I bought a CO2 monitor and it broke me
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I retrofitted my house with a demand controlled fresh air ventilation system that takes outside air runs it through a set of high performance filters and pushes it into the house.
I can consistently keep PM2.5 levels at zero and CO2 below 600ppm.
I wrote an article about it [1] including detailed charts about CO2 build up.
[1] https://www.airgradient.com/open-airgradient/blog/positive-p...
In the US at least, where building codes favor air sealed construction, door blower tests are fairly accessible: https://www.energy.gov/energysaver/blower-door-tests
I have a garage, and I had issues with using the thermal camera - if the building materials were not uniform they reflected/radiated IR unevenly. It could show a piece of uninsulated area as hot and very well insulated as cold.
Do I do the measurements from the outside then, not the inside? Seems difficult in some cases unless I have a drone (roof, other hard to reach areas).
Do you know if i can find a tutorial anywhere? I tried googling, but couldn't find anything easy to understand.
If you are concerned about the zero pm 2.5 environment, studies show negative health impacts from pm2.5 even on very low concentrations and the WHO just last year lowered their guideline levels to only 5 ug/m3 pm2.5.
It's obviously better to breathe clean air than dirty air, but there is a point to be had that being in a "too clean" or "too dirty" environment when your immune system is still calibrating itself could have long-term negative consequences.
What you're talking about does not apply to coal. The ideal amount of coal particles in your lungs is zero. There is no age where it helps to get exposed, no allergy to avoid getting. Let's call these "non-adaptive particles".
If you live in a city, it's very likely that the negative impact from these non-adaptive is way worse than the negative impact of missing out on the adaptive particles. Breathing the air, you're increasing your risk of asthma a lot to decrease your chance of allergies a bit.
https://en.m.wikipedia.org/wiki/Hygiene_hypothesis seems to suggest it is about specific microorganisms.
Isn’t it the case that you can open windows to the extent that the air purifier CADR can cope with the influx? Then they are still “effective”. The relative air quality inside and outside is also highly relevant. I say this as someone with AGs, since I frequently do this dance when CO2 rises.
Opening a window even for a few millimeters is enough for PM 2.5 to go to a significant portion of what's happening outside (which is almost always hundreds of micrograms, sometimes thousands), and no purifier can beat that. Maybe if I put ten of them in a row, but it's expensive and noise will be unbearable.
All I seem to find are either amazon frauds/scams or overprized professional grade meters.
It's cheap, but you have to do everything yourself. A friend of mine did something similar, but using ESPHome and Home Assistant, and I think he didn't have to write any code at all, just a bit of YAML to tie it all together.
ERV: Energy Recovery Ventilation eg: https://ephoca.com/aio-wall-mounted-pro/
An example of a less expensive module sized for a whole home: Panasonic intellibalance https://na.panasonic.com/us/home-and-building-solutions/vent...
They're definitely not "free", but they do return a lot of the heat you're using. 90% or so is pretty standard.
But pairing heat exchanger or pair of heat exchangers with your setup is probably not easy.
"There is also noticable noise if I am doing physical activity and it needs to blow the CO2 out more quickly"
significantly increases my sense of the strength of the evidence base that a device like this is actually doing its intended job. The idea of a repeatable (and repeated) experiment based on principles that we know a priori must be correct (that our lungs exhale more CO2 than they inhale, and at a greater scale during vigorous exercise)
Somehow it's more convincing than if poster had even said, 'I set a CO2 generator up and looked at the ventilation device's activity indicator and saw it increase whenever the CO2 generator's output setting was increased".
Rather, one hears the device working harder, when doing an activity that's familiar to all of us, in a repeatable way.
Also, the poster didn't have to tell us that lungs exhale more CO2 than they inhale, rather leaving that to our internal models of how that works. If they described that overtly, it would somehow already make me slightly more skeptical of the overall assertion of the device's efficacy.
I think the statement is made more powerfully convincing precisely because it leaves it to us to infer the implications of the obvious bits. When it's our own subconscious reminding us of the priors (1. lungs expel more CO2 during vigorous exercise than normal, and 2. many machines are noisier when they have to work harder to accomplish the task they are designed for), we intuitively trust that our own model of the situation is accurately informing us more than if someone else had to tell us that those underlying assumptions were correct.
I wonder how other demonstrations of innovations of less-apparent efficacy can be directed towards presenting their evidence in this more intuitively convincing framework. (Note I'm not saying I have particular reason to accept the poster's description without further diligence, merely that it 'feels' more convincing in a powerfully intuitive way, which is what I'm after here).
Like 'dependent variable X should be something familiar to everyone, drawing on principles that most people would have already ascertained a priori, and, 'dependent variable Y should manifest as an un-instrumented artifact of the device in question, one that can be intuitively perceived with as few opportunities for technical obfuscation (which could otherwise give rise to either intentional misinterpretation or simply misapprehension) as possible.' (in the example, this is the device making more noise).
Anyway, I found it very satisfying to read that sentence from the poster.
I still can't understand why the allied trades didn't press for building refits while everyone else was home and the "do something" sentiment among CEOs anxious to bring people "back to work"* was high.
* Please don't say "back to work"; it's propaganda that presumes remote or home can't work. Try "back to office" for something neutral, or consider "butts in seats" to throw shade on contentless managerialists who can't evaluate if someone's productive.
construction was an essential industry, they didn't stop working during the pandemic. that being said, a lot of construction involves people in close quarters with each other, which was a major risk factor for COVID, and so there was a bit of work trying to figure out how best to get construction going and also not get all the workers sick. And there has been a worker shortfall in the trades for a while now, so it's not like refits could've significantly ramped up with nobody to work on them.
