Structural humidity
Introduction
Humidity is the amount of water vapor in the air. This is the name given to the water that permeates a body or the vapor present in the atmosphere, which, through condensation "Condensation (change of state)"), comes to form clouds, which are no longer formed by vapor but by water.
Water is present in all living bodies, whether animals or plants, and that presence is of great importance and even fundamental for life. In fact, water is so necessary for living beings that, in the case of human beings, for example, they can survive longer without eating than without drinking.
Etymology
The word "humidity" comes from medieval Spanish humidad, this haplology of late Latin humidĭtas, -ātis 'quality of moist', and is formed by humĭdus 'humid, humid' and the qualitative suffix -itas '-ity'.[1][2].
Air humidity
It is the amount of water vapor present in the air, it can be expressed absolutely through absolute humidity, or relatively through relative humidity or degree of humidity. Relative humidity is the percentage relationship between the amount of actual water vapor contained in the air and the amount it would need to contain to be saturated at the same temperature.
Air humidity is a factor that serves to evaluate the thermal comfort of the living body that moves in a certain environment. It is used to evaluate the capacity of the air to evaporate moisture from the skin, mainly due to perspiration. It is also important, both air and land, for the development of plants.
Water vapor has a lower density than air, so humid air (a mixture of air and vapor) is less dense than dry air. Furthermore, substances, when heated, expand, therefore having a lower density. Hot air containing water vapor rises into the atmosphere. The temperature of the atmosphere decreases by an average of 0.6 °C every 100 m. Upon reaching colder areas, water vapor condenses and forms clouds (water droplets or ice crystals). When these water droplets or ice crystals come together by contact when they cool, they weigh too much and fall, causing precipitation in the form of rain or snow.