What is the content of water vapor in the air?

Calculate the saturated vapor pressure and check the saturated vapor pressure of water at air temperature. The ratio of this pressure to atmospheric pressure is the volume fraction of water in the air. Generally, when the temperature is 25 degrees and the relative humidity is 100%, the water content is 20g per cubic meter.

Water vapor is the gaseous form of water (H2O). When water reaches the boiling point, it becomes steam. At sea level-standard atmospheric pressure, the boiling point of water is 99.974°C or 212 F or 373.5438+05 K. When the water is lower than the boiling point, it can also slowly evaporate into steam. However, in the extremely low pressure environment (below 0.006 atmospheric pressure), ice will sublimate directly into water vapor. Water vapor may cause the greenhouse effect. It is a greenhouse gas.

Related information:

Fog and clouds are formed by condensation and nucleation of surrounding clouds. In the absence of nuclei, condensation can only occur at a lower temperature. After continuous condensation or deposition, cloud droplets or snowflakes form and contribute to their critical mass.

The average residence time of water vapor in the stratosphere is about 10 day. The replenishment, precipitation and evaporation of water are the results of evaporation of oceans, lakes, rivers and plants and other biological and geological processes.