13 ms·

First clean water, now clean air

285 points by finm 3y ago

sergioisidoro 3y ago
I bought a CO2 monitor, and although the effects of CO2 in cognition and energy levels are debatable[1], it shocked me and raised awareness to how poor my indoor ventilation is. We live in a small apartment, and just being 30 min with 2 people in the room raises the CO2 ppm from 400 to >1000. Opening a window quickly lowers it. Never-mind doing some light activity like yoga or similar. So if we want to do something, I think the first step is really to get visibility to the problem, especially to the costs of the problem (productivity, public health, sick leaves, etc). [1] at the levels found in my apartment
- rcme 3y ago
  I think the first step would be to buy a second monitor, ideally from a different manufacturer, and verify that your readings are actually correct. My experience is that cheap monitors are basically random.
  - lazide 3y ago
    At least one (Big Clive pulled it apart I think?) had an Ethanol sensor in it.
  - bsder 3y ago
    Precisely this. I haven't seen anybody take any of the cheap CO2 sensors and demonstrate that they are anywhere in the range of the readings of a lab grade CO2 sensor.
  - nicenewtemp84 3y ago
    If your reader raises it's reading as you sit in a small room, and lowers when you open a window... It's probably not at risk of being random. Inaccurate maybe, but still sensing in the correct direction.
- mypastself 3y ago
  Not to hijack your thread, but I wonder if anyone here’s built their own Raspberry/Arduino CO2 monitor? Which (reliable) sensors did you use? Did you find it more affordable than purchasing a monitor, especially if you already had unused microcontrollers lying around the house?
  - Lukas_Skywalker 3y ago
    I built one based on the AirGradient DIY sensor [1]. It is open source, and you can order PCBs or build them yourself. It is also compatible with ESPHome. It uses the "Senseair S8" CO2 sensor, which costs a bit (25-30$), but (according to AirGradient) has a very high quality. [1]: https://www.airgradient.com/open-airgradient/instructions/diy-pro-v37/ https://www.airgradient.com/open-airgradient/instructions/di...
    - Rebelgecko 3y ago
      Seconding this recommendation. I was surprised how easy and cheap it was to order my own tweaked PCBs. Airgradient has also done a lot of testing to determine which components work well and what their different failure modes are. Depending on how many you build at a time, you can source all the parts for maybe $40-$60. Assembly is straightforward as long as you're comfortable with through-hole soldering (and if not, this is a great chance to learn). The design is also modular enough that it's easy to skip on things like the thermometer or particulate matter sensor if you're so inclined.
  - deleted 3y ago
    [deleted]
  - ProZsolt 3y ago
    I'm currently developing my own monitor based on Sensirion SCD40(CO2/temperature/humidity) and Plantower PMS7003(PM2.5). The SCD40 is lot smaller than any NDIR sensor, but with the same accuracy[1]. My goal is to get a cheap (~$50) sensor in a small package that I can put in every room in my house. It will be modular so I skip the display and the PM2.5 sensor and it can be cheap as ~$25 [1]: https://www.airgradient.com/open-airgradient/blog/co2-sensors-photo-acoustic-vs-ndir/ https://www.airgradient.com/open-airgradient/blog/co2-sensor...
- isp 3y ago
  > So if we want to do something, I think the first step is really to get visibility to the problem A sensible first step would be to very visibly display CO₂ monitors in buildings (e.g., throughout office buildings, schools, etc) Once the CO₂ levels become visible, this in itself creates an incentive to improve. Related from UK (2021): "All schools to receive carbon dioxide monitors" - https://www.gov.uk/government/news/all-schools-to-receive-carbon-dioxide-monitors https://www.gov.uk/government/news/all-schools-to-receive-ca...
  - bsenftner 3y ago
    In Japan, it is common to see CO₂ monitor displays outside contained meeting spaces, such as theaters. My wife purchased an Aronet CO₂ monitor, and I took it with me on a business trip last week. The CO₂ while on the flight was in the 3000's range. The CO₂ at my client's office was in the mid 2000's range, as well as the hotel. Opening the hotel window the allowed 2 inches reduces CO₂ to the 600 range in 10 minutes, but the client's office windows do not open, and of course neither do the airplane windows. I've also noticed when working indoors or when driving, if the CO₂ is above 1500 I get drowsy, so the degree it is no longer responsible driving a car. Air safety: are we going to fight a moronic battle over this too?
    - giraffe_lady 3y ago
      No, there won't be any battle. If there were going to it would have been during covid, with improved indoor ventilation being one of the major components of an in-depth mitigation strategy. There was no meaningful attempt or debate about changing ventilation standards then when it would have tangibly saved lives, there certainly won't be now.
      - marcosdumay 3y ago
        The covid years were crazy. People kept cleaning everything with all kinds of poison (thank god somebody published early that alcohol at 70% is enough, otherwise I think we would see people dropping dead from too much poison), that was known to be useless by around April 2020, and yet everybody actively refused to talk about indoor ventilation. And most were the same people repeating the "are you for or against science?" line. Crazy years, dominated by completely random propaganda. Discussions on calmer times follow different rules, and if nobody decides to spend a lot of money stopping it, it can follow rational, evidence based lines.
- c3534l 3y ago
  > , it shocked me and raised awareness to how poor my indoor ventilation is. Do you want indoor circulation? Wouldn't that just mean your apartment loses heat/AC?
  - swiftcoder 3y ago
    In a heating/cooling system that has been specifically designed to improve ventilation, one can pull fun tricks like using the outgoing (stale) air to help heat/cool the incoming (fresh) air. Also in some places houses are built with enough thermal mass that the air within the building doesn't contain the majority of the heat therein. In general there is likely some level of ventillation that will be worth taking on slightly increased heating/cooling costs.
  - kevincox 3y ago
    You can use a heat exchanger to get "fresher" air while keeping the heat/cool inside. Although many places don't have this in place. It is probably mostly due to lack of awareness or concern than any technical reason.
    - endisneigh 3y ago
      Cost
      - switchbak 3y ago
        Letting your warm air go directly outside also has a cost. Getting poor air quality for decades also has a cost. Typing more than a one word reply is pretty cheap though.
        endisneigh 3y ago
        you're right. things have tradeoffs. the point is that most barely have central AC with vents, let alone an HRV.
        3y ago
- LeonM 3y ago
