[HN Gopher] Analyzing Carbon Dioxide levels while attending IETF... ___________________________________________________________________ Analyzing Carbon Dioxide levels while attending IETF-115 in London, UK Author : zdw Score : 112 points Date : 2022-11-12 18:05 UTC (4 hours ago) (HTM) web link (www.isi.edu) (TXT) w3m dump (www.isi.edu) | peteforde wrote: | Two years ago, I was living in a house which I suspected had | terrible air circulation, leading me to buy an Awair Element. It | is not cheap - at $299, a small army of RasPi hoarders will | dislocate their jaws, barking with with rage - but I genuinely | love it. https://www.getawair.com/products/element | | The immediate impact was that I became super nerdy about air | quality, specifically CO2. It was indeed super high in that | house; opening the window helped, but it led to me moving to a | place with much better air quality in general. Nature in view, | lots of green plants, and an HRV system. I can get <600ppm with | the windows closed. | | TL;DR: if you ponder complex things for a living, you owe it to | yourself to get nerdy about CO2 in your sleep and workspaces. | Havoc wrote: | Anybody know what the actual sensor inside that device is? Spec | sheet doesn't seem to say | bloggie wrote: | According to some quick duckduckgoogling for "aranet4 tear | down" it could be this: https://senseair.com/products/power- | counts/sunrise-hvac/ | nicoburns wrote: | This seems to pretty well justify my recent approach to covid | precautions which is to wear an N95 mask on public transport (and | nowhere else), and to try and avoid social situations in densely | packed rooms where practical. | MuffinFlavored wrote: | does wearing a mask stop from spreading if you have it or stop | you from getting it from others or both? | VancouverMan wrote: | Some long-term, large-scale studies of the effects of | widespread public masking have been performed recently. | | For example, one lasting over 1.5 years was done in the | province of Ontario, Canada, involving approximately | 15,000,000 participants, in environments ranging from dense | urban settings to sparse rural ones. In Ontario's largest and | densest population center, Toronto, the duration this study | was about 2 years in length. | | It was conclusively demonstrated that widespread public | masking does not prevent infection, and it does not prevent | transmission, of airborne viruses. | | It was conclusively proven that such masking did cause | accessibility problems, it did cause significant social | disruption, and it did cause environmental damage, among | numerous other harmful effects. | HyperSane wrote: | Can you provide a link to this study? | | If masks don't work then why do surgeons wear them? | samatman wrote: | To the latter question, it's to prevent droplets of | spittle from landing on exposed tissue. | | There are pathogens which spread by droplets, rather than | aerosols, the Sars2 virus doesn't happen to be one of | them. Yes, if you spit directly onto an open wound or | mucous tissue, but it doesn't live long on surfaces, and | the droplet-fomite route is how that vector of infection | works. | lucb1e wrote: | They're joking that there were infections in the city | despite mask requirements (surprise) and that mask | requirements caused "significant social disruption".... | At least I hope it's supposed to be a joke. | Baeocystin wrote: | An N95 does both, to a highly effective degree. | [deleted] | timr wrote: | We have no good evidence for this claim. The only studies | involving n95 masks and respiratory illness were conducted | in hospital settings (i.e. don't reflect "normal" life), | have high risk of bias (i.e. were small and were not | randomized, controlled trials), and have shown mixed | results. | | This is the WHO review that summarized the existing | evidence for masks at the start of the pandemic. There were | 4 studies on n95 masks in hospitals: | | https://www.thelancet.com/journals/lancet/article/PIIS0140- | 6... | | Additionally, this is the most comprehensive review of mask | literature I am aware of. It explicitly states that: | | > At least ten studies evaluate the clinical efficacy of | different types of masks compared to one another, but | without a no-mask control group most provide little insight | into mask efficacy. | | > Four RCTs, four meta-analyses, and one prospective cohort | study found surgical masks were non-inferior to N95s for | protection against respiratory infections, and one found | evidence that N95s provide greater protection than medical | masks against self-reported clinical respiratory illness | but not ILI. However, a recent review found that evidence | that N95s protect healthcare workers from clinical | respiratory infections at all is "low quality". One meta- | analysis of particular note, an April 2020 preprint of a | Cochrane review of clinical evidence for both surgical and | N95 masks, "did not find any differences in the clinical | effectiveness of either type of mask in the setting of | respiratory viral infection transmission to healthcare | workers," although the review's final November version | omitted this language. | | https://www.cato.org/sites/cato.org/files/2021-11/working- | pa... | | We simply don't know if n95 masks provide any