Since the existence of life, the comfort and safety of all organisms depend on it. The indicators of gases in the mixture are decisive for the study of problem areas or environmentally friendly areas.

General information

The term "atmosphere" refers to the gas layer that envelops our planet and many others. celestial bodies in the Universe. It forms a shell that rises above the Earth for several hundred kilometers. The composition contains a variety of gases, the main of which is oxygen.

The atmosphere is characterized by:

• Heterogeneity with physical point vision.
• Increased dynamism.
• Dependent on biological factors(high vulnerability in case of adverse events).

The main influence on the composition and processes of its changing, living beings (including microorganisms). These processes have been going on since the formation of the atmosphere - several billion years. Protective shell the planet is in contact with such formations as the lithosphere and hydrosphere, while it is difficult to determine the upper boundaries with high accuracy, scientists can only name approximate values. The atmosphere goes into interplanetary space in the exosphere - at a height
500-1000 km from the surface of our planet, some sources give a figure of 3000 km.

The importance of the atmosphere for life on earth is great, as it protects the planet from collision with space bodies, provides optimal indicators for the formation and development of life in its various forms.
The composition of the protective shell:

• Nitrogen - 78%.
• Oxygen - 20.9%.
• Gas mixture - 1.1% (this part is formed by substances such as ozone, argon, neon, helium, methane, krypton, hydrogen, xenon, carbon dioxide, water vapor).

The gas mixture performs important function- absorption of excess solar energy. The composition of the atmosphere varies depending on the height - at an altitude of 65 km from the Earth's surface, nitrogen will be contained in it
already 86%, oxygen - only 19%.

The constituent elements of the atmosphere

The diverse composition of the Earth's atmosphere allows it to perform various functions and protect life on the planet. Its main elements:

• Carbon dioxide (CO₂) is an essential component involved in the process of plant nutrition (photosynthesis). It is released into the atmosphere due to the respiration of all living organisms, decay and combustion of organic substances. If carbon dioxide disappears, then plants will cease to exist with it.
• Oxygen (O₂) - provides an optimal environment for the life of all organisms on the planet, is required for respiration. With its disappearance, life will end for 99% of organisms on the planet.
• Ozone (O 3) is a gas that acts as a natural absorber of ultraviolet radiation emitted solar radiation. Its excess negatively affects living organisms. Gas forms a special layer in the atmosphere - ozone screen. Under the influence external conditions and human activity, it begins to gradually collapse, so it is important to take measures to restore the ozone layer of our planet in order to save life on it.

Also in the composition of the atmosphere there are water vapor - they determine the humidity of the air. The percentage of this component depends on various factors. Influenced by:

• Air temperature indicators.
• The location of the area (territory).
• Seasonality.

It affects the amount of water vapor and temperature - if it is low, then the concentration does not exceed 1%, when it is elevated, it reaches 3-4%.
Additionally included in earth's atmosphere there are hard and liquid impurities- soot, ashes sea ​​salt, a variety of microorganisms, dust, water drops.

Atmosphere: its layers

It is necessary to know the structure of the earth's atmosphere by layers in order to have full view about the value of this gas envelope. They stand out because the composition and density gas mixture are different at different heights. Each of the layers differs in chemical composition and functions. Arrange the atmospheric layers of the earth in order as follows:

Troposphere - located closest to the rest earth's surface. The heights of this layer reach 16-18 km in tropical zones and 9 km on average over the poles. Up to 90% of all water vapor is concentrated in this layer. It is in the troposphere where clouds form. Air movement, turbulence and convection are also observed here. Temperature indicators are different and range from +45 to -65 degrees - in the tropics and at the poles, respectively. With an increase of 100 meters, there is a decrease in temperature by 0.6 degrees. It is the troposphere, due to the accumulation of water vapor and air, that is responsible for cyclonic processes. Accordingly, the correct answer to the question, what is the name of the layer of the earth's atmosphere in which cyclones and anticyclones develop will be the name of this atmospheric layer.

Stratosphere - this layer is located at an altitude of 11-50 km from the surface of the planet. In its lower zone, temperature indicators tend to values ​​of -55. There is an inversion zone in the stratosphere - the boundary between this layer and the next one, called the mesosphere. Temperature indicators reach values ​​of +1 degree. Airplanes fly in the lower stratosphere.

The ozone layer is a small area on the border between the stratosphere and mesosphere, but precisely ozone layer atmosphere protects all life on earth from the action of ultraviolet radiation. It also separates comfortable and favorable conditions for the existence of living organisms and harsh space, where it is impossible to survive without special conditions even bacteria. It was formed as a result of the interaction of organic components and oxygen, which comes into contact with ultraviolet radiation and enters into photochemical reaction which produces a gas called ozone. Since ozone absorbs ultraviolet radiation, it contributes to the heating of the atmosphere, maintaining optimal conditions for life in its usual form. Accordingly, to answer the question: what layer of gas protects the earth from cosmic radiation and excessive solar radiation, followed by ozone.