  I don't understand why you are being downvoted, you raise a good point. Based on some HN comment from a while ago I invested in a CO2 meter (they are still quite expensive for some reason). And I share the same experience, CO2 levels can raise rapidly indoors, but simply turning on ventilation or opening a window very quickly lowers CO2 contents. Using the meter I found CO2 levels in my bedroom can become quite high at night. So I improved the ventilation in my bedroom, and in my case it helped me to achieve better sleep.
  - ct0 3y ago
    I'm starting to think that having a better night's rest while sleeping in a tent is not from the ground you sleep on, but the fresh air you've had all night.
    - Cthulhu_ 3y ago
      It'll depend on the tent, I don't immediately associate tents with good ventilation.
      - gumby 3y ago
        A tent with poor ventilation rapidly becomes soggy.
    - prmoustache 3y ago
      you want to sleep below a tarp then, not in a tent.
    - kccqzy 3y ago
      My best sleep was on a camping trip when we decided that a tent wasn't necessary and we could just sleep outside watching the night sky. (This is of course highly location dependent. Now that I think about it, I was probably taking a bit more risk at that time than what I tolerate now.)
  - anonyfox 3y ago
    … and people make joke about us Germans need to do „stosslüften“ (opening all windows in parallel to get fresh air in fast). also, are there really people that can (or even prefer!) to sleep with closed windows?! Only with AC blasting, right?
- beebeepka 3y ago
  If possible, I recommend ventilation by creating a current by opening the front door and cycling every room (windos, balcony doors) of your apartment. I do this every day regardless of the season. Works best during windy weather
  - InCityDreams 3y ago
    *watch out for slamming doors and windows :-) Took me ages to work out how best to perform such in my place, and yes - daily opening, even for 5 minutes - does seem to help (me). I also do it last thing at night. In the morning - a less stuffy apartment. On work days, I'll probably open for a few minutes before going to work, but definitely after getting home.
    - oblak 3y ago
      I use mostly chairs and pillows to prevent doors from slamming. What challenges did you meet at your place?
- sbaiddn 3y ago
  That's why I'm not changing my very leaky and drafty windows - I don't want to live in a hermetically sealed Tupperware container. Once I install an HRV system then I'll do the windows!
  - Abekkus 3y ago
    Or you could save $2k on materials & labor, and put in a filtered vent fan. You only need around 15CFM per resident. Household HRVs & ERVs have suspiciously low heat efficiencies for their costs.
    - BizarroLand 3y ago
      85-95% isn't suspiciously low. Where are you getting this information from?
    - sbaiddn 3y ago
      Does this "filtered vent fan" exchange air with the outside? If not, Im not interested.
    - symlinkk 3y ago
      Are you talking about a fan that simply blows outside air in? Wouldn’t that basically fight what the HVAC is doing? AFAIK the only real solution is an ERV / HRV, and they are extremely expensive (like $10k in my area)
      - balfirevic 3y ago
        No direct experience, but single-room HRV units look pretty cheap https://www.amazon.co.uk/single-room-heat-recovery-ventilation-system/s?k=single+room+heat+recovery+ventilation+system https://www.amazon.co.uk/single-room-heat-recovery-ventilati...
- za3faran 3y ago
  Which monitor manufacturer are you using?
  - sergioisidoro 3y ago
    I bought mine from a construction material supply web store, and was looking for one of the cheaper ones. Its a Trotec. I wouldn't trust the absolute values so much, but i believe it's directionally correct.
- Cthulhu_ 3y ago
  It's a tradeoff, because good ventilation - ideally just open a window - also means heat is leaking out of the house, which costs money (and co2 emissions) to restore. There's cyclic systems, but I live in a neighbourhood where some houses were equipped with it; on the proper setting, it was too loud so people turned it down, then people got sick from high CO2 levels in their house.
  - BizarroLand 3y ago
    There are ERV and HRV systems that will cycle fresh air in while exchanging the heat and moisture from the outgoing air to the incoming air. It's a neat technology but the jury is still out on it. Some people praise them, other people revile them, and they seem to be either too bulky or too cumbersome or too expensive or too inefficient for a DIY retrofit project.
- clairity 3y ago
  > "although the effects of CO2 in cognition and energy levels are debatable" it's really not debatable. the feeling of stuffiness is a function of many things, but environmentally, it's mostly temperature and humidity (we humans are hot and breathe out lots of humidity). there are no cognitive/energy effects until you get into the 10's of thousand of ppm, as the mechanism of action is competing out oxygen, not some intrinsic maladaption to CO₂, which is actually vital to life on earth. it's fashionable to hate on carbon right now (it's mediopolitical), and that's really all there is to it. particulates, VOCs and chemical off-gassing, on the other hand, do have known mechanisms of harm, and that's something you should be more concerned about, but not yet alarmed. most of that pollution comes from cars and coal/gas power generation, so long-term, we should move toward more efficient habitation (e.g., denser cities, public transit) and cleaner power generation (including nuclear) if we really care about our collective health. practically no one should be worried about CO₂ in their daily lives. it's thoroughly a red herring.
  - sergioisidoro 3y ago
    Yes they are debatable. There are cognitive performance tests that show statistically significant decline in many tasks above 1500ppm, especially on planning tasks. That's independently of the feeling of "stuffiness". If these measurable declines have a sufficient impact on our lives and productivity is the debatable part. Edit: here's one reference: "We also found effects of CO2 (a proxy for ventilation) on cognitive function. For every 500ppm increase, we saw response times 1.4-1.8% slower, and 2.1-2.4% lower throughput" https://www.hsph.harvard.edu/healthybuildings/2021/09/09/impacts-of-indoor-air-quality-on-cognitive-function/ https://www.hsph.harvard.edu/healthybuildings/2021/09/09/imp...
    - clairity 3y ago
      if you look at the paper, you see no such conclusive evidence, but rather weak correlative assertions in noisy and complex environments. also notice the incentives and implicit bias of the involved. unbiased studies from the past several decades have so far shown cognitive effects require 10× that level of CO₂ to show any conclusive effects. even the pm2.5 effects attempt to make a short-term correlation, which is dubious at best. long-term pm2.5 effects are more conclusive, which is why we should be more concerned about them. CO₂ is a fashionable concern but not scientifically supported. more importantly, it distracts from things we really should be concerned about as states and nations, like actual pollution and the alarming concentration of power and wealth.
- aidenn0 3y ago