protection -- | personal or otherwise -- in the real world. That is the | only honest answer to the parent's question. Everyone who | claims otherwise is extrapolating from laboratory | experiments, low-quality observational data, or (this is | probably the most common) hearsay. | azakai wrote: | > We simply don't know if n95 masks provide any | protection -- personal or otherwise -- in the real world. | | That is simply not true. | | First, doctors and researchers consistently say that N95s | are known to provide protection against Covid. | | Second, this is the first google result on that topic: | | https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm | | Quoting from that CDC page: | | > What is already known about this topic? | | > Face masks or respirators (N95/KN95s) effectively | filter virus-sized particles in laboratory settings. The | real-world effectiveness of face coverings to prevent | acquisition of SARS-CoV-2 infection has not been widely | studied. | | > What is added by this report? | | > Consistent use of a face mask or respirator in indoor | public settings was associated with lower odds of a | positive SARS-CoV-2 test result (adjusted odds ratio = | 0.44). Use of respirators with higher filtration capacity | was associated with the most protection, compared with no | mask use. | | > What are the implications for public health practice? | | > In addition to being up to date with recommended | COVID-19 vaccinations, consistently wearing a | comfortable, well-fitting face mask or respirator in | indoor public settings protects against acquisition of | SARS-CoV-2 infection; a respirator offers the best | protection. | | You can say that that might be just correlation, but as | those quotes mention, we do know how N95s work: they | filter viral particles. That is easy to prove in lab | settings. Real-world settings involve more factors, like | how well-fitting the mask is, but it would be very | surprising if a good N95 properly used did not offer any | protection! | | N95 masks work. It's a good idea to wear one when | relevant. | andbberger wrote: | nonsense, N95s are highly effective and if you want to | make a good faith argument that they're not try citing | the new england journal of medicine and not the fucking | cato institute, good lord | HyperSane wrote: | Why do surgeons wear masks? | MobiusHorizons wrote: | Not an expert, but as I understand it, surgeons could be | exposed to much more than airborne viruses (bacteria, | bodily fluids, etc). So masks would be worn for more | possible reasons. It's a good question though, I hope | someone knowledgeable answers it. | azakai wrote: | Surgical masks and face shields are indeed designed | specifically to protect from fluids. That is very | important too. | | Separately from that, when there is a risk of airborne | transmission as there is with Covid, doctors and nurses | will wear appropriate masks like N95s. | stuaxo wrote: | I need to start using my Aranet 4, which case did you buy, I | already dropped mine on the floor once and it felt lucky it | didn't break. | MobiusHorizons wrote: | Not the op, but it looked like the case that comes with Chinese | iems (fancy earbuds) | bloggie wrote: | I wonder if he got COVID. | cobertos wrote: | The anecdote about being sleepy on a plane makes me wonder if we | couldn't just modulate our CO2 intake as a sleep aid. I find it | _incredibly easy_ to sleep on a plane, and I generally have a | very hard time with sleep due to brain not turning off. | | I think it would be interesting to see if there's any correlation | between restful sleep and CO2 levels too. Maybe change the CO2 | level to higher to induce sleep, and then fall asleep, and then | bring it back down to have a nicer sleep. | avian wrote: | I would hate to have a machine in my bedroom that is capable of | raising the CO2 level. I don't think anyone could convince me | that it would not decide to suffocate me at midnight next 29th | February or something, regardless of its safety features. | MobiusHorizons wrote: | I think the general idea would be to have a device that | typically reduces co2 level through ventilation, and just | turn it off at night. That would let your normal breathing | add the co2. | lucb1e wrote: | I wouldn't like to take hours for my sleep aid to kick in, | if I would need such a thing. | | Instead of the room, maybe a little device called blanket | could be used, but I don't know how reliably people get out | from under that if they get in the habit of associating | under blanket = sleep = good, because it certainly wouldn't | be good to be under that all night. | dzhiurgis wrote: | Normally your reflexes kick in when you start suffocating | from co2. Nitrogen tho... | | I wonder if sleepiness is some sort of evolutionary reflex or | actually caused by co2 in body. | lucb1e wrote: | > a machine in my bedroom that is capable of raising the CO2 | level. | | It doesn't have to be so complex. It could be as simple as a | little canister that you simply take up, open in the bedroom, | and empties itself (for a room of a given m3), then turn | ventilation on low and go to sleep. The CO2 level would spike | to the target level in a minute or so (presumably not a | dangerous level, just one that makes you temporarily less | smart