Source: Beijing Sharp Air Conditioning Repair Center http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3766461. Basic Knowledge of Sharp Air Conditioner Repair - What is Humid Air? A gas composed of dry air and a certain amount of water vapor is called humid air. The main components of dry air are nitrogen, oxygen, argon, and other trace gases. Under normal circumstances, the composition of dry air is relatively stable, with only a few components varying due to time, geographical location, altitude, and other factors. In air conditioning engineering, in order to unify the thermodynamic properties of dry air and facilitate calculations, the composition of clean dry air near sea level is generally used as the standard.
In daily life, what people refer to as air is actually humid air. Although the content of water vapor in humid air is small, usually only accounting for about twenty parts per thousand, its changes can affect the dryness or humidity of the humid air, thereby altering the physical properties of the air.
Under normal temperature and pressure, the water vapor in humid air is generally in a superheated state and has a low content, so it can be approximately regarded as an ideal gas. In the humid air at the Earth's surface, there are also some suspended dust, microorganisms, and chemical emissions, but these substances do not affect the physical properties of the humid air and are usually not considered in air conditioning repair processes.