  I do wonder how much of it is CO2 levels themselves and how much of it is high CO2 being a proxy for poor ventilation.
- kccqzy 3y ago
  This is of course also the reason why I don't like most office buildings. They don't have operable windows and rely on centrally managed HVAC. They sometimes have CO2 sensors but the system is too opaque for occupants to figure out at which level the mechanical ventilation starts.
throw0101b 3y ago
> Ultraviolet germicidal irradiation (UVGI) Please do not do/use this. Generally anything that is 'active', like UV lamps or ozone emitters, is not a good idea: * https://www.youtube.com/watch?v=hSFQQpgvgeo&t=6m1s https://www.youtube.com/watch?v=hSFQQpgvgeo&t=6m1s * Interviewee: https://civmin.utoronto.ca/home/about-us/directory/professors/jeffrey-siegel/ https://civmin.utoronto.ca/home/about-us/directory/professor... All that's needed for good indoor air quality (IAQ) is an ERV/HRV which exhausts stale indoor air and brings in fresh outdoor air (through a filter). For comfort you want a furnace+AC/heatpupmp and a dehumidifier. And try to make the enclosure as air-tight as possible so the air comes in and out on your terms and not 'randomly' through cracks (where it can carry dust and pollen, and bugs can perhaps get through as well).
- adolph 3y ago
  That is an interesting explanation. I won’t summarize other than to say that as someone who might have added UV next hardware cycle, there were several A-Ha moments. Well worth watching.
  - mensetmanusman 3y ago
    UV is more than UV, there is UVA UVB UVC, etc. Some UVC generates Ozone, some do not. Wavelength and spectral Q factor matter. It’s possible to have a UV system that does what you want without the downside, but it does cost.
    - throw0101a 3y ago
      > It’s possible to have a UV system that does what you want without the downside, but it does cost. The main downside is that you are introducing a chemistry experiment into your ventilation system. If you want clean air, then (a) cycle in/outside air at ASHRAE-recommended volumes, and (b) use high-MERV/HEPA filters. In wildfire zones and in wildfire season you can perhaps add charcoal filters—if your system is designed to handle the pressure/head loss—to get rid of the smoke-y smells.
ZeroGravitas 3y ago
It doesn't take away from the general thrust of the post but it's interesting that lack of quality sewage treatment leading to it being dumped into rivers is thought to be a key issue in the current British council voting: Local elections 2023: How sewage topped the political agenda https://www.bbc.co.uk/news/uk-politics-65190097 https://www.bbc.co.uk/news/uk-politics-65190097
- makomk 3y ago
  The Victorian-era sewage systems described in this article are actually one of the key reasons that sewage is ending up in rivers and the sea in the first place. Notice how they worked: sewage was collected, pumped, and dumped downstream of London. It was not treated. Most of the UK's sewage treatment is retrofitted to sewage systems that were never designed to have it. This causes various problems, the main one being that rainwater drainage and sewage are mixed in many areas and this overwhelms the sewage system during heavy rain. (As for why it became a key election issue, well, basically the British press lied to make it one - the BBC included. They made an increase in monitoring of sewage discharges look like a massive increase in sewage discharged whilst tricking people into thinking monitoring had got worse by deceptively-worded articles about the few overflows that weren't monitored yet, they told people the Environmental Agency was lying about only recently being able to measure the full extent of sewage discharges based on a hnadful of previously-recorded incidents, they claimed other European countries which still had Victorian-esque sewage systems with no treatment plants that just pumped directly into their rivers and seas in some urban areas were doing a better job, and so on.)
  - brianmcc 3y ago
    It also seems another Brexit issue - treatment chemicals being that bit harder to bring in: https://www.thelondoneconomic.com/news/brexit-to-blame-for-uks-sewage-problems-332728/ https://www.thelondoneconomic.com/news/brexit-to-blame-for-u...
    - Mvandenbergh 3y ago
      Not in practice, no. Companies were provided with a regulatory position statement from the EA that they would not usually be prosecuted if they ran out of treatment chemicals due to something that wasn't their fault. In fact, there never was a shortage due to either Brexit, Covid or a combo and this was never used.
panchtatvam 3y ago
[flagged]
sdfjkl 3y ago
The Thames is still very much opaque. Not near-opaque.
- dgroshev 3y ago
  It's just silt churned up by high tides. When you're on the river, you can easily see that bits shielded from the turbulent flow, where the silt has a chance to settle down, are crystal clear. You can also see eels, seals, cormorants, kingfishers, seagulls of all kinds, and lots of life generally. It's great.
MontyCarloHall 3y ago
If, hypothetically, we dramatically reduced the prevalence of airborne disease, what would the effect on our immune systems be? Some hypothesize that living in too sterile an environment leads to autoimmune diseases, since the immune system is calibrated to a certain baseline level of activity, and will turn on the body if this level is not met by external pathogens.
- GordonS 3y ago
  If that turned out to be the case, maybe we could have annual "vaccines", which would exist only to trigger anti-viral activity?
- mrob 3y ago
  If it turns out that actual pathogens are necessary, and we can't use the kinds of harmless bacteria that get sold as "probiotics", it would still be better to identify pathogens with optimal risk:benefit ratio and determine the optimal dose. Exposure to wild pathogens varies widely, so very few people will be lucky enough to have the best exposure.
- Symmetry 3y ago
  Our hunter gatherer ancestors living in bands suffered from drastically fewer respiratory diseases than we do, you need a large connected population for something like the flu to survive in a human population in the long term. The issue with sterile environments is about the lack of random bacteria, not human adapted pathogens.
  - MontyCarloHall 3y ago
    That’s likely true, but our hunter gatherer ancestors also saw way more water and foodborne pathogens, not to mention continual parasitic infections to more than make up for the relative lack of immune system stimulation from a lower level of airborne pathogens.
leblancfg 3y ago
I wish the author had spent more time to unfold the public vs private debate here: >if a country installed all the measures I mentioned As opposed to the wastewater infrastructure in the first section that can be mandated and put in motion by a government, it's up to individuals and institutions to install the measures. This makes implementation significantly more challenging, as it relies on the collective efforts and cooperation of numerous parties, each with their own priorities and resources. Government-led initiatives, on the other hand, can be more easily streamlined and enforced, ensuring a higher degree of compliance and effectiveness.
