [2] https://www.airgradient.com/open-airgradient/blog/air-purifier-vs-positive-pressure-fresh-air-system-an-unfair-battle/ https://www.airgradient.com/open-airgradient/blog/air-purifi... [3] https://ptis.ac.th/aqi-at-prem/ https://ptis.ac.th/aqi-at-prem/ [4] https://www.airgradient.com/open-airgradient/kits/ https://www.airgradient.com/open-airgradient/kits/

Siecje 4y ago
Do you have plans to measure radon?
- ahaucnx 4y ago
  Yes but so far we did not find suitable radon sensor modules available in the market that we could easily integrate into our monitor.
amluto 4y ago
Where were you that infiltration increased PM2.5 to over 50 ug/m3 in two hours? That seems rather extreme. I’m also interested in what PPS this was. The link for more information is broken: https://www.airgradient.com/blog/2020/01/08/positive-pressure-systems-for-clean-air/ https://www.airgradient.com/blog/2020/01/08/positive-pressur...

deleted 4y ago

[deleted]

londons_explore 4y ago

The usual caveat that this is correlation not causation applies. It seems entirely plausible that better teachers get assigned the more modern classrooms with better ventilation, while inexperienced/poor performing teachers end up in the unventilated storeroom converted into a classroom...

londons_explore 4y ago
I wonder how much an intervention study would cost? Ie. you enrol 200 classes into the study, then select 100 at random and fit a free ventilation system. Then look at test scores at the end of the year. School systems where the same students are assigned to the same room for the whole year would be a perfect fit for this. The study could be extended to various different air treatment options - eg. fresh air vs filtered room air. HEPA filters against particulates and viruses, vs carbon filters for volatile organics. Maybe even include CO2 scrubbing systems to see if you can get the CO2 levels in the classroom below 400ppm.