Considering the layers of the atmosphere in order from the surface of the earth, it should be noted that the next is the mesosphere. It is located at an altitude of 50-90 km from the surface of the planet. Temperature indicators - from 0 to -143 degrees (lower and upper limits). It protects the Earth from meteorites that burn up as they pass through
it is the phenomenon of the glow of the air. The gas pressure in this part of the atmosphere is extremely low, which makes it impossible to study the entire mesosphere, since special equipment, including satellites or probes, cannot work there.

The thermosphere is the layer of the atmosphere that is located at an altitude of 100 km above sea level. This is the lower limit, which is called the Karman line. Scientists conditionally determined that space begins here. The immediate thickness of the thermosphere reaches 800 km. Temperature readings reach 1800 degrees, but keep the skin spacecraft and missiles intact allows a slight concentration of air. In this layer of the earth's atmosphere, a special
phenomenon - Northern Lights – special kind glow, which can be observed in some regions of the planet. They appear due to the interaction of several factors - the ionization of air and the action on it cosmic radiation and radiation.

What layer of the atmosphere is farthest from the earth - the exosphere. There is a zone of air dispersion here, since the concentration of gases is small, as a result of which they gradually escape from the atmosphere. This layer is located at an altitude of 700 km above the Earth's surface. The main element that makes up
this layer is hydrogen. In the atomic state, you can find substances such as oxygen or nitrogen, which will be highly ionized by solar radiation.
The dimensions of the Earth's exosphere reach 100 thousand km from the planet.

By studying the layers of the atmosphere in order from the surface of the earth, people got a lot valuable information, which helps in the development and improvement of technological capabilities. Some facts are surprising, but it was their presence that allowed living organisms to develop successfully.

It is known that the weight of the atmosphere is more than 5 quadrillion tons. The layers are capable of transmitting sounds up to 100 km from the surface of the planet, above this property disappears, as the composition of gases changes.
Atmospheric movements exist because the heating of the Earth varies. The surface at the poles is cold, and closer to the tropics, warming increases, temperature indicators are influenced by cyclonic eddies, seasons, and time of day. The atmospheric pressure can be measured by using a barometer. Scientists have observed that the presence of protective layers helps to prevent contact with the surface of the planet of meteorites total weight 100 tons daily.

An interesting fact is that the composition of the air (a mixture of gases in layers) remained unchanged over a long time period - several hundred million years are known. Significant changes are taking place in recent centuries- since the moment when humanity is experiencing a significant rise in production.

The pressure exerted by the atmosphere affects the well-being of people. Normal for 90% are indicators of 760 mmHg, this value should occur at 0 degrees. It should be borne in mind that this value is valid for those parts of the earth's land where the sea level passes with it in the same band (without drops). How more height the lower the pressure will be. It also changes during the passage of cyclones, since changes occur not only vertically, but also horizontally.

The physiological zone of the earth's atmosphere is 5 km, after passing this mark, a person begins to manifest special condition- oxygen starvation. In this process, 95% of people experience a pronounced decrease in working capacity, and well-being also deteriorates significantly even in a trained and trained person.

That is why the importance of the atmosphere for life on earth is great - people and most living organisms cannot exist without this gas mixture. Thanks to their presence, it became possible to develop the habitual modern society life on earth. It is necessary to assess the damage caused by industrial activities, to carry out air purification measures in order to reduce the concentration certain types gases and bring in those that are not enough for a normal composition. It is important to think now about further measures to preserve and restore layers of the atmosphere in order to save optimal conditions for future generations.

The atmosphere is the gaseous shell of our planet that rotates with the Earth. The gas in the atmosphere is called air. The atmosphere is in contact with the hydrosphere and partially covers the lithosphere. But it is difficult to determine the upper bounds. Conventionally, it is assumed that the atmosphere extends upwards for about three thousand kilometers. There it flows smoothly into the airless space.

The chemical composition of the Earth's atmosphere

The formation of the chemical composition of the atmosphere began about four billion years ago. Initially, the atmosphere consisted only of light gases - helium and hydrogen. According to scientists, the initial prerequisites for the creation of a gas shell around the Earth were volcanic eruptions, which, together with lava, threw out great amount gases. Subsequently, gas exchange began bodies of water, with living organisms, with the products of their activity. The composition of the air gradually changed and modern form established several million years ago.

The main components of the atmosphere are nitrogen (about 79%) and oxygen (20%). The remaining percentage (1%) is accounted for by the following gases: argon, neon, helium, methane, carbon dioxide, hydrogen, krypton, xenon, ozone, ammonia, sulfur dioxide and nitrogen, nitrous oxide and carbon monoxide included in this one percent.

In addition, the air contains water vapor and particulate matter(plant pollen, dust, salt crystals, aerosol impurities).

AT recent times scientists note not a qualitative, but a quantitative change in some air ingredients. And the reason for this is the person and his activity. Only in the last 100 years carbon dioxide has increased significantly! This is fraught with many problems, the most global of which is climate change.

Formation of weather and climate

The atmosphere is playing essential role in the formation of climate and weather on Earth. A lot depends on the amount of sunlight, on the nature of the underlying surface and atmospheric circulation.

