Now Elon is getting into my world.
Today's ASHRAE Standards require an exchange rate between fresh air and exhaust. If local code requires it, CO2 sensors are placed in high occupancy spaces to measure levels. Most systems will send a signal if levels get above 900 ppm. Most cases, it will not get anywhere near that number as long as systems are actively in operation.
Truth be told, I know high-rise buildings around the nation that will minimize to completely shutting off outside air handling units to save money.
ALL ABOUT THE BENJAMINS!!!