Carbon dioxide sensor

Measuring carbon dioxide is important in monitoring indoor air quality,[1] the function of the lungs in the form of a capnograph device, and many industrial processes.

New developments include using microelectromechanical systems (MEMS) IR sources to bring down the costs of this sensor and to create smaller devices (for example for use in air conditioning applications).

Concentration of CO2 can be measured by subjecting a sample to pulses of electromagnetic energy (such as from a distributed feedback laser[4]) that is tuned specifically to the absorption wavelength of CO2.

[5] Chemical CO2 gas sensors with sensitive layers based on polymer- or heteropolysiloxane have the principal advantage of very low energy consumption, and that they can be reduced in size to fit into microelectronic-based systems.

On the downside, short and long term drift effects, as well as a rather low overall lifetime, are major obstacles when compared with the NDIR measurement principle.