Causes and consequences of the depletion of the ozone layer. Presentation on theme: "The Destruction of the Ozone Layer." Environmental impact

23.04.2020

Ministry of Education and Science of the Russian Federation

Federal State Budgetary Educational Institution of Higher Professional Education

GOU VPO Siberian State Aerospace University

named after academician M.F. Reshetnev"

Course: "Ecology"

Presentation on theme: "Ozone layer depletion. Fighting methods "

Completed: student gr. IUZU -04

Fedorov A.V.

Zheleznogorsk 2014

Introduction

The role of ozone and the ozone screen for the life of our planet

Environmental problems atmosphere

1 Depletion of the ozone layer and factors affecting it

2 Ozone-depleting substances and their mechanism of action

3 Production of ozone-depleting substances in Russia

4 "Ozone holes"

The impact of the depletion of the ozone layer on life on Earth

How can you help your planet

1 Measures taken to protect the ozone layer

2 Ozone layer restoration projects

The role of ionizers in human life

Conclusion

Bibliography

Introduction

The 20th century saw signs of climate change. The earth has become warmer. The last century has been the warmest of the millennium. What is it connected with? What consequences can this lead to? We have long been interested in problems environment. About the problems of the atmosphere, about the role of ozone and the ozone screen at the end of the last century, a lot was written and argued in scientific circles, this was widely covered in the press. Therefore, we had an idea about it. But in the process of working on the topic “Problems of the atmosphere: ozone”, we somewhat changed our opinion about the problem of the atmosphere and the state of the Earth's ozone layer. Did the person and his influence become the main thing in the appearance of this problem? This topic is as relevant and important today as ever.

Purpose: To study the problems of the ozone layer;

Tasks: Find out the impact of human activities on climate change on the planet;

Hypothesis: Man is only partly to blame for this problem;

Object of study: Ozone layer;

Subject of study: The ozone layer as a condition for life on Earth and the factors that destroy it.

Working on the topic, we studied and analyzed the literature: textbooks, journal articles, reference books and the analytical yearbook Russia in the Environment. In doing this work, we wanted to express our vision of this problem, its possible consequences for the environment and human ability to influence the solution of this problem.

1. The role of ozone and the ozone screen for the life of our planet

Ozone is triatomic oxygen (O3), a gas of rather rare intense of blue color, at low temperatures(-112o C) turns into a dark blue liquid, and at lower cooling it forms dark purple crystals. Ozone is extremely toxic (even more than carbon monoxide), its maximum permissible concentration in the air is 0.00001%. Part of the blue color of the Earth's atmosphere is due to ozone. Ozone is present in the atmosphere above the Earth from 15 to 50 km, in very small concentrations - even up to a height of 70 km. Its maximum concentration is at an altitude of about 40 km above the Earth's surface.

The ozone environment is an aggressive environment that corrodes iron, corrodes organic compounds, is a disinfectant solution (in liquids).

Most of the ozone is formed in the upper atmosphere under the influence of ultraviolet radiation. Its concentration depends on the intensity of ultraviolet radiation from the Sun in different wavelengths. Ultraviolet radiation from the Sun with a wavelength of less than 230 nm leads to an increase in ozone. The increase in radiation in waves with greater length causes an increase in temperature and, conversely, destroys ozone.

The ultraviolet breaks down ordinary oxygen molecules into atoms, and these free atoms attach to oxygen molecules, forming useful ozone of a few millimeters at a height of 19 to 40 km above the Earth's surface. A little ozone penetrates with air currents into the lower layers of the atmosphere.

Scientists learned about the ozone layer of the atmosphere in the 70s of the twentieth century. Along with visible light, the sun emits ultraviolet waves. The short-wave part of hard ultraviolet radiation is of particular danger. All life on Earth is protected from the aggressive effects of ultraviolet radiation, which has a high biological activity, because. over 90% of it is absorbed by the ozone layer, the so-called ozone layer. (According to the materials of the "Handbook on the protection of the geological environment")

Ozone screen - a layer of the atmosphere, closely coinciding with the stratosphere, lying between 7-8 km (at the poles) and 17-18 km (at the equator) and 50 km above the surface of the planet and characterized by an increased concentration of ozone, reflecting the hard shortwave / ultraviolet / cosmic radiation dangerous to living organisms. Most of the ozone is in the stratosphere. The thickness of the stratospheric ozone layer, reduced to normal conditions of atmospheric pressure (101.3 MPa) and temperature (0o C) on the Earth's surface, is about 3 mm. But the actual amount of ozone depends on the season, latitude, longitude, and more. This layer protects people and wildlife also from soft x-ray radiation. Thanks to ozone, the emergence of life on Earth and its subsequent evolution became possible. Ozone strongly absorbs solar radiation in different parts of the spectrum, but it is especially intense in the ultraviolet part (with a wavelength of less than 400 nm), and with a longer wavelength (more than 1140 nm) - much less.

Ozone formed close to the Earth's surface is called harmful. In the surface layers, ozone is formed under the influence of random factors. It occurs during a thunderstorm, during a lightning strike, the operation of x-ray equipment, its smell can be felt near a working copier. In the air polluted with ozone oxides, under the influence of sunlight, ozone is formed, which contributes to the formation of a dangerous phenomenon called photochemical smog. When light rays react with substances found in exhaust gases and industrial fumes, ozone is also formed. On a hot, foggy day in a polluted area, ozone levels can reach alarming levels. Breathing ozone is very dangerous as it destroys the lungs. Pedestrians who inhale large amounts of ozone suffocate and experience chest pain. Trees and bushes growing near polluted highways cease to grow normally at high ozone concentrations.

Fortunately, nature has endowed man with a sense of smell. A concentration of 0.05 mg / l, which is much less than the maximum permissible concentration, is perfectly felt by a person, and he can feel the danger. The smell of ozone is the smell of a quartz lamp.

But if ozone is at a high altitude, then it is very beneficial for health. Ozone absorbs ultraviolet rays. Only 47% reach the earth's surface solar radiation, about 13% of solar energy is absorbed ozone layer in the stratosphere, the rest is absorbed by clouds (according to reference and educational literature).

ozone ionizer ecological atmosphere

2. Environmental problems of the atmosphere

1 Depletion of the ozone layer and factors affecting it

The ozone layer protects life on Earth from harmful ultraviolet radiation from the sun. Over the years, the ozone layer has been found to experience a slight but constant weakening over certain regions of the globe, including densely populated areas in middle latitudes northern hemisphere. An extensive "ozone hole" has been discovered over Antarctica.

The destruction of ozone occurs due to exposure to ultraviolet radiation, cosmic rays, certain gases: nitrogen compounds, chlorine and bromine, fluorochlorocarbons (freons). Human activities that deplete the ozone layer are of the greatest concern. Therefore, many countries have signed an international agreement to reduce the production of ozone-depleting substances.

There are many reasons for the weakening of the ozone shield.

First, these are the launches of space rockets. Burning fuel “burns out” large holes in the ozone layer. It was once assumed that these "holes" were being closed. It turned out not. They have been around for quite some time.