Let's look at the factors in order.

1. The atmosphere transmits the heat of the sun's rays and absorbs harmful radiation. The fact that the rays of the Sun fall on different parts of the Earth under different angles the ancient Greeks knew. The very word "climate" in translation from ancient Greek means "slope". Yes, at the equator Sun rays they fall almost vertically, because it is very hot here. The closer to the poles, the more angle tilt. And the temperature is dropping.

2. Due to the uneven heating of the Earth, air currents are formed in the atmosphere. They are classified according to their size. The smallest (tens and hundreds of meters) are local winds. This is followed by monsoons and trade winds, cyclones and anticyclones, planetary frontal zones.

All these air masses are constantly moving. Some of them are quite static. For example, the trade winds that blow from the subtropics towards the equator. The movement of others is largely dependent on atmospheric pressure.

3. Atmospheric pressure is another factor influencing climate formation. This is the air pressure on the earth's surface. As you know, air masses move from an area with high atmospheric pressure towards an area where this pressure is lower.

There are 7 zones in total. Equator - zone low pressure. Further, on both sides of the equator up to the thirtieth latitudes - the region high pressure. From 30° to 60° - again low pressure. And from 60° to the poles - a zone of high pressure. Air masses circulate between these zones. Those that go from the sea to land bring rain and bad weather, and those that blow from the continents bring clear and dry weather. In places where air currents collide, atmospheric front zones are formed, which are characterized by precipitation and inclement, windy weather.

Scientists have proven that even a person's well-being depends on atmospheric pressure. By international standards normal Atmosphere pressure- 760 mm Hg column at 0°C. This figure is calculated for those areas of land that are almost flush with sea level. The pressure decreases with altitude. Therefore, for example, for St. Petersburg 760 mm Hg. - is the norm. But for Moscow, which is located higher, the normal pressure is 748 mm Hg.

The pressure changes not only vertically, but also horizontally. This is especially felt during the passage of cyclones.

The structure of the atmosphere

The atmosphere is like a layer cake. And each layer has its own characteristics.

. Troposphere is the layer closest to the Earth. The "thickness" of this layer changes as you move away from the equator. Above the equator, the layer extends upwards for 16-18 km, in temperate zones- at 10-12 km, at the poles - at 8-10 km.

It is here that 80% of the total mass of air and 90% of water vapor are contained. Clouds form here, cyclones and anticyclones arise. The air temperature depends on the altitude of the area. On average, it drops by 0.65°C for every 100 meters.

. tropopause- transitional layer of the atmosphere. Its height is from several hundred meters to 1-2 km. The air temperature in summer is higher than in winter. So, for example, over the poles in winter -65 ° C. And over the equator at any time of the year it is -70 ° C.

. Stratosphere- this is a layer, the upper boundary of which runs at an altitude of 50-55 kilometers. Turbulence is low here, water vapor content in the air is negligible. But a lot of ozone. Its maximum concentration is at an altitude of 20-25 km. In the stratosphere, the air temperature begins to rise and reaches +0.8 ° C. This is due to the fact that the ozone layer interacts with ultraviolet radiation.

. Stratopause- a low intermediate layer between the stratosphere and the mesosphere following it.

. Mesosphere- the upper boundary of this layer is 80-85 kilometers. Here, complex photochemical processes take place with the participation of free radicals. It is they who provide that gentle blue glow of our planet, which is seen from space.

Most comets and meteorites burn up in the mesosphere.

. mesopause- the next intermediate layer, the air temperature in which is at least -90 °.

. Thermosphere- the lower boundary begins at an altitude of 80 - 90 km, and the upper boundary of the layer passes approximately at the mark of 800 km. The air temperature is rising. It can vary from +500° C to +1000° C. During the day, temperature fluctuations amount to hundreds of degrees! But the air here is so rarefied that the understanding of the term "temperature" as we imagine it is not appropriate here.

. Ionosphere- unites mesosphere, mesopause and thermosphere. The air here consists mainly of oxygen and nitrogen molecules, as well as quasi-neutral plasma. The sun's rays, falling into the ionosphere, strongly ionize air molecules. In the lower layer (up to 90 km), the degree of ionization is low. The higher, the more ionization. So, at an altitude of 100-110 km, electrons are concentrated. This contributes to the reflection of short and medium radio waves.

The most important layer of the ionosphere is the upper one, which is located at an altitude of 150-400 km. Its peculiarity is that it reflects radio waves, and this contributes to the transmission of radio signals over long distances.

It is in the ionosphere that such a phenomenon as aurora occurs.

. Exosphere- consists of oxygen, helium and hydrogen atoms. The gas in this layer is very rarefied and hydrogen atoms often escape into space. Therefore, this layer is called the "scattering zone".

The first scientist who suggested that our atmosphere has weight was the Italian E. Torricelli. Ostap Bender, for example, in the novel "The Golden Calf" lamented that each person was pressed by an air column weighing 14 kg! But the great strategist was a little mistaken. An adult person experiences pressure of 13-15 tons! But we do not feel this heaviness, because atmospheric pressure is balanced by the internal pressure of a person. The weight of our atmosphere is 5,300,000,000,000,000 tons. The figure is colossal, although it is only a millionth of the weight of our planet.

