[HN Gopher] CO2 helps viruses stay alive longer in the air
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CO2 helps viruses stay alive longer in the air
Author : chapulin
Score : 121 points
Date : 2024-06-04 14:36 UTC (8 hours ago)
(HTM) web link (www.statnews.com)
(TXT) w3m dump (www.statnews.com)
| blueflow wrote:
| > In its call to action, the group proposed CO2 as one of three
| key metrics, suggesting ventilation rates that would keep CO2
| levels at 800 parts per million or below.
|
| Pre-industrial CO2 levels were at 280ppm, currently we have
| 420ppm, rising & accelerating. Give it three or four decades and
| ventilation won't help anymore.
|
| Edit: 420, not 480ppm
| SoftTalker wrote:
| Houseplants. Lots of houseplants.
|
| More seriously, a house air filter with CO2 scrubber is not
| really something that would be difficult to make.
| J_Shelby_J wrote:
| I would love that, but how? There is no available residential
| CO2 scrubbers.
| jefftk wrote:
| Bringing in external air (and filtering it, if it's
| polluted) will be way cheaper than scrubbing CO2 at current
| levels.
| unholythree wrote:
| Definitely. Filtering particulates and tempering the
| outside air is the way to go in anything but most extreme
| situations. I suspect even designing a fallout shelter
| you would want to go that route.
| somenameforme wrote:
| This is true, but mostly because the cost of bring in
| external air is near $0 in most cases - just open a few
| windows! But there's a lot of absurdly cool ways to scrub
| CO2 that are not especially expensive, like the video-
| game level of serendipity+convenience that's the Sabatier
| Reaction [1]. Combine hydrogen + CO2 at 300C => methane +
| water.
|
| It's already being used on the ISS to keep the air fresh.
| It'll also be a key component on Mars. There you have
| basically unlimited CO2 and unlimited hydrogen which
| yields unlimited methane and unlimited water. Carry out
| electrolysis on some of the water and you get hydrogen +
| oxygen. The hydrogen can be fed back into the original
| cycle, and so you end up left with methane + oxygen which
| is also known as rocket fuel, uncoincidentally the exact
| sort SpaceX's Starship is using.
|
| Back on Earth you could use this reaction to create
| practically endless carbon neutral fuel so long as the
| CO2 was sourced from either the air or a regrown natural
| capture source like trees or what not. Rockets using this
| fuel would even have a negative carbon footprint since
| some of that fuel will get burnt outside the atmosphere.
| It all seriously feels like a video game where there's
| just this perfect, but just utterly contrived, rule
| allowing you to thrive on the next level of difficulty.
|
| [1] - https://en.wikipedia.org/wiki/Sabatier_reaction
| autoexec wrote:
| Don't the activated carbon prefilters used in many
| residential air filters work to scrub CO2 at least a
| little?
| alexey-salmin wrote:
| Try calculating how much heavier the filter must become
| every day to make a difference
| TylerE wrote:
| Not in the slightest. Those are for filtering volatile
| organics.
| Filligree wrote:
| There will be. Mind you, I'm not too happy about a future
| in which nobody can go outside.
| IncreasePosts wrote:
| Instead of scrubbing CO2, just adding the other important
| components like N2 & O2 to reduce the percent of CO2 in the
| air would probably be easier
| hollerith wrote:
| Navies have been removing CO2 from submarines for decades.
| I think they use sodium hydroxide.
|
| Manned space programs must remove CO2 air breathed by
| astronauts. They used lithium hydroxide for decades
| (including famously in Apollo 13) but ISTR the
| international space station has a more sophisticated
| process.
| gpm wrote:
| The ISS has a clever trick of using zeolite beds to
| absorb CO2 (a rock with pores that selectively hold onto
| CO2, and H2O but they dry the air first), and then
| venting it to space to get rid of the CO2 and recharge
| them.
| hollerith wrote:
| I wonder whether they need to heat the zeolites to help
| them release the co2 or whether exposure to vacuum is
| enough.
| gpm wrote:
| If I recall correctly they do heat it (I dug up the
| documents on this awhile ago, just going from my memory
| right now).
| johnsimer wrote:
| IIRC you need ~300 plants to offset every one human in a
| house
| jefftk wrote:
| Yes, it's impractically high: we exhale about 1kg of carbon
| daily, so your plants collectively need to be getting about
| 1kg heavier daily to absorb that.
| CGamesPlay wrote:
| Don't the plants exhale oxygen? So they won't be getting
| 1kg heavier, closer to 300g, but I don't know the actual
| chemistry.
