Constant temperature and humidity air pressure

The pressure formed by the air layer surrounding the earth on a unit surface area of u200bu200bthe earth is called atmospheric pressure (or total pressure of humid air). The unit of atmospheric pressure is expressed in Pascals (Pa) and kilopascals (Kpa). ※Atmospheric pressure is not a fixed value, it varies with the altitude of each place. Normally, the annual average air pressure at sea level at 45 degrees north latitude is used as a standard atmospheric pressure or the pressure formed by the air layer surrounding the earth on a unit surface area of u200bu200bthe earth by the physical atmosphere is called atmospheric pressure (or total humid air pressure). The unit of atmospheric pressure is expressed in Pascals (Pa) and kilopascals (Kpa). ※Atmospheric pressure is not a fixed value, it varies with the altitude of each place. Usually, the annual average air pressure at sea level at 45 degrees north latitude is used as a standard atmospheric pressure or physical atmosphere, and its value is 101325 Pa. The higher the altitude, the lower the atmospheric pressure. Usually the pressure measured by the instrument is called the working pressure. Absolute pressure u003d local atmospheric pressure + working pressure ※ The partial pressure of water vapor and the partial pressure of saturated water vapor: in the humid air, water vapor alone occupies the volume of the humid air and has the same temperature as the humid air, the pressure generated is called Is the partial pressure of water vapor. According to Doyle's law, the total pressure of an ideal mixed gas is equal to the sum of the partial pressures of the various gases in the mixed gas. At a certain temperature, the more water vapor content in the air, the more humid the air, and the greater the water vapor partial pressure. If the amount of water vapor in the air exceeds a certain amount, the excess water vapor will condense into water. Precipitated in the air. This means that under certain temperature conditions, when the water vapor content in the moist air reaches the maximum, the moist air is said to be in a saturated state, which is also called saturated air.