The ozone layer is a wide atmospheric belt extending from 10 to 50 km above the Earth's surface. Chemically, ozone is a molecule consisting of three oxygen atoms (an oxygen molecule contains two atoms). The concentration of ozone in the atmosphere is very low, and small changes in the amount of ozone lead to large changes in the intensity of ultraviolet radiation reaching the earth's surface. Unlike ordinary oxygen, ozone is unstable; it easily transforms into the diatomic, stable form of oxygen. Ozone is a much stronger oxidizing agent than oxygen, and this makes it capable of killing bacteria and inhibiting plant growth and development. However, due to its low concentration in the surface layers of air under normal conditions, these features have practically no effect on the state of living systems.

Much more important is its other property, which makes this gas absolutely necessary for all life on land. This property is the ability of ozone to absorb hard (short-wave) ultraviolet (UV) radiation from the Sun. Hard UV quanta have energy sufficient to break some chemical bonds, so it is classified as ionizing radiation. Like other radiations of this kind, X-rays and gamma radiation, it causes numerous disturbances in the cells of living organisms. Ozone is formed under the influence of high-energy solar radiation, which stimulates the reaction between O2 and free oxygen atoms. When exposed to moderate radiation, it disintegrates, absorbing the energy of this radiation. Thus, this cyclical process “eats” dangerous ultraviolet radiation.

Ozone molecules, like oxygen, are electrically neutral, i.e. do not carry an electrical charge. Therefore, the Earth's magnetic field itself does not affect the distribution of ozone in the atmosphere. The upper layer of the atmosphere, the ionosphere, practically coincides with the ozone layer.

In the polar zones, where the Earth's magnetic field lines close on its surface, the distortions of the ionosphere are very significant. The number of ions, including ionized oxygen, in the upper layers of the atmosphere of the polar zones is reduced. But the main reason for the low ozone content in the polar region is the low intensity of solar radiation, which falls even during the polar day at small angles to the horizon, and is completely absent during the polar night. The area of ​​polar "holes" in the ozone layer is a reliable indicator of changes in the total ozone content in the atmosphere.

The ozone content in the atmosphere fluctuates due to many natural reasons. Periodic fluctuations are associated with solar activity cycles; Many components of volcanic gases are capable of destroying ozone, so an increase in volcanic activity leads to a decrease in its concentration. Due to the high, hurricane-like speeds of air flows in the stratosphere, ozone-depleting substances are carried over large areas. Not only ozone depleters are transported, but also ozone itself, so disturbances in ozone concentration quickly spread over large areas, and local small “holes” in the ozone shield, caused, for example, by a rocket launch, heal relatively quickly. Only in the polar regions is the air inactive, as a result of which the disappearance of ozone there is not compensated by its import from other latitudes, and the polar “ozone holes,” especially at the South Pole, are very stable.

Sources of ozone layer destruction. Among the ozone layer depleters are:

1) Freons.

Ozone is destroyed by chlorine compounds known as freons, which, also destroyed by solar radiation, release chlorine, which “tears off” the “third” atom from ozone molecules. Chlorine does not form compounds, but serves as a “breaking” catalyst. Thus, one chlorine atom can “destroy” a lot of ozone. It is believed that chlorine compounds can remain in the atmosphere from 50 to 1500 years (depending on the composition of the substance) of the Earth. Observations of the planet's ozone layer have been carried out by Antarctic expeditions since the mid-50s.

The ozone hole over Antarctica, which widens in the spring and decreases in the fall, was discovered in 1985. The discovery of meteorologists caused a chain of economic consequences. The fact is that the existence of the “hole” was blamed on the chemical industry, which produces substances containing freons that contribute to the destruction of ozone (from deodorants to refrigeration units).

There is no consensus on the question of how much humans are to blame for the formation of “ozone holes.”

On the one hand, yes, he is certainly guilty. The production of compounds that lead to ozone depletion should be minimized, or better yet stopped altogether. That is, to abandon an entire industry sector with a turnover of many billions of dollars. And if you don’t refuse, then transfer it to “safe” rails, which also costs money.

The point of view of skeptics: human influence on atmospheric processes, for all its destructiveness on a local level, is negligible on a planetary scale. The anti-freon campaign of the “greens” has a completely transparent economic and political background: with its help, large American corporations (DuPont, for example) are strangling their foreign competitors, imposing agreements on “environmental protection” at the state level and forcibly introducing a new technological stage that is more economically weak states are unable to withstand.

2) High altitude aircraft.

The destruction of the ozone layer is facilitated not only by freons released into the atmosphere and entering the stratosphere. Nitrogen oxides, which are formed during nuclear explosions, are also involved in the destruction of the ozone layer. But nitrogen oxides are also formed in the combustion chambers of turbojet engines of high-altitude aircraft. Nitrogen oxides are formed from the nitrogen and oxygen that are found there. The higher the temperature, i.e., the greater the engine power, the greater the rate of formation of nitrogen oxides.