- gizmo686 3y ago
  Governments are perfectly capable of setting building codes. This isn't an instance fix, but would be effective over the long term. Governments also have a well established mechanism to incentives faster compliance: tax refunds to offset the cost of improvement. We already offer such incentives for energy efficiency improvements (some of which actively harm ventilation). From an engineering perspective, the clean air proposals are much easier than wastewater management. There is no centralized infastructure needed. Every building can be upgraded independently, and the people in that building will see an immediate benefit. Further, the upgrades needed are typically not that major. Most building already have a forced air HVAC solution. These solutions already have inline air filters, and often already have the ability to actively pull in fresh air. We can get significant improvement my simply leaving the fan on these units running regardless of if they are actively heating/cooling; and using already available high quality filters. In that subject, a quick PSA to home owners: if you have not changed your HVACs filter recently, you probably should.
EGreg 3y ago
I designed this two years ago… https://uvspinner.com https://uvspinner.com Tried to get NYC officials to get interested — went through some channels that my friends had. Nothing. Anyone here interested in doing it?
photochemsyn 3y ago
Clean air and water issues are not limited to biological contamination with pathogenic microbes and viruses, and some of the suggestions (ensuring good ventilation) run into problems when external air quality is dangerously bad (when health agencies tell people to keep their windows closed). It's not entirely unlike water issues, for example the Thames was used to dispose of wastes from animal slaughtering, leather tanning, production of dyes from coal tar, alcohol distillery wastes as well as for human excrement. Cleaning up air quality requires addressing these issues as well (coal power plants, diesel truck emissions, agricultural dust, etc.).
kazanz 3y ago
As others of posted the big difference here - and also the big challenge - is that indoor air is a definitively NOT a public service. It requires a slew of regulation, enforcement bodies, and - from a US perspective - profitability for litigation attorneys. Again with a US slant, ADA is the obvious legislative model for similar clean air regulations. So it's possible, just more challenging than public sewage.
xmdx 3y ago
Other than the obvious benefits like avoiding a pandemic this hits close to home. My dad passed away 2 weeks ago from Pulmanory Fibrosis. A respiratory disease without a cure and one where we know very little about the causes. Better air quality would drop cases, relive strain on the health system and just let people live longer. Its something I want to help with where I can. I hadn't even thought about the obvious step of raising awareness about air quality.
markrankin 3y ago
“The expectation of clean water in wealthy countries is enabled by technology and infrastructure; like effective sewage systems and water treatment facilities. But to a large extent it is also enabled, and was initially bootstrapped, by sound policymaking and regulation. Regulation requires verification.” Regulation of water does not require verification. We live on a planet where clean water is abundant and cannot escape the planet’s atmosphere. Why you think we need to measure how this is verified is beyond the beyond’s. Here’s a wiki page reference if you need help measuring how much water exists on Earth: While the majority of Earth's surface is covered by oceans, those oceans make up just a small fraction of the mass of the planet. The mass of Earth's oceans is estimated to be 1.37 × 1021 kg, which is 0.023% of the total mass of Earth, 6.0 × 1024 kg. An additional 5.0 × 1020 kg of water is estimated to exist in ice, lakes, rivers, groundwater, and atmospheric water vapor.[20] https://en.m.wikipedia.org/wiki/Origin_of_water_on_Earth#Earth's_water_inventory https://en.m.wikipedia.org/wiki/Origin_of_water_on_Earth#Ear...
- twojacobtwo 3y ago
  There are only so many ways and places to extract clean water for large populations in an efficient way. Once water is used, it has to go somewhere, which is back into the water system. Every person/population downstream then no longer has 'clean water' without verification. We could have 10x the clean water we have now and we would still have to consider this aspect.
danans 3y ago
> An aside: ventilation plus filtration is the major reason that the risk of Covid infections on flights was and is so relatively low: air in the cabin is replaced every couple minutes, fresh air is drawn from outside the plane, and mixed with recycled air passed through HEPA filters. IME, the most effective thing to do in a house is filtration inline with the intake of a ventilation system. In my case, I have an activated carbon and a MERV13 filter that cleans incoming outdoor air just before it's fed to the heat recovery and distribution system. You still need a separate recirculating filtration system to deal with particulates generated within a house.
steviedotboston 3y ago
I don't think the clear water and clear air analogy works very well. They seem to be very different cases. Keeping clean and dirty water separate is trivial and requires no more advanced technology than plumbing. Keeping clean and "dirty" air separate is impossible. We will always breathe air that includes pathogens. That isn't to say there should be efforts to improve air quality, but I think a lot of times analogies like this oversimplify things. It's easy to eradicate cholera through cleanliness and modern plumbing, but we will never eradicate airborne viruses through air filters and masks.
- JBorrow 3y ago
  "Cleanliness and modern plumbing" include massive water treatment facilities, digging up every street, laying billions of miles of pipe.
  - steviedotboston 3y ago
    The main effort is separating drinking water and waste water. Keeping them as far away as possible and preventing contamination. There is no way to do that with air. The air we breath in and the air we breath out will always mix. The best we can hope for is some amount of dilution with fresh air/filters, bit at the end of the you are never going to be able to achieve the same thing with airborne viruses that we did with waterborne illnesses. The flu, covid, etc are with us for the long haul.
- gridspy 3y ago
  It's a good analogy. Invest in infrastructure to extract dirty air and deliver clean air into living spaces. Provide suitable standards and technologies to do so. It would be cheaper than the infrastructure to extract dirty water and deliver clean (treated) water because we don't need to transport the air anywhere near as far and air treatment is simpler.
vondur 3y ago
I wish more of the funds that were allocated to combat Covid were used to install better air handling systems in public areas here in the US. The education side received billions of dollars, which if used for better air would help keep kids more kids from getting sick and then bringing it home to families.

