I think your take is fine, but it's a far cry from saying we're spending the day at the 15 minute limit for CO2 concentration. The classroom I teach in easily h

I think your take is fine, but it's a far cry from saying we're spending the day at the 15 minute limit for CO2 concentration. The classroom I teach in easily hits the 1000 ppm level (I measured it at the start of the 2020-21 school year), so we're already suffering before the masks go on. The masks just make it a little bit worse.