How often do you need to change the inbound air filters?
https://www.realhomes.com/news/do-house-plants-remove-carbon...
Plus you need a lot.
"Poor air quality" isn't going to kill you.
You are going to die of heart failure, or in a road accident. Way way way behind that you're going to die of cancer, and about twice as far behind that are a bunch of other non-preventable diseases.
Stop buying toys and fix the big problem first.
I live in a city with air pollution levels that are considered extreme by Western standards (which I've checked and compared multiple times). Frequent SO₂ spikes up to 10 milligrams/m³ (and sometimes even more); NO₂ at 150-200 µg/m³ or higher; yearly PM2.5 averages of 200+ µg/m³, and so on.
Respiratory illness rates are 4× compared to national average. Life expectancy is lower by about 5-8 years.
If you look at this page, in most the world CVD beats cancers by about 2:1. Over here the ratio is much closer to 1:1.
https://en.wikipedia.org/wiki/List_of_causes_of_death_by_rat...
Everyone knows that air pollution is to blame, including the government, but they have shinier things to spend money on.
Either way, I'm not sure what the relevance of motor vehicle deaths is, just because I might die in a car accident doesn't mean I don't exercise and eat heathy to avoid having a heart attack.
Great introduction here: https://renew.org.au/renew-magazine/efficient-homes/mechanic...
I installed a larger ERV (about $2000) that is tied into our house central air. It has been a huge improvement to the comfort in the house.
I have a Hydrofarm Autopilot CO2 monitor and it pretty much stays at 600-800 all day, but I leave a window cracked open and live in a naturally windy area.
[0] <https://www.snopes.com/fact-check/apartment-radiator-pandemi...>
[1] <https://blogs.transparent.com/german/luften-germanys-airing-...>
Especially “Stoßlüften” (opening a window for a short period) or “Querlüften” (opening windows in opposite rooms to create a draft).
First thing in the morning we lüft, after cooking, we lüft, before going to bed…
It’s especially important in newer or well renovated houses/apartments, to get rid of excess humidity in order to prevent mold. Really new apartments are so well insulated that they have literal holes in the wall (Zwangsbelüftung) in order have some airflow.
Edit: I was so enthusiastic to write a comment about lüften, that I didn’t read your link which actually covers what I said.
We lüft the house in times of peace, and we lüft in times of war. We lüft the house before we lüft the house, and then we lüft some more!
We lüft the house as we wake up, we lüft the house at night.
We lüft it in the afternoon, it makes us feel alright.
We lüft the house in times of peace, we lüft in times of war.
We lüft it once, we lüft it twice, and then we lüft some more!
This is how a professional does it, and he teaches you how to do the same.
To really offset what a human produces, you need a lot more plants than you would probably be comfortable living with.
If I remember correctly, there were some studies that calculated you'd need to convert half of your room into a dense jungle to offset your own co2.
Also, plants release co2 at night, so even if they had any effect, it would be a bad idea to have them in bedroom to scrub air.
I feel like there is constant lüften going on with that, and wonder if such building standards explain why we don't have the same habits as the German one.
Simplest way is passive vents on the windows and a central blow-out fan that pulls air in. The more modern way uses a heatexchanger setup to take heat from the outflowing air and use it to warm air being pumped into the house.
It’s used in multi-story buildings everywhere, but it’s not as effective in lowrises.
It can be boosted by having mechanical ventilation equipment on the roof – a rooftop ventilator – pulling air through the exhaust flue more effectively, and modern apartment buildings typically have this type of mechanical ventilation. (So even if your apartment only has a passive vent in the wall, that doesn’t necessarily mean the entire system is passive!)
Today, the inlets may also be centralized; this allows for replacement air to be taken from wherever it’s the cleanest, eg. from the side not adjacent to a street. The air can also be filtered to improve its quality and even pre-heated to make heating more efficient and prevent the feeling of a draft.
Meanwhile, in Latvia there's a belief that "caurvējš" (drafts) are bad for you and that you'll catch a cold if you're in it for too long.
I've read some arguments for and against that online (mentions of cold stress, muscles posssibly tensing up to remain warm leading to a stiff neck, possibly nose being a bit more dry and susceptible to things in the air), but people over here typically just accept it as "fact". I can kind of understand caution when it's -10 C outside, but less so when you're in a stuffy room and it's 20 C outside.
Curiously, people in some other countries don't have such strongly held beliefs.
https://www.rbth.com/lifestyle/328478-why-russians-afraid-dr...
I've lived in six countries, and old people everywhere want to keep their joints warm.
I have the issue where we love a cold house but my hands don't, at least when I work, so the house is very cold, 14ºC/57º at night or even less, I get up wearing very little and make coffee in a chilly kitchen with pleasure, but then go to work in my shorts right beside a heater.
And of course billions of people live like this right now, domestic coal or kerosene burners being one of the most pressing air quality issues in the world!
I personally have an SCD30 monitor which claims the same accuracy and like it. The important thing is to calibrate them in outside air to 400ppm.
[0] https://www.digikey.com/en/products/detail/senseair/006-0-00...
[1] https://github.com/Senseair-AB/Sunrise-Examples---Arduino
I could even send levels to my home IOT InfluxDB for historical charting.
most people can't, or more precise they probably can put something together but can't make sure it works correctly under any situation (in operation range)
what you pay for is that someone makes sure it works properly
else you can get sensors with similar or same hardware on amazon too, it's just that their correct reliability is not guaranteed at all and just checking if the values outside seem right is by far not enough to verify that (because it e.g. might behave right on low but not high CO2 levels or not on high/low humidity, etc.)
