Earth's atmosphere is air envelope planet, which includes gas and impurities, such as dust, salt, or water of combustion products, the amount of them is not constant, in contrast to the gas concentration.Consider in detail the gas composition of the atmosphere in a percentage: Nitrogen - 78% Oxygen - 21% xenon - 8.7% hydrogen - 5%, nitrous oxide - 5% helium is also - 4.6%, neon - 1.8% methane - 1.7% krypton - 1.1% argon - 0.9%, water - 0.5% and carbon dioxide - 0.03%.
The composition of the atmosphere include water vapor, which varies in space and time, and is concentrated in the troposphere.Has the ability to change and carbon dioxide, its content depends on human life and plants.Aerosol particles produced by human activities, often found in the troposphere and at a great height, but in the latter case they are in small doses.
Thus, the composition of the atmosphere varies with the altitude.In the layers that are close to the ground, the amount of carbon dioxide increases and oxygen - is reduced.In some places, increasing the percentage of methane and other gases that contribute to the destruction of the ozone layer, the appearance of the greenhouse effect and acid rain.About 10% of impurities into the atmosphere as a result of natural processes.For example, during the eruption of volcanoes in her fall ash, sulfuric and other acids, and toxic gases.It is also a source of sulfur are decaying plant remains a drop of sea water, and forest fires.In addition, recent promote release of VOC (volatile organic compounds).The remaining 90% of impurities, which are part of the atmosphere to fall as a result of human activity.This may be, for example, emission of smoke, soil erosion and other waste storage.
It should be noted that the atmosphere has five layers whose boundaries are determined by changes in temperature-dependent differences in the absorption of radiation.
Thus, the lower layer (troposphere) receives gases from the ground.Troposphere accommodates two main blowing components, nitrogen and oxygen.Also, this layer has a large quantity of aerosols and steam flowing through evaporation of water from the ocean surface.
followed by the stratosphere, which is similar to the composition of the troposphere.However, here the amount of water vapor in a thousand times less, and ozone is a thousand times greater.
Furthermore, the composition of the atmosphere includes a variety of substances that contaminate it and have a harmful effect on living organisms.Consider some of them.
1. Sulphur dioxide emitted into the atmosphere by evaporation of sea water, gas emission and other natural processes, as well as the combustion of fuel.There it reacts with water vapor to form sulfuric acid.
2. Carbon monoxide generated by the combustion of wood fuel and tobacco, as well as when the internal combustion engine.
3. VOCs (isoprene, terpenes and methane) are formed due to the activity of chemical plants, thermal power plants, as well as the evaporation of the moisture in the rice plantations and marshes.
4. oxide (dioxide) is formed when a nitrogen shortage of oxygen in the combustion of fuel, and when a large amount of exhaust gases and emissions by power plants.
5. Photochemical oxidants (PAN, formaldehyde and ozone) are formed as a result of chemical reactions taking place with the participation of the solar radiation.
Thus, in the earth's atmosphere contains a large number of different elements and substances.Some of these are essential for maintaining the activity of organisms on the planet, others are playing for their harmful role, contributing to their destruction.It is therefore necessary to ensure that the atmosphere has been received large amounts of harmful substances that are gradually destroying it.