It's not just the power of an airplane's engine that matters, but also the altitude at which it flies and releases ozone-depleting nitrogen oxides. The higher the nitrous oxide or oxide is formed, the more destructive it is to ozone.

The total amount of nitrogen oxide that is emitted into the atmosphere per year is estimated at 1 billion tons. About a third of this amount is emitted by aircraft above the average tropopause level (11 km). As for aircraft, the most harmful emissions are from military aircraft, the number of which amounts to tens of thousands. They fly primarily at altitudes in the ozone layer.

3) Mineral fertilizers.

Ozone in the stratosphere can also decrease due to the fact that nitrous oxide N2O enters the stratosphere, which is formed during the denitrification of nitrogen bound by soil bacteria. The same denitrification of fixed nitrogen is also carried out by microorganisms in the upper layer of oceans and seas. The process of denitrification is directly related to the amount of fixed nitrogen in the soil. Thus, you can be sure that with an increase in the amount of mineral fertilizers applied to the soil, the amount of nitrous oxide N2O produced will also increase to the same extent. Further, nitrogen oxides are formed from nitrous oxide, which lead to the destruction of stratospheric ozone.

4) Nuclear explosions.

Nuclear explosions release a lot of energy in the form of heat. A temperature of 60,000 K is established within a few seconds after a nuclear explosion. This is the energy of the fireball. In a highly heated atmosphere, transformations of chemical substances occur that either do not occur under normal conditions, or proceed very slowly. As for ozone and its disappearance, the most dangerous for it are the nitrogen oxides formed during these transformations. Thus, during the period from 1952 to 1971, as a result of nuclear explosions, about 3 million tons of nitrogen oxides were formed in the atmosphere. Their further fate is as follows: as a result of atmospheric mixing, they end up at different heights, including the atmosphere. There they enter into chemical reactions with the participation of ozone, leading to its destruction. ozone hole stratosphere ecosystem

5) Fuel combustion.

Nitrous oxide is also found in flue gases from power plants. Actually, the fact that nitrogen oxide and dioxide are present in combustion products has been known for a long time. But these higher oxides do not affect ozone. They, of course, pollute the atmosphere and contribute to the formation of smog in it, but they are quickly removed from the troposphere. Nitrous oxide, as already mentioned, is dangerous for ozone. At low temperatures it is formed in the following reactions:

N2 + O + M = N2O + M,

2NH3 + 2O2 =N2O = 3H2.

The scale of this phenomenon is very significant. In this way, approximately 3 million tons of nitrous oxide are formed in the atmosphere annually! This figure suggests that this source of ozone destruction is significant.

Ozone hole over Antarctica

A significant decrease in total ozone over Antarctica was first reported in 1985 by the British Antarctic Survey based on an analysis of data from the Halley Bay ozone station (76°S). A decrease in ozone was also observed by this service in the Argentine Islands (65 degrees S).

From August 28 to September 29, 1987, 13 flights of the laboratory aircraft were carried out over Antarctica. The experiment made it possible to register the birth of the ozone hole. Its dimensions were obtained. Studies have shown that the greatest decrease in ozone occurred at altitudes of 14 - 19 km. This is also where the instruments recorded the largest number of aerosols (aerosol layers). It turned out that the more aerosols there are at a given altitude, the less ozone there is. The aircraft laboratory recorded a decrease in ozone equal to 50%. Below 14 km. ozone changes were insignificant.

Already by the beginning of October 1985, the ozone hole (the minimum amount of ozone) covers levels with pressure from 100 to 25 hPa, and in December the range of altitudes at which it is observed expands.

Many experiments measured not only the amount of ozone and other small components of the atmosphere, but also temperature. The closest connection was established between the amount of ozone in the stratosphere and the air temperature there. It turned out that the nature of the change in the amount of ozone is closely related to the thermal regime of the stratosphere over Antarctica.

The formation and development of the ozone hole in Antarctica was observed by British scientists in 1987. In the spring, the total ozone content decreased by 25%.

American researchers carried out measurements in Antarctica in the winter and early spring of 1987 of ozone and other small components of the atmosphere (HCl, HF, NO, NO2, HNO3, ClONO2, N2O, CH4) using a special spectrometer. Data from these measurements made it possible to delineate an area around the South Pole in which the amount of ozone is reduced. It turned out that this region coincides almost exactly with the extreme polar stratospheric vortex. When passing through the edge of the vortex, the amount of not only ozone, but also other small components that influence the destruction of ozone, changed sharply. Within the ozone hole (or, in other words, the polar stratospheric vortex), the concentrations of HCl, NO2 and nitric acid were significantly lower than outside the vortex. This occurs because chlorins, during the cold polar night, destroy ozone in the corresponding reactions, acting as catalysts in them. It is in the catalytic cycle with the participation of chlorine that the main decrease in ozone concentration occurs (at least 80% of this decrease).