I have seen tests with sensing devices which seemingly where good outside but then e.g. scaled wrongly being way of at higher CO2 levels (either way higher or way lower).
Perhaps you've left the auto calibration on? That's usually a recipe for disaster (and one that can be avoided by reading the datasheet).
This includes all the sensors integrated in these off the shelf products like the author is using, which could explain the extremely high readings.
The outside ppm changes quite a bit in cities. CO2 dome effects can push it 2x higher.
https://www.researchgate.net/figure/The-maps-of-global-histo...
Older study https://www.sciencedirect.com/science/article/abs/pii/S13522...
... tldr a higher planetary boundary layer over cities can form under various weather conditions. That reduces mixing, and cities are large sources of CO2.
So I can say - I stand corrected, and TIL :)
Anywhere that traps smog should show similar correlations with CO2.
So far people that were interested in the combination of enclosure and pcb or the whole kit.
Does the sensor in your project need to be taken outside to calibrate?
I stopped when I realised many sensors (like scd30/40) need this making it very impractical.. Has to be done once while powered on the whole time in a 7 day period.
https://sensirion.com/products/catalog/SCD41/
https://www.digikey.com/en/products/detail/sensirion-ag/SCD4...
Personally I've been very happy with Sensirion's sensors and I've played with the SCD41 quite a bit. The trouble with it for hobbyists is the assembly. It has what seems to me to be pretty picky requirements for soldering. I've attempted to do it myself but I keep managing to pop off the metal covering.
Haven't tried the Senseair Sunrise but such low power requirements are very very appealing because they mean the sensor can be battery-powered. The SCD41 isn't bad but powering it for a year means a lot more batteries. With a 1 min sampling period, the SCD41 uses 1.5mA while the Sunrise uses 21µA.
I think they're around 60 bucks (e.g. the T6793) so they aren't the cheapest around, but they're good quality.
They have a normal header you can solder a few wires into. Probably the best approach for the Sensirion sensor is to oversize the pads a bit and use paste to re-flow underneath.
The way I soldered the SCD41 is with a pre-made PCB footprint, some solder paste and a mini PCB heater. I think the problem was too high heat. I need to try it again with low-temperature solder paste.
But for my application the Senseair Sunrise looks a lot better.
As a diver I use oxygen sensors, and those should be calibrated once every third day, and linearity can go bad from everything between 6 months to a few years.
If I went with a DIY solution i would definitively go with 3 sensors so one can at least use voting to determine which sensors to trust, and to measure relative drift.
This can still situation where either a bad sensor is marked as good, or a good sensor marked as bad, so a human operator is still required to monitor the decisions made.
The navy routinely operates submarines at 3500ppm or more, and they've been conducting studies since the 60s which have failed to show a cognitive decline from levels as high as 30,000ppm.
Here's a HN comment with a good summary.
FWIW, CO2 can cause cognitive decline. I mean hypoxia is a thing. But usually CO2 levels are a correlating factor (confounder) rather than the direct cause. So we can use it as a tool to help, but it isn't the problem. These types of things are the hard part about causality and why we are so easily fooled (because it makes sense and reflects what we (naively) observe).
(To the other comment, the 2021 paper I linked is not "pop science".)
The context of the paper you linked is "stressors in a disabled submarine". It's not a summary of the Navy's research. It does contain a few paragraphs out of nearly 100 pages that briefly summarizes a few relevant studies, both civilian and military.
Here's the relevant section:
>While some studies have found that elevated CO2 may impair cognitive functions including decision making (Satish et al., 2012), attention (Schaefer, 1951), mental efficiency (Karlin, 1945), and mathematical processing (Sayers, Smith, Holland, & Keatinge, 1987), these findings are not consistently replicated (Rodeheffer, Chabal, Clarke, & Fothergill, 2018; Ryder et al., 2017; X. Zhang, Wargocki, & Lian, 2016; X. Zhang, Wargocki, Lian, & Thyregod, 2016). In fact, many studies have been unable to establish a relationship between CO2 exposure and cognitive deficits (e.g., Bloch- Salisbury, 2000; Francis et al., 2002; Sheehy, Kamon, & Kiser, 1982; Vercruyssen, Kamon, & Hancock, 2007).
It lists 3 studies showing a cognitive impact impact. 2 out of the 3 show that there is a cognitive impact at extreme levels far beyond the levels that build up in a conference room, or levels that we'll be exposed to because of increased atmospheric C02.
--Sayers, Smith, Holland, & Keatinge, 1987 This study showed a cognitive impact at 65,000ppm, but nothing at 45,000ppm.
--Schaefer, 1951 Showed that submariners were slightly affected after prolonged exposure to 30,000ppm
Then it lists 7 studies showing no impact on cognition even at very high levels. Out of 10 studies listed, 1 civilian study shows cognitive impact at 1,000ppm. The preponderance of the evidence indicates that that study is a fluke. By the way, this study is the one that kicked off the whole normal indoor levels of C02 make you dumber thing in the first place.
This statement:
>the relationship between CO2 exposure and cognition is debated
is in the context of whether or not concentrations of up to 30,000ppm seen in a submarine disaster will impact cognition, not whether 1,000ppm in a conference room will.
I also have other air quality meters. (I collect measuring devices.) I wish there was a do-it-all air meter.
Also, have you ever put all of your devices near each other to compare the variance between them all?
You can get wifi bridges as well, see https://devel.aranet.com/products/
I've seen Aranet4's on eBay for under $150 pretty regularly, so I'd look there.
