Dismantling the confusion between the equivalent CO2 and CO2 concentration levels

The paper presents the results of the simultaneous determinations carried out on the same gaseous media, on the one hand with a sensor measuring CO
₂
concentration, and on the other with a digital gas sensor which, based on intelligent algorithms, processes the measurement data and offers them in equivalent CO
₂
levels. The purpose of the paper is to demonstrate through experimentation the erroneous idea to interchange the terms due to confusion. Experiments were performed using as reference a dedicated instrument for measuring carbon dioxide based on infrared absorption principle, Testo 535, from Testo. The digital gas sensor was the ultra-low power digital gas sensor for monitoring indoor air quality, CCS811, from AMS.