Answer: Air containing a certain amount of water vapor is called humid air, and air without water vapor is called dry air. The air around us is all humid air. At a certain altitude, the composition and proportion of dry air are basically stable and unchanged, and it has no special significance for the thermal performance of the entire humid air. Although the water vapor content in humid air is not large, the change in content has a great impact on the physical properties of humid air. The amount of water vapor content determines the dryness and humidity of the air. The working object of the air compressor is humid air.
