The Akihabara Taito (over rated chain) had a CO2 meter running. Floor 4 was 898 and floor 5 was 1322.

No comment other than without the public meters, I wouldn't have noticed. I have no idea what outdoor Tokyo is, I assume 400 but are cities different?

Can't understand what you don't interact with.

(Picture of their meter (display?)) - https://imgur.com/a/PfjNgjO