A carbon dioxide sensor or CO2 sensor is an instrument for the measurement of carbon
dioxide gas. The most common principles for CO2 sensors are infrared gas sensors (NDIR) and
chemical gas sensors. Measuring carbon dioxide is important in monitoring indoor air quality, the
function of the lungs in the form of a capnograph device, and many industrial processes.
For HVAC applications, CO2 sensors can be used to monitor the quality of air and the
tailored need for fresh air, respectively. Measuring CO2 levels indirectly determines how many
people are in a room, and ventilation can be adjusted accordingly.