and attentive) and then has some half life depending on | your ventilation method. | | I'm not a doctor, I have no idea if it's smart to raise the | level to 3, 4, idk how many thousand ppm are being proposed | for this, even if it's for only 30 minutes or whatever. Just | saying, I don't see obstacles to doing this safely if the | action itself is safe. | nicoburns wrote: | Does anyone have any idea why CO2 levels would spike so high when | a plane takes off? | akira2501 wrote: | I'm not exactly sure, but during take off the "packs" are | typically disabled. This removes air conditioning and probably | lowers the amount of air that would be circulating when they | are enabled. | sokoloff wrote: | The air cycle machine ("packs") are turned off if maximum | power is needed (as their use requires bleed air, which takes | power from the engine). | mleonhard wrote: | The author's DEN-LHR flight was on a Boeing 787 aircraft, | which use electrically-powered air compressors [0]. They do | not draw air from the engine. | | 787 maintain internal air pressure equivalent to 6,000 feet | of elevation. All other commercial aircraft maintain 8,000 | feet air pressure. I think most of my discomfort from long | flights is due to altitude sickness. The only time I have | slept on a long flight and awakened refreshed was on a 787. | | Jet engines use a neuro-toxic lubricant. Occasionally, some | of this enters the cabin through the compressed air feed | and poisons the passengers [1]. 787 passengers don't have | this risk because the planes don't draw air from engines. | | [0] https://en.wikipedia.org/wiki/Boeing_787_Dreamliner#Int | erior | | [1] https://pubmed.ncbi.nlm.nih.gov/24713335/ | Baeocystin wrote: | I sometimes take commuter flights between San Jose and | San Diego, which are almost always Southwest 737's, and | I've only seen 6,000 feet on the barometer when I've | checked, probably about half a dozen times out of | curiosity. FWIW. | MichaelZuo wrote: | So then what explains the mysterious lack of air | circulation during takeoffs on the 787? | Reason077 wrote: | > _" I think most of my discomfort from long flights is | due to altitude sickness."_ | | Seems unlikely. Actual altitude sickness is generally | considered to occur only above 8000 ft, and above 10000 | ft is where the real risk begins. Symptoms generally | don't appear until 12-24 hours after climbing to | altitude. Also, risk of altitude sickness increases with | physical exertion, and you're probably not doing much of | that on a plane! | pstrateman wrote: | When planes take off there's often a strong smell of exhaust. | | Presumably the external air mix is just full of exhaust before | they're at speed. | pornel wrote: | Or perhaps external air intake is closed/limited because of | the smell. | etrautmann wrote: | Almost certainly the effect of combustion of jet fuel - which | is not a good proxy for Covid risk of course. This article | seems to conflate those two a bit, though the data is | interesting | jeffbee wrote: | Bleed air is taken from the compressors before the combustion | section, so it's probably not CO2 from combustion. If it was, | it would also be humid and stink of kerosene, which it's not | (cabin air is notoriously dry except on the 787) and doesn't | (fuel smells in cabins have other causes). | | CO2 rises in the cabin during taxi because the bleed air | system is not effective while the aircraft is moving slowly. | This is another good feature of the 787: cabin air | conditioning works adequately even with the aircraft at rest. | ahaucnx wrote: | We do indoor air quality monitoring and see very different | results across buildings. | | The biggest differentiator is if the building has mechanical | ventilation and to what extent this mechanical ventilation uses | fresh air vs internal circulation. | | In unventilated crowded spaces like e.g. classrooms, we regularly | see CO2 exceeding 3500 ppm. [1] | | However in classrooms with a well designed ventilation system you | can keep the CO2 < 1000ppm during the whole school day. | | What the author did in his hotel room to turn on the fan or play | around with the A/C settings is a good idea but many hotels Hvac | systems do not draw in sufficient fresh air and you will see high | CO2 developments. | | [1] https://www.airgradient.com/open-airgradient/blog/we- | measure... | Reason077 wrote: | Perhaps CO2 sensors should be part of the standard HVAC sensor | suite in big buildings? | | That is, along with measuring temperature, the sensors in each | room should also measure CO2 levels. If CO2 is rising, fans can | be turned on/turned up to bring more fresh air into the room. | ArchitectAnon wrote: | They are legally required in the primary bedroom of all new | build houses in Scotland, possibly also in England and Wales. | Reason077 wrote: | Huh? Really? Are you thinking of Carbon Monoxide detectors, | perhaps? Sometimes these are incorrectly called "CO2 | detectors". | sampo wrote: | Appears to be true: | | > CO2 monitoring equipment should be provided in the | apartment expected to be the main or principal bedroom in | a dwelling where infiltrating air rates are less than | 15m3/hr/m2 @ 50 Pa. | | https://www.gov.scot/publications/building- | standards-2017-do... | | Well