These reactions occur on the surface of the particles that make up the polar stratospheric clouds. This means that the larger the area of ​​this surface, that is, the more particles of stratospheric clouds, and therefore the clouds themselves, the faster the ozone ultimately decays, and therefore the more efficiently the ozone hole is formed.

Recently, the public is increasingly concerned about environmental issues - protecting the environment, animals, reducing the amount of harmful and dangerous emissions. Surely everyone has also heard about what an ozone hole is, and that there are a lot of them in the modern stratosphere of the Earth. This is true.

Modern anthropogenic activities and technological development threaten the existence of animals and plants on Earth, as well as the very lives of people.

The ozone layer is the protective shell of the blue planet, which is located in the stratosphere. Its height is approximately twenty-five kilometers from the earth's surface. And this layer is formed from oxygen, which undergoes chemical transformations under the influence of solar radiation. A local decrease in ozone concentration (in common parlance this is the well-known “hole”) is currently caused by many reasons. First of all, this is, of course, human activity (both production and everyday life). There are, however, opinions that the ozone layer is destroyed under the influence of exclusively natural phenomena not related to humans.

Anthropogenic influence

Having understood what the ozone hole is, it is necessary to find out what kind of human activity contributes to its appearance. First of all, these are aerosols. Every day we use deodorants, hairsprays, eau de toilette with spray bottles and often do not think about the fact that this has a detrimental effect on the protective layer of the planet.

The fact is that the compounds that are present in the cans we are used to (including bromine and chlorine) readily react with oxygen atoms. Therefore, the ozone layer is destroyed, turning after such chemical reactions into completely useless (and often harmful) substances.

Destructive compounds for the ozone layer are also present in air conditioners, which are life-saving in the summer heat, as well as in cooling equipment. Widespread human industrial activity also weakens the earth's defenses. It is oppressed by industrial water (some of the harmful substances evaporate over time), polluting the stratosphere and cars. The latter, as statistics show, is becoming more and more numerous every year. Negatively affects the ozone layer and

Natural influence

Knowing what an ozone hole is, you also need to have an idea of ​​how many there are above the surface of our planet. The answer is disappointing: there are many gaps in earthly defenses. They are small and often represent not a hole, but a very thin remaining layer of ozone. However, there are also two huge unprotected spaces. This is the Arctic and Antarctic ozone hole.

The stratosphere above the Earth's poles contains almost no protective layer at all. What is this connected with? There are no cars or industrial production there. It's all about natural influence, the second reason. Polar vortexes arise when warm and cold air currents collide. These gas formations contain large quantities of nitric acid, which, when exposed to very low temperatures, reacts with ozone.

Environmentalists began to sound the alarm only in the twentieth century. Destructive ones that make their way to the ground without encountering an ozone barrier can cause skin cancer in humans, as well as the death of many animals and plants (primarily marine ones). Thus, international organizations have banned almost all compounds that destroy the protective layer of our planet. It is believed that even if humanity abruptly stops any negative impact on ozone in the stratosphere, the currently existing holes will not disappear very soon. This is explained by the fact that freons that have already made their way to the top are able to independently exist in the atmosphere for decades to come.

“We can, perhaps, say that the purpose of man is, as it were, to destroy his race, first making the globe uninhabitable.”

J.B. Lamarck.

Since the formation of a highly industrialized society, dangerous human intervention in nature has sharply increased, it has become more diverse and threatens to become a global danger to humanity. A real threat of a global environmental crisis looms over the world, understood by the entire population of the planet. The real hope for its prevention lies in continuous environmental education and enlightenment of people.

The main reasons leading to environmental disaster can be identified:

· pollution;

· poisoning of the environment;

· depletion of the atmosphere in oxygen;

· formation of ozone “holes”.

This message summarizes some literature data on the causes and consequences of ozone layer destruction, as well as ways to solve the problem of the formation of “ozone holes”.

Chemical and biological characteristics of ozone

Ozone is an allotropic modification of oxygen. The nature of the chemical bonds in ozone determines its instability (after a certain time, ozone spontaneously turns into oxygen: 2O 3 → 3O 2) and high oxidizing ability. The oxidative effect of ozone on organic substances is associated with the formation of radicals: RH + O 3 → RО 2. +OH.

These radicals initiate radical chain reactions with bioorganic molecules (lipids, proteins, nucleic acids), which leads to cell death. The use of ozone to sterilize drinking water is based on its ability to kill microbes. Ozone is also important for higher organisms. Prolonged exposure to an environment containing ozone (for example, in physiotherapy rooms and quartz irradiation) can cause severe damage to the nervous system. Therefore, ozone in large doses is a toxic gas. The maximum permissible concentration in the air of the working area is 0.1 mg/m3.