Their data sheet also advises calibration if used at “high elevation.”
CO2 is much easier for our bodies to deal with than CO. CO2 won't kill you unless it's at exceptionally high concentrations. In cold regions, gas burning furnaces produce a good deal of CO.
There are alarms for CO, of course. But in the course of researching CO & UL standards around alerting, I found that most consumer CO alarms don't even alert until CO is above 30ppm. Additionally, for UL-certified CO alarms with an ambient "max reading" function, they don't even report anything below 10ppm.
Levels as low as 5.5ppm have been shown to significantly increase risk for low birth weight: https://pubmed.ncbi.nlm.nih.gov/9872713/
For context, the CO level outside, where there is fresh air, is 0-2ppm.
Carbon monoxide really is the silent killer and doesn't get talked about enough.
They will intentionally NOT alarm if there is a low, persistent level of CO that probably has devastating health effects over the long term (think 20ppm in your house all the time).
Some years ago, my furnace had a cracked heat exchanger and, unknown to me, was pushing CO into my living space. I only noticed by luck. I walked by one of my CO alarms, hit the "max level" button and thought to myself that 25ppm is quite high. So I reset it and checked it again the next day. Sure enough, it shot back up.
It's very common for natural gas to be used to heat homes and office spaces, at least in the US.
Additionally, water heaters and dryers might use natural gas. Gas stoves do, too.
You ever notice how CO alarm instructions have a blurb about not putting the alarm too close to your furnace, or too close to a gas stove?
CO is something everyone is aware of - growing awareness that less lethal things are also important is what's driving CO2 checking.
I was shocked to see how fast CO2 will build up in just a few hours. Specifically online meetings when I do a lot of talking seem to drive it up.
That said, opening windows will drive the CO2 down to 500ppm in a few minutes. I think the OP does not know how to properly ventilate a room. You need to completely open the window or even multiple windows. They probably just had it half-open which will waste energy.
Also, if you look at the actual limits, no 1.2k ppm is not horrible. It will regularly reach 1.5k or more for me. Prolonged exposure of that can make you a bit sleepy but there is not reason to panic.
So, ventilate a few times a day properly. Don't just have the windows open all the day or the heating bill will kill you.
Can you explain that? I recently started to leave the window open 1-5 inches and it's done a good job, I am curious why half opening a window is problematic.
So you want maximum airflow for a short time. Best way is to fully open windows on different sides of the house and hope that creates the flow.
Very common method in Germany, they call it Stoßlüftung.
I have exactly the opposite problem from you. I don't even have AC, plus I'm comfortable at 82F/28C inside so I can keep the windows open all summer. In winter on the other hand, "keeping the window cracked open" like people have commented is definitely not an option. All modern buildings have mechanized ventilation systems for managing this but I live in an old apartment without ventilation, so a large airflow for short periods seems to be the best approach to get fresh air without losing the precious heat.
The only way you're going to bring down CO2 levels in your dwelling is to bring in outside air. The best way would be installing a heat recovery vent that will save some energy. The simple way would be to open two windows and stick the fan in one for a short time (blowing in for turbulence to clear out the corners of the room).
Leaving your windows open with passive circulation for a longer time is going to cool down all the stuff inside, wasting much more heat.
We live in a nice suburb near the water so outside air is clean. I now crack the windows open and co2 stays reasonable. I feel much better.
Before this, I was anal about insulation and making sure windows were closed when the heat was on. Now I know that's not the right calculus.
I could have figured out that I feel worse in the winter at home and feel good the moment I step outside. But having the numbers shown to me really drove a change in behavior
This include some system for automatic air exchange (which also keeps the heat in and isn't prone to fungi and isn't loud/distracting and doesn't draw a lot of energy; not easy to get right at all).
Guess what basically is non existing in close to all modern apartments I have seen...
Instead they tell you you have to "appropriately" air you apartment and skipping over the fact that this might mean 3 times a day 30min no matter what temperature is outside (on dais you stay home all day).
around 5 minutes with windows fully open and heating closed will do the trick. You want to maximize air exchange while minimizing heat loss.
This is common wisdom in Germany but the rest of the world seems to either prefer to heat the outside air instead of insulating their houses or must live in very sticky rooms. I just can't imagine not ventilating a room regularly.
no it won't not at all it's a common misconception especially in Germany
EDIT: jut to be clear it does work if you do the 5m airing often enough, but this is where the problem comes in it is fundamentally unpractical. I mean I can measure it tomorrow (through after long airing after sleep).
most ideas about insulation circulating in Germany are only half thought thru and sometimes do more environmental harm then good (depending on the building).
Of course it would depend on the size of the room and windows but I would be very surprised if you got vastly different measurements.
And yes, you obviously need to do it multiple times a day but that is a given. That is a problem with how fast CO2 builds up again though.
At my parents’ house, I have to leave multiple windows fully open for hours to get the CO2 reading to budge at all. The air is just too stagnant. Things improve a lot when I put a fan in front of one of the windows to blow air out.
(Another problem is that their HVAC system is always recirculating the air, so the room I’m trying to ventilate is continually getting replacement air from a 1500 ppm wing of the house).
So 55m no airing then 5min airing.
That's not at all something viable with home office, too disruptive.
Now if I would be fine with having it constantly roughly between 1000ppm and 1400ppm then I could air it out much less often (because the higher the difference outside/inside is the less volume of fresh air you need to let in to make it drop the same absolute amount).
I can't really follow how you checked and were able to come up with these number from apparently one single measurement?