done, Scotland. | [deleted] | icelancer wrote: | 3500ppm? That would imply an average CO2 level well above | 1000ppm. No wonder why it's impossible to stay focused in | lecture halls... | MichaelZuo wrote: | Yeah, that really makes me rethink my entire education | experience... | JohnBooty wrote: | ...you could always distract yourself by thinking about all | of the political and military decisions that have been made | throughout history, affecting millions and billions of | human lives, in stuffy cramped rooms with excessively high | CO2 levels. | | ...wait, that's not helping? | mistr0 wrote: | I teach in a UK secondary school; the building with my | classroom in was built in the 1960s, as many of them are. | Ventilation is poor and after a 60-minute lesson with 25-30 | students (age ~15) CO2 will be at 2000-2500 ppm. If there are | back-to-back lessons it'll be 3000-3500. I can open some doors, | but they lead to connected classrooms so this is only practical | if those rooms are not in use. Retro-fitting an AC system is | likely possible, but expensive. | Arbortheus wrote: | Air quality should be a bigger consideration in schools, I | bet students will be more attentative and able to focus | better without high CO2 levels. We should create the | conditions to allow them to succeed. | FollowingTheDao wrote: | This is not going to change anytime soon. No one really cares | about staying alive; climate change, diet, COVID. And COVID is | now endemic and a pandemic. | | So either quit your job or learn about staying healthy when | exposed to viruses that deplete zinc and other nutrients. | | Zinc deficiency lowers Tertrahydrobiopterin, which lowers coupled | NOS, which lowers your immune system (NOS2) and gives you | hypertension (NOS3) and makes you mental (NOS1). The Lower zinc | also gives you diabetes. PubMed links for anyone who cares, but | you probably don't. | stuaxo wrote: | Please post the links, I feel like I live i a weird opposites | world, where in the sane world we would have dealt with Covid | by now, and have sorted out clean air in our public spaces (and | to some extent homes too). | FollowingTheDao wrote: | EDITIED TO ADD: | | Before taking Zinc get your Serum Zinc and RBC Zinc levels | tested. Easy to do in the US if you have some money. | | Also get your Serum Copper and Ceruloplasmin tested since | taking zinc at high dose for a while will lower copper since | zinc creates Metallothioneins that capture the copper in the | intestine before it can be absorbed. | | -- | | Hey, thanks for being curious! Science! | | Zinc and Tetrahydrobipoterin: | | https://pubmed.ncbi.nlm.nih.gov/31732151/ | | The Gene GCH1 is central to making Tetrahydrobiopterin and | uses zinc as a cofactor. | | https://www.uniprot.org/uniprotkb/P30793/entry | | The zinc coupling of NOS via GCH1: | | https://www.ahajournals.org/cms/asset/2cc8b7a0-a31a-4759-bc8. | .. | | Uncoupled NOS makes a lot of superoxides, BAD!: | | https://www.liebertpub.com/cms/10.1089/ars.2013.5566/asset/i. | .. | | Here is a diagram of all the enzymes that need | Tetrahydroibiopterin (BH4): | | https://www.researchgate.net/figure/Metabolic-pathway-of- | BH4... | | NOS2 and the immune system: | | https://pubmed.ncbi.nlm.nih.gov/24477906/ | | https://www.jimmunol.org/content/167/5/3000 | | COVID and NOS2: | | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7754882/ | | Zinc and hypertension: | | https://pubmed.ncbi.nlm.nih.gov/32090294/ | | NOS3 uncoupling and hypertension: | | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4816601/ | | NOS1 and psychosis: | | https://pubmed.ncbi.nlm.nih.gov/12140778/ | | Zinc and Diabetes: | | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6984028/ | | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407731/ | | And the BIG one, Zinc and Heart Arrhythmia, you know the | thing that all these your people are suddenly dying with? | https://publichealth.jhu.edu/2022/covid-and-the-heart-it- | spa... | | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7328074/ | | You know, they are avoiding looking at zinc, purposefully, | and I feel it is a crime against humanity. Seriously. | dzhiurgis wrote: | I bought Qingping and it's best and worst purchase at the same | time. On one hand it proved you need to open windows frequently | and it's cool to monitor co2 in public places. On other hand it's | depressing good ventilation won't happen for decades if not | centuries and it's unfeasible to open windows in super cold, hot | or humid climates. | | Also, my measurements were different from author. On a plane co2 | was pretty bad until AC was turned on (usually around midway | boarding), then it hovered around 1000ppm. On a train it also | stayed around 1000ppm. | jeroenhd wrote: | One thing I wonder about, especially seeing the numbers during | take-off: how well can an Aranet 4 sensor deal with changes in | pressure and temperature? | | As I understand it, these sensors require (sometimes lengthy) | calibration to remain accurate. | | For automatic calibration, the device needs to be in fresh air | for 30 minutes, no closer than 1 meter from the nearest person. | There is also a manual calibration method. I don't know how often | calibration is necessary, but I also think this use case may not | be what the sensor was designed to