The XENSIVTM PAS CO2 is a real CO2 sensor in an exceptionally small form factor based on the photoacoustic spectroscopy (PAS) principle. Infineon's MEMS microphone, which is optimized for low-frequency operation, detects the pressure change generated by CO2 molecules within the sensor cavity. CO2 concentration is then delivered in the form of a direct ppm readout thanks to the integrated microcontroller. Highly accurate CO2 readings are guaranteed. It has an operating range of 0ppm to 32000 ppm with a lifetime of 10 years.