285 points by finm 3y ago

I bought a CO2 monitor, and although the effects of CO2 in cognition and energy levels are debatable[1], it shocked me and raised awareness to how poor my indoor ventilation is. We live in a small apartment, and just being 30 min with 2 people in the room raises the CO2 ppm from 400 to >1000. Opening a window quickly lowers it. Never-mind doing some light activity like yoga or similar. So if we want to do something, I think the first step is really to get visibility to the problem, especially to the costs of the problem (productivity, public health, sick leaves, etc). [1] at the levels found in my apartment

rcme 3y ago
I think the first step would be to buy a second monitor, ideally from a different manufacturer, and verify that your readings are actually correct. My experience is that cheap monitors are basically random.
- lazide 3y ago
  At least one (Big Clive pulled it apart I think?) had an Ethanol sensor in it.
- bsder 3y ago
  Precisely this. I haven't seen anybody take any of the cheap CO2 sensors and demonstrate that they are anywhere in the range of the readings of a lab grade CO2 sensor.
- nicenewtemp84 3y ago
  If your reader raises it's reading as you sit in a small room, and lowers when you open a window... It's probably not at risk of being random. Inaccurate maybe, but still sensing in the correct direction.
mypastself 3y ago
Not to hijack your thread, but I wonder if anyone here’s built their own Raspberry/Arduino CO2 monitor? Which (reliable) sensors did you use? Did you find it more affordable than purchasing a monitor, especially if you already had unused microcontrollers lying around the house?
- Lukas_Skywalker 3y ago
  I built one based on the AirGradient DIY sensor [1]. It is open source, and you can order PCBs or build them yourself. It is also compatible with ESPHome. It uses the "Senseair S8" CO2 sensor, which costs a bit (25-30$), but (according to AirGradient) has a very high quality. [1]: https://www.airgradient.com/open-airgradient/instructions/diy-pro-v37/ https://www.airgradient.com/open-airgradient/instructions/di...
  - Rebelgecko 3y ago
    Seconding this recommendation. I was surprised how easy and cheap it was to order my own tweaked PCBs. Airgradient has also done a lot of testing to determine which components work well and what their different failure modes are. Depending on how many you build at a time, you can source all the parts for maybe $40-$60. Assembly is straightforward as long as you're comfortable with through-hole soldering (and if not, this is a great chance to learn). The design is also modular enough that it's easy to skip on things like the thermometer or particulate matter sensor if you're so inclined.
- deleted 3y ago
  [deleted]
- ProZsolt 3y ago
  I'm currently developing my own monitor based on Sensirion SCD40(CO2/temperature/humidity) and Plantower PMS7003(PM2.5). The SCD40 is lot smaller than any NDIR sensor, but with the same accuracy[1]. My goal is to get a cheap (~$50) sensor in a small package that I can put in every room in my house. It will be modular so I skip the display and the PM2.5 sensor and it can be cheap as ~$25 [1]: https://www.airgradient.com/open-airgradient/blog/co2-sensors-photo-acoustic-vs-ndir/ https://www.airgradient.com/open-airgradient/blog/co2-sensor...
isp 3y ago
> So if we want to do something, I think the first step is really to get visibility to the problem A sensible first step would be to very visibly display CO₂ monitors in buildings (e.g., throughout office buildings, schools, etc) Once the CO₂ levels become visible, this in itself creates an incentive to improve. Related from UK (2021): "All schools to receive carbon dioxide monitors" - https://www.gov.uk/government/news/all-schools-to-receive-carbon-dioxide-monitors https://www.gov.uk/government/news/all-schools-to-receive-ca...
- bsenftner 3y ago
  In Japan, it is common to see CO₂ monitor displays outside contained meeting spaces, such as theaters. My wife purchased an Aronet CO₂ monitor, and I took it with me on a business trip last week. The CO₂ while on the flight was in the 3000's range. The CO₂ at my client's office was in the mid 2000's range, as well as the hotel. Opening the hotel window the allowed 2 inches reduces CO₂ to the 600 range in 10 minutes, but the client's office windows do not open, and of course neither do the airplane windows. I've also noticed when working indoors or when driving, if the CO₂ is above 1500 I get drowsy, so the degree it is no longer responsible driving a car. Air safety: are we going to fight a moronic battle over this too?
  - giraffe_lady 3y ago
    No, there won't be any battle. If there were going to it would have been during covid, with improved indoor ventilation being one of the major components of an in-depth mitigation strategy. There was no meaningful attempt or debate about changing ventilation standards then when it would have tangibly saved lives, there certainly won't be now.
    - marcosdumay 3y ago
      The covid years were crazy. People kept cleaning everything with all kinds of poison (thank god somebody published early that alcohol at 70% is enough, otherwise I think we would see people dropping dead from too much poison), that was known to be useless by around April 2020, and yet everybody actively refused to talk about indoor ventilation. And most were the same people repeating the "are you for or against science?" line. Crazy years, dominated by completely random propaganda. Discussions on calmer times follow different rules, and if nobody decides to spend a lot of money stopping it, it can follow rational, evidence based lines.
c3534l 3y ago
> , it shocked me and raised awareness to how poor my indoor ventilation is. Do you want indoor circulation? Wouldn't that just mean your apartment loses heat/AC?
- swiftcoder 3y ago
  In a heating/cooling system that has been specifically designed to improve ventilation, one can pull fun tricks like using the outgoing (stale) air to help heat/cool the incoming (fresh) air. Also in some places houses are built with enough thermal mass that the air within the building doesn't contain the majority of the heat therein. In general there is likely some level of ventillation that will be worth taking on slightly increased heating/cooling costs.
- kevincox 3y ago
  You can use a heat exchanger to get "fresher" air while keeping the heat/cool inside. Although many places don't have this in place. It is probably mostly due to lack of awareness or concern than any technical reason.
  - endisneigh 3y ago
    Cost
    - switchbak 3y ago
      Letting your warm air go directly outside also has a cost. Getting poor air quality for decades also has a cost. Typing more than a one word reply is pretty cheap though.
      - endisneigh 3y ago
        you're right. things have tradeoffs. the point is that most barely have central AC with vents, let alone an HRV.
        3y ago
LeonM 3y ago
I don't understand why you are being downvoted, you raise a good point. Based on some HN comment from a while ago I invested in a CO2 meter (they are still quite expensive for some reason). And I share the same experience, CO2 levels can raise rapidly indoors, but simply turning on ventilation or opening a window very quickly lowers CO2 contents. Using the meter I found CO2 levels in my bedroom can become quite high at night. So I improved the ventilation in my bedroom, and in my case it helped me to achieve better sleep.