do. | phphphphp wrote: | I think you might have it the wrong way round, as the product | information mentions fresh air as a requirement for manual | calibration, not automatic. | | "If a drift of the CO2 measurements occurs, calibration feature | of the device should be used. Auto calibration mode is | utilizing ABC algorithm whereas Manual calibration mode demands | sensor to be exposed to fresh air." | | "CO2 sensor of the device is calibrated at standard atmospheric | pressure. CO2 readings are pressure compensated and comply with | the specifications down to 750 hPa. If the device has to be | used at high altitude for a prolonged period of time, manual | calibration of the unit should be performed for optimal | performance. It is not intended to use the device higher than | 4000 m (13 000 ft) above the sea level." | | https://cdn.bfldr.com/FS48XT6B/at/k9b9wjnv8f455crkp7846j/Ara... | mox1 wrote: | yea I recently started monitoring my homes CO2 levels with some | DIY sensors. You need to enter your elevation above sea level | or have a pressure sensor hooked up. | | So if the op set a static pressure I assume that would affect | the readings a lot. | | Calibration is also just the sensor looking for the co2 floor | (ie the lowest level possible). You need to do this weekly or | monthly maybe..? | | Auto calibration just sets the lowest level it has recently | seen as the floor. | ahaucnx wrote: | What was your experience with the DIY monitor that you build? | | I am asking because we maintain an open source / open | hardware indoor air quality project [1] that we continuously | update and I am interested to learn about missing features we | might have. | | Did your build have a dedicated pressure sensor? | | [1] https://www.airgradient.com/open-airgradient/kits/ | ahaucnx wrote: | From our experience normal temperature fluctuations do not | impact the accuracy. However many NDIR sensors do not like | vibrations and get inaccurate after being moved around. Then | you need to wait for the automatic baseline calibration to kick | in or do a manual calibration. | | The Aranet 4 uses the Senseair Sunrise that is more resistant | to vibrations. | | However I could imagine that sudden air pressure changes could | have an impact on the measurement accuracy. | jcdavis wrote: | The Aranet has both temperature and pressure sensors, though | how those are used as part of the CO2 calculation (if at all) I | don't know | iudqnolq wrote: | Many cheaper CO2 sensors require frequent calibration. Often | they just assume the weekly min reading is fresh air (420), or | something like that, which is extremely imprecise. | | I bought the Aranet4 because it claims not to need | recalibration except in exceptional circumstances. They suggest | keeping the factory calibration unless you can guarantee a | proper controlled environment. I don't have the equipment to | test their claims, but the readings have stayed plausible for | months with no calibration. | | Edit: Note that if you're using your CO2 sensor as a proxy for | the rate at which the air in an occupied room is replaced with | fresh air the calibration imprecision doesn't matter. You're | probably eyeballing the second derivative over the course of | minutes-to-hours. | | I use my CO2 sensor for that, but I also care about the | absolute. There's some evidence that normal rates of CO2 in | modern buildings make your brain foggy. I'm trying to figure | out if a program better when I use various interventions to | increase fresh air. | lucb1e wrote: | Easy way to test pressure changes: have a small room with a | well-fitting door. Ventilate it well, then put the sensor in | there. Open and close the door fast (mainly to/from the | almost-fully-closed position) to get pressure changes. The | pressure will only change briefly, but if it didn't keep up | with the airplane, it definitely won't keep up with this. | Depending on how frequent the readings are, at some point | while opening/closing you'll get readings during a change and | an outlier if it's sensitive to this. (You can also fashion | something with e.g. cling wrap and stuff, but this seems | simpler and you don't use throwaway plastic or anything.) | | I've used a barometer on a plane before. When they turn on | the pressurization system, it's very clearly noticeable, but | not a huge change. (A train in a tunnel is worse.) I'd expect | this would be a similar effect. | ahaucnx wrote: | Yes the ABC is often an issue and can lead to an | underestimation of the CO2 values. | | This often happens in non ventilated and relatively air tight | rooms. | | We collect air quality data from many schools and see this | happening in some classrooms that even over the unoccupied | time during the night the CO2 will not reach ambient levels | the next morning. | p1esk wrote: | What do you think about Air Quality Egg product [1]? How | does it compare to Aranet4? How do these two compare to | AirGradient ONE product? Which chemicals are most important | to monitor in a typical 40yo house in Florida: CO2, CO, | NO2, SO2, O3? | | [1] https://airqualityegg.com/shop | djmips wrote: | I have a few thoughts. | | One: that even if the C02 seems fine, if the din of the room | means everyone is shouting then viral dispersal | | will be much