CO2 as a proxy to air ventilation is a good start BUT doesn't show the full picture of what makes up IAQ (indoor air quality).
Better (but more expensive) would be monitors that could measure PM2.5 molecules in the air like that of the airborne aerosols that transmit Covid (phlegm, spittle etc).
Better (but more expensive) would be monitors that could measure PM2.5 molecules in the air like that of the airborne aerosols that transmit Covid (phlegm, spittle etc).