I’ve wondered if we can do better, with my Aranet in Spring, and living close to the forest with the windows open on a breezy day my CO₂ reading went down to 410.

I’m guessing if someone had their air go through a conservatory first it could go lower.

In some climate YouTube videos people slip in the CO₂level of when they were born, an interesting point, mine was 325, but I guess there was more lead in the air then…

Is there much of an improvement, impractical as it is, to a far lower CO₂ level.