In nature, plants use CO2 for photosynthesis. CO2 combinate with moisture under the action of the sun to produce sugar (and oxygen). We know about how much CO2? How does it work?
CO2 can absorb infrared wavelengths of light. The absorption can be used to measure the concentration of carbon dioxide per unit volume. The infrared absorption function of CO2 is causing part of the greenhouse effect. The greenhouse effect is one of the characteristics of all the planet's atmosphere, it makes the planet's surface temperature is higher than without the atmosphere. Any gas absorbs the sun's rays will lead to the greenhouse effect, the most important greenhouse gas for surface of the earth include: water vapor, CO2 and methane, they can absorb infrared wavelengths of light.
Most of gas sensors could give the corresponding signal according to the molecular density, even down to one over one million as units. According to the ideal gas law, when the pressure and/or temperature change, density of molecules will change, and PPM value is displayed on the sensor. Accuratly say this is wrong, as density of the gas (in PPM) will not change with the change of temperature and pressure. The change of gas sensor readings can also be used to correct for the temperature and the pressure change of gas sensor readings errors.
Considering the water vapor to the effect of CO2 sensor, the information is very important. For example: in the same pressure, temperature and volume, add water vapour in the process of gas drying, then water had taken over of general mixture of other gas molecules.
Our CO2 gas sensors could be used for accurate CO2 detection.