There is very little ozone, which smells so wonderful during a thunderstorm, in the atmosphere - 3-4 ppm (per mille) - (3-4) * 10 -4%. However, its presence is extremely important for the flora and fauna of the planet. After all, life that originated in the ocean depths was able to “crawl” onto land only after the ozone shield was formed 600–800 million years ago. By absorbing biologically active solar ultraviolet radiation, it ensured its safe level on the surface of the planet. Life on Earth is unthinkable without the ozone layer, which protects all living things from harmful ultraviolet radiation from the Sun. The disappearance of the ozonosphere would lead to unpredictable consequences - an outbreak of skin cancer, the destruction of plankton in the ocean, mutations of flora and fauna. Therefore, it is so important to understand the causes of the ozone “hole” over Antarctica and the decrease in ozone levels in the Northern Hemisphere.

Ozone is formed in the upper stratosphere (40-50 km) during photochemical reactions involving oxygen, nitrogen, hydrogen and chlorine. Atmospheric ozone is concentrated in two areas - the stratosphere (up to 90%) and the troposphere. As for the tropospheric ozone layer distributed at an altitude of 0 to 10 km, it is precisely due to uncontrolled industrial emissions that it is becoming more and more abundant. In the lower stratosphere (10-25 km), where ozone is most abundant, air mass transfer processes play a major role in seasonal and longer-term changes in its concentration.

The thickness of the ozone layer over Europe is decreasing at a rapid pace, which cannot but worry the minds of scientists. Over the past year, the thickness of the ozone “coat” has decreased by 30%, and the rate of deterioration of the natural protective shell has reached the highest level in the last 50 years. It has been established that chemical reactions that destroy ozone occur on the surface of ice crystals and any other particles trapped in the high stratosphere above the polar regions. What danger does this pose to humans?

The thin ozone layer (2-3 mm when distributed around the globe) is unable to prevent the penetration of short-wave ultraviolet rays, which cause skin cancer and are dangerous to plants. Therefore, today, due to the high activity of the sun, sunbathing has become less useful. In general, environmental centers should give recommendations to the population on how to act depending on the activity of the sun, but in our country there is no such center.

Climate change is associated with a decrease in the ozone layer. It is clear that changes will occur not only in the area over which the ozone hole “stretches”. The chain reaction will entail changes in many deep processes of our planet. This does not mean that rapid global warming will begin everywhere, as they scare us in horror films. Still, this is too complex and time-consuming process. But other disasters may arise, for example, the number of typhoons, tornadoes, and hurricanes will increase.

It has been established that “holes” in the ozone layer appear over the Arctic and Antarctica. This is explained by the fact that acid clouds form at the poles, destroying the ozone layer. It turns out that ozone holes arise not from the activity of the sun, as is commonly believed, but from the daily activities of all the inhabitants of the planet, including you and me. Then the “acid gaps” shift, most often to Siberia.

Using a new mathematical model, it was possible to link together data from ground-based, satellite and aircraft observations with the levels of likely future emissions of ozone-depleting compounds into the atmosphere, the timing of their transport to Antarctica and weather in southern latitudes. Using the model, a forecast was obtained according to which the ozone layer over Antarctica will recover in 2068, and not in 2050, as was believed.

It is known that currently the level of ozone in the stratosphere over areas far from the poles is approximately 6% below normal. At the same time, in the spring, the ozone content over Antarctica can decrease by 70% relative to the annual average. The new model makes it possible to more accurately predict the levels of ozone-depleting gases over Antarctica and their temporal dynamics, which determine the size of the ozone “hole.”

The use of ozone depleting substances is limited by the Montreal Protocol. It was believed that this would lead to a rapid “tightening” of the ozone hole. However, new research has shown that in reality the rate of decline will only become noticeable from 2018.

History of ozone research

The first observations of ozone date back to 1840, but the ozone problem received rapid development in the 20s of the last century, when special ground stations appeared in England and Switzerland.

Airborne soundings of atmospheric ozone and releases of ozone probes have opened up additional avenues for studying the connections between ozone transfer and atmospheric stratification. The new era is marked by the emergence of artificial Earth satellites that observe atmospheric ozone and provide a wealth of information.

In 1986, the Montreal Protocol was signed to limit the production and consumption of ozone-depleting substances that deplete the ozone layer. To date, 189 countries have joined the Montreal Protocol. Time limits have been established for the cessation of production of other ozone-depleting substances. According to model forecasts, if the Protocol is observed, the level of chlorine in the atmosphere will decrease by 2050 to the 1980 level, which could lead to the disappearance of the Antarctic “ozone hole”.

Reasons for the formation of the “ozone hole”

In summer and spring, ozone concentrations increase. It is always higher over the polar regions than over the equatorial ones. In addition, it changes on an 11-year cycle, coinciding with the solar activity cycle. All this was already well known when in the 1980s. Observations have shown that over Antarctica there is a slow but steady decrease in stratospheric ozone concentrations from year to year. This phenomenon was called the “ozone hole” (although, of course, there was no hole in the proper sense of the word).

Later, in the 90s of the last century, the same decrease began to occur over the Arctic. The phenomenon of the Antarctic “ozone hole” is not yet clear: whether the “hole” arose as a result of anthropogenic pollution of the atmosphere, or whether it is a natural geoastrophysical process.

