The air cover of our planet is called the terrestrial atmosphere. All planets have atmospheres, everyone differs from another on the structure. The terrestrial atmosphere represents the mix consisting approximately of 20 gases.
The atmosphere – the natural mix of gases consisting mainly of oxygen and nitrogen and also important impurity: water vapor, ozone and carbon dioxide. The gases which are a part of air have a certain density and render pressure which is equal to air column weight from the surface of the sea to the upper bound of the atmosphere on each square centimeter of the Earth's surface, on average having the size of 1.033 kg/cm2 above sea level. The federal law "About Protection of Atmospheric Air" says that the concept "atmospheric air" is understood as "the vital component of the environment representing the natural mix of gases of the atmosphere which is outside inhabited, production and other rooms". The atmosphere is necessary for normal existence of overwhelming number of the living organisms living on the earth since the oxygen which is contained in air in the course of breath comes to cages of an organism and is used in oxidizing process of which allocation of energy, necessary for activity is result (aerobes, metabolism). In life and the industry oxygen is used for combustion of fuel for obtaining heat and mechanical energy in internal combustion engines. Also air serves for receiving the inert gases which are transformed by a combustion method. The carbon dioxide which is in the atmosphere is so-called heater of Earth because passing short-wave solar radiation it at the same time the thermal radiation proceeding from the Earth's surface detains, causing thereby greenhouse effect. It is a peculiar construction material for synthesis of organic matter at photosynthesis. Also in the atmosphere there are photochemical processes promoting formation of ozone. Ozone, in turn, absorbs a considerable part of ultra-violet radiation of the Sun.