Scary. Or does everyone just carry oxygen tanks with them in the future?
[0] see https://en.wikipedia.org/wiki/Carbon_dioxide_scrubber (The amine methods wouldn't be a good idea, because the smell is reportedly extremely vile. It's what nuclear submarines' life support uses -- I forgot the link but there was interesting article about this).
[1] https://www.dhs.wisconsin.gov/chemical/carbondioxide.htm
edit: I guess plants work too
You'd basically need to fit the entire food production capacity for each person inside a building to counteract the CO2 from breathing. Exhaled CO2 comes from food, so the same mass of carbon would have to be converted back into food or other plants.
Chemical scrubbing seems more viable, and might be a thing we start seeing in HVAC systems of the future.
More specifically, the CO2 has to get out of your blood to make way for the next load of oxygen, and that happens in your lungs not via your digestive tract.
A home oxygen concentrator can be had for <$1k. The most difficult thing might be reliably monitoring the gas levels to make sure an unsafe imbalance isn't created.
Check the wikipedia article I linked: this is a solved problem in multiple contexts.
Versus several pounds of scrubbing mixture.
If need pure gas, for example you're trying to avoid losing your air conditioning or you're aiming for sub-ambient CO2, then you can't mix in lots of outside air. For the former you'd need enormous amounts of cooling and humidity adjustment, and for the latter outside air will actually make your job harder. So in those circumstances, the math is very simple. A human outputs X CO2, you want X to be a fraction of a thousandth of the air, you either scrub it or you add thousands of X in purified oxygen+nitrogen.
Also, the US Navy's submarine service, the Space Shuttle and the Apollo missions solved the problem by removing CO2, not by adding other gasses.
https://news.stanford.edu/news/2011/december/extracting-carb....
And that's at an industrial scale - residential scale would be even more expensive. Not all of the CO2 in the air has to be removed though and humans are not at home all the time.
It would cost, at the very highest range, $50t to stop climate change over 20 years. That's $2.5t per year, or $2,500 per middle class person for 20 years. Plus, we get a whole lot of benefits from a cleaner environment without oil and coal.
https://www.globalgiving.org/learn/cost-to-end-climate-chang....
Its cheaper and more effective to just... deal with oil and coal usage as a collective, rather than all of these ad-hoc individual amelioration measures.
2011 is getting old for this kind of analysis.
Go long oxygen!
All of these schemes about CO2 capture don't make sense atmospherically (we're physically digging out too much carbon to put it back into the ground economically) -
But CO2 capture makes sense inside buildings.
Of course, all of this is just an extra burden on the individual - buying air filters, CO2 capture, expensive ventilation, CO2 monitors - when we could just restrict our coal and oil usage in the first place, much more economically.