Introduction
An ozone hole with a diameter of over 1000 km was first discovered in 1985 in the Southern Hemisphere of Antarctica by a group of British scientists. Every August it appeared, ceasing to exist by December or January. Another smaller hole was forming over the Northern Hemisphere in the Arctic.
The ozone hole- a local drop in the concentration of ozone-ozone layer of the Earth. According to the theory generally accepted in the scientific community, in the second half of the 20th century, the ever-increasing impact anthropogenic factor in the form of the release of chlorine- and bromine-containing freons has led to a significant thinning of the ozone layer, see, for example, the report of the World Meteorological Organization:
These and other recent scientific data strengthen the conclusion of previous assessments that the preponderance of scientific evidence indicates that observed ozone loss at mid- and high-latitudes is primarily due to anthropogenic chlorine- and bromine-containing compounds
According to another hypothesis, the process of formation of “ozone holes” may be largely natural and not associated solely with the harmful effects of human civilization.
Education mechanism
A combination of factors leads to a decrease in ozone concentration in the atmosphere, the main of which is the death of ozone molecules in reactions with various substances of anthropogenic and natural origin, the absence of solar radiation during the polar winter, a particularly stable polar vortex that prevents the penetration of ozone from subpolar latitudes, and the formation polar stratospheric clouds (PSC), the surface of which particles catalyze ozone decay reactions. These factors are especially characteristic of the Antarctic; in the Arctic, the polar vortex is much weaker due to the absence of a continental surface, the temperature is several degrees higher than in the Antarctic, and PSOs are less common and also tend to disintegrate in early autumn. Being chemically active, ozone molecules can react with many inorganic and organic compounds. The main substances that contribute to the destruction of ozone molecules are simple substances (hydrogen, oxygen atoms, chlorobromine), inorganic (hydrogen chloride, nitrogen monoxide) and organic compounds (methane, fluorochlorine and fluorobromofreons, which release chlorine and bromine atoms). In contrast, for example, to hydrofluorofreons, which decompose into fluorine atoms, which, in turn, quickly react to form stable hydrogen fluoride. Thus, fluorine does not participate in ozone decomposition reactions. Iodine also does not destroy stratospheric ozone, since iodine-containing organic substances are almost completely consumed in the troposphere. The main reactions that contribute to the destruction of ozone are given in the article pro-ozone layer.
Consequences
The weakening of the ozone layer increases the flow of solar radiation onto the earth and causes an increase in the number of skin cancers in people. Plants and animals also suffer from increased levels of radiation.
Restoring the ozone layer
Although humanity has taken measures to limit emissions of chlorine- and bromine-containing freons by switching to other substances, such as fluorine-containing freons , the process of restoring the ozone layer will take several decades. First of all, this is due to the huge volume of freons already accumulated in the atmosphere, which have a lifetime of tens and even hundreds of years. Therefore, the ozone hole should not be expected to close until 2048.
Misconceptions about the ozone hole
There are several widespread myths regarding the formation of ozone holes. Despite their unscientific nature, they often appear in the media - sometimes due to ignorance, sometimes supported by supporters conspiracy theories. Some of them are listed below.
Freons are the main ozone destroyers
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. (for more details about the contribution of various cycles, see Art. ozone layer). That is, human intervention greatly increases the contribution of the chlorine cycle. And with the existing tendency to increase the production of freons before the entry into force Montreal Protocol(10% per year) 30 to 50% of total ozone loss in 2050 would be due to exposure to CFCs. 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. As for the polar ozone holes, the situation here is completely different. The mechanism of ozone destruction is fundamentally different from higher latitudes, the key stage being 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%.
DuPont initiated a ban on old and the transition to new types of freons because their patent was expiring
DuPont, after publishing data on the participation of freons in the destruction of stratospheric ozone, took this theory with hostility and spent millions of dollars on a press campaign to protect freons. Chairman DuPont wrote in an article in Chemical Week on July 16, 1975, that the theory of ozone depletion was science fiction, nonsense, and made no sense. In addition to DuPont, a number of companies around the world have produced and are producing various types of freons without royalty payments.
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 and not 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. The processes of vertical mass transfer, convection, and turbulence completely mix the atmosphere below the turbopause much faster. Therefore, even such heavy gases as inert freons are evenly distributed in the atmosphere, including reaching the stratosphere. Experimental measurements of their concentrations in the atmosphere confirm this, see, for example, on the right, the graph of the distribution of CFC-11 freon by height. Measurements also show that it takes about five years for gases released on the Earth's surface to reach the stratosphere, see the second graph on the right. If the gases in the atmosphere did not mix, then such heavy gases from its composition as 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. Ikrypton, with an atomic mass of 84, and helium, with an atomic mass of 4, have the same relative concentration, both near the surface and up to 100 km altitude. Of course, all of the above is true only for gases that are relatively stable, such as freons or inert gases. Substances that react and are also subject to various physical influences, say, dissolve in water, have a concentration dependence on altitude.