Secondly, planes. Especially flying at altitudes of 12-15 km. The steam and other substances emitted by them destroy ozone. But, at the same time, aircraft flying below 12 km. Give an increase in ozone. In cities, it is one of the components of photochemical smog. Thirdly, it is chlorine and its compounds with oxygen. A huge amount (up to 700 thousand tons) of this gas enters the atmosphere, primarily from the decomposition of freons. Freons are not entering into any chemical reactions gases that boil at room temperature and therefore increase their volume dramatically, making them good nebulizers. Since their temperature decreases as they expand, freons are widely used in the refrigeration industry.

Every year the amount of freons in the earth's atmosphere increases by 8-9%. They gradually rise up into the stratosphere and become active under the influence of sunlight - they enter into photochemical reactions, releasing atomic chlorine. Each particle of chlorine is capable of destroying hundreds and thousands of ozone molecules.

On February 2004, the NASA Earth Institute website announced that scientists at Harvard University had found an ozone-destroying molecule. The scientists named this molecule "chlorine monoxide dimer" because it is made up of two molecules of chlorine monoxide. The dimer only exists in the particularly cold stratosphere above the polar regions when chlorine monoxide levels are relatively high. This molecule comes from chlorofluorocarbons. The dimer causes ozone destruction by absorbing sunlight and decaying into two chlorine atoms and an oxygen molecule. Free chlorine atoms begin to interact with ozone molecules, leading to a decrease in its amount.

2 Ozone-depleting substances and their mechanism of action

For the first time, freons began to be used in the 20s of the last century. Freons are inert, non-flammable, easy-to-manufacture substances, widely used in aerosols as solvents, they are used in fire extinguishers, in the operation of refrigeration equipment as coolants, in the manufacture of disposable polystyrene tableware and packaging for packaging and storage of products.

3 Production of ozone-depleting substances in Russia

The mechanism of action of freons is as follows: getting into the upper layers of the atmosphere, they are transformed. Molecular bonds are broken. As a result, chlorine is released, which, when combined with ozone, destroys it:

O3 + Cl2 O2 + O + Cl2

One molecule of chlorine is enough to destroy tens of thousands of ozone molecules and thereby reduce its amount in the atmosphere. More than a million tons of freons are produced annually in the world. Freons are volatile and rise into the stratosphere. Ozone enters into active photochemical reactions with freons, nitrogen oxides. Freons decompose, releasing atomic chlorine, which destroys the ozone layer. In the place of such interaction, the ozone layer disappears.

The rate of atmospheric pollution by some ozone-depleting substances has begun to slow down. By 2030, their production should be completely stopped. Over the past 15 years, the amount of freon emissions has dropped dramatically: from 1.1 million tons to 160 thousand tons today. Freons are very slowly removed from the atmosphere and live in it for decades (and some for 139 years!) /based on the analytical yearbook "Russia in the Environment"/

4 "Ozone holes"

In the "ozone hole" the ozone content is less than in the screen itself. Here the content of this gas is below the norm by 30 - 50%. The protective properties of this ozone layer are reduced. Over 2000 years, the total amount of ozone has changed little. This is evidenced by the reconstruction of the gas composition of the atmosphere, made according to the results of the analysis of air bubbles from the Antarctic ice cores.

In 1974, American scientists S. Rowland and M. Molina discovered that the Earth's ozone layer is being destroyed by chlorine, which is contained in freons. From now on scientific world split into two parts. Some believe that fluctuations in the thickness of the ozone layer are quite natural and are regulated by quite regular, natural processes; others believe that human beings are to blame for ozone suffering, with their technical impact on the environment.

In 1995, the scientists Rowland, Molina and the German scientist P. Krutzen were awarded Nobel Prize for research on the formation and decay of ozone in the earth's atmosphere. The concentration of ozone is usually increased in the polar and subpolar regions. Studying the concentration of ozone in the atmosphere using satellite observations, scientists noticed that the total content of stratospheric ozone decreases every spring: in 1986 - 1991. its amount over Antarctica was 30 - 40% lower than in 19967 -1971, and in 1993 the total content of stratospheric ozone decreased by 60%, and in 1987 - 1994. its small number turned out to be a record: almost four times less than normal. In 1994, during six spring weeks over Antarctica, ozone completely disappeared in the lower stratosphere.

So a significant depletion of ozone each spring was established first over Antarctica, and then over the Arctic. The area of each hole is about 10 million km2. It has now been clarified how the Antarctic ozone hole is formed: it occurs as a result of a combination of many processes in the Antarctic atmosphere. Freons, which deliver chlorine and its oxides, and the so-called polar stratospheric clouds, which form during the polar night in a very cold stratosphere, play a decisive role here. Thus, if freon emissions continue, we can expect the expansion of "holes" above the poles.

The size of the ozone hole, as well as the ozone content in it, can vary considerably. When the direction of the prevailing winds changes, the ozone hole is filled with ozone molecules from nearby areas of the atmosphere, while the amount of ozone in neighboring areas decreases. Holes can even move. For example, in the winter of 1992, the ozone layer over Europe and Canada became 20% thinner.

Now there are more than 120 ozonometric stations in the world, 40 of them are in Russia. Measurements of total ozone from the Earth are usually made using a Dobsonian spectrophotometer. The accuracy of such measurements is + 1-3%. In Russia, to measure the total ozone content, filter ozonometers are more often used, the accuracy of their measurements is somewhat lower. The distribution of ozone in the atmosphere is also studied using instruments installed on satellites (in Russia - the Meteor satellite, in the USA - the Nimbus satellite).

The ozone hole is formed over those territories where enterprises producing ozone-depleting substances are concentrated. In the 1970s and 1980s, the decrease in ozone concentration over the territory of Russia was episodic. But from the second half of the 90s in winter time this phenomenon began to be observed over vast areas of Russia already regularly. ozone holes in last years are formed over Siberia and Europe, leading to an increase in the incidence of skin cancer in humans and other diseases. This will certainly affect other inhabitants of the planet (according to the site www.nature.ru).

3. Impact of ozone depletion on life on Earth

A decrease in the ozone content in the upper atmosphere by only 1% on a planetary scale causes an increase in the incidence of skin cancer by 3-6% in humans and animals, up to 150,000 cases of cataracts, as the permeability of the atmosphere for ultraviolet rays increases by 2%. In addition, ultraviolet rays have a damaging effect on immune system organism, making it more susceptible to infectious diseases, (for example, to malaria). Ultraviolet rays also destroy plant cells - from trees to cereals, reduce the growth rate of phytoplankton, accelerate the extinction of marine and oceanic life forms due to a decrease in the amount of plant food. A breakthrough through the ozone hole of solar X-ray and ultraviolet rays, the photon energy of which exceeds the energy of visible spectrum rays by 50-100 times, increases the number of forest fires.

4. How you can help your planet

1 Measures taken to protect the ozone layer

International community, concerned about this trend, has already introduced restrictions on the emission of freons. In 1985, the Vienna Convention for the Protection of the Earth's Ozone Layer was adopted in Vienna (Austria). The main provisions of this convention were:

cooperation in the field of research on substances and processes that affect changes in the ozone layer;

creation of alternative substances and technologies;

monitoring of the ozone layer;

cooperation in the development and application of measures that control activities that lead to adverse effects in the ozone layer;

cooperation in the development and transfer of technologies and scientific knowledge.

In 1987, the governments of 56 countries (including the USSR) signed the Montreal Protocol, according to which the production of fluorochlorocarbons should be halved by the beginning of the 21st century. Later agreements - 1990 in London, 1992 - in Copenhagen, call for a complete cessation of the production of these substances.

