What is eCO2 that the Air Quality Breakout - CCS811 measures?

Sensors Biometrics
1

this product: https://www.sparkfun.com/products/14193

measures eCO2 how is this different from carbon dioxide?

thanks!

2

eCO2 – means estimated concentration of carbon dioxide calculated from known TVOC concentration. This is based on the assumption that the VOC produced by humans is proportional to their exhaled CO2. That means it gives similar signal to real CO2 sensor, in the case the main, prevailing source of air pollution in such room are people who stay inside.