CO2 levels rise to unhealthy levels (700ppm) within a few hours of a typical bedroom if you keep the doors and windows closed. Its also why Submarines have CO2 scrubbers.
I have a CO2 monitor, and I can confirm that it goes up at least that fast in my home. I can't speak for submarines or healthy levels. I've been wondering for a while why environmental rhetoric only talks about the global rise in CO2 in terms that make people think it's just an atmospheric phenomenon rather than notably changing what they're breathing. It looks like we've nearly doubled the CO2 we're breathing in the past couple centuries, not including our more sealed up lifestyle.
>only talks about the global rise in CO2 in terms that make people think
Because the levels in the global rise are negligible in comparison to what is dangerous for breathing. Here's a hint, if you think you've spotted something blindingly obvious in a field scrutinized by hundreds of thousands of scientists, you're probably making a mistake.
Thanks for the hint. The thought that the health effects of a waste product from the most profitable of industries may have gone under-reported is indeed preposterous.
Here's a study showing reduced cognitive performance at various CO2 levels in the ranges we're talking about.