higher. | | Two: it seems like having fresher air, will be more costly in the | winter unless people can put up with lower temperature. | | I wonder how effective an airplane filter really is with regard | to viruses. | | Should buildings and enclosed spaces be redesigned to include | better filtering and at what running cost will that be? | kortilla wrote: | > wonder how effective an airplane filter really is with regard | to viruses. | | Airplanes are far better than any normal indoor building space. | It's a constant blend of outside air that means the entire | cabin's volume of air is gone within something like 5 mins. | sampo wrote: | > Airplanes are far better than any normal indoor building | space. | | But only when they fly. When you are waiting that 30 minutes | sitting in the plane after boarding, the fraction of re- | breathed air can get high. People have measured 2000 and 4000 | ppm CO2 readings. | MichaelZuo wrote: | Looking from the chart it seems like the CO2 levels were | elevated for the entire flight? | | As in it never dips below 1200pm on either the short haul | or long haul flight. | | Also with the caveat in the article: "Note that the graphs | below aren't calculated for altitude adjustment. Since | planes are generally pressurized to an equivalent of 8000 | feet, and senor drift is typically 3 per 1000 feet of | elevation, it means that while in the air the CO2 levels | are likely $24% higher than shown on the graph." | | It seems the logged numbers are underestimating it. | ThrowawayTestr wrote: | This level of obsession over covid is not healthy. | NotYourLawyer wrote: | CO2 levels are interesting in their own right. But imagine being | a vaccinated person, wearing N95 masks, and still being this | afraid of covid. | | Lose the mask and hire a therapist. | Reason077 wrote: | > _" Conclusions ... don't ride the buses is probably an early | and obvious one."_ | | Yes, the air quality on London buses is consistently terrible on | cold days. There is very little ventilation in those buses other | than "open the windows", and when it gets cold people don't do | that. Often it seems like you're not only breathing in everyone | else's food smells and stinky breath, but road fumes and dust as | well. | dzhiurgis wrote: | Do brits also have "cold air and draft causes common cold" too? | Arbortheus wrote: | Yes, but it's something your grandparents might say rather | than a widely held belief. I think people nowadays are clever | enough to know that colds are a transmissible infection. | Reason077 wrote: | Yeah. But most bus passengers still dislike being cold more | than they dislike stale air. So most of the windows are | usually closed. | dzhiurgis wrote: | Typical response here is "but cold air weakens immunity"! | thrown_22 wrote: | This thread is a perfect example of why normal people don't take | obvious repercussions. | | The covid tangent is largely bullshit. You will get it regardless | of what precausiosn you take. | | The point is that in a large number of venues we have CO2 levels | that are actively detrimental to your ability to think. This is a | problem that we need better ventilation to solve. That bedrooms | had the poorest air quality is something I wasn't expecting and | will likely buy my own sensor to measure. | sampo wrote: | > (it turns out my office really needs a fan as the single plant | on the opposite side of the room is failing to keep up even with | my sedentary exhaling) | | A human exhales about 1 kg of CO2 in a day (24 hours). That is | about 270 grams of C. You'd need enough plants to sequester 270 | grams of carbon, or about 0.5 kg of biomass (dry weight) per day, | to "keep up" with your exhaling. This is much more than one | houseplant. | aaron695 wrote: | thadk wrote: | Several of us have built visualization tools which produce output | a bit similar to the one in this article for the aranet4 unit. | These can be found linked from: | https://observablehq.com/@thadk/aranet4-explorer. Works best with | the iPad app on an M1/M2 macOS computer. | | There are also several other ways to get the output such as a | bleak project on GitHub | (https://github.com/Anrijs/Aranet4-Python). | rufus_foreman wrote: | I guess when I was born, background CO2 was around 330 ppm. Is | there anything I can do to breathe air like that again in my | house? | yourMadness wrote: | You could add 80% nitrogen and 20% oxygen to dilute the CO2 to | the desired level. | | But that's not exactly easy or cheap. And dangerous when done | wrong. | rufus_foreman wrote: | How exactly would I do that? | | I'm OK with not easy, not cheap, dangerous, and done wrong. | samatman wrote: | As long as you're okay with not cheap, Alfaintek has you | covered. | rufus_foreman wrote: | Do I have to relocate to the EU? | tpmx wrote: | > background CO2 was around 330 ppm. | | When were you born and where did you get that number from? | rufus_foreman wrote: | Around 50 years ago. I was looking at this chart: | https://www.climate.gov/news-features/understanding- | climate/... | tpmx wrote: | thanks! | ThrowawayTestr wrote: | Get a co2 scrubber or a bunch of plants. | xenonite wrote: | Plants increase CO2 levels at night, though. Photosynthesis | unavailable then, thus they use dark breathing, setting free | CO2. | jefftk wrote: | I think maybe some plants do their carbon fixation at | night? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC540897/ | jefftk wrote: | You would need absurd numbers of plants. You breathe out | ~11L/hr CO2, which is ~22g. Over a day this is ~0.5 kg. So | your plants would need to be getting collectively 0.5kg | heavier daily by pulling CO2 from the air just to balance out | your own breathing, let alone the CO2 coming in from the | outside. | rufus_foreman wrote: | What's the math if I have a cat? | jefftk wrote: | Maybe the cat weighs 5% of what you do, and respirates 5% | as much as well? In which case it's within the margin of | error of the above. | rufus_foreman wrote: | I'm from the midwest. The cat weighs like half a percent | of what I do. | jefftk wrote: | A really small housecat weighs 5lb. For that to be 0.5% | of your weight you'd need to be half a ton, at which | point my math above is a bit low. | rufus_foreman wrote: | All right so do the math. | | Have you ever been to the midwest? | rufus_foreman wrote: | Is that a thing? Like a CO2 scrubber you can run at home? | | That's what I want. | Reason077 wrote: | What you really want is a heat exchange / heat recovery | ventilation system. Brings in fresh, filtered air from | outside, and warms it up by swapping heat with the stale, | warm air that it removes. | rufus_foreman wrote: | If the air comes from outside, it's 450 ppm CO2. I want | 330 ppm CO2. | | Is that possible? | ThrowawayTestr wrote: | They exist but you'd have to contact a commercial HVAC | supplier. Easier just to get a bunch of plants. | batch12 wrote: | Open a window? | layer8 wrote: | Unlikely: https://imageio.forbes.com/specials- | images/imageserve/629c7e... | | That's in the middle of the Pacific Ocean. | rufus_foreman wrote: | It's 420 ppm outside now. | ad404b8a372f2b9 wrote: | Background ppm is no longer at 330, so opening a window would | not get you there. You would need to keep the window closed | and remove more CO2 than you produce. | batch12 wrote: | Fair point. I wonder if there is a big difference depending | on where one lives. For instance, if one were to live in | the country, surrounded by trees... | rufus_foreman wrote: | Yeah that's my question. How would I remove more CO2 than I | produce. | | I've got the window closed, I have a few houseplants, and I | am already considering getting rid of Mr. Tiddlesworth, my | cat. | | Is there some sort of machine I can buy? Like direct air | capture? | | I only need this in like two rooms of the house. | ad404b8a372f2b9 wrote: | I don't think so. I guess what you want is a CO2 scrubber | like they had in Apollo 13, but I don't know of any | consumer, room-scale, ones. | | Plants make basically no difference sadly, in my room it | gets to 1600ppm in under an hour just from me and my cat | Gazpacho, although I've admonished him for breathing so | much. | rufus_foreman wrote: | Gets to like 1200 here. | | I think you might have a bad cat. | | Wasn't Apollo 13 pretty much room sized? | HyperSane wrote: | I will never understand how people can just get rid of | their pets. | rufus_foreman wrote: | You just drive it up to the country and open the door and | let it free. You know? | | Like, run free! | stuaxo wrote: | Just checked my Aranet 4, in a room no one has occupied for | a few hours, it's at 497 | pfdietz wrote: | If the window opened onto 1980, sure. | | I guess you could try to live in a place where the plants are | photosynthesizing vigorously. | rufus_foreman wrote: | Is that like an actual thing? Like you would have a CO2 | meter somewhere and it would be down to 330 because of all | the vegetation? | pfdietz wrote: | With no wind, a corn field in full sunlight will become | CO2 limited in just 10 minutes or so. | MobiusHorizons wrote: | That's fascinating. How do you know? (Research? Personal | experience?) | pfdietz wrote: | I was told that, but I can't find a link for that | specific claim. However, I can find a link to some old | research that shows CO2 falling during the day in low | wind: | | https://joannenova.com.au/2013/09/plants-suck-half-the- | co2-o... | pfdietz wrote: | That would be a worrying level of CO2 for the cockpit. | | https://www.newsweek.com/carbon-dioxide-levels-flight-deck-a... | jll29 wrote: | Thanks, great post. When you visit London, you should also | measure your exposure to PM2.5, PM10, NO, NO2, ... - the risk of | catching a virus is only one risk from your cocktails of risk | types. | | https://eu.usatoday.com/story/news/world/2017/04/10/london-t... | | https://www.london.gov.uk/press-releases/mayoral/londons-tox... | | https://www.unep.org/news-and-stories/press-release/revealed... | dataflow wrote: | I've heard some people can (train themselves to?) tell when the | CO2 level rises in the room. Has anyone here managed to? If so, | do you have any tips on how (or whether!) to do this, and/or what | it feels like (if it's possible to give any vague explanation in | text)? | JohnBooty wrote: | Has anyone here managed to? If so, do you have any | tips on how (or whether!) to do this | | I have, basically. | | The easiest (only?) way to do this is simply to have a CO2 | sensor, and pay attention to it. You'll quickly learn to | intuitively correlate what you're seeing on the