- ct0 3y ago
  I'm starting to think that having a better night's rest while sleeping in a tent is not from the ground you sleep on, but the fresh air you've had all night.
  - Cthulhu_ 3y ago
    It'll depend on the tent, I don't immediately associate tents with good ventilation.
    - gumby 3y ago
      A tent with poor ventilation rapidly becomes soggy.
  - prmoustache 3y ago
    you want to sleep below a tarp then, not in a tent.
  - kccqzy 3y ago
    My best sleep was on a camping trip when we decided that a tent wasn't necessary and we could just sleep outside watching the night sky. (This is of course highly location dependent. Now that I think about it, I was probably taking a bit more risk at that time than what I tolerate now.)
- anonyfox 3y ago
  … and people make joke about us Germans need to do „stosslüften“ (opening all windows in parallel to get fresh air in fast). also, are there really people that can (or even prefer!) to sleep with closed windows?! Only with AC blasting, right?
beebeepka 3y ago
If possible, I recommend ventilation by creating a current by opening the front door and cycling every room (windos, balcony doors) of your apartment. I do this every day regardless of the season. Works best during windy weather
- InCityDreams 3y ago
  *watch out for slamming doors and windows :-) Took me ages to work out how best to perform such in my place, and yes - daily opening, even for 5 minutes - does seem to help (me). I also do it last thing at night. In the morning - a less stuffy apartment. On work days, I'll probably open for a few minutes before going to work, but definitely after getting home.
  - oblak 3y ago
    I use mostly chairs and pillows to prevent doors from slamming. What challenges did you meet at your place?
sbaiddn 3y ago
That's why I'm not changing my very leaky and drafty windows - I don't want to live in a hermetically sealed Tupperware container. Once I install an HRV system then I'll do the windows!
- Abekkus 3y ago
  Or you could save $2k on materials & labor, and put in a filtered vent fan. You only need around 15CFM per resident. Household HRVs & ERVs have suspiciously low heat efficiencies for their costs.
  - BizarroLand 3y ago
    85-95% isn't suspiciously low. Where are you getting this information from?
  - sbaiddn 3y ago
    Does this "filtered vent fan" exchange air with the outside? If not, Im not interested.
  - symlinkk 3y ago
    Are you talking about a fan that simply blows outside air in? Wouldn’t that basically fight what the HVAC is doing? AFAIK the only real solution is an ERV / HRV, and they are extremely expensive (like $10k in my area)
    - balfirevic 3y ago
      No direct experience, but single-room HRV units look pretty cheap https://www.amazon.co.uk/single-room-heat-recovery-ventilation-system/s?k=single+room+heat+recovery+ventilation+system https://www.amazon.co.uk/single-room-heat-recovery-ventilati...
za3faran 3y ago
Which monitor manufacturer are you using?
- sergioisidoro 3y ago
  I bought mine from a construction material supply web store, and was looking for one of the cheaper ones. Its a Trotec. I wouldn't trust the absolute values so much, but i believe it's directionally correct.
Cthulhu_ 3y ago
It's a tradeoff, because good ventilation - ideally just open a window - also means heat is leaking out of the house, which costs money (and co2 emissions) to restore. There's cyclic systems, but I live in a neighbourhood where some houses were equipped with it; on the proper setting, it was too loud so people turned it down, then people got sick from high CO2 levels in their house.
- BizarroLand 3y ago
  There are ERV and HRV systems that will cycle fresh air in while exchanging the heat and moisture from the outgoing air to the incoming air. It's a neat technology but the jury is still out on it. Some people praise them, other people revile them, and they seem to be either too bulky or too cumbersome or too expensive or too inefficient for a DIY retrofit project.
clairity 3y ago
> "although the effects of CO2 in cognition and energy levels are debatable" it's really not debatable. the feeling of stuffiness is a function of many things, but environmentally, it's mostly temperature and humidity (we humans are hot and breathe out lots of humidity). there are no cognitive/energy effects until you get into the 10's of thousand of ppm, as the mechanism of action is competing out oxygen, not some intrinsic maladaption to CO₂, which is actually vital to life on earth. it's fashionable to hate on carbon right now (it's mediopolitical), and that's really all there is to it. particulates, VOCs and chemical off-gassing, on the other hand, do have known mechanisms of harm, and that's something you should be more concerned about, but not yet alarmed. most of that pollution comes from cars and coal/gas power generation, so long-term, we should move toward more efficient habitation (e.g., denser cities, public transit) and cleaner power generation (including nuclear) if we really care about our collective health. practically no one should be worried about CO₂ in their daily lives. it's thoroughly a red herring.
- sergioisidoro 3y ago
  Yes they are debatable. There are cognitive performance tests that show statistically significant decline in many tasks above 1500ppm, especially on planning tasks. That's independently of the feeling of "stuffiness". If these measurable declines have a sufficient impact on our lives and productivity is the debatable part. Edit: here's one reference: "We also found effects of CO2 (a proxy for ventilation) on cognitive function. For every 500ppm increase, we saw response times 1.4-1.8% slower, and 2.1-2.4% lower throughput" https://www.hsph.harvard.edu/healthybuildings/2021/09/09/impacts-of-indoor-air-quality-on-cognitive-function/ https://www.hsph.harvard.edu/healthybuildings/2021/09/09/imp...
  - clairity 3y ago
    if you look at the paper, you see no such conclusive evidence, but rather weak correlative assertions in noisy and complex environments. also notice the incentives and implicit bias of the involved. unbiased studies from the past several decades have so far shown cognitive effects require 10× that level of CO₂ to show any conclusive effects. even the pm2.5 effects attempt to make a short-term correlation, which is dubious at best. long-term pm2.5 effects are more conclusive, which is why we should be more concerned about them. CO₂ is a fashionable concern but not scientifically supported. more importantly, it distracts from things we really should be concerned about as states and nations, like actual pollution and the alarming concentration of power and wealth.
aidenn0 3y ago
I do wonder how much of it is CO2 levels themselves and how much of it is high CO2 being a proxy for poor ventilation.
kccqzy 3y ago
This is of course also the reason why I don't like most office buildings. They don't have operable windows and rely on centrally managed HVAC. They sometimes have CO2 sensors but the system is too opaque for occupants to figure out at which level the mechanical ventilation starts.