Previously, it was believed (before the advent of artificial satellites) that as the distance from the earth's surface increased, the atmosphere gradually became more rarefied and smoothly passed into interplanetary space.

It has now been established that energy flows from the deep layers of the Sun penetrate into outer space far beyond the orbit of the Earth, up to the highest limits of the solar system. This so-called "solar wind" flows around earth's magnetic field, forming an elongated "cavity" within which the earth's atmosphere is concentrated.

The Earth's magnetic field is noticeably narrowed on the day side facing the Sun and forms a long tongue, probably extending beyond the orbit of the Moon, on the opposite night side.

Upper boundary of the earth's magnetosphere from the day side at the equator, the distance is approximately equal to 7 (seven) radii of the Earth.

6371: 7 = 42000 km.

Upper boundary of the Earth's magnetosphere from the day side near the poles a distance of approximately 28,000 km is considered. (which is due to the centrifugal force of the Earth's rotation).

In terms of volume, the atmosphere (about 4x10 12 km) is 3000 times larger than the entire hydrosphere (together with the World Ocean), but in terms of mass it is much smaller and is approximately 5.15x10 15 tons.

Thus, the "weight" of the atmosphere per unit area, or atmospheric pressure, at sea level is approximately 11 tons / m. The atmosphere is many times larger than the Earth, but only 0.0001 of the mass of our planet.

Natural gas composition of atmospheric air and the impact of some of its components on human health

Gas composition atmospheric air by volume is a physical mixture of nitrogen (78.08%), oxygen (20.94%), - the ratio of nitrogen and oxygen is 4: 1, argon (0.9%), carbon dioxide (0.035%) at the Earth's surface , as well as a small amount of neon (0.0018%), helium (0.0005%), krypton (0.0001%), methane (0.00018%), hydrogen (0.000015%), carbon monoxide (0, 00001%), ozone (0.00001%), nitrous oxide (0.0003%), xenon (0.000009%), nitrogen dioxide (0.000002%).

In addition, the air always contains a variety of fumes, dust and steam, suspended particles, aerosols and water vapor.

water vapor its concentration is about 0.16% of the volume of the atmosphere. At the earth's surface, it ranges from 3% (in the tropics) to 0.00002% (in Antarctica).

With height, the amount of water vapor decreases rapidly. If all the water were collected together, it would form a layer about 2 cm thick on average (1.6 -1.7 cm in temperate latitudes). This layer is formed at an altitude of up to 20 km.

The gas composition of the lower layers of the atmosphere at an altitude of up to 110 km. from the Earth's surface, especially the troposphere, is almost constant. The pressure and density in the atmosphere decreases with height. Half of the air is contained in the lower 5.6 km., and the second half up to a height of 11.3 km. At an altitude of 110 km. the density of air is a million times less than at the surface.

In the high layers of the atmosphere, the composition of the air changes under the influence of solar radiation, which leads to the breakdown of oxygen molecules into atoms.

Approximately up to an altitude of 400 - 600 km. the atmosphere remains oxygen- nitrogen.

A significant change in the composition of the atmosphere begins only from a height of 600 km. Here it begins to exceed helium. helium crown Earth - so called the helium belt V. I. Vernadsky, extends approximately to 1600 km. from the surface of the earth. Above this distance 1600 - 2 - 3 thousand km. there is an excess of hydrogen.

Some of the molecules decompose into ions and form ionosphere.

Over 1000 km. radiation belts are located. They can be considered as part of the atmosphere filled with very energetic nuclei of hydrogen atoms and electrons captured magnetic field planets. So constantly the gaseous shell of the Earth turns into interplanetary gas (space), which consists of:

Of 76% by weight of hydrogen;

Of 23% by weight of helium;

From 1% by mass from space dust.

Interestingly, our atmosphere differs sharply in composition from the atmospheres of other planets in the solar system. Our nearest neighbors Venus and Mars have mostly carbon dioxide atmospheres, more distant neighbors Jupiter, Saturn, Uranus, Neptune are surrounded by a helium-hydrogen atmosphere, at the same time there is a lot of methane in these atmospheres.

Atmospheric air is one of the most important natural resources, without which life on Earth would be absolutely impossible. Any component in its chemical composition is important for life in its own way.

OXYGEN – colorless and odorless gas with a density of 1.23 g/l. The most common chemical element on Earth.

In the atmosphere 20.94%, in the hydrosphere 85.82%, in the lithosphere 47% oxygen. When exhaling, a person releases 15.4 - 16.0% of oxygen atmospheric air. A person in a day at rest inhales about 2722 liters (1.4 m) of oxygen, exhales 0.34 m 3 of carbon dioxide, in addition, throws out per day in environment about 400 substances. Atmospheric air in this case passes through the lungs 9l. per minute, 540 l. per hour, 12960l. per day, and with a load of 25000 - 30000l. per day (25 - 30m 3). For a year he inhales 16950m at rest, with physical activity 20000 - 30000m, and throughout life from 65000 to 180000m. air.

