Indicators of air humidity. Absolute humidity

If for an ordinary person the absolute humidity of air in everyday life has a comparative value and only affects the comfort of the microclimate in the room or on the relative perception of the weather on the street, then at the professional level, many types of human activity require regular monitoring and even regulation of this indicator.

The air surrounding us is a natural cocktail, which contains a full range of components necessary for the life of all living things on planet Earth. Water vapor has the status of a necessary component in the life-saving recipe written by Nature itself. Fluctuations in the concentration of moisture in the environment occur in limits that are acceptable for the life of living organisms.

But at certain points it is the amount of water (vapor) that is in the air that can provoke the emergence of various physical, biological and chemical processes. In such cases, absolute humidity becomes very important, requiring constant monitoring and finding ways to regulate it. Accepting for a purposeful study of the concentration of water vapor in the air, we will define the most important measuring quantity that determines the amount of moisture dissolved in the gas.

Most scientific sources give an explanation that absolute air humidity is the amount of water (vapor) dissolved in a certain amount of air. The system of SI units measures this value in grams per cubic meter. In the GHS standard, absolute humidity is measured in grams per cubic centimeter. In the terrestrial atmosphere, this range ranges from 0.1-1.0 g / m3, fixed above the continents in winter, in polar latitudes, and up to 30 g / m3 (and even higher) for the equatorial zone.

The study of the behavior of water (vapor), dissolved in gas, made it possible to reveal a number of interesting regularities. By creating a certain pressure, the water vapor introduces its own corrections to the barometric pressure of the air. But the pressure of water vapor, which directly affects the absolute humidity, rises to a certain limit, which depends only on temperature. This value is also called the saturation pressure.

Having reached the saturation limit, the absolute humidity of the air does not change any more. The dependence table accurately records how at a certain moment the amount of moisture in the air can not rise, and its excess drops out in the form of condensate during physical experiments or dew, fog, rain under natural conditions.

We clearly see that neither the pressure of the environment nor the presence of other gases in the air affect the changes in the pressure of water vapor. Cooling of saturated warm air can lead to condensation. Physics temperature, which accompanies a similar phenomenon, is called the saturation point temperature. It is usually indicated in degrees Celsius.

Using the saturation point, the water vapor pressure is found for moist air. In other words, the saturation point determines the moment when the absolute humidity of air reaches its limiting dimensions. The use of different dimensions does not change the indications of their relationships with each other.

Despite the most complete assessment of the amount of moisture in the air, in most cases, not absolute, but relative humidity is used. To determine this value, take the ratio of absolute humidity to the maximum possible amount of moisture that can be contained in the ambient air for a particular temperature. Measure the relative humidity in percent.

It is on the value of relative humidity that the intensity of evaporation of moisture from the parquet, wooden furniture or from the human skin depends. An increased amount of moisture content can affect the safety of certain substances in storage facilities. In the reports of the Hydrometeorological Center, it is relative humidity.