It was easiest to solve the problem of replacing freons with other substances in aerosols - they are replaced with hydrocarbon propellants such as propane or butane. Since 1994, aerosols with a hydrocarbon propellant have been produced in Russia by JSC Khiton in Kazan.

The introduction of ozone-friendly substances causes greatest difficulties in the production of refrigeration equipment. New non-ozone depleting refrigerants already exist, such as R-134A, R-404A, R-407C, R-507 and some others. They are made, however, not in Russia. They are very expensive. Producers of new freons do not hide the fact that these new freons will be replaced by other, even better freons (one of the leading manufacturers of them is the American corporation DuPont). The new refrigerants that exist today will not stay on the market for long.

In fact, a course has been taken to replace the refrigerant every 5-6 years (and along with this oil, spare parts, if not all equipment). What has become the norm in the West in household appliances is being transferred to industrial cold. What consumer can handle it? Especially in Russia and in the CIS. All this comes at a huge cost. The economic difficulties here are great, so freons are still mainly used in refrigeration equipment. In Russia alone, for a one-time refueling of all refrigeration equipment, 30-35 thousand tons of freons would be required. Its annual amount for refueling is 4.5 thousand tons.

The freon crisis forced the development of new promising methods of obtaining cold. Compressor refrigeration machines have survived the last decades. Most likely, the main source of cold in industrial refrigeration plants will be endothermic chemical reactions that go with the absorption of heat. According to theoretical estimates, the energy efficiency of such coolers is expected to be 1.5 - 2 times higher than that of compressor systems (based on the book by V.N. Kiselev "Fundamentals of Ecology" and the analytical yearbook "Russia in the Environment")

2 Ozone layer restoration projects

According to the materials of the site www.natura.ru, according to the calculations of physicists, it is possible to clear the atmosphere of freons in just a year, having one power unit of a nuclear power plant with a capacity of 10 GW as an energy source. It is known that the sun produces 5-6 tons of ozone per second, but the destruction is faster. To restore the ozone layer, it must be constantly fed. One of the first projects for the treatment of our planet was, but remained unfulfilled, such a project: several “ozone” factories were to be created on earth, and cargo planes were supposed to “throw” ozone into the upper atmosphere.

Currently, there are other projects: to artificially obtain ozone in the stratosphere. To do this, 20 - 30 satellites equipped with lasers need to be launched into the Earth's orbit. Each satellite is a space platform weighing 80 - 100 tons, carrying a solar convector - a "heat trap", accumulating solar energy and converting heat into electricity. Laser beams should "shake" the ozone molecules, and then, with the help of the Sun, the process will go on its own. The idea behind this project is to create 20,000 tons of ozone and keep that number going until people come up with something better.

Of the already existing ozone protection programs, one can name the Russian-American project "Meteor 3 - TOMS". Another way is proposed by the Russian consortium Interozon: to produce 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 ozone can be obtained from diatomic oxygen. With the help of the ISS, it is possible to create several space platforms with energy sources and lasers at an altitude of about 400 km. Laser beams will be directed to the central part of the ozone layer and will constantly feed it. The energy source in this project can be solar panels. Astronauts on these platforms would be needed only for their periodic inspections and repair. Yes, there are projects to restore the ozone layer, but they all require huge financial costs, and whether they will be implemented, time will tell (from the book by A.D. Yanshin “ scientific problems protection of nature and ecology).

5. The role of ionizers in human life

Air ions are either positive or negative. The process of formation of a charge on a molecule is called ionization, and a charged molecule is called an ion or an air ion. If an ionized molecule settles on a particle or a grain of dust, then such an ion is called a heavy ion.

Heavy ions are harmful to human health, while light ions, especially negative ones, have a beneficial and healing effect. Negative air ions relieve fatigue, fatigue, reduce diseases, strengthen immunity. In the mountain air, the number of air ions of both charges reaches 800-1000 pieces per cubic centimeter. And in some resorts their number rises to several thousand. In the air of cities, the number of light ions can drop to 50-100, and heavy ions can rise to tens of thousands per cubic centimeter.

To make the air “alive” means to create oxygen ions in the air in such a concentration that exists in the air of mountain resorts. This is what air ionizers are designed to do.

Air ionizers are designed to create negative air ions in the room. Manufacturers of ionizers are so concerned about the voltage on the electrodes of their devices. Why? The answer is simple! Because the higher the voltage, the greater the range of propagation of air ions. This is known to all manufacturers and even to many consumers. But the engineers who develop these devices also know that the maximum allowable tension (PDN) electromagnetic field should be no more than 25 kV / m.

To this day, ionizers with a voltage of 50 kV are widely used; 30kV; 25kV.

If the voltage on the electrode of the ionizer is 50 kV, then in order to find out at what distance a person should be, it is necessary to carry out simple calculations. Dividing the voltage on the electrode by the PDN, we get 2 meters (50:25 = 2). This means that this device should not be approached during its operation closer than 2 meters.

For example, the Malm-aeron ionizer is calculated as follows: 10: 625 = 0.4m

Most powerful medical institutions of the country conducted clinical testing of modern Chandelier Chizhevsky (ionizers) and confirmed the unique effect of aeroionotherapy in the treatment of asthma. This is the Research Institute. Sklifosovsky, Institute of Higher nervous activity and Neurophysiology RAS, Institute of Theoretical and Experimental Biophysics RAS and some others.

Every fifth child in Moscow is diagnosed bronchial asthma . Among adults, about 14% suffer from this disease. And the situation is getting worse. After a course of aeronotherapy in 50% of patients, seizures stop for up to five years. Another 40% achieve a significant improvement, attacks stop on average for a year.

Moreover, the improvement often occurs after 4-5 sessions of inhalation of air ions, and the attack stops 3-5 minutes after the ionizer is turned on.

Clinical trials have shown that in 90% of cases, aeroionotherapy completely and permanently relieves the manifestation of bronchial asthma, allowing you to abandon hormonal drugs. In addition, it significantly increases the body's resistance to allergens. Such an effective action of the ionizer is due, firstly, to the fact that it purifies the air of dust, microbes and allergens, and secondly, saturates it with healing oxygen air ions.

Tests in the laboratory of bacteriology NII SP them. Sklifosovsky confirmed that after 30 minutes of operation of the device, the microbial contamination of the air decreases by 5 times. The content of dust and any allergens in the air decreases by the same amount. The latter is just a lifesaver for those who react to house dust or pollen.

Conclusion

Billions of dollars have already been spent all over the world just to keep the ozone layer from completely thinning out. Scientists have calculated that even if measures are taken and all human activity destroying the ozone layer, then it will take 100-200 years to restore it in full.

