Carbon dioxide is what I was going for, sorry.
I was under the impression airtight (or near isolated) could be somewhat related to soundproofed. I do feel a huge difference if I leave the window a bit open when I sleep (fresh air), and when I don't. I think the excess CO2 makes me sleep more profoundly (or maybe I'm just fackin paranoid). For working on a (composing) session with headphones or monitors is way better for me to leave the window open, except for the fucking nosy neighbors 20 ft away partying-pucking-cursing-fighting/car honks/airplanes passing by/dogs barking/children crying/trucks reversing/doors slamming etc etc etc. I was thinking of inquiring in depot stores about a double paned window for the bedroom.
Not to go as far as 'dying' but I've read confining a space from adecuate ventilation can lower levels of oxigen, which in turn can lead to less concentration and productivity, sleepiness, and even other issues over the long run. When I was beginning at the University the guy who was introducing us to the studio facilities said it could even be dangerous to stay asleep inside the recording room (because it had no AC), that we might not even wake up again (but then again maybe he just didn't want us to sleep through class, or that some couple would turn it into their 'love nest' lol). Maybe that 'teacher' just wanted to brag about how well the noise insulation in that then-recently built studio turned up.
If you install ventilation it means a hole (or two) conecting to the outside I guess? Doesn't the noise escape through there? (bear in mind I'm talking about a home studio, where each household/apartment lies right next to each other)
Do you vent a home studio with AC? and if so, how could it be done without the noise filtering out as well?