sensor with | what you're experiencing. After a while you'll be able to | vaguely approximate the CO2 levels without even looking at the | sensor. | | Of course, you won't be able to pinpoint an exact CO2 level, | but you'll be able to tell when it's e.g. > 1000. | | You've already been doing this your whole life, of course. | You've already been distinguishing between "fresh" and "stuffy" | air. "Stuffy" air is just our colloquial term for air with | undesirably high CO2. | dataflow wrote: | I've been trying that; I do have a sensor. I can probably | guess the CO2 level with decent accuracy, but that's not | because I feel any different--but rather because I know how | long I've been in the room with closed doors/windows. | | With respect to "stuffy" vs. "fresh" air, I don't know | whether my sense of it is the same as others'. What I would | call "stuffy" is probably affected by humidity, dust, odors, | plants, etc. and not just CO2. | lucb1e wrote: | Don't you think those 'experience correlations' are based on | proxy parameters? Temperature being one of the main ones I | would expect. I don't experience water as fresh unless it is | cold, for example. | JohnBooty wrote: | Don't you think those 'experience correlations' | are based on proxy parameters? | | Yeah, I think that's probably a huge portion of it. | Nonetheless, I'm much more attuned to it now. | | Situations with high CO2 are usually situations with lots | of warm, stagnant, exhaled air in rooms filled with lots of | people. | | Would I be able to detect high CO2 levels in an environment | with cool, well-circulated air? I'm not sure. Certainly not | as well, and perhaps not at all. | | In practice, it probably doesn't matter. I don't think | there are many of those pathologically counterintuitive CO2 | situations. If the air _seems_ stuffy or stagnant then 99% | you can be quite certain it 's full of CO2 and/or airborne | pathogens. | quakeguy wrote: | That's called grandpa-tells-you-to-go-sleep Syndrom, it is | harmless usually. | afusalan wrote: | > I've heard some people can (train themselves to?) tell when | the CO2 level rises in the room. Has anyone here managed to? If | so, do you have any tips on how (or whether!) to do this, | and/or what it feels like (if it's possible to give any vague | explanation in text)? | | The best indication is feeling sleepy. Once you become sleepy | go outside and take deep breaths, then you understand the | sensation difference between O2 and CO2. | dataflow wrote: | Unfortunately that doesn't seem to work for me. Right now my | room has > 1200ppm CO2 (due to closed doors/windows) but I | don't feel sleepy at all, or any differently (that I can | discern) from when it's < 600ppm. Do you know if it needs to | be significantly higher for that feeling to kick in? If so, | approximately how much? | JohnBooty wrote: | Unfortunately that doesn't seem to work for me. | Right now my room has > 1200ppm CO2 (due to closed | doors/windows) but I don't feel sleepy at all | | It's a very gradual difference. If you're doing something | interesting at 1000-2000ppm you probably won't feel sleepy, | but it will probably be harder to focus on something you | don't find stimulating and you'll be more inclined to feel | sleepy. | dataflow wrote: | Interesting, I guess I can try to see if I can notice | that. Thanks! | afusalan wrote: | Hmm, I've never had the device to measure the levels tbh. I | can say I'm fairly sensitive to air as i do breathwork | regularly. 1200 ppm sounds a lot, maybe that's coming from | not just CO2 in the air but maybe dust particles, smoke, | food vapour, or chemicals such as odor, ozone, perfume, | house cleaning products etc. | colechristensen wrote: | Have a meter going and look at it. I'd describe it as a | feeling in my lungs as i breathe I can start to feel above | 800ppm. The air feels heavy maybe? | | I think some people are more sensitive to it than others. | rwmj wrote: | At KVM Forum 2019 [1] there was a particular theatre where the | enclosed space with many people and lack of ventilation was | very obvious. I felt dizzy and sleepy a few times at lectures | there (and nowhere else). No training needed! Edit: It was the | room shown in this picture: [2] | | [1] https://events19.linuxfoundation.org/events/kvm- | forum-2019/a... | | [2] https://locations.filmfrance.net/location/lyon-convention- | ce... | quantum_magpie wrote: | I can't say anything about training it, but beside the usual | sleepiness, at >1000 ppm I get a feeling of swelling eyeballs | and tingling teeth/dentures. I've been this way as long as I | remember. | zahrc wrote: | It feels stuffy. I get headaches and get tired. When you open a | window it's almost like instant relief | JohnBooty wrote: | Yeah the thing we've casually called "stuffy air" forever is, | essentially, 100% equivalent with high CO2 levels. | | There are some other situations where non-"stuffy" air might | have too much CO2, I guess. I guess you could pump CO2 into a | room with cool, dry air. | | But barring a contrived situation like that, stuffy=CO2. | dzhiurgis wrote: | I'm not very sensitive to it but I start getting stuffy nose, | especially overnight. ___________________________________________________________________ (page generated 2022-11-12 23:00 UTC)