Many scientists still continue to believe that talk of "ozone holes" is a storm in a cup of water. And, perhaps, it was started by several Western companies that have their very considerable economic interest in this problem. We also wondered, but is it only man to blame for the decrease in the ozone layer? Probably not. Perhaps not freons - the main culprits of ozone destruction. Russian researchers from the Faculty of Geology of Moscow State University attribute the appearance of ozone holes to the release of hydrogen and methane from deep oceanic faults, in comparison with which any human refrigerators look pathetic. All factors are important. Catastrophic volcanic eruptions with huge emissions of pollutants into the atmosphere, oceanic faults causing powerful tsunamis and typhoons, earthquakes with faults earth's crust cause powerful emissions of gases and dust into the atmosphere. These factors cannot be influenced. Perhaps they are much more important in destroying the planet's ozone layer than human influence. After all, volcanoes have always erupted, and fluorine and chlorine derivatives are also present in the emissions. Kamchatka volcanoes and volcanoes in Indonesia emit natural gases into the atmosphere, similar in composition to freon-11 and freon-12. The Earth's ozone layer is being restored by the same sunbeams who create it. Nothing irreversible happens. The main thing here is periodic fluctuations. This is convincingly evidenced by satellite observations.

People know that the complete disappearance of ozone from the atmosphere will be followed by a catastrophe: the inevitable death of all life, including humans. But this shouldn't happen. We believe that man will help our planet not get sick. Today, people are thinking and taking action to reduce their negative impact on atmospheric changes and ozone depletion.

Bibliography

Karol. I.I., Kiselev A.A. Who or what destroys the ozone layer of the Earth? // Ecology and life. - 1998. - No. 3 - p.30-33

Kiselev V.N. Fundamentals of Ecology - Minsk: Universitetskaya, 1998. - 143-146.

Snakin V. Ecology and nature conservation. Dictionary - reference book. - Ed. Academician Yanshin A.L. - M .: Akademia. 2000.- 362-363.

Yanshin A.D. Scientific problems of nature conservation and ecology // Ecology and life.-1999.-№ 3-p.8-9.

Russia in the surrounding world. Analytical Yearbook. Project leader: Marfenin N.N. Under total editors: Moiseeva N.N., Stepanova S.A. - M.: MNEPU, 1998.- 67-81

Handbook on the protection of the geological environment. T.1./ G.V. Voitkevich, I.V. Golikov and others / Ed. Voytkevich G.V. - Rostov-on-Don: Phoenix, 1996.

Living organisms on Earth are protected from the short-wave ultraviolet (UV) radiation of the Sun, which is detrimental to all living things, by the ozone screen (ozone layer).

Ozone screen- this is an air layer in the upper layers of the atmosphere (stratosphere), consisting of a special form of oxygen - ozone (Fig. 1).

The thickness of the ozone layer on the scale of the atmosphere is no more than a sheet of paper in the volume of a home library.

Ozone has significant ecological and biological significance and is the most important component of the atmosphere, despite the fact that its percentage is small - less than 0.0001%. This is due to the fact that it is ozone that actively absorbs UV radiation.

Ozone- the form molecular oxygen(0 3). Its main amount is concentrated in the stratosphere at an altitude of 15-25 km (the upper limit is 45-50 km). Paradoxically, the same ozone molecules in the troposphere (lower layer of the atmosphere) are dangerous elements that destroy living tissue, including human lungs. However, there is very little ozone here, and it is formed only during lightning discharges.

The beginning of ozone formation in the stratosphere is associated with the reaction of splitting molecular oxygen by short-wavelength (X< 242 нм) УФ-излучением Солнца:

0 2 + hv -> O + O

Rice. 1. Ozone screen: a - ozone (0 3) in the stratosphere absorbs the UV rays of the Sun; b - ozone is formed in the stratosphere when, under the action of UV rays, the 0 2 molecules decompose into free atoms that can attach to its other molecules

O + O 2 + m -> O 3 + M

Atmospheric researchers from the British Antarctic Survey in 1985 reported an unexpected fact: the spring ozone content in the atmosphere over Halle Bay Station in Antarctica decreased from 1977 to 1984 by 40%! Soon this conclusion was confirmed by other researchers, who also showed that the area of low ozone extends beyond Antarctica and covers a layer from 12 to 24 km in height, i.e. much of the lower stratosphere. In fact, this means that there is an ozone "hole" in the polar atmosphere. In the early 80s. 20th century The Nimbus-7 satellite discovered a similar hole in the Arctic, although it covered a much smaller area and the ozone level drop in it was not so large - about 9%. On average, from 1979 to 1990, the ozone content decreased by 5%.

So what is the ozone layer in the atmosphere? Theoretically, if all the ozone is "compressed" to the density of water and placed on the surface of the Earth, then it would form a film only 2-4 mm thick, with a minimum at the equator and a maximum at the poles. The altitude distribution of ozone is such that the maximum concentration is observed at an altitude of 25 km. But it also rises at an altitude of 70 km. Most of the ozone is in the stratosphere, and this layer is usually low in the Arctic, while in tropical zone- high. As for the troposphere, there is less ozone, moreover, it is more subject to both seasonal and other changes, in particular caused by pollution.

The thinning of the ozone layer can lead to serious consequences for humanity. A decrease in ozone concentration by 1% causes an increase in the intensity of hard ultraviolet near the Earth's surface by an average of 2%. In terms of its effect on living organisms, hard ultraviolet is close to ionizing radiation, however, due to its longer wavelength than that of y-radiation, it is not able to penetrate deep into tissues, therefore it affects only superficial organs. Hard ultraviolet has enough energy to destroy DNA and other organic molecules.

Hard ultraviolet rays can cause skin cancer in humans, in particular rapid malignant melanoma, as well as cataracts and immune deficiency, not to mention the usual burns of the skin and cornea. They harm animals and plants, in particular marine ecosystems, because they are poorly absorbed by water.

The idea of the danger of ozone depletion was first expressed in the late 1960s. There has been great concern among environmentalists Negative influence water vapor and nitrogen oxides (NO x), which are emitted by jet engines of supersonic aircraft and rockets at an altitude of 20-25 km. It is at this height that the protective layer of ozone is located, which traps the harsh ultraviolet radiation of space. Such concerns are based on the property of nitric oxide to destroy ozone:

2NO + 0 3 = N 2 0 +20 2

In 1974, scientists found that chlorofluorocarbons (CFCs) could cause ozone depletion (Figure 2). Since that time, the so-called "chlorofluorocarbon problem" has become one of the main ones in research on atmospheric pollution. Chlorofluorocarbons include, in particular, freons - chemically inert substances on the surface of the Earth. They have been used for more than 60 years as refrigerants in refrigerators and air conditioners, propellants for aerosol mixtures (in household aerosol cans), ionizing agents in fire extinguishers, cleaners for electronic devices, in dry cleaning of clothes, in the production of foam plastics.

Almost all Freon (or organofluorine) produced in the world eventually rises to the upper atmosphere and decomposes there under the influence of ultraviolet rays, which destroy normally stable CFC molecules. The latter decompose into highly reactive components, in particular atomic chlorine. During the photochemical decomposition of freon in the stratosphere, the chlorine ion acts as an ozone depletion agent. Thus, CFCs transport chlorine from the Earth's surface through the troposphere and lower atmosphere, where less inert chlorine compounds are destroyed, into the stratosphere, to the layer with the highest concentration of ozone. Fragments of freon molecules have a destructive effect on the atmospheric ozone layer. CFCs have already destroyed 3 to 5% of the ozone layer in the atmosphere.

