Often from TV screens or from radio speakers we hear about air pressure and humidity. But few know what their indicators depend on and how their particular values affect the human body.
Humidity is a characteristic of atmospheric saturation with water vapor. At different points on the globe, its performance can be dramatically different. In nature, there is no air without water vapor. There is no place on Earth where zero relative humidity occurs. So, in the desert, sugar - 25 percent, in the Brazilian jungle - 90.
Relative humidity is the ratio of the amount of moisture in the atmosphere compared to the maximum possible at a given temperature or the degree of saturation with water. That is, this indicator indicates how much more vapor is needed for the condensation process to begin. Relative humidity is one of the most important characteristics of the environment.
The absolute value is measured in 1 g / m3 or in millimeters of mercury. At the equator, it is 20-30 g / m3, while in the Arctic and Antarctic it is 0.1-1.
Humidity for humans
Humidity, the norm of which for residential premises is from 40 to 60 percent, is clearly felt by a person. It reaches its greatest value in the summer during rainy weather: then its indicator is located at around 80-90%.
In winter, the opposite situation is observed in the apartments of Russians. Due to heating, relative humidity reduces as much as 15 percent. This is due to an increase in temperature from heaters, which, in turn, causes the active evaporation of moisture from the surface of the body and furniture.
Humidity is often an underestimated factor. When this indicator strives for minimum or maximum values, the person's well-being worsens: fatigue increases, memory properties and concentration decrease. In order to stay in physical and mental tone, it is necessary to ensure optimal humidity in the rooms in which people live and work. For this, there are special air conditioning systems.
The evaporation of moisture from the skin also depends on humidity, which, in turn, determines the temperature of the human body and the state of his body. A favorable indicator for life is 40-60%. It is this humidity that makes you feel good. This figure is artificially maintained in the spaceship compartments.
Means and methods of determination
To determine the saturation of air with water vapor, special devices are used: psychrometers and hydrometers. The Augustus Psychrometer is a bar with two thermometers: wet and dry.
The first is wrapped in a cloth dampened with water, which cools its body during evaporation. Based on the readings of these thermometers, the relative humidity is determined from the tables. There are many different hydrometers, their work can be based on weight, film, electric or hair, as well as a number of other principles of action. In recent years, integrated measurement sensors have gained popularity. In order to check the accuracy of measuring instruments, hydrostats are used.
