A carbon dioxide sensor is a device that measures the level of carbon dioxide in a gas or liquid. Carbon dioxide sensors are used in many scientific fields and industries to determine the carbon dioxide (CO2) content of an environment or product. Carbon dioxide sensors are also used to monitor indoor air quality.
In consumer use, carbon dioxide sensors are often used in air conditioners to measure the quality of air, because high carbon dioxide levels can cause headaches and can even be lethal at extremely high levels. A sensor in an air conditioning (AC) unit can also determine how many people are in a room by the amount of carbon dioxide produced by the room's inhabitants. With this information, an air conditioning unit can adjust the AC to a comfortable temperature for that situation. A carbon dioxide sensor has similar uses for determining the number of animals in an environment or the respiratory condition of those animals.
The ability to measure carbon dioxide in a gas is critical in several industries. Using a carbon dioxide sensor in a hyperbaric chamber allows doctors to perform operations in carefully controlled atmospheric conditions. A sensor is also used in determining carbon dioxide levels underwater or in space, which can be used to determine the habitability of a new environment.
A carbon dioxide sensor can also be used to identify CO2 content in a liquid. These sensors are used to measure carbon dioxide levels in blood. This is a crucial measurement during surgery and when a patient is hospitalized under intensive care.
A dissolved carbon dioxide sensor can be used in producing several common items. Sensors are used to monitor CO2 in carbonated beverages, such as soda, beer and sparkling wine, which are carbonated by pressurized carbon dioxide. Dissolved carbon dioxide sensors are also used in the pharmaceutical industry, where CO2 has several uses.
The main type of carbon dioxide gas sensor is a known as a non-dispersive infrared sensor (NDIR). An NDIR determines the amount of carbon dioxide in a gas by measuring the absorption of a certain wavelength of light in the gas. Carbon dioxide has a unique absorption quality, and the amount of light absorbed by the gas will show how much carbon dioxide is contained in that gas. Other carbon dioxide sensors measure thermal conductivity, or the ability of a substance to conduct heat, in order to determine the CO2 content.