Carbon dioxide monitors measure the concentration of CO2 in a room to alert users to high levels and help manage ventilation. They can also be used to reduce the potential transmission of germs and aid productivity.
How is carbon dioxide monitored?
The most common type of Carbon dioxide monitor uses NDIR technology to detect CO2. Air enters the sensor through a chamber – normally passively, but some have an intake fan to increase speed. As air passes through the sensor, a beam of light is activated. The carbon dioxide particles in the air absorb different amounts of the light, causing a change in light absorption that the sensor can then detect.
Another key feature of many carbon dioxide monitors is the ability to autocalibrate. This works by finding a new baseline concentration of carbon dioxide, usually around 400 ppm. If you’re using a monitor that doesn’t have this feature, it’s important to manually calibrate it regularly as left uncalibrated, it may start skewing readings.
Most monitors can be used standalone, but most will also have an app to view data and change settings. Those that support historical data views can be especially useful as they allow users to see ventilation trends over time.
Typically, you should position CO2 monitors over 50cm from people as their exhaled breath contains CO2. If the monitor is too close it will give a falsely high reading. This can make the device appear ‘inaccurate’ and potentially cause false alarms.