Among the versions of the formation of ozone holes are:

· influence of particles emitted during atomic explosions;

· flights of rockets and high-altitude aircraft;

· reactions of certain substances produced by chemical plants with ozone. These are primarily chlorinated hydrocarbons and especially freons - chlorofluorocarbons, or hydrocarbons in which all or most of the hydrogen atoms are replaced by fluorine and chlorine atoms.

Chlorofluorocarbons are widely used in modern household and industrial refrigerators (that’s why they are called “freons”), in aerosol cans, as dry cleaning agents, for extinguishing fires in transport, as foaming agents, and for the synthesis of polymers. World production of these substances has reached almost 1.5 million tons/year.

Being highly volatile and quite resistant to chemical influences, chlorofluorocarbons enter the atmosphere after use and can remain in it for up to 75 years, reaching the height of the ozone layer. Here, under the influence of sunlight, they decompose, releasing atomic chlorine, which serves as the main “disturber of order” in the ozone layer.

The widespread use of fossil resources is accompanied by the release of large masses of various chemical compounds into the atmosphere. Most anthropogenic sources are concentrated in cities, occupying only a small part of the territory of our planet. As a result of the movement of air masses on the leeward side of large cities, a multi-kilometer plume of pollution is formed.

The sources of air pollution are:

1) Road transport. It can be assumed that the contribution of transport to air pollution will increase as the number of cars increases.

2) Industrial production. The basic products of basic organic synthesis are ethylene (almost half of all organic substances are produced on its basis), propylene, butadiene, benzene, toluene, xylenes and methanol. Emissions from chemical and petrochemical industry enterprises contain a wide range of pollutants: components of feedstock, intermediate, by-products and target synthesis products.

3) Aerosols. Chlorofluorocarbons (freons) are widely used as volatile components (propellants) in aerosol packages. For these purposes, about 85% of freons were used and only 15% in refrigeration units and artificial climate units. The specificity of using freons is such that 95% of their quantity enters the atmosphere 1-2 years after production. It is believed that almost the entire amount of freon produced must sooner or later enter the stratosphere and be included in the catalytic cycle of ozone destruction.

The earth's crust contains various gases in a free state, sorbed by different rocks and dissolved in water. Some of these gases reach the Earth's surface through deep faults and cracks and diffuse into the atmosphere. The existence of hydrocarbon respiration in the earth's crust is indicated by the increased methane content in the ground layer of air above oil and gas basins compared to the global background.

Studies have shown that the gases of Nicaragua's volcanoes contain noticeable amounts of HF. Analysis of air samples taken from the crater of the Masaya volcano also showed the presence of freons along with other organic compounds. Halocarbons are also present in gases from hydrothermal vents. These data required evidence that the detected hydrofluorocarbons were not of anthropogenic origin. And such evidence was obtained. Freons have been discovered in air bubbles in 2,000-year-old Antarctic ice. NASA specialists undertook a unique study of the air from a hermetically sealed lead coffin, discovered in Maryland and reliably dated to the 17th century. Freons were also found in it. Another confirmation of the existence of a natural source of freons was “raised” from the seabed. CFCl 3 was found in water recovered in 1982 from depths of more than 4,000 meters in the equatorial Atlantic Ocean, at the bottom of the Aleutian Trench and at a depth of 4,500 meters off the coast of Antarctica.

Misconceptions about ozone holes

There are several widespread myths regarding the formation of ozone holes. Despite their unscientific nature, they often appear in the media - sometimes out of ignorance, sometimes supported by conspiracy theorists. Some of them are listed below.

1) The main ozone destroyers are freons. This statement is true for middle and high latitudes. In the rest, the chlorine cycle is responsible for only 15-25% of ozone loss in the stratosphere. It should be noted that 80% of chlorine is of anthropogenic origin. That is, human intervention greatly increases the contribution of the chlorine cycle. Before human intervention, the processes of ozone formation and destruction were in equilibrium. But freons emitted by human activity have shifted this balance towards a decrease in ozone concentration. The mechanism of ozone destruction in the polar regions is fundamentally different from that at higher latitudes; the key stage is the conversion of inactive forms of halogen-containing substances into oxides, which occurs on the surface of particles of polar stratospheric clouds. And as a result, almost all ozone is destroyed in reactions with halogens (chlorine is responsible for 40-50% and bromine is responsible for about 20-40%).

2) Freons are too heavy to reach the stratosphere .

It is sometimes argued that since freon molecules are much heavier than nitrogen and oxygen, they cannot reach the stratosphere in significant quantities. However, atmospheric gases are completely mixed, rather than separated or sorted by weight. Estimates of the required time for the diffusion stratification of gases in the atmosphere require times of the order of thousands of years. Of course, in a dynamic atmosphere this is impossible. Therefore, even such heavy gases as inert gases or freons are evenly distributed in the atmosphere, including reaching the stratosphere. Experimental measurements of their concentrations in the atmosphere confirm this. If the gases in the atmosphere did not mix, then such heavy gases from its composition as argon and carbon dioxide would form a layer several tens of meters thick on the Earth’s surface, which would make the Earth’s surface uninhabitable. Fortunately this is not the case.

