[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.
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