| alexey-salmin wrote:
| That's just dry mass and plants are mostly water.
| SoftTalker wrote:
| Yeah it was sort of a joke, but having houseplants will
| make _some_ difference. Not that they would be practical
| to absorb all the CO2 in the air. On the downside,
| keeping indoor plants healthy does take some ongoing time
| and effort and isn 't everyone's cup of tea.
| alexey-salmin wrote:
| It often makes a negative difference because bacteria in
| the soil produce a lot of co2.
| alexey-salmin wrote:
| It's an order of magnitude worse than that, plants are
| mostly water, not carbon. They'll gain tens of kilos per
| day.
|
| If you can feed off your house plants alone, then you
| have a chance of closing the carbon loop. This was tried
| (e.g. biosphere2) and it's extremely hard even at the
| industrial scale.
| chuckadams wrote:
| > They'll gain tens of kilos per day.
|
| Feed me Seymour.
| Retric wrote:
| People don't need to eat 10's of kilos of plants per day
| which should suggest your off by an order of magnitude.
|
| Chemistry means converting 1kg of CO2 > O2 would mean
| removing ~273 grams of carbon. Hydrogen and Wet vs dry
| weight more than offsets this, but you're at closer to
| 2kg than tens of kilos.
|
| This still assumes an air tight system where people never
| leave home, so plants can make a difference long before
| they are a 1:1 replacement.
| hedgehog wrote:
| Living on Earth surface all that's necessary is to bring
| in outdoor air and reduce it to say 300ppm, currently
| that's only a 120ppm gap.
| gpm wrote:
| I don't know what portion of a typical plants mass is
| carbon, and your 273 grams of carbon number is right (the
| 1kg number is CO2), but I don't think "people don't need
| to eat 10's of kilos of plants per day" actually
| justifies your claim about their density or invalidates
| GPs claim as to how much plant-mass you need to offset
| what you eat.
|
| We don't just eat random (average) parts of plants, we
| eat selected ones, primarily things like fruits and bulbs
| that plants store energy in. If you just tried to eat,
| say, lettuce... at 2000 calories per day you would need
| roughly 14kgs [1, 2]. Which is surprisingly close to GPs
| 10s of kg number all things considered.
|
| Either way, growing 2kg of plant/day or 20kg of
| plant/day... seems impractical to me. There's also the
| issue that if you equalize CO2 levels with the outdoors
| during the day as you open doors and windows, you're
| going to make night _worse_ as both you and the plants
| output CO2 during the night.
|
| [1] Lettuce is 14 calories / 100g -
| https://www.fatsecret.com/calories-
| nutrition/generic/lettuce...
|
| [2] Math here: https://www.wolframalpha.com/input?i=2000+
| calories+%2F+%2814...
| mrob wrote:
| About 1kg of carbon dioxide, not carbon. 1kg of CO2 is
| only about 0.27kg carbon.
| mistrial9 wrote:
| this ignores "system balance" and assumes "closed system"
| no? In other words, no one says that plants _alone_ will
| compensate.. but instead they tip a system in a more
| favorable direction.. Plus some people really respond to
| house plants in lots of complimentary positive ways.
| Jarmsy wrote:
| More like 700 according to this
|
| https://medium.com/@candidegardening/how-many-plants-
| would-i...
| IvyMike wrote:
| When plants remove CO2 and release O2, they have to do
| something with that carbon atom. They can use it to make sap
| or fruit, but mostly they use it to build more plant.
|
| A plant that isn't growing, like, a LOT, can't possibly be
| removing much CO2.
| BurningFrog wrote:
| Most of a tree is CO2 that the plant has taken out of thin
| air.
|
| This only clicked for me when I started wondering why you
| never have to refill the soil for a houseplant even when it
| grows.
| teh_infallible wrote:
| Richard Feynman talked about this in his talk about "What
| is Fire?"
|
| https://www.youtube.com/watch?v=N1pIYI5JQLE
| somenameforme wrote:
| The soil itself is also storing CO2, in a variety of
| different less than intuitive processes. The most obvious
| is when parts of the plant die and breakdown into the
| soil itself.
| elevation wrote:
| > currently we have 480ppm
|
| Where are you measuring 480? [0] says the recent global average
| is 419.3.
|
| [0] https://www.climate.gov/news-features/understanding-
| climate/...
| coldtea wrote:
| Does the global average count where most people live, or does
| it average New York and Mexico City with rural Idaho and
| Bretagne?