Rice. 2. Scheme of destruction of the ozone screen

It is very important that during the destruction of ozone, chlorine acts like a catalyst: during chemical process its quantity does not decrease. As a consequence, one chlorine atom can destroy up to 100,000 ozone molecules before it is deactivated or re-enters the troposphere. Now CFC emissions into the atmosphere are estimated at millions of tons, but it should be noted that even in the event of a complete cessation of the production and use of CFCs, an immediate result will not be achieved: the effect of CFCs that have already entered the atmosphere will continue for several decades.

For use as a propellant in aerosols, a good substitute for CFCs has already been found - a propane-butane mixture. In terms of physical parameters, it is practically not inferior to freons, but, unlike them, it is flammable. Nevertheless, such aerosols are already produced in many countries, including Russia. The situation is more complicated with refrigeration units - the second largest consumers of freons. The fact is that, due to the polarity of CFC molecules, they have a high heat of vaporization, which is very important for the working fluid in refrigerators and air conditioners. The best CFC substitute known today is ammonia, but it is toxic and still inferior to CFCs in terms of physical parameters. Good results have been obtained for fully fluorinated hydrocarbons. In many countries, new substitutes are being developed, but this problem has not yet been completely solved.

A decrease in the density of the planet's ozone shield entails a decrease in crop yields and livestock productivity, a sharp decrease in the biological productivity of the near-surface layer of the World Ocean, and, consequently, fish catches, and a significant increase in the incidence of skin cancer in humans. It is clear that without knowledge of general environmental laws, the further progress of mankind and the progressive development of the economy are impossible.

Destruction of the ozone layer

It is found in the atmosphere between 15 and 40 km above the Earth's surface. This layer acts as a screen for deadly ultraviolet radiation, attenuating it by about 6,500 times. In the atmosphere, ozone is formed from oxygen by the action of electrical discharges and cosmic radiation (Fig. 3).

Depletion of the ozone layer by 50% would increase UV radiation by a factor of 10, which would affect human and animal vision and could have other detrimental effects on living organisms.

The disappearance of the ozone layer would lead to unpredictable consequences - outbreaks of skin cancer, the destruction of plankton in the ocean, mutations of flora and fauna.

For the first time, the appearance of an ozone "hole" over Antarctica was recorded back in the 1970s. As measurements from satellites showed, the ozone in this "hole" was 30-50% less than the norm. Similar phenomenon in Antarctica, it is observed in autumn, while at other times of the year, the ozone content fluctuates around the norm. Later it turned out that the thickness of the ozone layer also changes in the middle and high latitudes of the Northern Hemisphere, especially over Europe, the USA, Pacific Ocean, European part Russia, Japan and Eastern Siberia. The causes of the destruction of the ozone layer could be: supersonic aircraft, launch spaceships, large scale freon production.

Rice. 3. Mechanisms for the formation of the ozone layer (bottom) and its role in the atmosphere (top)

Based on scientific research, it was found that the main cause is freons, widely used in refrigeration and in aerosol cans.

The international community has taken a number of measures aimed at preventing the destruction of the ozone layer. In 1977, the United Nations Environment Program adopted an action plan for the ozone layer, and in 1985 a conference was held in Vienna that adopted the Convention for the Protection of the Ozone Layer. A list of substances that adversely affect the ozone layer was established, and a decision was made to mutually inform states about the production and use of these substances and about the measures taken.

Thus, the harmful effects of changes in the ozone layer on human health and the environment were officially announced, and that measures to protect the ozone layer require international cooperation.

Decisive was the signing of the Montreal Protocol in 1987, according to which control was established over the production and use of freons. The protocol was signed by most countries of the world, including Russia. According to these agreements, the production of freons was to be stopped by 2010. However, the agreement was not fully implemented by 2011 either. The ozone hole over the Arctic in 2011, according to the latest data, is 2 million km2. But it is not completely clear; Is it only due to anthropogenic factors that it appears!

the most important integral part The atmosphere that influences climate and protects all life on Earth from solar radiation is the ozonosphere. The bulk of ozone is located at altitudes from 10 to 50 km, and its maximum - at 18 -26 km. In total, the stratosphere contains 3.3 trillion tons of ozone. In the ozonosphere layer, ozone is in a very rarefied state.

The role of ozone in the preservation of biological life on Earth is exceptionally great. Ozone molecules absorb the hard ultraviolet radiation of the Sun precisely in that spectral region, which is the most destructive for biological systems. Organic molecules are destroyed by ultraviolet (UV) radiation. This also applies to DNA molecules, which are known to be responsible for the transmission of hereditary traits. The ozone layer, like a shield, not only protects living matter from direct destruction, but also ensures the course of evolution.

Rice. 1 Ozone in the Earth's atmosphere

If the thickness of ozone decreased, it would cause irreparable harm to all living organisms. Solid ultraviolet is poorly absorbed by water and therefore poses a great danger to marine ecosystems. Experiments have shown that plankton living in the near-surface layer, with an increase in the intensity of hard UV, can be seriously damaged and even die completely. Plankton is at the base of the food chains of almost all marine ecosystems, so it can be said without exaggeration that almost all life in the near-surface layers of the seas and oceans can disappear. Plants are less sensitive to hard UV, but if the dose is increased, they can also be affected. The complete disappearance of the ozone layer would undoubtedly mean the disappearance of higher forms of life. In humans, it is now estimated that even a slight decrease in the thickness of the ozone layer can increase the incidence of skin cancer. However, humanity will easily find a way to protect itself from hard UV radiation, but at the same time risk starving to death. A different distribution of ozone in height will also significantly affect the climate, since the nature of the absorption of UV radiation by ozone will change, and hence the temperature of the stratosphere.

The problem of ozone, as one of the small gaseous components of the atmosphere, was previously of interest only to a small circle of scientists, but has now acquired global significance. This dramatic change is due to the discovery that the normal content of ozone in the atmosphere is under threat as a result of economic activity person.

If the entire amount of ozone was collected at a normal pressure of 760 mmHg. Art. and a temperature of 273.15 K, then the thickness of this layer would be only 2.5 -3 mm. Ozone is a corrosive, slightly bluish gas. Its molecule consists of three oxygen atoms (O 3), so ozone is the "chemical relative" of the more stable and rich substance in the atmosphere necessary for human breathing, which is composed of two oxygen atoms (O 2).

Ozone properties:

The ability to absorb biologically dangerous ultraviolet radiation from the sun.

Ozone is the strongest oxidizing agent (in other words, a poison), so ground-level ozone is dangerous.

Absorption of infrared radiation from the earth's surface.

The ability to directly and indirectly influence chemical composition atmosphere.

Since the mechanism for creating ozone molecules is in balance with the mechanism for their destruction, scientists consider the average amount of ozone in the stratosphere to be a relatively constant value from the moment of formation modern atmosphere Earth.

Unlike other atmospheric constituents, ozone appeared in the atmosphere exclusively by chemical means and is the youngest atmospheric component. From an ecological point of view, a valuable property of ozone is its ability to absorb biologically dangerous ultraviolet radiation from the sun; while the chemical compound ozone is the strongest oxidizing agent (simply a poison), capable of poisoning the same flora and fauna upon direct contact that it protects as the stratospheric ozone layer. In addition, ozone is an effective greenhouse gas. And, finally, ozone affects the small active components of the atmosphere, and through them, the stable components, which, like ozone itself, absorb both ultraviolet and infrared radiation. Thus, ozone makes not only a direct, but also an indirect effect on Greenhouse effect and the level of ultraviolet radiation on the Earth's surface.

