So you want to use plants to reduce CO₂

Trees respire. They breath in and out. At night time, many trees emit more CO2.

And trees don't exist in isolation as these napkin calculation articles consider them (spherical cows and all that). Every single tree on earth relies on mycorrhizal fungi for the vast majority of its nutrients. Fungi break things down release CO2.

Most of our oxygen comes not from forest but from oceans (specifically from phytoplankton, algae, and photosynthetic bacteria). Between 50-80% of it in fact. Likewise, most of the CO2 that has been captured has been captured by the ocean not by forests. About 25-30% of all human emissions have been captured by the ocean.

Forests (and grasslands) are tremendously important for ecosystems and our health but I think this focus on CO2 and oxygen is simply misleading. If that's your concern you should really be focusing on the ocean. Which IMO is in an even more dire strait than our forests

OK, so we can’t use plants.

What are the options, then?

In my apartment I’m running 2 AirGradients. One in the bedroom and one in the main room.

Awesome little devices, btw. They monitor temp, humidity, CO2, TVOC, and various particulate matter metrics. They expose prometheus metrics for scraping, and can be configured through a REST API to never phone home. I’ve got grafana alerts set up to push notifications to my phone when things get to “bad” ranges.

Anyway, the big issue is that the only way I’ve found to clear CO2 and TVOC is to open windows. However, windows open means increased humidity and particulate matter, even with air purifiers running aggressively. Also, opening windows at night kind of sucks for obvious reasons. In the summer it also sucks to lose that cool air.

I found these devices you put in your window, sort of like window fans, that can open/close airflow completely, but they don’t fit in my side-opening windows.

The only other thing I can think of is some kind of home automation with a little gadget that cracks the window until the metrics are back in an acceptable range. My AC unit unfortunately does not have a mode where it takes air from outside. I know some things like this exist for opening blinds, etc, but haven’t gone down that rabbit hole yet.

Anyone find a good way to solve this problem?

Or… you could go outside?

But the analysis rests on 0 ventilation, which doesn’t work at all.

I think the main thing to keep in mind is plants really aren’t industrial carbon sinks. They were never evolved to be. Their biological functions are about growing and thriving, and the soil they grow in are net carbon producers.

In a broad open system, they are net carbon sinks over the long term. But any analysis in a closed system is bound to fail, you don’t even need numbers to know intuitively this won’t work.

Crack open a window. Run a fan. Have plants because they have many benefits. Reducing CO2 around you meaningfully isn’t one of them.

(Author here) I've added the word "indoor" to the title, which will hopefully make it harder to miss that this is not about climate change or carbon sequestration.

Of course, do it with vats of plant cells in floating oceanic CO2 factories. Not in your living room.

Or, just let the oceans recover, let the mollusks return to the bays and shores, let them do their efficient thing.

You can sequester carbon with plants, but you can't let them decay or it will release it back into the environment (it's called the "carbon cycle" of a reason).

A startup has solved this problem the following way (for example): grow microalgae near a very dry desert, and bury it in trenches. It never decays and thus never releases CO2 due to lack of water.

Basically, we'd have to permanently stick it back underground again.

I have had the same impulse to reduce CO2 to about half(Close to pre-industrial levels 200 to 280 ppm). Of course my first thought was CO2 scrubbing by chemical means, plants are obviously silly. But was convinced not to pursue given the fact that

1. Cognitive decline starts above 600 ppm according to air quality studies.

2. Levels below 200 ppm are actually dangerous.

This guy actually built an algae farm to test how much you need to breathe. https://youtu.be/AAbyUaLN2QA

I'm a big proponent of transitioning to no-till agriculture when it makes sense. Perennial plants have deeper roots, which means they require significantly less water and fertilizer, all while sequestering more carbon.

Two examples:

-Switchgrass for ethanol. Currently, ~15% of irrigation water in the US goes towards corn, and more than 1/3rd of that is converted into ethanol for gasoline. Studies show that perennial switchgrass would be a 5x more efficient source of ethanol.

- Salish Blue - a perennial wheat-wheatgrass hybrid. I made savory crepes last week with pure salish blue flower, and they were excellent!

The BBC did this in their 2012 documentary mini-series "How to Grow a Planet" with Iain Stewart. It was a lovely series; I highly recommend it.

Related tangent: I recently bought an inexpensive consumer CO2 monitor for under $40. It confirmed my suspicion about air quality in my home office; after a few hours, levels rise above 1000ppm unless I leave a window partway open. Mid-afternoon mental fog cleared right up.

What if the plants were algae?

The vast interior of the world's oceans are a nutrient desert. It has been proposed to grow algae by spreading silt, the same way that Saharan winds do.

Get an HRV/ERV if you can't open a window.

I’ve always wanted to jam on how to create an indoor carbon dioxide removal system. (I think that’s what this article is about but perhaps it’s indirectly about the changing climate)

1 kg per day of material adds up fast but that assumes zero ventilation. If I simply wanted a system to keep my office below 500 ppm all day, I wonder how much material that would produce.

Anyone ever build a little carbon dioxide zapping system for indoor air quality? I’ve also heard that indoor CO2 isn’t actually all that bad but it’s VOCs that are what make me feel sluggish.

Bamboo it is.

How is it that 132.5 watts is 3 light bulbs but 918 watts is 765 light bulbs? Is there a typo?

That one final number is all one needs as a reply for "but they help a little".

> Real plants do photosynthesis through a physical process

(nit) it is more accurate to call this a biological process, or chemical process

Saying "physical process" makes me think of inclined planes, free-body diagrams, and EM fields.

I don't really understand this. First of all, you can just weigh the plant, and tell how much CO2 it has captured, right?

Second of all, what does it matter how much CO2 I produce? What's harmful is the additional CO2 that goes into the atmosphere for burning fossil fuels. All other CO2 is just in the same cycle that's been happening for ever.

EDIT: My child comment is dead and vouching doesn't resurrect it, but now the post makes sense, thanks for the clarification.

no, we are useing solar PV to eliminate the excess carbon bieng added to the atmosphere, and plants, rocks, and many other natural processes will return CO² levels to a more moderate level.

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This seems trivial: if you could add enough plants to your room to reduce CO2, we could easily do the same thing at planet-scale and global warming wouldn't be an issue.

Sadly I am a bit hopeless about climate change. Even if every person on earth dropped everything and started making biochar to be buried it would not sequester enough carbon to make a difference.