It is a part of all living organisms (in the human body it is about 65% by weight).

Oxygen is an active oxidizing agent for most chemical elements, as well as in metallurgy, the chemical and petrochemical industries, in rocket fuels, it is used in breathing apparatus in space and submarine ships. People, animals, plants receive the energy necessary for life due to the biological oxidation of various substances with oxygen that enters the body. different ways through the lungs and skin.

Oxygen is an essential part of any combustion. Exceeding the oxygen content in the atmosphere by 25% can lead to fire on Earth.

It is released by plants during photosynthesis. At the same time, about 60% of oxygen enters the atmosphere during the photosynthesis of oceanic plankton and 40% of green plants sushi.

Physiological changes in healthy people observed in the event that the oxygen content drops to 16 - 17%, at 11 - 13% marked hypoxia is noted.

Oxygen starvation due to a decrease in atmospheric oxygen pressure can occur during flights (altitude sickness), when climbing mountains (mountain sickness), which begins at an altitude of 2.5 - 3 km.

A low concentration of oxygen can be created in the air of enclosed and hermetically sealed spaces, such as in submarines during accidents, as well as in mines, mines and abandoned wells, where oxygen can be displaced by other gases. It is possible to prevent the effect of oxygen deficiency during flights with the help of individual oxygen devices, space suits or pressurized aircraft cabins.

The life support system of spacecraft or submarines includes equipment that absorbs carbon dioxide, water vapor and other impurities from the air and adds oxygen to it.

For the prevention of mountain sickness, constant acclimatization (adaptation) at intermediate stations in a rarefied atmosphere is of great importance. When staying in the mountains, the amount of hemoglobin and red blood cells increases in the blood, and the oxidative processes in the tissues proceed more fully due to the increased synthesis of certain enzymes, which allows a person to adapt to life at higher altitudes.

There are mountain villages located at an altitude of 3-5 km. above sea level, especially trained climbers manage to climb mountains 8 km high. and more without the use of oxygen devices.

Oxygen in pure form has toxic effects. When breathing pure oxygen in animals, after 1-2 hours, telectases are formed in the lungs (due to blockage of the mucus of small bronchi), and after 3-5 hours, a violation of the permeability of the capillaries of the lungs, after 24 hours.

Symptoms of pulmonary edema. Under conditions of normal atmospheric pressure, when it is necessary to increase a person's working capacity with great physical exertion or in the treatment of patients with hypoxia, the pressure and oxygen supply are significantly increased up to 40%.

OZONE- modification of oxygen, which ensures the preservation of life on Earth; The ozone layer of the atmosphere traps some of the Sun's ultraviolet radiation and absorbs the Earth's infrared radiation, preventing it from cooling. It's gas of blue color with a pungent odor. The bulk of ozone is obtained from oxygen during electrical discharges in the atmosphere at altitudes of 20-30 km. oxygen absorbs ultra-violet rays, in this case, ozone molecules are formed, which consist of three oxygen atoms. It protects all life on Earth from the harmful effects of short-wave ultraviolet radiation from the Sun. In the overlying layers, there is not enough oxygen for the formation of ozone, and in the lower layers - ultraviolet radiation. Small amounts of ozone are also present in the surface layer of air. The total ozone content in the entire atmosphere corresponds to a layer of pure ozone 2-4 mm thick, provided that the air pressure and temperature are the same as at the Earth's surface. The composition of the air when rising even for several tens of kilometers (up to 100 m) changes little. But due to the fact that the air is discharged with height, the content of each gas per unit volume decreases (atmospheric pressure drops). Impurities include: Ozone, phytoncides released by vegetation, gaseous substances resulting from biochemical processes and radioactive decay in the soil, etc. Ozone is used to disinfect drinking water, neutralize industrial wastewater, to produce camphor, vanillin and other compounds, to bleach fabrics , mineral oils, etc.

CARBON DIOXIDE(carbon oxide) - a colorless, odorless gas, below -78.5 0 С exists in solid form (dry ice). It is 1.5 times heavier than air and is found in the air (0.35% by volume), in the waters of rivers, seas and mineral springs. Carbon dioxide is used in the production of sugar, beer, carbonated waters and sparkling wines, urea, soda, to extinguish fires, etc.; dry ice is a refrigerant. It is formed during decay and combustion of organic substances, during the respiration of animal organisms, it is assimilated by plants and plays an important role in photosynthesis. The importance of photosynthesis is that plants release oxygen into the air. That is why the lack of carbon dioxide is dangerous. people exhale carbon dioxide

(3.4 - 4.7% of exhaled air), animals, it is also released during the combustion of coal, oil and gasoline,

Therefore, as a result of intensive combustion of mineral fuels in recent years, the amount of carbon dioxide in the atmosphere has increased. An increase in the content of carbon dioxide in the atmosphere leads to a global danger to people - greenhouse effect. Carbon dioxide, like greenhouse glass, lets in the sun's rays, but retains the heat of the heated surface of the Earth. As a result, the average air temperature rises,

The microclimate is deteriorating, which affects human health. Every year, as a result of photosynthesis, about 300 million tons of carbon dioxide are absorbed and about 200 million tons of oxygen are released, about 3,000 billion tons of carbon dioxide are obtained, and its amount is constantly increasing. If 100 years ago the content of carbon dioxide in the air was 0.0298%, now it is 0.0318%. In cities, this content is even higher.