Almost the only source of ozone in the atmosphere is the photodissociation of molecular oxygen into atoms, followed by the rapid lulling of an atom to an O 2 molecule to form an ozone molecule:

O 2 + H N \u003d O + O (1)

O + O 2 + M = O 3 + M (2)

(Here M is any air molecule).

This process occurs at altitudes above 30 km, since short-wave solar radiation does not penetrate below this altitude. As a result, ozone molecules and oxygen atoms appear quite high in the atmosphere.

The death of atmospheric ozone occurs as a result of the following processes:

O 3 + H N \u003d O + O 2 (3)

O + O 3 \u003d O 2 + O 2 (4)

Thus, the atoms that were once formed from oxygen molecules are recombined into a molecule. We only note that, in order to "decompose" the ozone molecule, short-wave radiation is not required. The bond of the O atom with the O 2 molecule in ozone is very weak, therefore, even when irradiated with visible light, the ozone molecule will be photodissociated into the original components.

I also note that reaction (3) is the main supplier of oxygen atoms; its velocity at all heights of the troposphere and stratosphere is three or more orders of magnitude higher than the reaction rate (1).

The above mechanism was proposed in the early 1930s by the English geophysicist Chapman and was the first attempt to explain the formation of the ozone layer in the atmosphere.

Ozone in the stratosphere is constantly born and dies, therefore, its layer consists of an equilibrium amount. And since this equilibrium is mobile, the thickness of the ozone layer can change. There are daily, seasonal fluctuations in the ozone content, as well as cycles associated with long-term changes in solar activity. The largest amount of ozone (46%) is formed in the stratosphere of the tropical belt, where its maximum density is located approximately at an altitude of 26 km of the surface. In mid-latitudes, it is located lower: in winter - at an altitude of 22 km, and in summer - 24 km. In the polar regions, the height of the maximum is only 13-18 km, and here ozone is most intensively transferred to the lower layers of the atmosphere.

There are many reasons for the weakening of the ozone shield caused by anthropogenic activities. In general, they can be divided into two groups.

1. Emissions from high-altitude aircraft and missiles

Firstly, are launches of space rockets. Fuel burns out, "burns out" large holes in the ozone layer. It was once assumed that these "holes" were being closed. It turned out not. They have been around for quite some time.

Secondly, - airplanes. Especially those that fly at altitudes of 12-15 km. The steam emitted by them and other substances destroy ozone. But, at the same time, planes flying below 12 km give an increase in ozone. In cities, it is one of the components of photochemical smog.

Thirdly, - nitrogen oxides. They are thrown out by the same planes, but most of all they are released from the soil surface, especially during the decomposition of nitrogen fertilizers.

Since supersonic flights are not carried out very often today, they do not cause significant harm to the ozone layer. Rocket launches are also not very frequent, but they can cause very serious damage to the ozone layer. So, with the total mass of the Space Shuttle orbiter one hundred and forty-three and a half tons, in the process of lifting to a height of 50 km, the solid-propellant rocket system emits 187 tons of Cl 2 and its compounds, 7 tons of nitrogen oxides and destroys 10 million tons of ozone during the flight. This is a lot, because the earth's atmosphere contains only 3,000,000,000 tons of ozone.

Nitrogen oxides play important role in the formation and destruction of ozone, and in the stratosphere there is a catalytic destruction of ozone in the troposphere - catalytic formation.

2. Chlorofluorocarbons (CFCs), or freons

Freons were once considered ideal for practical application chemicals, because they are very stable and inactive, and therefore non-toxic. Paradoxically, it is the inertness of these compounds that makes them hazardous to atmospheric ozone. CFCs do not break down quickly in the troposphere (lower layer of the atmosphere extending from the earth's surface to a height of 10 km), as happens, for example, with most nitrogen oxides, and eventually penetrate into the stratosphere, the upper limit of which is located at an altitude of about 50 km. When CFC molecules rise to a height of about 25 km, where the ozone concentration is highest, they are exposed to intense ultraviolet radiation (Fig. 2), but do not penetrate to lower altitudes due to the shielding effect of ozone. Ultraviolet destroys freon molecules that are stable under normal conditions, decompose into highly reactive components, in particular, atomic chlorine. Thus, CFCs transport chlorine from the earth's surface through the troposphere and lower atmosphere, where less inert chlorine compounds are destroyed, into the stratosphere, to the layer with the highest concentration of ozone. It is very important that chlorine acts like a catalyst during the destruction of ozone: its amount does not decrease during the chemical process. As a result, one chlorine atom can destroy up to 100,000 ozone molecules before it is deactivated or returned to the troposphere. Now the release of freons into the atmosphere is estimated at millions of tons, but it should be noted that even in the hypothetical case of a complete cessation of production and use of CFCs, an immediate result cannot be achieved: the action of freons that have already entered the atmosphere will continue for several decades. The two most widely used CFCs, Freon-11 (CFCl 3) and Freon-12 (CF 2 Cl 2), are thought to have lifetimes in the atmosphere of 75 and 100 years, respectively.

Rice. 2 Destruction of the Earth's ozone layer by freons One of the most impressive pieces of evidence that chlorine is indeed the agent responsible for the ozone hole came in September 1987, when scientists flew a plane from South America straight to the South Pole, into the ozone hole. Increasing and decreasing ozone concentration is almost accurate mirror reflection decrease and increase in the concentration of ClO. Moreover, the concentration of Cl in the ozone hole itself is hundreds of times higher than any level that could be explained in terms of atmospheric chemistry. This phenomenon is often referred to as "smoke gun". Even CFC producers have become convinced that the ozone hole is not normal. This is evidence of profound changes in the atmosphere caused by artificial chlorine pollutants.

It took scientists several years to find an explanation for the appearance of the ozone hole. Briefly, this is it.

Since Antarctica is surrounded by ocean, winds can continuously circulate around the continent, which has no mountain ranges. During the southern winter, they form around the pole vortex, a funnel of winds that collects air over Antarctica and holds it, not allowing it to mix with the other atmosphere. This vortex serves as an isolated "reaction pot" for polar atmospheric chemical compounds (it stronger than that, which forms over the North Pole, so the northern ozone hole appears much weaker).

Rice. 3 Ozone hole over Antarctica Under the pressure of the arguments above, many countries have begun to take measures aimed at reducing the production and use of freons. Since 1978, the use of freons in aerosols has been banned in the United States. Unfortunately, the use of freons in other industries was not limited. In September 1987, 23 leading countries of the world signed a protocol in Montreal obliging them to reduce their consumption of CFCs. Today, about 150 countries have signed up to it.

In addition, in 1985, the Vienna Convention for the Protection of the Ozone Layer was signed, in which developed countries recognized the fact of the problem of ozone layer depletion.

According to the agreement reached in Montreal, developed countries were to reduce the consumption of chlorofluorocarbons to half the 1986 level by 1999. A good substitute for freons, propane, has already been found in aerosols for use as a propellant (i.e., an inert chemical that creates excess pressure) - butane mixture. In terms of physical parameters, it is practically not inferior to freons, but, unlike them, it is flammable. However, such aerosols are already being produced in many countries. More difficult is the case with refrigeration units - the second largest consumer of freons. The fact is that, due to the polarity of CFC molecules, they have a high heat of vaporization, which is very important for the working fluid in refrigerators and air conditioners. The best known substitute for freons today is ammonia, but it is toxic and still inferior to freons in terms of physical parameters. Good results have been obtained for fully fluorinated hydrocarbons. In many countries, new substitutes are being developed and good practical results have already been achieved, but this problem has not yet been completely solved.