3) The main sources of halogens are natural, not anthropogenic

Sources of chlorine in the stratosphere

It is believed that natural sources of halogens, such as volcanoes or oceans, are more significant for the process of ozone destruction than those produced by humans. Without questioning the contribution of natural sources to the overall balance of halogens, it should be noted that they generally do not reach the stratosphere due to the fact that they are water-soluble (mainly chloride ions and hydrogen chloride) and are washed out of the atmosphere, falling as rain on the ground.

4) The ozone hole must be located above the sources of freons

Dynamics of changes in the size of the ozone hole and ozone concentration in Antarctica by year.

Many people do not understand why the ozone hole forms in Antarctica when the main emissions of CFCs occur in the Northern Hemisphere. The fact is that freons are well mixed in the troposphere and stratosphere. Due to their low reactivity, they are practically not consumed in the lower layers of the atmosphere and have a lifespan of several years or even decades. Therefore, they easily reach the upper layers of the atmosphere. The Antarctic “ozone hole” does not exist forever. It appears at the end of winter - beginning of spring.

The reasons why the ozone hole forms in Antarctica are related to the local climate. The low temperatures of the Antarctic winter lead to the formation of a polar vortex. The air inside this vortex moves mainly along closed trajectories around the South Pole. At this time, the polar region is not illuminated by the Sun, and ozone does not arise there. With the arrival of summer, the amount of ozone increases and returns to its previous level. That is, fluctuations in ozone concentration over Antarctica are seasonal. However, if we trace the yearly averaged dynamics of changes in ozone concentration and the size of the ozone hole over the past decades, then there is a strictly defined tendency for ozone concentration to fall.

5) Ozone is only destroyed over Antarctica

Dynamics of changes in the ozone layer over Arosa, Switzerland

This is not true; ozone levels are also falling throughout the atmosphere. This is shown by the results of long-term measurements of ozone concentrations in different parts of the planet. You can look at the graph of changes in ozone concentration over Arosa (Switzerland).

Ways to solve problems

To begin global recovery, it is necessary to reduce the access to the atmosphere of all substances that very quickly destroy ozone and are stored there for a long time. People need to understand this and help nature start the process of restoring the ozone layer; in particular, new forest plantings are needed.

To restore the ozone layer, it needs to be recharged. At first, for this purpose, it was planned to create several ground-based ozone factories and “throw” ozone into the upper layers of the atmosphere on cargo planes. However, this project (probably it was the first project to “treat” the planet) was not implemented. A different way is proposed by the Russian consortium Interozon: producing ozone directly in the atmosphere. In the near future, together with the German company Daza, it is planned to raise balloons with infrared lasers to a height of 15 km, with the help of which they can produce ozone from diatomic oxygen. If this experiment turns out to be successful, in the future it is planned to use the experience of the Russian Mir orbital station and create several space platforms with energy sources and lasers at an altitude of 400 km. Laser beams will be directed into the central part of the ozone layer and will constantly replenish it. The energy source can be solar panels. Astronauts on these platforms will only be required for periodic inspections and repairs.

Time will tell whether the grandiose peace project will be realized.

Taking into account the emergency of the situation, it seems necessary:

Expand the complex of theoretical and experimental research on the problem of preserving the ozone layer;

Create an International Fund for the Preservation of the Ozone Layer through active means;

Organize an International Committee to develop a strategy for the survival of humanity in extreme conditions.

Bibliography

1. (ru -).

2. ((cite web - | url = http://www.duel.ru/200530/?30_4_2 - | title = “Duel” Is it worth it? - | accessdate = 07/3/2007 - | lang = ru - ) )

3. I.K.Larin. The ozone layer and the Earth's climate. Errors of the mind and their correction.

4. National Academy of SciencesHalocarbons: Effects on Stratospheric Ozone. - 1976.

5. Babakin B. S. Refrigerants: history of appearance, classification, application.

6. Magazine "Ecology and Life". Article by E.A. Zhadina, candidate of physical and mathematical sciences.

Earth is undoubtedly the most unique planet in our solar system. This is the only planet suitable for life. But we do not always appreciate this and believe that we are unable to change and disrupt what has been created over billions of years. In the entire history of its existence, our planet has never received such loads as those given to it by man.

Our planet has an ozone layer, which is so necessary for our life. It protects us from exposure to ultraviolet rays emanating from the sun. Without it, life on this planet would not be possible.

Ozone is a blue gas with a characteristic odor. Each of us knows this pungent smell, which is especially noticeable after rain. It’s not for nothing that ozone means “smelling” in Greek. It is formed at an altitude of up to 50 km from the surface of the earth. But most of it is located at 22 - 24 km.