I still think the main issue is that you are not airing properly. The best way is is to create a draft situation by opening windows that are across from each other. If you can open the front door, even better. Again, you need to FULLY open windows, no in between state. Like fully open. If you don't have to remove the plants from the window still, you are doing it wrong. Having windows half-open will do barely anything for air circulation.
If you are not able to sharply drop the CO2 in a few minutes, there might be something else going one that you haven't mentioned. Maybe a HVAC system like another commenter suggested.
> Now if I would be fine with having it constantly roughly between 1000ppm and 1400ppm then I could air it out much less often (because the higher the difference outside/inside is the less volume of fresh air you need to let in to make it drop the same absolute amount).
I mostly use 1.2-1.5k ppm as a signal that it is time to air again. Obviously it is not realistic to never go above 1k ppm and that is fine. Long term exposure might make you slightly sleepy but a few hours of it are probably fine.
So I guess the 15 times would kind of check out if you wanted to keep the CO2 constantly low but that would be indeed excessive.
I had done measurements in the past and just doubled checked if I remembered correctly and how a 55m wait 5m airing cycle would work by doing it for the first 6 or so hours of my day.
> I mostly use 1.2-1.5k ppm as a signal that it is time to air again.
The think is if I as much as reasonable possible air out my apartment for 5min when it hit 1200ppm it e.g. just now went down to around 1000ppm...
And yes the airing situation in my apartment is not optimal, but that is with what I meant a lot of German "common knowledge" and (worse) regulations are often not fully thought through. It's based on the "how it should be" situation and blindly applied instead of how it actually is. And a lot of apartments in Germany have sub-par airing conditions in Germany, including worse then mine.
In Italy, the tradition has always been that when you wake up in the morning you open windows and let the air change, but the "new generations" are forgetting this, just when houses are built (or refitted) in a much more airtight way.
The only way out, mechanical ventilation systems, possibly with a heat exchanger[0]), are still rare, even in new constructions, I have seen a lot of issues in the houses built with (badly designed) energy saving goals (original A and B classes) built or renovated in the last 15 years or so.
[0] which bring their own issues, needed maintenance, periodical cleaning of filters, sometimes noise, etc.
Live in the PNW with only electric heating/stove/oven. Cracking the window very slightly was enough to keep CO2 relatively low (600-800). Had to crack the window more when the temp is around 70 outside, less when the temp delta is higher (cold or warm).
Eventually ditched the device once I understood how to keep CO2 low. The cloud integration was creepy. I could tell when my wife or I went to bed based on CO2 spiking near the sensor.
(Specifically the Wave+ though; the hub apparently will want to connect over wifi instead, so I think it's better to just go for the Wave.)
> At baseline, the levels in my apartment were already dancing around 1,200 (ppm)...(marketing numbers)... I flung open a window... Two hours laterthe Aranet still hadn’t budged below 1,000 ppm
Something is very wrong here if your house/apartment is getting cold and a CO2 meter near a window is not dropping. Author should take it outside and check to see a number <500ppm (probably closer to 420). Device could be broken or poorly calibrated. It happens.
As for air flow in the apartment, this can often still be quite a mystery and weird to solve. My bedroom would constantly be above 800ppm, and above 600ppm with an open window. The solution? Opening a window on the other side of the apartment (need to pay very careful attention to paths that air can travel). A cracked window in my bedroom, a cracked window on the other side of the apartment, and boom, my bedroom is constantly near 400ppm (near ambient levels in my area).
But opening any other window in the apartment would not lead to this solution. Houses weren't designed with air flow in mind. Lots of hard corners can make it difficult to move air around (eddy currents are a pain). I do sleep better and there's probably some cognitive increase (I don't buy the 15-50%), but one of the larger benefits is the temperature is more stable (stable temperature is a good indication of good air flow btw). So I do encourage others to try this problem solving, but just want to note that the solutions are non-obvious. If you're having these issues, brute force the solution. You'll over think it (I did) but you're too clever by half[0]. You're working with a chaotic system and even the state of a door that doesn't seem in the flow path might affect the flow. If it isn't working, try dumb things and also use temperature as an indicator in addition to CO2. You can always use a fan too (draw air in on the opposite side of the house).
She tried that: "I wondered, briefly, if my neighborhood just had terrible outdoor air quality—or if my device was broken. Within minutes of my bringing the meter outside, however, it displayed a chill 480."
Check the ventilation system to see if it's working properly. It may need to be cleaned or replaced. Maybe have some plants in your home. Maybe replace the gas stove with induction.
Or accept the higher CO2 levels. CO2 isn't personally dangerous like CO is. It's not ideal, but I think those warnings about loss of cognitive function are excessively alarmist.
So many types of "broken" CO2 sensors might accurately work around 400ppm.
I'm just learning about these, so I may not be understanding correctly.
Different places I’ve loved have had significantly different characteristics for what co2 concentration defaults to.
I’m guessing a not so small proportion of mental health issues and things like chronic fatigue are actually breathing issues and sensitivity to higher co2 concentrations.
For me a big factor is I broke my nose long ago and don’t breathe as well as I should.
pollution, on the other hand, is a real concern. that's stuff like radon, VOCs, methane, dioxins, and SOₓ emissions. as such, one thing we should be doing with vigor and relentless focus is phasing out coal plants (if we were actually putting our priorities in the right place) rather than worrying about the sideshow that is carbon emissions.
It took me a sec to figure out you were talking about something totally different.
Have you used the wrong numbers here or are you advocating some novel and unorthodox ideas about CO2? Did you mean 5,000-10,000?
Because as far as I can tell, those (5-10%) are the levels where people start to do things like lose consciousness from CO2 poisoning.