Interestingly, some scientists have linked acceleration - the accelerated growth of children, especially in cities - with an increase in carbon dioxide in the atmosphere. Even a small increase in carbon dioxide

in the air significantly enhances the respiratory process, rapid growth begins chest and, accordingly, the whole organism.

Carbon dioxide is 1.5 times heavier than air and can therefore accumulate at the bottom of enclosed spaces. These properties can contribute to poisoning outside populated areas in the air atmosphere.

0.03 - 0.04% carbon dioxide; in industrial centers, its content increases to 0.06%, and near ferrous metallurgy enterprises - up to 1%.

An increase in the concentration of carbon dioxide in the inhaled air leads to the development of acidosis, increased respiration and tochacardia. With an increase in concentration to 1-2%, performance decreases, toxic effects appear in some people, and at a concentration of more than 2-3%, intoxication is more pronounced. With a "free choice" of the gas environment, people begin to avoid carbon dioxide only when its concentration reaches 3%. At a concentration of 10-12%, there is a rapid loss of consciousness and death.

Cases of severe carbon dioxide poisoning in closed or hermetically sealed premises (mines, mines, submarines), as well as confined spaces where intensive decomposition of organic substances took place - deep wells, silo pits, fermentation tanks at breweries, sewer wells, etc. Taking into account the above data, it is believed that in industries where there are sources of carbon dioxide, in spacecraft, on submarines, its concentration should not exceed 0.5-1%. In shelters, as well as in other critical conditions, it can be assumed that the concentration of carbon dioxide is up to 2%.

NITROGEN- a colorless and odorless gas, it is the main component of air (78.09% by volume), is part of all living organisms (in the human body about 3% by mass of nitrogen, in proteins up to 17%), participates in the cycle of substances in nature . The main area of ​​application is the synthesis of ammonia; nitrogen compounds - nitrogen fertilizers. Nitrogen is an inert medium in chemical and metallurgical processes, in vegetable stores, etc.

Nitrogen and other inert gases are physiologically inactive at normal pressure, their significance lies in the dilution of oxygen.

ARGON- inert gas, in air 0.9% by volume, density 1.73 g / l. Used in industry in argon welding, with chemical processes, for filling electric lamps and gas discharge tubes.

Atmosphere(from the Greek atmos - steam and spharia - ball) - air envelope Earth rotating with it. The development of the atmosphere was closely connected with the geological and geochemical processes taking place on our planet, as well as with the activities of living organisms.

The lower boundary of the atmosphere coincides with the surface of the Earth, since air penetrates into the smallest pores in the soil and is dissolved even in water.

The upper limit at an altitude of 2000-3000 km gradually passes into outer space.

Oxygen-rich atmosphere makes life possible on Earth. atmospheric oxygen used in the process of human respiration, animals, plants.

If there were no atmosphere, the Earth would be as quiet as the moon. After all, sound is the vibration of air particles. The blue color of the sky is explained by the fact that the sun's rays, passing through the atmosphere, as if through a lens, are decomposed into their component colors. In this case, the rays of blue and blue colors are scattered most of all.

The atmosphere delays most ultraviolet radiation The sun, which has a detrimental effect on living organisms. It also keeps heat at the surface of the Earth, preventing our planet from cooling.

The structure of the atmosphere

Several layers can be distinguished in the atmosphere, differing in density and density (Fig. 1).

Troposphere

Troposphere- the lowest layer of the atmosphere, whose thickness above the poles is 8-10 km, in temperate latitudes - 10-12 km, and above the equator - 16-18 km.

Rice. 1. The structure of the Earth's atmosphere

The air in the troposphere is heated from the earth's surface, i.e. from land and water. Therefore, the air temperature in this layer decreases with height by an average of 0.6 °C for every 100 m. At the upper boundary of the troposphere, it reaches -55 °C. At the same time, in the region of the equator, upper bound the air temperature in the troposphere is -70 °C, and in the region North Pole-65 °С.

About 80% of the mass of the atmosphere is concentrated in the troposphere, almost all water vapor is located, thunderstorms, storms, clouds and precipitation occur, and vertical (convection) and horizontal (wind) air movement occurs.

We can say that the weather is mainly formed in the troposphere.

Stratosphere

Stratosphere- the layer of the atmosphere located above the troposphere at an altitude of 8 to 50 km. The color of the sky in this layer appears purple, which is explained by the rarefaction of the air, due to which the sun's rays almost do not scatter.

