Anyone selling house-size CO2 absorbers to keep CO2 in my house to more like pre-industrial 200ppm rather than the 800ppm that's more common of house air in cities?
You'd only need a few hundred grams of triethanolamine if you regenerate it several times a day (with a vent to outdoors), but there are probably some spill risks and maybe mist. Soda-lime is cheaper but requires inconveniently high temperatures to regenerate, which probably result in unwanted emissions requiring mitigation as well as too much energy use. Regular lime (without the soda) avoids the emissions but takes a month to absorb the carbon dioxide. Alkali-metal oxides, hydroxides, and peroxides like those discussed in the article are extremely compact and fast-acting but even more difficult to regenerate. Bioreactors with spirulina or chlorella have been tested successfully but require hundreds of kilograms of algae per person and are finicky, being prone to infection. I think it's eminently possible at a technical level, but at a political level, basically you can only do this kind of experimentation if you live in China.
An actually physically feasible thing you can do is to whitewash some walls. You need to apply about 7kg of whitewash per person per week, so you are going to need a lot of walls, on the order of 400 square meters of wall per person, because the whitewash is regular lime, not soda lime. (If you're daring enough to dope your whitewash with lye, maybe you can get by with less wall area, but you still need to keep applying the whitewash at 7kg per person per week.) You can make them out of plywood, sheetrock, sheet metal, old sheets, whatever whitewash will stick to. After a few months you will need to start throwing out 14kg of fully cured whitewash per person per week, or calcining it to make fresh whitewash. Try to get whitewash with as little chalk in it as possible.
At this small scale, dozens of kilograms per week, you might be able to calcine the used whitewash in a pottery kiln on your patio. Beware that electric kilns generally do not handle reducing atmospheres well. I'm not sure if carbon dioxide would be too much for them. I think it should be fine, but don't blame me if you ruin your Kanthal.
A caution I should have thought to include: if you do this to remove the carbon dioxide you exhale, you need to make sure you have enough ventilation that you don't asphyxiate. In the absence of carbon dioxide to tell you to seek fresh air, you won't notice the oxygen levels dropping; you'll just get stupid, then lose consciousness, then die. Homemade rebreathers have a high fatality rate. I don't think such good sealing is likely at the scale of an entire house unless it's literally underwater or something. But keep it in mind.
Honest question: Why would you want to? The average CO2 concentration in your lungs is something like 20,000 ppm, so it doesn't matter much whether ambient CO2 is at 200ppm or 800ppm. Other aspects of air quality do matter, but I'm highly skeptical about the value of capturing CO2 in your house.
Are you not familiar with any of the research linking high CO2 with harmed cognition and harmed alertness? It is manifest at as low as 800 ppm, certainly at 1000 ppm, and personally even at 600 ppm for me. There is good reason to want the preindustrial level that humans lived with for almost their entire history.
The average human exhales about 1 kilogram of carbon dioxide on an average day.
Carbon makes up 27.3% of that: ~300 grams. That's the weight of a smartphone.
The logistics would be complicated, average plants aren't going to be accumulating so much mass so quickly. You would need aquariums full of algae. Just isn't worth it.
Probably way more important than lowering the CO2 is getting rid of PM2.5/PM10.
Rooftops nowadays are best used to mount solar panels. Some system growing circulating algae, be it on the roof or on the sun drenched walls while doable would have way higher at least the operating costs. Clining is one thing. If you live in the area with below zero temperatures either you drain the system or invest even more in some glasshouse, maybe thermal isolation at night or heating.
As mentioned by others, there are chemical solutions.
I think measuring CO2 is mostly only useful as a proxy for how well you are ventilating (which is correlated to the health of your air unless outside air is filled with ie small particles or smog), and when you measure 800 ppm it is more than adequate. 800 is not doing anything to the body (that we know of).
Do you want to use chemicals and devices that make the climate problem worse just to lower the CO2 concentration in your personal space? Sure it’s a small effect but not something we can all do.
IIRC 1000 is where it starts having easily detectable negative effects on human cognition, which means it has less easy to detect negative effects on human cognition at numbers lower than that.
> The triumph of the movie, as described at the time, was making people care about a story they already knew the ending to.
One could, I think, argue the same about any movie about a historical event. I think that it would seem strange, for example, to say that that was the main achievement of Sands of Iwo Jima.
The comments have time stamps for some particularly interesting moments, but the incident occurs 8 minutes in, and the infamous "Houston, we've had a problem" remark happens at 9:20.
The blog post talked about how everything had to be communicated verbally because you could not share images, but since we're so used to Hollywood adaptions or documentaries, I find the recordings really drive the point home.
The scenes where they identify the square peg/round hole problem and where John Aaron and Ken Mattingly get the power draw down are some of my favorite in any movie. Must watch for any engineer
I love how their solution was not to fit the square peg into the round hole, but to use the suit air hose system to pull air through the filter instead.
They achieved the important function ("flow cabin air through the filter") in a totally different way.
It's a fun read. It does seem to imply that the parachutes slowed them down from 25,000 mph, but the heat shield smashing through the atmosphere would have slowed them down first.
I watched the moon landing as a young kid. On our rich neighbors TV. We didn't have one. I do hope that live to see another one. Not sure as they keep delaying it.