Causes of ozone holes

In the early 70s, scientists began to notice a decrease in the ozone layer. The reason for this is the entry into the upper layers of the stratosphere of ozone-depleting substances used in industry, rocket launches, and many other factors. These are mainly chlorine and bromine molecules. Chlorofluorocarbons and other substances released by humans reach the stratosphere, where, under the influence of sunlight, they break down into chlorine and burn ozone molecules. It has been proven that one chlorine molecule can burn 100,000 ozone molecules. And it lasts in the atmosphere from 75 to 111 years!

As a result of the fall of ozone in the atmosphere, ozone holes occur. The first was discovered in the early 80s in the Arctic. Its diameter was not very large, and the drop in ozone was 9 percent.

Ozone hole in the Arctic

An ozone hole is a severe drop in the percentage of ozone in certain places in the atmosphere. The very word “hole” makes this clear to us without further explanation.

In the spring of 1985 in Antarctica, over the Hally Bay station, the ozone content dropped by 40%. The hole turned out to be huge and had already moved beyond Antarctica. Its layer reaches a height of up to 24 km. In 2008, it was calculated that its size was already more than 26 million km2. This stunned the whole world. Has it become clear? that our atmosphere is in greater danger than we imagined. Since 1971, ozone levels have fallen by 7% worldwide. As a result, our planet began to receive ultraviolet radiation from the Sun, which is biologically dangerous.

Consequences of ozone holes

Doctors believe that as a result of the decrease in ozone, the percentage of skin cancer and blindness due to cataracts has increased. Human immunity also decreases, which leads to various types of other diseases. The inhabitants of the upper layers of the oceans suffer the most. These are shrimp, crabs, algae, plankton, etc.

An international UN agreement has now been signed to reduce the use of ozone-depleting substances. But even if you stop using them. It will take more than 100 years to close the holes.

Can ozone holes be repaired?

To date, scientists have proposed one way to restore ozone using aircraft. To do this, it is necessary to release artificially created oxygen or ozone at an altitude of 12-30 kilometers above the Earth and disperse it with a special sprayer. This way, little by little, the ozone holes can be filled. The disadvantage of this method is that it requires significant economic waste. In addition, it is impossible to release a large amount of ozone into the atmosphere at one time. Also, the process of transporting ozone itself is complex and unsafe.

Myths about ozone holes

Since the problem of ozone holes remains open, several misconceptions have formed around it. Thus, they sought to turn the depletion of the ozone layer into a fiction that is beneficial to industry, supposedly due to enrichment. On the contrary, all chlorofluorocarbon substances have been replaced with cheaper and safer components of natural origin.

Another false claim is that ozone-depleting CFCs are too heavy to reach the ozone layer. But in the atmosphere, all elements are mixed, and polluting components can reach the level of the stratosphere, where the ozone layer is located.

You should not trust the statement that ozone is destroyed by halogens of natural origin, and not of anthropogenic origin. This is not true; it is human activity that contributes to the release of various harmful substances that destroy the ozone layer. The consequences of volcanic explosions and other natural disasters have virtually no effect on the state of ozone.

And the last myth is that ozone is destroyed only over Antarctica. In fact, ozone holes form throughout the atmosphere, causing the amount of ozone to decrease overall.

Forecasts for the future

Since ozone holes began to exist, they have been closely monitored. Recently the situation has become quite ambiguous. On the one hand, in many countries, small ozone holes appear and disappear, especially in industrialized areas, and on the other hand, there is a positive trend in the reduction of some large ozone holes.

During the observations, the researchers recorded that the largest ozone hole hung over Antarctica, and it reached its maximum size in 2000. Since then, judging by satellite images, the hole has been gradually closing. These statements are presented in the scientific journal Science. Ecologists estimate that its area has decreased by 4 million square meters. kilometers.

Research shows that the amount of ozone in the stratosphere is gradually increasing from year to year. This was facilitated by the signing of the Montreal Protocol in 1987. In accordance with this document, all countries are trying to reduce emissions into the atmosphere, and the amount of transport is being reduced. China has been especially successful in this regard. There, the appearance of new cars is regulated and there is the concept of a quota, that is, a certain number of car license plates can be registered per year. In addition, certain successes in improving the atmosphere have been achieved, because people are gradually switching to alternative energy sources, and there is a search for effective resources that would help save.

After 1987, the problem of ozone holes was raised more than once. Many conferences and meetings of scientists are devoted to this problem. Issues are also discussed at meetings of state representatives. So in 2015, the Conference on Climate Change was held in Paris, the purpose of which was to develop actions against climate change. This will also help reduce emissions into the atmosphere, which means that ozone holes will gradually close. For example, scientists predict that by the end of the 21st century the ozone hole over Antarctica will completely disappear.

