Oxygen consumption increases with activity, obviously. Air handling is rated on square footage, structure design and intended purpose. A home is going to carry

Oxygen consumption increases with activity, obviously. Air handling is rated on square footage, structure design and intended purpose. A home is going to carry a very different set of requirements than a factory floor or a restaurant (which often has high CFM exhaust hoods and requires a large amount of fresh-air infiltration to make up for exhausted air). Max occupancy permits as based on these factors, and often limited by egress (exits) plus a safety-factor is added to that. But that's about the limits of my expertise. Beyond this lies architects & permitting inspectors. The calculation of human heat load and perception of temperature (sensible/latent heat, and psychrometrics in general) is a big part of system design. I'd have to break out the software and start asking specifics to get you an actual number but my gut feel is that a dance hall is going to easily pass the air quality tests. Of course, somebody could pack 100 people into a low-ceiling windowless 200 ft^2 room without forced ventilation and have a problem with not just air quality but also heat (each person is approx 20W at rest, 200W w/vigorous activity), but I'm speaking in generalities about properly used residential & commercial space.