Our Earth is protected by an amazing shell - the atmosphere. It prevents cosmic bodies from falling onto the planet and is one of the main conditions for human life. What is air made of and why is it so important for animals and plants existing on Earth? The answers to these and other questions can be found in this article.
What structure does the atmosphere have?
The air shell of the Earth consists of several layers that have distinctive features.
- Troposphere. This is the lowest and most dense layer of the atmosphere. 80% of air is concentrated in it. Its thickness varies depending on the location: in the equator, it is greater than above the poles. It is here that weather forms, fog and clouds form. The maximum thickness of the troposphere reaches 17 kilometers.
- Stratosphere. In this layer, located at an altitude of 50 km, the opposite is observed than in the troposphere, the temperature changes with height - it rises. Here is the ozone layer and contains the minimum number of water molecules. An ozone layer is formed in the stratosphere at an altitude of 20 kilometers.
- Mesosphere. Here clouds form, which consist of ice crystals, and a decrease in air density is observed. The mesosphere is located at a distance of 80-85 kilometers from the surface of the earth and has a temperature of minus 90 degrees Celsius.
- Thermosphere. Here, as a result of the collision of air particles with cosmic particles, a special glow appears, called the "aurora." This layer also has a maximum temperature in the atmosphere - plus 1500 degrees Celsius.
- Exosphere. It extends to an altitude of 20,000 kilometers and has a second name "the crown of the Earth" due to the diffuse shape of its borders.
What substances does air consist of?
It should be noted that the atmosphere on the planet has formed a very long time. But at the time of the youth of our Earth, it consisted mainly of the waste products of volcanoes. Only with the spread of the first plants along it, the air began to be enriched with oxygen, which made it suitable for human breathing. Many planets in the solar system have an atmosphere. But the composition that is suitable for human and animal life is only ours. Currently, the main share of atmospheric air is composed of two main gases: nitrogen and oxygen. In percentage terms, the content of these substances is as follows: 78:21. Finding out what gases the air consists of, it is necessary to indicate the composition of the one percent that remains after subtracting the sum of the main gases from 100%. In the atmosphere, along with nitrogen and oxygen, contains carbon, hydrogen, inert gases, water vapor and other impurities. Oxygen is one of the main conditions of life for people and animals, but carbon is needed by plants.
Is water in the air?
Along with gases, there is water vapor in the air, which, depending on the height, can also be in the form of crystals. The content of this substance in the air under certain conditions leads to the formation of fog and clouds. The total amount of atmospheric water on our planet is 14,000 cubic kilometers. By the way, the weight of air directly depends on the amount of water vapor contained in it. The more of them, the lighter the air, since the air is heavier than them.
What impurities can be in the air of big cities?
Harmful gases enter the atmosphere during the combustion of coal, gasoline, chemicals and artificial materials. As a result of the spread of automobile, railway and other modes of transport, as well as the activities of industrial enterprises, the air is polluted with impurities. What does air in a big city consist of? Not only from substances such as carbon, oxygen and nitrogen, but also from carbon monoxide, methane and sulfur dioxide, which cause irreparable harm to the Earth’s biosphere.
For example, if the air contains more than 3% carbon dioxide, then this can cause the death of a living organism, since 0.03% is considered the norm. A large amount of smoke, gases and soot, which are contained in a polluted atmosphere, is called "smog". It envelops many industrial areas and large cities on Earth.
How is acid rain formed?
The formation of such precipitation can be explained by knowing the structure of the atmosphere. What are the molecules of air? It is a gas mixture and water vapor. It contains water molecules and other substances. When foreign impurities enter the atmosphere, the atoms of these components combine with water, turn into acid and fall to the ground. Such rains cause great harm to plants, animals and people and are a real environmental disaster.
What is the ozone layer and where is it located?
It is formed in the stratosphere, at a distance of 20 kilometers from the Earth. The ozone layer protects the biosphere of our planet from harmful UV radiation. It also neutralizes the effects of many harmful substances and bacteria. What does the air in the ozone layer consist of? It contains active oxygen, which is formed as a result of the influence of electrical discharges or sunlight on molecular. The release of methane, chlorine, bromine and nitric oxide contained in air conditioners and refrigeration units into the atmosphere leads to the destruction of this layer, which is one of the global environmental problems of civilization.
What does atmospheric air consist of?
The air composition given in the article is characteristic only for the lower atmosphere, which is called the "troposphere". The farther from the surface of the earth, the more changes in it occur. What is the composition of air in the upper atmosphere? The first changes are found in the ozone layer - active oxygen appears. Further, at a distance of 1,000 km and above the surface of the Earth, the predominance of atomic hydrogen and helium begins. The pressure also changes with height - it decreases, as the air becomes more discharged.
What pollutes the atmosphere?
The worse the ecological situation in the region, the more foreign matter is contained in the air and the more dangerous it is for human and animal life. With the development of civilization, the negative impact on the air shell of the Earth has greatly increased. Industrial enterprises, automobile and railway transport, innovative benefits of civilization (air conditioners, cooling plants, etc.) pollute the surrounding area, which leads to a decrease in the ozone layer, the formation of smog and acid rain.
Today, all over the world, preference is given to environmentally friendly technologies and transport, but a complete transition to such industries will require a certain amount of time and high material costs and will last quite a long time.
Conclusion
Even 30 years ago, we were surprised when we heard that in Western countries they sell simple bottled drinking water. Today, any resident of a big city, more or less concerned about his health, will not drink what flows from the tap in our apartments. Purchasing water to quench your thirst and cook has become the norm.
In major cities of China, the sale of clean air in cans began. And before such facts were described only in science fiction stories. What air consists of today depends on each earthling. Any person can do a lot for the environment, following simple rules every day: do not wash the car in natural reservoirs, put out fires on time, quit smoking, start burning trash and foliage in specially designated places, etc. After all, it is very important for us to know what air our descendants will breathe on Earth! And will they breathe ...