throw0101b 3y ago

> Ultraviolet germicidal irradiation (UVGI) Please do not do/use this. Generally anything that is 'active', like UV lamps or ozone emitters, is not a good idea: * https://www.youtube.com/watch?v=hSFQQpgvgeo&t=6m1s https://www.youtube.com/watch?v=hSFQQpgvgeo&t=6m1s * Interviewee: https://civmin.utoronto.ca/home/about-us/directory/professors/jeffrey-siegel/ https://civmin.utoronto.ca/home/about-us/directory/professor... All that's needed for good indoor air quality (IAQ) is an ERV/HRV which exhausts stale indoor air and brings in fresh outdoor air (through a filter). For comfort you want a furnace+AC/heatpupmp and a dehumidifier. And try to make the enclosure as air-tight as possible so the air comes in and out on your terms and not 'randomly' through cracks (where it can carry dust and pollen, and bugs can perhaps get through as well).

adolph 3y ago
That is an interesting explanation. I won’t summarize other than to say that as someone who might have added UV next hardware cycle, there were several A-Ha moments. Well worth watching.
- mensetmanusman 3y ago
  UV is more than UV, there is UVA UVB UVC, etc. Some UVC generates Ozone, some do not. Wavelength and spectral Q factor matter. It’s possible to have a UV system that does what you want without the downside, but it does cost.
  - throw0101a 3y ago
    > It’s possible to have a UV system that does what you want without the downside, but it does cost. The main downside is that you are introducing a chemistry experiment into your ventilation system. If you want clean air, then (a) cycle in/outside air at ASHRAE-recommended volumes, and (b) use high-MERV/HEPA filters. In wildfire zones and in wildfire season you can perhaps add charcoal filters—if your system is designed to handle the pressure/head loss—to get rid of the smoke-y smells.

ZeroGravitas 3y ago

It doesn't take away from the general thrust of the post but it's interesting that lack of quality sewage treatment leading to it being dumped into rivers is thought to be a key issue in the current British council voting: Local elections 2023: How sewage topped the political agenda https://www.bbc.co.uk/news/uk-politics-65190097 https://www.bbc.co.uk/news/uk-politics-65190097

makomk 3y ago
The Victorian-era sewage systems described in this article are actually one of the key reasons that sewage is ending up in rivers and the sea in the first place. Notice how they worked: sewage was collected, pumped, and dumped downstream of London. It was not treated. Most of the UK's sewage treatment is retrofitted to sewage systems that were never designed to have it. This causes various problems, the main one being that rainwater drainage and sewage are mixed in many areas and this overwhelms the sewage system during heavy rain. (As for why it became a key election issue, well, basically the British press lied to make it one - the BBC included. They made an increase in monitoring of sewage discharges look like a massive increase in sewage discharged whilst tricking people into thinking monitoring had got worse by deceptively-worded articles about the few overflows that weren't monitored yet, they told people the Environmental Agency was lying about only recently being able to measure the full extent of sewage discharges based on a hnadful of previously-recorded incidents, they claimed other European countries which still had Victorian-esque sewage systems with no treatment plants that just pumped directly into their rivers and seas in some urban areas were doing a better job, and so on.)
- brianmcc 3y ago
  It also seems another Brexit issue - treatment chemicals being that bit harder to bring in: https://www.thelondoneconomic.com/news/brexit-to-blame-for-uks-sewage-problems-332728/ https://www.thelondoneconomic.com/news/brexit-to-blame-for-u...
  - Mvandenbergh 3y ago
    Not in practice, no. Companies were provided with a regulatory position statement from the EA that they would not usually be prosecuted if they ran out of treatment chemicals due to something that wasn't their fault. In fact, there never was a shortage due to either Brexit, Covid or a combo and this was never used.

panchtatvam 3y ago

[flagged]

sdfjkl 3y ago

The Thames is still very much opaque. Not near-opaque.

dgroshev 3y ago
It's just silt churned up by high tides. When you're on the river, you can easily see that bits shielded from the turbulent flow, where the silt has a chance to settle down, are crystal clear. You can also see eels, seals, cormorants, kingfishers, seagulls of all kinds, and lots of life generally. It's great.

MontyCarloHall 3y ago

If, hypothetically, we dramatically reduced the prevalence of airborne disease, what would the effect on our immune systems be? Some hypothesize that living in too sterile an environment leads to autoimmune diseases, since the immune system is calibrated to a certain baseline level of activity, and will turn on the body if this level is not met by external pathogens.

GordonS 3y ago
If that turned out to be the case, maybe we could have annual "vaccines", which would exist only to trigger anti-viral activity?
mrob 3y ago
If it turns out that actual pathogens are necessary, and we can't use the kinds of harmless bacteria that get sold as "probiotics", it would still be better to identify pathogens with optimal risk:benefit ratio and determine the optimal dose. Exposure to wild pathogens varies widely, so very few people will be lucky enough to have the best exposure.
Symmetry 3y ago
Our hunter gatherer ancestors living in bands suffered from drastically fewer respiratory diseases than we do, you need a large connected population for something like the flu to survive in a human population in the long term. The issue with sterile environments is about the lack of random bacteria, not human adapted pathogens.
- MontyCarloHall 3y ago
  That’s likely true, but our hunter gatherer ancestors also saw way more water and foodborne pathogens, not to mention continual parasitic infections to more than make up for the relative lack of immune system stimulation from a lower level of airborne pathogens.