I would like to hope that the problem of the ozone layer will teach us to treat all substances that enter the atmosphere as a result of anthropogenic activity with great attention and caution.

Ozone is a type of oxygen found in the stratosphere, approximately 12-50 kilometers from the earth. The highest concentration of this substance is at a distance of approximately 23 kilometers from the surface. Ozone was discovered in 1873 by the German scientist Schönbein. Subsequently, this modification of oxygen was found in the surface and upper layers of the atmosphere. In general, ozone consists of triatomic oxygen molecules. Under normal conditions, it is a blue gas with a characteristic aroma. Under various factors, ozone turns into an indigo-colored liquid. When it becomes solid, it acquires a dark blue hue.

The value of the ozone layer lies in the fact that it acts as a kind of filter, absorbing a certain amount of ultraviolet rays. It protects the biosphere and people from direct solar radiation.

Causes of ozone depletion

For many centuries, people did not suspect the existence of ozone, but their activity adversely affected the state of the atmosphere. AT this moment scientists talk about such a problem as ozone holes. Depletion of oxygen modification occurs for a variety of reasons:

launching rockets and satellites into space;
operation of air transport at an altitude of 12-16 kilometers;
freon emissions into the air.

Major depleters of the ozone layer

The biggest enemies of the oxygen modification layer are hydrogen compounds and chlorine. This is due to the decomposition of freons, which are used as atomizers. At a certain temperature, they are able to boil and increase in volume, which is important for the manufacture of various aerosols. Quite often, freons are used for freezing equipment, refrigerators and cooling units. When freons rise into the air, chlorine is split off under atmospheric conditions, which in turn converts ozone into oxygen.

The problem of ozone depletion was discovered long ago, but by the 1980s, scientists sounded the alarm. If ozone is significantly reduced in the atmosphere, the earth will lose its normal temperature regime and stop getting cold. As a result, a huge number of documents and agreements were signed in various countries in order to reduce the production of freons. In addition, a replacement for freon was invented - propane-butane. According to its technical parameters, this substance has high performance, it can be used where freons are used.

Today, the problem of ozone depletion is very relevant. Despite this, the use of technologies using freons continues. At the moment, people are thinking about how to reduce the amount of freon emissions, are looking for substitutes to save and restore the ozone layer.

Fighting methods

Since 1985, measures have been taken to protect the ozone layer. The first step was the introduction of restrictions on the emission of freons. Further, the government approved the Vienna Convention, the provisions of which were aimed at protecting the ozone layer and consisted of the following points:

representatives different countries adopted a cooperation agreement regarding the study of processes and substances that affect the ozone layer and provoke its changes;
systematic monitoring of the state of the ozone layer;
creation of technologies and unique substances that help minimize damage;
cooperation in various areas of development of measures and their application, as well as the control of activities that provoke the appearance of ozone holes;
transfer of technology and acquired knowledge.

Over the past decades, protocols have been signed, according to which the production of fluorochlorocarbons should be reduced, and in some cases completely stopped.

The most problematic was the use of ozone-friendly products in the production of refrigeration equipment. During this period, a real "freon crisis" began. In addition, developments required significant financial investments, which could not but upset entrepreneurs. Fortunately, a solution was found and manufacturers instead of freons began to use other substances in aerosols (hydrocarbon propellant such as butane or propane). Today, the use of installations capable of using endothermic chemical reactions that absorb heat is common.

It is also possible to purify the atmosphere from the content of freons (according to physicists) with the help of a nuclear power plant, the power of which should be at least 10 GW. This design will serve as an excellent source of energy. After all, it is known that the Sun is capable of producing about 5-6 tons of ozone in just one second. By increasing this figure with the help of power units, it is possible to achieve a balance between the destruction and production of ozone.

Many scientists consider it expedient to create an "ozone factory" that will improve the condition of the ozone layer.

In addition to this project, there are many others, including the production of ozone artificially in the stratosphere or the production of ozone in the atmosphere. The main disadvantage of all ideas and proposals is their high cost. Large financial losses push projects into the background and some of them remain unrealized.

Five-minute video on protecting the ozone layer

The ozone layer is a part of the Earth's stratosphere that protects the planet from the effects of cosmic radiation. The causes and possible consequences of ozone depletion are not well understood, but changes in the stratosphere are definitely caused by human activities.

Formation and functions of the ozone layer

The formation of the protective layer began 1.85 billion years ago and continues slowly to this day. Photons (particles electromagnetic radiation Sun) collide with oxygen molecules in the atmosphere. As a result, the molecule loses an oxygen atom, which then joins another O 2 molecule. Ozone (O 3) in its normal state is a bluish gas. It weakens the impact of solar radiation on the surface of the planet by 6500 times.

Location and distance to the planet

The ozone layer ranges from 20 (polar latitudes) to 30 km (tropics) above sea level.

If, at a pressure of 1 atmosphere, wrap the globe with it, its thickness will be no more than 3 mm. Since the air in the stratosphere is rarefied, the pressure there is low, so formally the thickness of the ozone layer is measured in kilometers.

Ozone holes

Under the influence of natural and anthropogenic factors, the anti-radiation protection of the planet is weakening in some areas. Ozone molecules do not disappear in them, but the ozone layer is depleted. More solar radiation reaches the Earth's surface.

Discovery history

In 1840, the German X. F. Schönbein described a new substance - ozone. The existence of a layer of this substance was proved in 1912 by conducting spectroscopic measurements of the atmosphere. Thinning of the ozone layer was discovered only in the 1970s. Since then, the problem of the destruction of natural anti-radiation protection has been discussed in scientific circles.

Mechanism of Education

Due to emissions from thermal power plants, factories and factories, substances that destroy the ozone layer enter the air:

nitrogen and its oxides;
freon;
bromine;
chlorine.

The flight of aircraft at an altitude of 12-16 kilometers (lower boundary of the layer) also affects the composition of the atmosphere. Extremely negatively affected the natural protective screen of the planet nuclear tests in the middle of the 20th century, as explosions raised a huge amount of dust into the atmosphere.

Antarctic ozone hole

This anomaly with a diameter of up to 1000 km was the first and largest discovered ozone hole. Thinning is not observed constantly: during the polar night, there is no ultraviolet radiation, so measurements are not carried out. As of 2019, the anomaly has reached its smallest size in 37 years of observations, having decreased by 2.5 million km2.

The presence of a hole above south pole, and not over the North, where the content of freon in the atmosphere is higher, caused by a stronger polar vortex. The vortex is stronger due to the presence of a continent in the Antarctic, while even ice fields prevail in the area of the North Pole. The composition of the polar vortex contains freons, the destruction is also affected by the nitric acid contained in the polar clouds.

Common myths about ozone holes

In the yellow press, ozone holes are sometimes called one of the main threats to the existence of life. Sometimes the opposite opinion is expressed. The thinning of the anti-radiation screen is called a purely natural phenomenon, and the hype around it and freon is considered a cunning marketing ploy by manufacturers of expensive refrigerants.

