A vendor of VOC (Volatile Organic Compound) sensor claims the VOC concentration correlates highly to CO₂ concentration in a typical conference room:
Figure 2 illustrates the correlation of true CO₂ and concentration of mixed gases measured in a typical conference room.
Other VOC vendors also claim a cheap VOC sensor can be used as a reliable counterpart of a more expensive CO₂ to help decide when to ventilate in an office or a household, and quite a few of them recompute the measured VOC concentration to a "CO₂ equivalent level":
When an occupant emits CO2, this creates a proportional amount of emissions/impurities which are measurable by the VOC sensor
Breath: Acetone, Ethanol, Isoprene
Example: 25% CAC output signal is equivalent to CO2 800 ppm
The BA/BS3 VOC measures these VOCs and serves as an indicator of space occupancy with the same reliability as CO2 transmitters. VOC: 0 to 2,000 CO2 PPM equivalent
The output of the BAPI Volatile Organic Compound (VOC) Sensor is 0 to 100% VOC contamination. The VOC contamination can be turned into a CO2 ppm equivalent by multiplying by 2,000
As the VOC vendor claim is obviously not independent, I would like to know what independent sources say about this?