"poisoning" is a needlessly loaded word in this context. CO₂ is literally critical for life. just about any molecule/compound at those concentration levels (outside of those we co-evolved with, like nitrogen) will have noticeable effects as well.
I think it was this one: https://www.youtube.com/watch?v=kUfF2MTnqAw
Sadly I remember it all.
I was lucky enough to avoid intubation, but I suspect I wasn't too far away from it. CPAP with pure O2/a high-flow nasal canula at 90L/min pure O2 (I initially couldn't tolerate the CPAP mask for extended periods due to an anxiety disorder, though I felt myself becoming more fatigued over time on the HFNC) was keeping me at 88-90% (arterial blood gas measurement) initially, and that slowly started to climb a few days into treatment.
My wife does not notice any difference in herself. I dunno if she's less sensitive or maybe less aware.
That isn't going to do a thing about CO2.
It should, because of the V in HVAC.
one of the reasons some people swear on living in houses build around 1900 where I live, the larger ceiling height adds air volume (there are other reasons like large windows, wooden floors, etc.).
Seems like we're forgetting that the objective is not to reduce CO2, it's to reduce the pathogens in the air.
Since it's difficult to measure pathogens directly, we use CO2 concentrations as a proxy, since high CO2 means poor ventilation which means potentially high pathogens.
You can be right that turning on circulation makes the number go down. But that doesnt matter. Over time the concentration can go up and up and up, even with h"v"ac running.
Few residential HVAC systems actually ventilate. The focus on energy-efficiency has been a bit blind to the need to get rid of od co2 & take in oxygen. You can get fancy energy-recovery ventilation (ERV) devices that actually do air-exchange with thermal coupling, to cool or heat the incoming air. But this sort of system is alas exceptionally rare.
With an ERV, the best thing that I found to do is wire it to my furnace such that when the furnace kicks on, it will trigger the ERV to start. Otherwise you'll get furnace blower cycles separate from ERV cycles and it won't be as effective.
I've taken to just running the HVAC fan at all times, regardless of whether heating/cooling is happening. This tends to even out the temperature throughout the house, as well as CO2 concentration, it keeps the air filtering through the HVAC HEPA filter, and the ERV can run continuously, so rooms rarely get above 600 ppm CO2. Unsure about the energy use impact, but the air quality difference is palpable.
Can you elaborate? We are considering moving into an older house and renovating. Adding insulation being part of the idea. Our current home has full foam insulation with erv so I am curious what difference you experienced.
First the off-gassing. It emits a lot of harmful compounds as it cures and I understand the emissions to go on for a long time. So if you mind about air quality it wouldn't be my choice.
Second is the potential for damp to build up in the building fabric. The foam is airtight so make sure the ventilation is right on both sides of it.
A bonus third is the pain of removing it when you need to do building repairs. With board or batts you can lift them out; with spray foam you have to cut then scrape off.
Using the stove or oven will definitely spike it though to scary levels! I've made a habit of keeping the windows fully open when I cook now.
Most people I know don't air out their room/apartment long enough and/or often enough.
And I have been thinking about getting some form of huge fan to speed up the airing exchange process in winter.
Would it work to just open small openings on opposite sides of the apartment and put a small fan on one and run it continuously? With the right fan speed that should be equivalent to the big 30 minute airing ever few hours, but I'd expect it would be less disruptive when it comes to comfort because it should result in much less temperature variation.
E.g. if you have a apartment in the 5th floor where always have a bit of wind and can open windows so that the wind flows through just opening it for 5min might have as much effect as other people get with 40min.
Or e.g. if you have the right kind of wind putting windows into tilting mode can work well and in other cases (like my apartment) you will leak heat with very little air exchange.
I have been thinking about using some sort of fan but haven't tried it out. Part of the reason is that in summer I just can keep the window open all the time and currently we have winter temperatures around 4-7C during the day and my room temperature is most times around 16C in winter anyway, so ... it's not too much of a heating problem (compared to people heating their room to 20+C).
Living in a center of a city next to a 10-line highway opening a window drops a properly calibrated sensor into 400s inside a few minutes.
It goes up when we're together in a small room with no door open, I'm planning on eventually retrofitting MVHR which should help improve indoor air quality and allow me to insulate.
In the meantime the Aranet is good for getting a handle on general air quality and how you can improve it.
The basic idea idea is you run a heat exchanger between the air you’re venting outside and the air you’re replace it with. Commercial versions run around 1,000$ but you can DIY something that’s reasonably efficient for far less.
Just remember counter current flow: https://en.wikipedia.org/wiki/Heat_exchanger#/media/File:Com...
The worst thing you can do is to close yourself in your room for the night. Always have either door or window open. If it is cold outside, just buy a goose down duvet. You will sleep much better in a cold room than in a warm with stuffy air.
I am looking into putting heat exchanger in my apartment so that I can change air with less energy waste.
I also changed some of my habits. I try to use less of the gas stove and more of electric grill, Instant Pot, etc. If I need to use gas then I always change air afterwards.
Source: am firefighter, sleeps in bedroom.
I'm not sure why it's such a problem to have a possible 15% cognitive decline while I'm sleeping. I'm already an idiot in my dreams.
My doctor is constantly asking me to do a surgery on my temporomandibular joint to prevent my teeth going out of whack constantly and my face to look better. And I am constantly telling him I would prefer to keep fixing my teeth every so often than go through an extremely invasive operation and risk possible problems.
Source: retired anesthesiologist (38 years).
I was co-chief of the Oral Surgery Anesthesia Division at the UCLA School of Medicine Department of Anesthesiology 1980-83.