Such a contradictory attitude appears due to a lack of understanding of the mechanism for the formation of holes and insufficient knowledge of the issue. There are 4 main myths about ozone:

"The main culprit is freon used in refrigerators." In fact, it is only one of the substances that affect the destruction of the layer. If freon is removed, the threat will remain due to nitrogen oxides, chlorine compounds and other hazardous substances that enter the atmosphere from car exhaust pipes, aircraft jet engines and CHP pipes.
"Natural factors prevail over anthropogenic ones." Natural thinning of the ozone layer is possible (for example, during polar nights), but then it is restored to normal values. The main threat is industrial emissions of hazardous substances (freons, nitrogen oxides, etc.) into the atmosphere.
“Freons are too heavy, so they cannot affect the atmosphere” . In the atmosphere, all substances are mixed, and the gravity of the freon molecules does not play a big role. Carbon dioxide is also heavier than air, but it rises into the atmosphere, as evidenced by the greenhouse effect.
"The only problematic region is Antarctica." The concentration of gas is dropping throughout the atmosphere, in Antarctica it is simply the most noticeable.

Causes of Ozone Layer Depletion

Despite the short period of observations and the lack of information, scientists have identified two groups of factors that affect the thinning of the Earth's anti-radiation protection. There is debate about which group has more negative impact.

natural factors

Solar radiation is necessary for the formation of ozone. Consequently, during the polar nights, the process stops, but the natural factors affecting the destruction persist. Due to polar vortices and nitric acid polar stratospheric clouds, the layer becomes thinner. In temperate, tropical and equatorial latitudes, the process is less noticeable.

During volcanic eruptions, thousands of tons of ash enter the atmosphere, which contains compounds that contribute to the breakdown of ozone molecules.

Anthropogenic factors

The main reason for the thinning of the anti-radiation layer is considered to be chlorofluorocarbons (CFCs). These substances are stable and do not pose a danger to humans, but when interacting with air, they contribute to the breakdown of ozone molecules.

Anthropogenic causes of ozone depletion

Freon emissions into the atmosphere

The clearest example of chlorofluorocarbons is freons, which can be in the state of aggregation of liquid or gas. They are used as a cheap refrigerant in refrigerators, they are contained in aerosol cans. Previously, freons were considered the main culprit in the destruction of the ozone layer. Now scientists are inclined to believe that their influence is overestimated.

Launching satellites and rockets

When a launch vehicle passes through the stratosphere, its engines emit an enormous amount of gases (nitrogen oxides, carbon dioxide). Some researchers estimate that 300 shuttle launches would be enough to completely deplete the ozone layer. Solid propellant rocket engines are more dangerous than liquid rocket engines because they emit chlorine compounds.

Use of air transport at high altitudes

Civil aviation flies at altitudes up to 13 km. Military aircraft can fly higher into the stratosphere. During operation, a jet or rocket engine releases oxides of nitrogen. Since the flight takes place at the height of the formation of the ozone layer, nitric oxide immediately reacts with ozone molecules and destroys them.

Application of nitrogen fertilizers

Nitrogen fertilizers have been used since the end of the 19th century, but now the scale of their use poses a threat to the atmosphere. The following substances are commonly used:

ammophos and diammophos;
ammonium chloride;
ammonium carbonate;
ammonium sulfide;
ammonium sulfate.

When they decompose, nitrogen oxides are released, which in the atmosphere react with ozone molecules and destroy them.

Other reasons

Research in this area is ongoing, and it is possible to identify new factors associated with the thinning of the Earth's ozone layer. The true state of affairs remains a matter of controversy. It is not entirely clear how significant the effect of modern refrigerants and aerosols on the natural anti-radiation screen is.

Possible consequences of the thinning of the ozone layer

Scientists agree on negative consequences changes in the stratosphere. Now they are not clearly expressed, but according to the most pessimistic forecasts, the situation will become critical at the end of the 21st century.

Human impact

A 1% thinning of the ozone layer increases the risk of developing skin cancer by 3% (that's about 7,000 new cancers every year). Being outdoors makes it easier to get sunburned.

Environmental impact

Since the planet is a balanced system, damage to one element causes changes in all others. Further thinning of anti-radiation protection and an increase in the intensity of UV radiation will lead to warming and the extinction of some species.

Hard ultraviolet radiation kills the phytoplankton involved in the process of photosynthesis. It is a food base for whales and other marine life. Removing this link from the food chain will cause changes in the entire aquatic biosystem.

If the ozone layer is completely destroyed

Complete destruction of the protective screen is impossible, as it is constantly being restored. If the concentration of ozone molecules approached zero, on Earth, due to the high level of radiation, most life forms would disappear. The average temperature would rise.

Measures to restore the ozone layer

When the data about the hole over Antarctica was confirmed, in 1985 they held the Vienna Convention for the Protection of the Ozone Layer. Two years later, the Montreal Protocol was prepared. This document became the basis for legislative regulation of the impact on the ozone layer.

Montreal Protocol

The treaty is observed by 197 countries. Participating States have committed to reduce the production of chlorofluorocarbons. The original plan was to freeze CFC production at the 1986 level. By 1993, they planned to reduce their production by 20%, and by 1998 - by 30%. Restrictions were imposed on the import and export of substances that deplete the ozone layer.

Subsidies and incentives have been provided for developing countries to facilitate the transition of industry to environmentally sound technologies.

Based on the results of the first years of the agreement, it turned out that it was not accurate. Amendments were made to the calculated coefficients for the removal of hazardous substances from production.

Ozone production options

The generators of this substance are called ozonizers. It is theoretically possible to slow down ozone depletion by running multiple ozone factories around the world. the globe. Ozone is produced in various ways:

exposure to artificial ultraviolet;
directed electric discharges;
electrolysis, where the electrolyte is a solution of perchloric acid;
chemical reaction, such as the oxidation of pinene.

The disadvantages of these methods are low productivity, high cost, high energy consumption. According to some estimates, the implementation of this project on a global scale will require at least 10 gigawatts of energy, which is equivalent to 1/3 of the capacity of a nuclear power plant.

Use of environmentally friendly fuel

ICEs running on refined oil contribute to an increase in the concentration of substances that deplete the ozone layer in the air. The widespread introduction of electric traction (especially the creation of passenger electric aircraft) will reduce the negative impact on the atmosphere.

Promising developments such as biodiesel and waste-based engines are a potential key to solving the problem.

Their emissions are less toxic than products formed after the combustion of gasoline or diesel fuel. To solve the problem, similar developments should be introduced at enterprises.

The use of environmentally friendly fuel in launch vehicles is still a fantasy. Modern technologies do not allow spacecraft to be put into orbit without resorting to burning tens of tons of toxic fuel.

planting forests

Creation green spaces in cities and at the site of clearings - a promising way to combat not only the destruction of the ozone layer, but also atmospheric pollution.

Trees give off oxygen, which is then converted to ozone by UV radiation from the sun.

Protection of the ozone layer in Russia

Russia as a legal successor Soviet Union complies with the requirements of the Montreal Protocol. The country has a law "On Environmental Protection", it concerns the protection of the ozone layer.

In accordance with the law, enterprises operating in the country must not emit more ozone-depleting substances into the atmosphere than is allowed in a special list. For failure to comply with this condition, production may be suspended or closed.

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