Composition of the atmosphere

The Earth's atmosphere is the air envelope of the planet, which consists of gases and impurities, for example, dust, salts, combustion products or water, while their quantity is not a constant, unlike the concentration of gases. Let's consider in detail the gas composition of the atmosphere in a percentage ratio: nitrogen - 78%, oxygen - 21%, xenon - 8.7%, hydrogen - 5%, nitrous oxide - 5%, helium - 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 includes water vapor, which varies in space and time and is concentrated in the troposphere. Has the property to change and carbon dioxide, its content directly depends on the vital activity of man and plants. Aerosol particles, formed as a result of human activity, are often found in the troposphere and at great altitudes, but in the latter case they are in small doses.

Thus, the composition of the atmosphere varies with height. In layers that are near the ground, the amount of carbon dioxide is increased, and oxygen is reduced. In some places, 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 increases . About 10% of the impurities enter the atmosphere as a result of natural processes. For example, during the eruption of volcanoes, ashes, sulfuric and other acids, and also poisonous gases enter it. Also, the source of sulfur is decomposing plant remains, drops of sea water and forest fires. In addition, the latter contribute to the release of VOC (volatile organic compounds). The remaining 90% of the impurities that make up the atmosphere come from people's activities. This can be, for example, smoke emissions, soil erosion, waste storage and so on.

It should be noted that the atmosphere has five layers whose boundaries are determined by changes in the temperature regime, which depends on differences in the absorption of radiation.

Thus, the lower layer (troposphere) receives gases from the earth's surface. The troposphere contains two main gassing components: nitrogen and oxygen. Also this layer has a large amount of aerosols and water vapor, coming from evaporation from the surface of the oceans of water.

Next comes the stratosphere, which has a composition similar to the troposphere. However, here the amount of water vapor is a thousand times smaller, and the ozone is a thousand times larger.

In addition, the composition of the atmosphere includes various substances that pollute it and have a harmful effect on living organisms. Let's consider some of them.

1. Sulfuric gas enters the atmosphere during the evaporation of sea water, the emission of gases and other natural processes, as well as the combustion of fuel. Here it reacts with water vapor and forms sulfuric acid.

2. Carbon monoxide is formed as a result of the combustion of wood, fuel and tobacco, as well as the operation of the internal combustion engine.

3. VOCs (isoprene, terpene and methane) are formed due to the activities of chemical plants, thermal power plants, as well as evaporation of moisture in rice plantations or swamps.

4. Oxide (dioxide) of nitrogen is formed with a lack of oxygen as a result of fuel combustion, as well as with a large amount of exhaust gases and emissions at TPPs.

5. Photochemical oxidants (PAN, formaldehyde and ozone) are formed as a result of chemical reactions involving solar radiation.

Thus, the composition of the earth's atmosphere includes a large number of different elements and substances. Some of them are indispensable for maintaining the life of organisms on the planet, others play a destructive role for them, contributing to their destruction. That is why it is necessary to ensure that the atmosphere does not receive a large amount of harmful substances that gradually destroy it.