The atmosphere is an odorless, colorless and tasteless gaseous layer that surrounds the Earth and accompanies all its movements, attaching itself to it by the action of gravity.
Formed by a mechanical mixture of gases that make up the air , it is indispensable for the existence of the plant and animal world: it provides the oxygen necessary for breathing, acts in the maintenance of the planet’s thermal balance, enables combustion , the transmission of sound, the diffusion of light and, mainly, absorbs a large part of the energy emitted by the Sun, allowing only the passage of solar radiation necessary for life.
Thus, over millions and millions of years, it has moved towards the current atmosphere, with its approximately 21% free oxygen, in a balance that is increasingly fragile in the face of the many and constant polluting actions of human society.
In defense of the quality of the air we breathe, we must rely on the indispensable action of vegetation cover, especially forests, and hence our concern with safeguarding this priceless green heritage.
Atmosphere composition
Our atmosphere is rich in oxygen, while on other planets this gas is very scarce and the atmospheres mainly contain hydrogen or carbon dioxide (CO 2 ).
On Earth, with the exception of some bacteria and fungi, all living things need oxygen . It is the second element of the atmosphere in quantity, but the most important for living beings to obtain energy for their survival.
Air is a mixture of gases: 78% nitrogen, 21% oxygen, 1% carbon dioxide, dust and very small amounts of other gases. Although the concentration of these gases is fixed, it is currently verified that, with regard to some of its constituents, changes are taking place.
Our atmosphere is also rich in water , which is found in the form of steam, raindrops or tiny crystals of ice suspended in the clouds. The atmosphere looks like a large reservoir of water, which originates from the evaporation of water from rivers, lakes, oceans and even the soil, by heating the sun and, mainly, by the transpiration of vegetables.
Depending on the location and temperature, this vapor leaves the air with more or less humidity. Very dry air becomes unsuitable for breathing, causing allergic attacks in people with diseases such as bronchitis and rhinitis.
The most abundant gas on Earth is nitrogen (N 2 ), a colorless gas that makes up 78% of the air volume. Nitrogen is an important chemical element for all living beings, in the synthesis of proteins. This gas is of great importance for the development of vegetables and, in the soil, it is widely used by various types of bacteria.
Another gas in reduced quantity (only 0.04%) is carbon dioxide (CO 2 ). It is the product of the breathing of living beings and all combustion processes. Like nitrogen, it does not cause or maintain combustion and with a high amount of this gas in the atmosphere it would be impossible to survive.
Less than 1% of the air consists of a set of little-known gases, which, because they are in very small quantities, in addition to the chemical stability they present, are called noble gases . Are they:
In the air, there are still a lot of microorganisms, invisible to our eyes: bacteria , viruses , mites and fungal spores .
In places of greater population concentration, the presence of these beings is greater. They are responsible for many diseases, such as pneumonia, flu, respiratory allergy, etc.
The atmosphere may still contain the presence of harmful chemicals (harmful to health), many of which are carcinogenic. Industries, factories and the population itself are responsible for the presence of these substances in the atmosphere, due to attitudes of disrespect to nature, such as burning tires, unregulated exhausts, lack of filters in chimneys, etc.
Atmosphere layers
The atmosphere is divided into two main layers: troposphere and stratosphere, with the mesosphere, ionosphere and exosphere.
- The troposphere, which has an average height of 11 kilometers, is the layer that directly surrounds the earth. This is where meteorological phenomena, such as rain, occur.
- The stratosphere is right after the troposphere. It practically does not register atmospheric phenomena.
- The mesosphere, with its protective ozone layer, decreases the amount of ultraviolet rays whose excess would be fatal to the life of the planet.
- The ionosphere has very thin air.
- The exosphere starts some six hundred kilometers above the Earth’s surface. In it, nitrogen is specially registered .
Without this mantle that surrounds our planet, living beings would not be able to survive. Therefore, air pollution is a constant danger, the consequences of which can be catastrophic for the entire life of the planet.