We shake our heads at round vs. square filter in the distant 1970 past, but flash forward 55 years and we have that a very similar situation in the active American space capsules - none of the spacesuits are compatible with any of the other ships.
The Boeing spacesuit isn't compatible with the SpaceX capsule, which was recently an issue with the Crew 9 mission. And neither are compatible with the NASA Orion capsule.
> On July 21, 1969, Neil Armstrong stepped off the ladder of his spacecraft and became the first human to walk on the Moon. The first words spoken by him on the Moon that day are still remembered.
Until recently I believed that too. However, I came across some discussion which made me realize I was mixing up the sequence. The transmission interruption, which can be clearly heard, didn't happen at that point in the quote; it happened a moment later, after the word "man". The critical part of the quote seems to come through clear. It's more of a linguistic question about how "for a" and "for" may sound almost indistinguishable in Armstrong's accent.
Also, the blog post in the submission omits a major detail: the on-orbit docking maneuvers for the CSM to mate with the LM. A minor detail is that the Saturn V's third stage performed TLI (trans-lunar injection) and it actually impacted the Moon. After this TLI, the LM and the CSM were flying free in space, with a bit of separation, and it was the CSM pilot who needed to turn 180° and nose-in to the LM in order to be in the proper configuration for the hypothetical Moon landing.
It was an unusual configuration for Apollo 13, to say the least, because of course they did not land on the Moon, but also because the "base/legs" part of the LM wouldn't be "left behind" on the lunar surface, so they sort of lugged it around awhile. I don't know the exact sequence of jettisoning that base, but they certainly relied on the LM "head" as a lifeboat and a source of additional life-support functions.
Readit News
An actually physically feasible thing you can do is to whitewash some walls. You need to apply about 7kg of whitewash per person per week, so you are going to need a lot of walls, on the order of 400 square meters of wall per person, because the whitewash is regular lime, not soda lime. (If you're daring enough to dope your whitewash with lye, maybe you can get by with less wall area, but you still need to keep applying the whitewash at 7kg per person per week.) You can make them out of plywood, sheetrock, sheet metal, old sheets, whatever whitewash will stick to. After a few months you will need to start throwing out 14kg of fully cured whitewash per person per week, or calcining it to make fresh whitewash. Try to get whitewash with as little chalk in it as possible.
At this small scale, dozens of kilograms per week, you might be able to calcine the used whitewash in a pottery kiln on your patio. Beware that electric kilns generally do not handle reducing atmospheres well. I'm not sure if carbon dioxide would be too much for them. I think it should be fine, but don't blame me if you ruin your Kanthal.
The logistics would be complicated, average plants aren't going to be accumulating so much mass so quickly. You would need aquariums full of algae. Just isn't worth it.
Deleted Comment
Rooftops nowadays are best used to mount solar panels. Some system growing circulating algae, be it on the roof or on the sun drenched walls while doable would have way higher at least the operating costs. Clining is one thing. If you live in the area with below zero temperatures either you drain the system or invest even more in some glasshouse, maybe thermal isolation at night or heating.
As mentioned by others, there are chemical solutions.
Efficient Direct Air Capture in Industrial Cooling Towers Mediated by Electrochemical CO2 Release
https://onlinelibrary.wiley.com/doi/10.1002/anie.202412697
Do you want to use chemicals and devices that make the climate problem worse just to lower the CO2 concentration in your personal space? Sure it’s a small effect but not something we can all do.
Deleted Comment
One could, I think, argue the same about any movie about a historical event. I think that it would seem strange, for example, to say that that was the main achievement of Sands of Iwo Jima.
The comments have time stamps for some particularly interesting moments, but the incident occurs 8 minutes in, and the infamous "Houston, we've had a problem" remark happens at 9:20.
The blog post talked about how everything had to be communicated verbally because you could not share images, but since we're so used to Hollywood adaptions or documentaries, I find the recordings really drive the point home.
They achieved the important function ("flow cabin air through the filter") in a totally different way.
https://www.nasa.gov/history/afj/ap13fj/15day4-mailbox.html
https://spacecenter.org/apollo-13-infographic-how-did-they-m...
https://en.wikipedia.org/wiki/HIAD#Inflatable_heat_shield_en...
https://en.wikipedia.org/wiki/MOOSE
The Boeing spacesuit isn't compatible with the SpaceX capsule, which was recently an issue with the Crew 9 mission. And neither are compatible with the NASA Orion capsule.
A not-at-all-famous-but-maybe-it-should-be CO2 absorber is azolla.
https://en.wikipedia.org/wiki/Azolla_event
>[img that misquotes Neil Armstrong]
is a hilarious way to start
Also, the blog post in the submission omits a major detail: the on-orbit docking maneuvers for the CSM to mate with the LM. A minor detail is that the Saturn V's third stage performed TLI (trans-lunar injection) and it actually impacted the Moon. After this TLI, the LM and the CSM were flying free in space, with a bit of separation, and it was the CSM pilot who needed to turn 180° and nose-in to the LM in order to be in the proper configuration for the hypothetical Moon landing.
It was an unusual configuration for Apollo 13, to say the least, because of course they did not land on the Moon, but also because the "base/legs" part of the LM wouldn't be "left behind" on the lunar surface, so they sort of lugged it around awhile. I don't know the exact sequence of jettisoning that base, but they certainly relied on the LM "head" as a lifeboat and a source of additional life-support functions.
Deleted Comment