| mike_hearn wrote:
| Believe it or not the standard is to report the CO2 level
| measured at the top of an active volcano (Mauna Loa). This
| is for historical reasons, because it's where the first
| measurements were taken, but also they claim it's more
| accurate because the measurement site is surrounded by
| miles of lava and thus there's no trees or vegetation which
| could absorb CO2 locally nor any human settlements that
| could emit CO2.
|
| There is of course the small problem of it being a volcano.
| Other measurements come from a collection of sensors on TV
| or telecom towers. Some of them come from planes.
|
| You can see a map of sites here:
|
| https://gml.noaa.gov/dv/iadv/index.php?code=sgi
|
| The trend is the same in every site, although absolute
| readings vary somewhat. There are cleaner sites than Mauna
| Loa, like in Antarctica, but those show about 10ppm lower.
| Others give the same reading as at Mauna Loa but with more
| seasonal variance. It's unclear whether these differences
| really matter and they tend to be ignored.
| cozzyd wrote:
| I have two vials of "the world's cleanest air" from the
| south pole NOAA observatory
| blueflow wrote:
| I probably read 420 somewhere and misremembered.
| logifail wrote:
| > Pre-industrial CO2 levels were at 280ppm, currently we have
| 480ppm, rising & accelerating. Give it three or four decades
| and ventilation won't help anymore
|
| Just to add a little context, here's a table from
| https://www.dhs.wisconsin.gov/chemical/carbondioxide.htm
| 400 ppm: average outdoor air level. 400-1,000 ppm:
| typical level found in occupied spaces with good air exchange.
| 1,000-2,000 ppm: level associated with complaints of drowsiness
| and poor air. 2,000-5,000 ppm: level associated
| with headaches, sleepiness, and stagnant, stale, stuffy air.
| Poor concentration, loss of attention, increased heart rate and
| slight nausea may also be present. 5,000 ppm: this
| indicates unusual air conditions where high levels of other
| gases could also be present. Toxicity or oxygen deprivation
| could occur. This is the permissible exposure limit for daily
| workplace exposures. 40,000 ppm: this level is
| immediately harmful due to oxygen deprivation.
| IvyMike wrote:
| The outlier to this the US Navy's experiments. Discussion on
| an older HN thread:
| https://news.ycombinator.com/item?id=19863319
| taeric wrote:
| Thanks for linking that! Will be hunting a bit for any
| recent takes on these studies.
|
| I'm finding I can't really tell any difference in
| mood/alertness/whatever despite what my sensor thing
| reports. To the point that I don't know why I bother
| keeping this thing in the office.
| robxorb wrote:
| How did we measure CO2 accurately pre-industry? Isn't the rise
| of industry kind of coincident with the ability to measure
| gases accurately? And if the trend as accuracy increased was
| up, wouldn't it suggest initial underestimates?
|
| Or is there some reliable way we can measure in retrospect?
| leptons wrote:
| Sometimes air gets trapped in unusual places. When these
| types of things are found, that air can be tested with modern
| equipment.
|
| "Ancient air pockets changing the history of Earth's oxygen"
|
| https://www.sciencedaily.com/releases/2016/08/160822174234.h.
| ..
| gpm wrote:
| CO2 levels are increasing at ~3ppm/year*. In 40 years we're
| looking at roughly 120ppm. Noticeable but not "we're all going
| to have headaches and covid" numbers.
|
| I mean we might all have headaches and covid, but not directly
| because of CO2 at outdoor concentrations.
|
| * 2.8ppm in 2022-2023, the rate at which CO2 is increasing is
| very slowly increasing but it's close enough to constant for
| rough calculations, especially after rounding up to 3.
| genman wrote:
| The rate is increasing, it is not constant. It used to be
| 1ppm per year. So it will be not 120ppm extra, it will be
| more. It might appear not much but when you consider indoor
| air then when currently room stayed below the recommended CO2
| limit, it maybe now be above of it or you need more air
| changes that will require more energy (to move air and to
| condition it). And while 120ppm in 40 years might appear not
| a lot then you should also consider that 40 years is actually
| very short time - in 120 years it will be about twice as
| today - there would be no fresh air anymore.
| s0rce wrote:
| Title seems misleading. It seems that they have results that
| elevated levels of CO2 in the air increase survivability of viral
| aerosol particles and infectiousness. Since CO2 is so low
| (400-1000ppm) this is surprising. Haven't had time to look
| through the paper closely but seems to be pH related which makes
| sense.
