Since getting this CO2 meter, I’ve found there’s a high correlation with being unfocused and/or irritable with 800+ readings. Reminder to get some fresh air, open the window, etc.

+1, I find I'm okay until 800-1000, then it's very noticeable above that. Below 600 is definitely noticeably ideal. Temperature/humidity also have an effect too (cooler/lower humidity increases CO2 tolerance a bit, at least reduces the "stuffy room" feeling).

A doodler and computerer. I like permissive/permissionless open source, smart contracts, p2p systems, room-scale VR, and NixOS.

Currently: WhatsABI

Knowing this, it's wild that a couple centuries ago the baseline outdoor CO2 was in the 200's (now it's high 300s/low 400s), and likely approaching 600s by 2050s. :(