I attended MANY (≥100) complex mandibular/maxillary/TMJ procedures intended to improve function and appearance.
Often the intended procedure — which always started at 7:30 am — had to be cut short because of time constraints.
For example: where a bone graft had been planned — using bone from the patient's hip obtained while under anesthesia — to unite intentionally fractured/repositioned bone segments, lack of time resulted in a titanium plate + screws being used instead, a less than ideal solution.
Iron Rule: Patient MUST be out of OR/in recovery room by 3 pm or dental surgeon's allotted operating time will be curtailed. NO EXCEPTIONS.
https://en.wikipedia.org/wiki/Carbon_dioxide#Below_1%
The most convincing evidence is from the ISS: at 5000ppm CO2, the crew experienced "headaches, lethargy, mental slowness, emotional irritation, and sleep disruption." - so you can feel too high a CO2 level and open a window (if you know to consider that as a problem which causes these symptoms).
The studies suggesting 1000ppm may be harmful are called out in the wiki article and it seems the jury is still out as to if the effects are real/are the result of CO2 and not confounding issues.
I guess I should look at some studies, hm.
Also it seems to take a long time for a well ventilated space to build up to high CO2 levels - days for my apartment. I could entirely prevent any buildup at measuring heights of it by not quite closing a window furthest from my apartment door. My theory is that movent in the hallways of my apartment building slowly pushed air out that window thus replacing the air in my apartment fully over days.
By not quite closed I mean closed but the lever that presses the window into its the seals only slightly engaged. A Year after I started my Measurements there was some maintenance done on the windows to make them more airtight. Since then I do not need to keep the window half closed anymore because I can't get the CO2 meter to show anything but baseline except when sitting right in front of me on my desk.
Don't know if you're aware but CO2 is denser than normal dry air and therefore tends to sink, so this would agree with your observations.
For completed products my Awair lite cost me €100 including VAT (so about $80 pre sales tax) and it also includes an NDIR sensor. As well as fine particle and VOC.
One thing to avoid are Chinese sensors which only use "eCO2" - these estimate CO2 levels based on volatile organic compounds and are virtually useless.
Also it looks like the author has not understood well how a CO2 sensor functions. It needs to see direct fresh air at least once a week or it won't be accurate. If you don't see a reading of 400 (outside CO2 levels) you're doing it wrong and you're measurements are off.
My house rarely goes above 1000 so I think this is part of what got her so scared.
Does anyone else see the problematic nature of "knowing" too much everyday data?
This article suggests the fear started due to COVID. This seems like an obsessive-compulsive health anxiety thing. Seems likely given the author writes mostly COVID & health opinion pieces(and a great writer at that).
Like many with Apple watches, being able to constantly monitor your vitals can bring both peace of mind and rumination.
I can't help but ask...is this a healthy thing to be doing? You can't control the environment.
This way you change the air, without losing too much heat from the floors/mattresses/furniture.
> When Jose-Luis Jimenez, an atmospheric chemist at the University of Colorado at Boulder, first picked one up three years ago, he was shocked that it could hold its own against the machines he used professionally. And in his personal life, “it allows you to find the terrible places and avoid them,” he told me, or to mask up when you can’t
Let him stuck the aranet in his mask and see how the reading goes.
I have a question - is CO2 filterable by active carbon filter?
I’m basically a layman here and I agree that CO2 and PM2.5 particles are completely unrelated.
PPM is Parts Per Million, i.e. a general measure of density of one substance in another. So, CO2 at 500 ppm makes sense.
Absolutely not. If you want to lower CO2, open a window.
Particulate matter, VOC, and other kinds of substances are a breeze to filter out compared to co2.
It depends on the model. High (>90%) efficiency, condensing furnaces are completely sealed off from the house: they take in air from the outside (via PVC pipe), combust, extract the heat, and exhaust the results (via PVC pipes).
* https://www.youtube.com/watch?v=lBVvnDfW2Xo
Older lower efficiency (<85-90%) furnaces suck in air from the house, exhaust into metal pipes (PVC would melt because not as much heat is extracted from the fumes), can be back-drafted and you have to worry about CO.
Basically: if the furnace has vents in which you can see a pilot light, it's the older style.
Of the gas appliances... I have never heard anyone having issues with their gas stove as any cooking is usually followed by ventilating the kitchen.
Although I've heard a lot of horror stories about CO (carbon monoxide) poisonings from faulty appliances like water heaters.
A CO monitor is something I would recommend to anyone having gas appliances at home. Again, based on third-hand experience.
The Halo can also control an air purifier, which has been really handy. It's pretty cool to see the air quality improve while the purifier does its thing. This was especially important when we had horrible air quality due to forest fires.
Edit: The app actually let's me export all data as CSV.
For me, it's the heated house over freezing outside. Sorry lungs.
That's 93 m2. That's not small at all, even if they had kids.
I despise chirpy, wishy-washy science articles. If you're running at the levels described in the article you need to fix it or get out. End of story.
On top of that, if someone really cared about making their body utilize O2 better they would be outside doing hill repeats to improve their VO2max. Worrying about carbon dioxide being a hindrance is silly, because having perfect air doesn't by itself make your lungs bring O2 into the bloodstream better.
If someone is buying an air quality monitor for life extension purposes they should find one that detects PM2.5 and PM10, and figure out how never to breathe that stuff, daggers for the alveoli.
Furthermore, filtering the air doesn't magically reduce CO2. That's stupid. If the author really wanted to reduce CO2, they would have bought 20 plants and placed them around their house.