|
| https://www.nature.com/articles/s41467-024-47777-5
| dang wrote:
| We've replaced the page title with the HTML doc title now. is
| that better?
| bilsbie wrote:
| Found the critical thinker.
| glitchc wrote:
| If the concentration is so low, would the pH change
| appreciably? Air is not a liquid after all.
| gpm wrote:
| Air isn't a liquid, but the virus is contained within a tiny
| bubble of water as I understand it.
|
| Atmospheric CO2 change acidifying the oceans is a well known
| effect [1]. Once it's pointed out it isn't surprising that a
| tiny bubble of water surrounded by atmosphere would change PH
| quickly in response to atmospheric CO2 levels (the surface
| area to volume ratio is _huge_ compared to the ocean after
| all). Nor that that affects viruses.
|
| [1] https://www.noaa.gov/education/resource-
| collections/ocean-co...
| SwellJoe wrote:
| How is that new information "challenging old ventilation
| doctrine"? It confirms old ventilation doctrine: monitoring CO2
| remains a good proxy for general air quality, including viral and
| bacterial threats, and reducing CO2 via ventilation reduces other
| threats. That's doctrine, and now it has stronger evidence to
| support it, and another possible explanation for why and how well
| CO2 is correlated with other air quality issues.
|
| Ventilation good. CO2 bad. No challenge to old ventilation
| doctrine detected. (The article and the research seems much more
| nuanced than the silly title.)
| itronitron wrote:
| I think it's challenging the old ventilation doctrine which was
| that the people who wanted fresh air were just neurotic
| hypochondriacs.
| jefftk wrote:
| The old doctrine was that CO2 was a proxy for air quality, and
| the (somewhat overblown title) is about seeing CO2 additionally
| as having a causal effect.
|
| For example, under the "proxy" model, if you're worried about
| infection risk it's sufficient to filter the air, but under the
| new model filtering will work less well than you'd expect
| because the viruses you miss will stay active longer.
| SwellJoe wrote:
| "The old doctrine was that CO2 was a proxy for air quality"
|
| That's not accurate, though. CO2 is, on its own, an air
| quality concern.
|
| It has also been known, or at least part of the conversation,
| since Florence Nightingale's time, that fresh air reduces
| infections
| (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9300299/). This
| research makes a small tweak to our understanding, but it's
| also something that's been suspected/suggested by others for
| decades.
|
| This research isn't "challenging" anything, it's merely
| expanding our understanding of causation about previously
| observed correlations. It's good to know what's happening.
| It's silly to make it out to be something it's not.
| kolbe wrote:
| Listen. You don't get tenure confirming centuries-known
| ideas. You get it upending known doctrines. So if your
| research doesn't upend the doctrine, find a way to make
| your title say it does
| WhatIsDukkha wrote:
| Your quibble with the title is addressed by reading 3-4
| paragraphs into the long story.
|
| This sort of aggressive argument obscures the meaning and
| intent of the actual article in favor of some kind of editorial
| flavoring issue.
|
| This behavior is warranted at times but here it just
| argumentative for no purpose.
| francisofascii wrote:
| Honestly the OP comment was helpful for me, because I was
| confused I read the story wrong, or that I missed something.
| chasil wrote:
| If supermarkets and other public spaces had installed CO2
| scrubbers on their ventilation output/exhaust, could we have
| expected to lower COVID's r-naught?
|
| In what we did over the pandemic with masking, we drove some
| flu variants extinct. Is this an alternative to accomplish the
| same effect?
|
| Are hospitals already doing this with existing ventilation?
| gpm wrote:
| CO2 scrubbers don't exist in an economically feasible form.
| Rather the trick is just ventilation, replace indoor air with
| ourdoor air. If supermarkets and other public spaces just
| installed ventilation systems that exchanged their indoor air
| with outdoors air (preferably with heat exchanges so as to
| avoid air-conditioning or heating the outdoors), it would
| absolutely have helped. Ignoring this very interesting study,
| ventilation still just flat out works to reduce the amount of
| covid in the air.
|
| Increasing ventilation is unsurprisingly recommended by the
| CDC, the EPA, and basically every other relevant group. The
| EPA has a list of papers here if you're interested in
| scientific measurements backing this (but can I also say it's
| just common sense?): https://www.epa.gov/indoor-air-quality-
| iaq/indoor-air-and-co...
