[nix23]

CO2 or Oxygen levels are normally never a problem, not even on mount Everest (where the air pressure is the problem). It's for sure not a solution but an interesting research field to remove toxic chemicals...for long duration spaceflight/bases ;)

https://en.wikipedia.org/wiki/NASA_Clean_Air_Study

[valenceelectron]

The crucial part of this study is the following quote: "These results are not applicable to typical buildings, where outdoor-to-indoor air exchange already removes VOCs at a rate that could only be matched by the placement of 10–1000 plants/m2 of a building’s floor space."

In general, the amount of plants needed is just too high to be practical. At least among those plants tested in this study. This also applies to plants commonly sold as "air cleaners" (the common ones were all tested in this study). They do little to nothing for non-sealed rooms. Specific algea may be better suited.

[nix23]

That's why i wrote "moonbase" where your fresh veggies could also clean the air.

But yes algea are maybe better if you have the power to circulate them, pressured air to blow it truth and a filter to take the dead ones out, bacteria etc in check, earlier or later your water will start to foul otherwise.