I played a bit with small oxygen concentrator, CO2 sensor and a garbage bag. In few minutes CO2 levels in the bag dropped to unmeasurable.
I really like mine. It helped me discover that I was sensitive to volatile organic compounds: every time I felt the air was stuffy inside my apartment, it corresponded to a VOC peak that was happening right then.
The one downside to the Airthings Wave is that it looks like hospital equipment. Grey, lifeless plastic pill design that was probably outdated even in the 1970s.
If you ignore how it looks, it works fantastic.
Seems like a really nice design. I was impressed that bluetooth LE was enough to connect reliably across 3 floors (with the gateway on the middle floor) of my house. The view plus automatically acts as a hub if you plug in USB for power, but falls back to batteries as needed.
All in all just about perfect, it works, easy to setup, and collects tons of data (Radon, PM2.5, CO2, Humidity, Temp, VOC, and pressure). I do wish it collected carbon monoxide though.
1: https://breathesafeair.com/qingping-air-monitor-lite-review/
It works well enough and home assistant integrates with it. I cannot comment on it's accuracy since I've never owned another CO2 monitor as a reference. However, it is very responsive to the various things I've tried to manage CO2 in my bedroom - such as opening the windows to differet degrees, position of my curtains etc.
You will not be able to get something of higher value than that, because technically it's a demonstration device and likely doesn't make them much if any profit.
The thing needs to be powered on and taken outside every so often for calibration, who does this for residential use I'm not sure but for most with busy lives I don't think it's a great idea.
If it is powered off at any time it needs to be done again if I'm not mistaken.
And it's not as much as of a hassle as first appears. After a week you can expect readings to drift downward by 50-200 ppm depending on whether or not you aired out the room at all - and it's a one time thing, won't happen continuously every week. Then you just take it outside and it will be fixed in under 10 minutes (<400 ppm reading trigger auto calibration immediately).
I'm not confident that the other co2 meter options are in any way better. They most likely also do auto calibration but don't tell you. Counting on the fact that most people won't notice the drift.
It is required by law in most European countries in new constructions.
It seems like a prayer plant might be the best.
I have heard about some people keeping an aquarium (with growth lights) full of algae and they swear by it, but maintenance is high.
There are no other ways that are affordable enough to be feasible, and don't cause giant energy consumption/pollute the air with smelly chemicals.
Unless you live in a commercial-scale greenhouse, literally in the same room as the plants, you can forget about photosynthesis.
A family of 4 can easily create over 1,000 pounds of CO2 per year. Common houseplants like Spathiphyllum can absorb about 0.8g of CO2 per day, so we can be super generous and call it 1 pound per year. So you'd need around 1,000 plants, reduced depending on ventilation and how much exhalation you do outside of home.
https://www.amazon.com/Lights-Plant-Indoor-Plants-Spectrum/d...
https://urbanplants.co.in/blogs/news/most-effective-co2-abso...
So, if you've accidentally spiked your CO2 levels up to 2000ppm, one of these bad boys should get you back down to a mere 1000ppm in a tidy 1000 hours or so.... assuming you've evacuated all humans and animals from the house and nullified all other sources of CO2 emission.
There are a lot of great reasons to have indoor plants; just be realistic about their ability to meaningfully impact indoor CO2 levels.
I'm saying its significantly cheaper and potentially more
rewarding as a hobby than trying to play god with air quality
and a 1k budget
And anyway, you can do a lot with indoor air quality for 1K.
In what environment? 2ppm in a small enclosed room and 2ppm in a large warehouse are very different quantities of CO2.
One common estimate for humans seems to be 1kg of CO2 exhaled per day.
A single bird's nest fern is estimated to absorb about 0.0002677kg of CO2 per day.
So about 3,700 bird's next ferns in your house for each human being should even things out. Regardless of exact numbers this seems consistent with everything I've ever read over the years, that indoor plants are nice but the amount needed to really reduce CO2 is impractical.
Edit: Found some dude who is bubbling air through plastic bottles filled with algal cultures to scrub his air. Since algae does grow pretty quickly in the right conditions, this might be pretty efficient, albeit kinda gross looking. He could dry and weigh the algae to get a pretty good estimate how much carbon he has collected, and from there calculate how much CO2 he's removing. https://www.instructables.com/Simple-Algae-Home-CO2-Scrubber...
Seems like a few snake plants would easily handle that level.
https://balconygardenweb.com/most-effective-co2-absorbing-ho...
"In a study at Naresuan University, Phitsanulok, Thailand, the snake plant can absorb CO2 at 0.49 ppm/m3 in the closed system."
That would require an enormous number of snake plants to do anything. A tiny apartment is 50m^2 * 3m = 150 cubic meters, so it requires 300 snake plants just to bring down by 1ppm (though not sure over what timescale or other assumptions in the work cited)
Because you need to take time into account and it's more coherent with the result of other studies (an optimist case with good sunlight but 0.4ppm/m3/m is ok I guess for young plant).
'The approximate amount of carbon exhaled by a single human in 1 d is 300 g, whereas the carbon content of 1 L of gasoline is 640 g. In comparison, a single Spathiphyllum in a 15-cm pot grown at a PPF of 20 mmolm–2s–1 fixed 0.8 g C per day, so it would take 400 plants to offset a single human or 845 plants to offset a gasoline use of 1 Ld–1.'
[1] https://www.realhomes.com/news/do-house-plants-remove-carbon...
Planting more plants is at least a step in the right direction. Everything else is more or less simply turning it into someone else's problem.
You're right that the practical consideration is important. It needs to be addressed and engineered to be made practical.
On top of that maybe we eat too much, but that's a off topic.