| rapjr9 wrote:
| One way it challenges old doctrine is that 1000ppm CO2 was
| considered good air quality in the past. Now it seems 800ppm or
| perhaps lower should be considered good air quality. They
| haven't tested other viruses yet (both colds and flu viruses
| are now considered airborne I understand, and other respiratory
| viruses probably are also), and each virus may react
| differently, so nobody actually knows yet what an optimal value
| is. It is even possible that the optimal CO2 value is somewhere
| below the current average concentration of CO2 in the air
| around the world when taking all airborne viruses into
| consideration, but nobody knows. More research is needed. But
| at least for covid, 1000ppm CO2 should probably no longer be
| considered good air quality (though replication of the study
| would be good.)
| andrewflnr wrote:
| Even if the title is silly, the article is well worth reading
| IMO.
| dilippkumar wrote:
| Tangential, but I've had this monitor[0] at home for about 2
| years and I can recommend it.
|
| I live in a place that's generally cold for a large part of the
| year, so I have all windows shut for most of the time. I've
| discovered that tracking CO_2 levels is a very good proxy for
| general air quality, and a good measure of both when to open
| windows and for how long to keep windows open.
|
| For my apartment, I was surprised that the amount of time I
| needed to keep the windows open was 5x longer than what I
| initially assumed (I assumed 5 mins would be enough. Data shows
| that I need about 25 mins to get CO2 levels down to around
| 500ppm). I was also surprised to see how much more rapidly CO2
| builds up when I have just 2 additional people at home.
|
| [0] https://www.airthings.com/view-plus
| victor106 wrote:
| How accurate is this?
| dilippkumar wrote:
| I don't have any equipment to calibrate it or measure it's
| calibration against. However, when I leave the windows open
| for extended periods of time, the CO2 levels hit levels that
| are within 50ppm of [0]. (I live in a different city from
| this station, with different population density, traffic
| patterns and all sorts of other micro-climate stuff that can
| contribute to a baseline difference. Additionally, CO2 levels
| swing by several hundred ppm when the air quality goes bad,
| and the ~50ppm range is insignificant in comparison)
|
| It seems good enough for how I use it. I wouldn't conduct
| chemistry experiments using this as an instrument.
|
| [0] https://gml.noaa.gov/ccgg/trends/monthly.html
| jauer wrote:
| I have several CO2 monitors including some from AirThings,
| Aranet4, and a industrial sensor in the form of a Vaisala
| GMP252 CO2 probe. They all track closely enough that I don't
| worry about it. The Vaisala is rated to +/- 40PPM which is
| accurate enough for living space environmentals.
| amelius wrote:
| Which one has a good price/accuracy ratio?
| twothamendment wrote:
| I use an Awair, also in a cold climate. Seeing the data for my
| air quality motivated me to install an air exchanger. Having
| the monitor allowed me to see how much we needed to exchange in
| order to keep the CO2 at a decent level.
|
| For anyone with a modern home that is sealed up average or
| better, an air monitor indoors is almost a must.
|
| On the topic of the number of people and CO2, I'm tempted to
| have it alert me when I'm out of town and the CO2 rises. I have
| an alarm, but who would think to defeat the innocent looking
| air monitor on the shelf?
| dmix wrote:
| What's the risk of co2 build up in doors?
| viraptor wrote:
| Making you more stupid
| https://www.smithsonianmag.com/science-nature/the-carbon-
| dio...
| serial_dev wrote:
| Getting sleepy, getting a headache, performing worse
| physically and mentally. Might be more stuff if you look into
| it, but to me this is the obvious stuff that matters and
| already justifies frequently opening windows.
| fwungy wrote:
| I bought a cheap AQ monitor off Amazon that does CO2.
| Anecdotally, I feel better when CO2 is lower. It's definitely
| sold me on the value of fresh air.
| verisimi wrote:
| I've read the title....
|
| Viruses + global warming. Ok.
|
| Is the fix that everyone needs a biometric id and should be
| highly monitored in order to be taxed on their CO2 emissions?
|
| The cynic in me thinks this is a solution looking for a problem.
| And this is the study to prove the problem.
| sharpshadow wrote:
| Interesting, maybe because of less oxidation.
| chipsdip wrote:
| Viruses are non-living. They are not organisms and cannot be
| "alive".
| quercusa wrote:
| Main takeaway: _That extra CO2 acted like a buffer keeping the
| particles closer to a neutral pH, where respiratory viruses are
| quite content._
| ThomPete wrote:
| lol yes and thats a good thing
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