Where are the ozone holes (VIDEO)

Ozone holes

It is known that the bulk of natural ozone is concentrated in the stratosphere at an altitude of 15 to 50 km above the Earth's surface. The ozone layer begins at altitudes of about 8 km above the poles (or 17 km above the Equator) and extends upward to altitudes of approximately 50 km. However, the density of ozone is very low, and if you compress it to the density that air has at the surface of the earth, the thickness of the ozone layer will not exceed 3.5 mm. Ozone is formed when ultraviolet radiation from the sun bombards oxygen molecules.

Most ozone is in the five-kilometer layer at an altitude of 20 to 25 km, which is called the ozone layer.

Protective role. Ozone absorbs part of the ultraviolet radiation from the Sun: its wide absorption band (wavelength 200-300 nm) also includes radiation that is harmful to all life on Earth.

Causes of the formation of the "ozone hole"

In summer and spring, ozone concentrations increase; over the polar regions it is always higher than over the equatorial ones. In addition, it changes on an 11-year cycle, coinciding with the solar activity cycle. All this was already well known when in the 1980s. Observations have shown that over Antarctica there is a slow but steady decrease in stratospheric ozone concentrations from year to year. This phenomenon was called the “ozone hole” (although, of course, there was no hole in the proper sense of the word) and began to be carefully studied. Later, in the 1990s, a similar decrease began to occur over the Arctic. The phenomenon of the Antarctic “ozone hole” is not yet clear: whether the “hole” arose as a result of anthropogenic pollution of the atmosphere, or whether it is a natural geoastrophysical process.

At first it was assumed that ozone was affected by particles emitted from atomic explosions; tried to explain the change in ozone concentration by the flights of rockets and high-altitude aircraft. In the end, it was clearly established that the cause of the undesirable phenomenon was the reaction of certain substances produced by chemical plants with ozone. These are primarily chlorinated hydrocarbons and especially freons - chlorofluorocarbons, or hydrocarbons in which all or most of the hydrogen atoms are replaced by fluorine and chlorine atoms.

It is assumed that due to the destructive effects of chlorine and similarly acting bromine, by the end of the 1990s. ozone concentration in the stratosphere decreased by 10%.

In 1985, British scientists released data according to which, over the previous eight years, ozone holes had been detected over the North and South Poles, increasing every spring.

Scientists have proposed three theories to explain the reasons for this phenomenon:

nitrogen oxides - compounds formed naturally in sunlight;

destruction of ozone by chlorine compounds.

The first thing to be clear is that the ozone hole, contrary to its name, is not a hole in the atmosphere. The ozone molecule differs from an ordinary oxygen molecule in that it consists of not two, but three oxygen atoms connected to each other. In the atmosphere, ozone is concentrated in the so-called ozone layer, at an altitude of approximately 30 km within the stratosphere. This layer absorbs ultraviolet rays emitted by the Sun, otherwise solar radiation could cause great harm to life on the surface of the Earth. Therefore, any threat to the ozone layer deserves to be taken very seriously. In 1985, British scientists working at the South Pole discovered that during the Antarctic spring, the level of ozone in the atmosphere there was significantly below normal. Every year at the same time the amount of ozone decreased - sometimes to a greater extent, sometimes to a lesser extent. Similar, but less pronounced ozone holes also appeared over the North Pole during the Arctic spring.

In subsequent years, scientists figured out why the ozone hole appears. When the sun goes down and the long polar night begins, temperatures plummet and high stratospheric clouds containing ice crystals form. The appearance of these crystals causes a series of complex chemical reactions leading to the accumulation of molecular chlorine (a chlorine molecule consists of two joined chlorine atoms). When the sun appears and the Antarctic spring begins, under the influence of ultraviolet rays, intramolecular bonds are broken, and a stream of chlorine atoms rushes into the atmosphere. These atoms act as catalysts for reactions that convert ozone into simple oxygen, proceeding according to the following dual scheme:

Cl + O3 -> ClO + O2 and ClO + O -> Cl + O2

As a result of these reactions, ozone molecules (O3) are converted into oxygen molecules (O2), with the original chlorine atoms remaining in a free state and again participating in this process (each chlorine molecule destroys a million ozone molecules before they are removed from the atmosphere by other chemical reactions). As a result of this chain of transformations, ozone begins to disappear from the atmosphere over Antarctica, forming an ozone hole. However, soon, with warming, the Antarctic vortexes collapse, fresh air (containing new ozone) rushes into the area, and the hole disappears.

In 1987, the Montreal Protocol was adopted, according to which a list of the most dangerous chlorofluorocarbons was determined, and the countries producing chlorofluorocarbons pledged to reduce their production. In June 1990, in London, clarifications were made to the Montreal Protocol: by 1995, reduce the production of freons by half, and by 2000, stop it completely.

It has been established that the ozone content is influenced by nitrogen-containing air pollutants, which appear both as a result of natural processes and as a result of anthropogenic pollution.

Thus, NO is formed in internal combustion engines. Accordingly, the launch of rockets and supersonic aircraft leads to the destruction of the ozone layer.

The source of NO in the stratosphere is also the gas N2O, which is stable in the troposphere, but in the stratosphere it decays under the influence of hard UV radiation.