The stratosphere contains 20% of the mass of the atmosphere. The air in this layer is rarefied, there is practically no water vapor, and therefore clouds and precipitation are almost not formed. However, stable air currents are observed in the stratosphere, the speed of which reaches 300 km / h.

This layer is concentrated ozone(ozone screen, ozonosphere), a layer that absorbs ultraviolet rays, preventing them from passing to the Earth and thereby protecting living organisms on our planet. Due to ozone, the air temperature at the upper boundary of the stratosphere is in the range from -50 to 4-55 °C.

Between the mesosphere and the stratosphere there is a transitional zone - the stratopause.

Mesosphere

Mesosphere- a layer of the atmosphere located at an altitude of 50-80 km. The air density here is 200 times less than at the surface of the Earth. The color of the sky in the mesosphere appears black, stars are visible during the day. The air temperature drops to -75 (-90)°C.

At an altitude of 80 km begins thermosphere. The air temperature in this layer rises sharply to a height of 250 m, and then becomes constant: at a height of 150 km it reaches 220-240 °C; at an altitude of 500-600 km it exceeds 1500 °C.

In the mesosphere and thermosphere under the influence of cosmic rays gas molecules break up into charged (ionized) particles of atoms, so this part of the atmosphere is called ionosphere- a layer of very rarefied air, located at an altitude of 50 to 1000 km, consisting mainly of ionized oxygen atoms, nitric oxide molecules and free electrons. This layer is characterized by high electrification, and long and medium radio waves are reflected from it, as from a mirror.

In the ionosphere there are auroras- the glow of rarefied gases under the influence of electrically charged particles flying from the Sun - and sharp fluctuations of the magnetic field are observed.

Exosphere

Exosphere- the outer layer of the atmosphere, located above 1000 km. This layer is also called the scattering sphere, since gas particles move here with high speed and can dissipate into outer space.

Composition of the atmosphere

The atmosphere is a mixture of gases consisting of nitrogen (78.08%), oxygen (20.95%), carbon dioxide (0.03%), argon (0.93%), a small amount of helium, neon, xenon, krypton (0.01%), ozone and other gases, but their content is negligible (Table 1). Modern composition The air of the Earth was established more than a hundred million years ago, but the sharply increased human production activity nevertheless led to its change. Currently, there is an increase in the content of CO 2 by about 10-12%.

The gases in the atmosphere perform various functional roles. However, the main significance of these gases is determined primarily by the fact that they very strongly absorb radiant energy and thereby exert significant influence on the temperature regime Earth's surface and atmosphere.

Table 1. Chemical composition dry atmospheric air near the earth's surface

	Volume concentration. %	Molecular weight, units
Oxygen
Carbon dioxide
Nitrous oxide
	0 to 0.00001
Sulfur dioxide	from 0 to 0.000007 in summer; 0 to 0.000002 in winter
	From 0 to 0.000002	46,0055/17,03061
Azog dioxide
Carbon monoxide

Nitrogen, the most common gas in the atmosphere, chemically little active.

Oxygen, unlike nitrogen, is a chemically very active element. The specific function of oxygen is oxidation organic matter heterotrophic organisms, rocks and under-oxidized gases emitted into the atmosphere by volcanoes. Without oxygen, there would be no decomposition of dead organic matter.

The role of carbon dioxide in the atmosphere is exceptionally great. It enters the atmosphere as a result of the processes of combustion, respiration of living organisms, decay and is, first of all, the main construction material to create organic matter during photosynthesis. Besides, great value has the property of carbon dioxide to pass short-wave solar radiation and absorb part of the thermal long-wave radiation, which will create the so-called the greenhouse effect, which will be discussed below.

The influence on atmospheric processes, especially on the thermal regime of the stratosphere, is also exerted by ozone. This gas serves as a natural absorber of solar ultraviolet radiation, and absorption solar radiation leads to warmer air. Average monthly values general content ozone in the atmosphere vary depending on the latitude of the area and the season within 0.23-0.52 cm (this is the thickness of the ozone layer at ground pressure and temperature). There is an increase in the ozone content from the equator to the poles and an annual variation with a minimum in autumn and a maximum in spring.

A characteristic property of the atmosphere can be called the fact that the content of the main gases (nitrogen, oxygen, argon) changes slightly with height: at an altitude of 65 km in the atmosphere, the content of nitrogen is 86%, oxygen - 19, argon - 0.91, at an altitude of 95 km - nitrogen 77, oxygen - 21.3, argon - 0.82%. The constancy of the composition of atmospheric air vertically and horizontally is maintained by its mixing.

In addition to gases, air contains water vapor and solid particles. The latter can have both natural and artificial (anthropogenic) origin. These are flower pollen, tiny salt crystals, road dust, aerosol impurities. When the sun's rays penetrate the window, they can be seen with the naked eye.

Especially a lot of particulate matter in the air of cities and large industrial centers, where emissions of harmful gases and their impurities formed during fuel combustion are added to aerosols.

The concentration of aerosols in the atmosphere determines the transparency of the air, which affects the solar radiation reaching the Earth's surface. The largest aerosols are condensation nuclei (from lat. condensatio- compaction, thickening) - contribute to the transformation of water vapor into water droplets.

