The earth can probably not be called a purely water world, but 70% of the planet’s surface is covered with water. Without her, life would have been impossible. The air we breathe is saturated with moisture, and our bodies are mostly composed of water. And a measure of the atmospheric water content is air humidity.
What does such a concept mean? Water in the air may be contained in the form of drops or water vapor. The water content in grams per 1m3 of air is the absolute humidity of the air. But the possible amount of water in the atmosphere depends on the temperature. The higher it is, the more moisture can be in the air. In order to somehow circumvent this dependence, the concept of relative humidity was introduced.
It is understood as the ratio of the existing humidity to the maximum possible at the current temperature. Relative humidity shows how much of the maximum possible is the current humidity. If the current is 60%, then the air contains 60% of the maximum possible amount of water vapor at the current temperature.
To measure the content of water vapor in the atmosphere, special instruments are used - psychrometers. The fact is that air humidity is an extremely important parameter that directly affects human health and the performance of equipment. As already mentioned, the human body contains a large amount of water, which is critical to its content in the air. If the presence of moisture in the atmosphere is very different from normal, then this will negatively affect health.
If there is insufficient water in the surrounding atmosphere, then the skin and mucous membranes of a person will begin to dry. For humans, normal air humidity is in the range of forty to sixty percent. At the same time, the body works in optimal conditions for it. It should be noted here that in summer the air is sufficiently humidified, however, in winter, especially indoors, humidity can be no more than 15%.
The reason is that the central heating system warms up the air in the room, which means that there can be more water vapor in it at elevated temperatures. But the water content in the air does not change, and therefore the humidity decreases. The consequence of this will be increased fatigue and decreased immunity due to dry skin and mucous membranes.
High humidity has its negative sides. In a person under such conditions, the evaporation of moisture through the skin worsens, its excess is formed in the body, which again leads to a deterioration in well-being. In addition, in rooms with high humidity, all conditions are created for the propagation of harmful microbes and mold, which may result in asthma and allergies. And the service life of household appliances and furniture in such conditions is significantly reduced.
When observing nature, it was found that there is a change in humidity during the day, the so-called diurnal course. Moreover, in the process of observation over the seas it was found that during the day the water vapor content in the atmosphere is one minimum and one maximum. A minimum is observed in the morning, a maximum of about thirteen to fourteen hours. A similar behavior of humidity occurs similarly with respect to the course of temperature and evaporation of water.
The obtained data on humidity, its rate of change and daily course allow using these data for short-term weather forecasts. So, it is generally accepted that if the daily course of humidity corresponds to the course of temperature, then we can expect that in the next 12-24 hours the weather caused by the anticyclone will remain.
Humidity in the atmosphere surrounding a person is a factor affecting his health. And ensuring optimal humidity conditions in the room will allow for a long time to ensure health and performance.