leblancfg 3y ago

I wish the author had spent more time to unfold the public vs private debate here: >if a country installed all the measures I mentioned As opposed to the wastewater infrastructure in the first section that can be mandated and put in motion by a government, it's up to individuals and institutions to install the measures. This makes implementation significantly more challenging, as it relies on the collective efforts and cooperation of numerous parties, each with their own priorities and resources. Government-led initiatives, on the other hand, can be more easily streamlined and enforced, ensuring a higher degree of compliance and effectiveness.

gizmo686 3y ago
Governments are perfectly capable of setting building codes. This isn't an instance fix, but would be effective over the long term. Governments also have a well established mechanism to incentives faster compliance: tax refunds to offset the cost of improvement. We already offer such incentives for energy efficiency improvements (some of which actively harm ventilation). From an engineering perspective, the clean air proposals are much easier than wastewater management. There is no centralized infastructure needed. Every building can be upgraded independently, and the people in that building will see an immediate benefit. Further, the upgrades needed are typically not that major. Most building already have a forced air HVAC solution. These solutions already have inline air filters, and often already have the ability to actively pull in fresh air. We can get significant improvement my simply leaving the fan on these units running regardless of if they are actively heating/cooling; and using already available high quality filters. In that subject, a quick PSA to home owners: if you have not changed your HVACs filter recently, you probably should.

EGreg 3y ago

I designed this two years ago… https://uvspinner.com https://uvspinner.com Tried to get NYC officials to get interested — went through some channels that my friends had. Nothing. Anyone here interested in doing it?

photochemsyn 3y ago

Clean air and water issues are not limited to biological contamination with pathogenic microbes and viruses, and some of the suggestions (ensuring good ventilation) run into problems when external air quality is dangerously bad (when health agencies tell people to keep their windows closed). It's not entirely unlike water issues, for example the Thames was used to dispose of wastes from animal slaughtering, leather tanning, production of dyes from coal tar, alcohol distillery wastes as well as for human excrement. Cleaning up air quality requires addressing these issues as well (coal power plants, diesel truck emissions, agricultural dust, etc.).

kazanz 3y ago

As others of posted the big difference here - and also the big challenge - is that indoor air is a definitively NOT a public service. It requires a slew of regulation, enforcement bodies, and - from a US perspective - profitability for litigation attorneys. Again with a US slant, ADA is the obvious legislative model for similar clean air regulations. So it's possible, just more challenging than public sewage.

xmdx 3y ago

Other than the obvious benefits like avoiding a pandemic this hits close to home. My dad passed away 2 weeks ago from Pulmanory Fibrosis. A respiratory disease without a cure and one where we know very little about the causes. Better air quality would drop cases, relive strain on the health system and just let people live longer. Its something I want to help with where I can. I hadn't even thought about the obvious step of raising awareness about air quality.

markrankin 3y ago

“The expectation of clean water in wealthy countries is enabled by technology and infrastructure; like effective sewage systems and water treatment facilities. But to a large extent it is also enabled, and was initially bootstrapped, by sound policymaking and regulation. Regulation requires verification.” Regulation of water does not require verification. We live on a planet where clean water is abundant and cannot escape the planet’s atmosphere. Why you think we need to measure how this is verified is beyond the beyond’s. Here’s a wiki page reference if you need help measuring how much water exists on Earth: While the majority of Earth's surface is covered by oceans, those oceans make up just a small fraction of the mass of the planet. The mass of Earth's oceans is estimated to be 1.37 × 1021 kg, which is 0.023% of the total mass of Earth, 6.0 × 1024 kg. An additional 5.0 × 1020 kg of water is estimated to exist in ice, lakes, rivers, groundwater, and atmospheric water vapor.[20] https://en.m.wikipedia.org/wiki/Origin_of_water_on_Earth#Earth's_water_inventory https://en.m.wikipedia.org/wiki/Origin_of_water_on_Earth#Ear...

twojacobtwo 3y ago
There are only so many ways and places to extract clean water for large populations in an efficient way. Once water is used, it has to go somewhere, which is back into the water system. Every person/population downstream then no longer has 'clean water' without verification. We could have 10x the clean water we have now and we would still have to consider this aspect.

danans 3y ago

> An aside: ventilation plus filtration is the major reason that the risk of Covid infections on flights was and is so relatively low: air in the cabin is replaced every couple minutes, fresh air is drawn from outside the plane, and mixed with recycled air passed through HEPA filters. IME, the most effective thing to do in a house is filtration inline with the intake of a ventilation system. In my case, I have an activated carbon and a MERV13 filter that cleans incoming outdoor air just before it's fed to the heat recovery and distribution system. You still need a separate recirculating filtration system to deal with particulates generated within a house.

steviedotboston 3y ago

I don't think the clear water and clear air analogy works very well. They seem to be very different cases. Keeping clean and dirty water separate is trivial and requires no more advanced technology than plumbing. Keeping clean and "dirty" air separate is impossible. We will always breathe air that includes pathogens. That isn't to say there should be efforts to improve air quality, but I think a lot of times analogies like this oversimplify things. It's easy to eradicate cholera through cleanliness and modern plumbing, but we will never eradicate airborne viruses through air filters and masks.

JBorrow 3y ago
"Cleanliness and modern plumbing" include massive water treatment facilities, digging up every street, laying billions of miles of pipe.
- steviedotboston 3y ago
  The main effort is separating drinking water and waste water. Keeping them as far away as possible and preventing contamination. There is no way to do that with air. The air we breath in and the air we breath out will always mix. The best we can hope for is some amount of dilution with fresh air/filters, bit at the end of the you are never going to be able to achieve the same thing with airborne viruses that we did with waterborne illnesses. The flu, covid, etc are with us for the long haul.
gridspy 3y ago
It's a good analogy. Invest in infrastructure to extract dirty air and deliver clean air into living spaces. Provide suitable standards and technologies to do so. It would be cheaper than the infrastructure to extract dirty water and deliver clean (treated) water because we don't need to transport the air anywhere near as far and air treatment is simpler.

vondur 3y ago

I wish more of the funds that were allocated to combat Covid were used to install better air handling systems in public areas here in the US. The education side received billions of dollars, which if used for better air would help keep kids more kids from getting sick and then bringing it home to families.