The value of water vapor is determined primarily by the fact that it delays long-wavelength thermal radiation the earth's surface; represents the main link of large and small moisture cycles; raises the temperature of the air when the water beds condense.

The amount of water vapor in the atmosphere varies over time and space. Thus, the concentration of water vapor near the earth's surface ranges from 3% in the tropics to 2-10 (15)% in Antarctica.

The average content of water vapor in the vertical column of the atmosphere in temperate latitudes is about 1.6-1.7 cm (the layer of condensed water vapor will have such a thickness). Information about water vapor in different layers atmospheres are inconsistent. It was assumed, for example, that in the altitude range from 20 to 30 km, the specific humidity strongly increases with height. However, subsequent measurements indicate a greater dryness of the stratosphere. Apparently, the specific humidity in the stratosphere depends little on height and amounts to 2–4 mg/kg.

The variability of water vapor content in the troposphere is determined by the interaction of evaporation, condensation, and horizontal transport. As a result of the condensation of water vapor, clouds form and precipitation occurs in the form of rain, hail and snow.

Processes phase transitions water flows mainly in the troposphere, which is why clouds in the stratosphere (at altitudes of 20-30 km) and mesosphere (near the mesopause), called mother-of-pearl and silver, are observed relatively rarely, while tropospheric clouds often cover about 50% of the entire earth's surface.

The amount of water vapor that can be contained in the air depends on the temperature of the air.

1 m 3 of air at a temperature of -20 ° C can contain no more than 1 g of water; at 0 °C - no more than 5 g; at +10 °С - no more than 9 g; at +30 °С - no more than 30 g of water.

Conclusion: The higher the air temperature, the more water vapor it can contain.

Air can be rich and not saturated steam. So, if at a temperature of +30 ° C 1 m 3 of air contains 15 g of water vapor, the air is not saturated with water vapor; if 30 g - saturated.

Absolute humidity- this is the amount of water vapor contained in 1 m 3 of air. It is expressed in grams. For example, if they say "absolute humidity is 15", then this means that 1 mL contains 15 g of water vapor.

Relative humidity- this is the ratio (in percent) of the actual content of water vapor in 1 m 3 of air to the amount of water vapor that can be contained in 1 m L at a given temperature. For example, if the radio during the transmission of the weather report reported that the relative humidity is 70%, this means that the air contains 70% of the water vapor that it can hold at a given temperature.

The greater the relative humidity of the air, t. the closer the air is to saturation, the more likely it is to fall.

Always high (up to 90%) relative humidity is observed in equatorial zone, because it stays there throughout the year heat air and there is a large evaporation from the surface of the oceans. The same high relative humidity is in the polar regions, but only because at low temperatures not even a large number of water vapor makes the air saturated or close to saturation. In temperate latitudes, relative humidity varies seasonally - it is higher in winter and lower in summer.

The relative humidity of the air is especially low in deserts: 1 m 1 of air there contains two to three times less than the amount of water vapor possible at a given temperature.

To measure relative humidity, a hygrometer is used (from the Greek hygros - wet and metreco - I measure).

When cooled, saturated air cannot retain the same amount of water vapor in itself, it thickens (condenses), turning into droplets of fog. Fog can be observed in the summer on a clear cool night.

Clouds- this is the same fog, only it is formed not at the earth's surface, but at a certain height. As the air rises, it cools and the water vapor in it condenses. The resulting tiny droplets of water make up the clouds.

involved in the formation of clouds particulate matter suspended in the troposphere.

Clouds may have different shape, which depends on the conditions of their formation (Table 14).

The lowest and heaviest clouds are stratus. They are located at an altitude of 2 km from the earth's surface. At an altitude of 2 to 8 km, more picturesque cumulus clouds can be observed. The highest and lightest are cirrus clouds. They are located at an altitude of 8 to 18 km above the earth's surface.

families	Kinds of clouds	Appearance
A. Upper clouds - above 6 km	I. Pinnate	Threadlike, fibrous, white
	II. cirrocumulus	Layers and ridges of small flakes and curls, white
	III. Cirrostratus	Transparent whitish veil
B. Clouds of the middle layer - above 2 km	IV. Altocumulus	Layers and ridges of white and gray
	V. Altostratified	Smooth veil of milky gray color
B. Lower clouds - up to 2 km	VI. Nimbostratus	Solid shapeless gray layer
	VII. Stratocumulus	Opaque layers and ridges of gray
	VIII. layered	Illuminated gray veil
D. Clouds of vertical development - from the lower to the upper tier	IX. Cumulus	Clubs and domes bright white, with torn edges in the wind
	X. Cumulonimbus	Powerful cumulus-shaped masses of dark lead color

Atmospheric protection

The main source are industrial enterprises and cars. AT big cities the problem of gas contamination of the main transport routes is very acute. That is why in many major cities world, including in our country, introduced environmental control car exhaust toxicity. According to experts, smoke and dust in the air can halve the flow of solar energy to the earth's surface, which will lead to a change in natural conditions.