The main sources of halogens are natural, not anthropogenic
It is believed that natural sources of halogens, such as volcanoes and 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. Also, natural compounds are less stable than freons; for example, methyl chloride has an atmospheric lifetime of only about a year, compared to tens and hundreds of years for freons. Therefore, their contribution to the destruction of stratospheric ozone is quite small. Even the rare eruption of Mount Pinatubo in June 1991 caused a drop in ozone levels not due to the released halogens, but due to the formation of a large mass of sulfuric acid aerosols, the surface of which catalyzed the reactions of ozone destruction. Fortunately, after just three years, almost the entire mass of volcanic aerosols was removed from the atmosphere. Thus, volcanic eruptions are relatively short-term factors affecting the ozone layer, in contrast to freons, which have lifetimes of tens and hundreds of years.
The ozone hole must be located above the sources of freons
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.
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 ozone concentrations over Arosa in Switzerland on the right.
There are many hypotheses trying to explain the decline in ozone concentrations. The reasons for its fluctuations in the Earth's atmosphere are related to:
- · with dynamic processes occurring in the Earth’s atmosphere (internal gravity waves, Azores anticyclone, etc.);
- · with the influence of the Sun (fluctuations in its activity);
- · with volcanism as a consequence of geological processes (outflow of freons from volcanoes involved in the destruction of the ozone layer, variations in the Earth’s magnetic field, etc.);
- · with natural processes occurring in the upper shells of the Earth, including the activity of nitrogen-producing microorganisms, sea currents (El Niño phenomenon), forest fires, etc.;
- · with the anthropogenic factor associated with human economic activity, when significant volumes of ozone-depleting compounds are produced into the atmosphere.
In recent decades, the impact of anthropogenic factors has increased sharply, which has led to the emergence of environmental problems that were unexpectedly turned into global ones by people themselves: the greenhouse effect, acid rain, forest destruction, desertification of territories, environmental pollution with harmful substances, and reduction of the planet’s biological diversity.
Some scientists believe that it was human economic activity that largely increased the share of the halogen decay pathway of stratospheric ozone, which provoked the occurrence of ozone holes.
The 1987 Montreal Protocol banned the production of refrigerants, which have been used to preserve food for the past half century, not only making human life more comfortable, but also saving the lives of many millions of people suffering from food shortages. As cheap refrigerants were banned, underdeveloped countries were unable to purchase expensive refrigerants. Therefore, they cannot store the agricultural products they produce. Expensive imported equipment developed in the countries of the initiators of the “fight against ozone holes” brings them considerable income. The ban on refrigerants has contributed to an increase in mortality in the poorest countries.
Today we can say with confidence that there is no strictly scientifically proven evidence regarding the destructive effect of artificially created chlorofluocarbon molecules on the ozone layer of the planet. But in the scientific community, the prevailing point of view is that in the second half of the 20th century, the reason for the decrease in the thickness of the ozone layer was the anthropogenic factor, which in the form of the release of chlorine- and bromine-containing freons led to a significant thinning of the ozone layer.
Freons are fluorine-containing derivatives of saturated hydrocarbons (mainly methane and ethane), used as refrigerants in refrigeration machines. In addition to fluorine atoms, freon molecules usually contain chlorine atoms, less often bromine. More than 40 different freons are known. Most of them are produced by industry.
Freon 22 (Freon 22) - belongs to substances of the 4th hazard class. When exposed to temperatures above 400°C, it can decompose to form highly toxic products: tetrafluoroethylene (4th hazard class), hydrogen chloride (2nd hazard class), hydrogen fluoride (1st hazard class).
Thus, the data obtained strengthened the conclusion of many (but not all!) researchers that the observed loss of ozone in the middle and high latitudes is mainly due to anthropogenic chlorine- and bromine-containing compounds.
But according to other ideas, the formation of “ozone holes” is largely a natural, periodic process, not associated exclusively with the harmful effects of human civilization. This point of view today is not shared by many, not only because they lack arguments, but because it turned out to be more profitable to follow in the wake of “global utopias.” Many scientists, in the absence of funds for scientific research, have become and are becoming victims of grants to substantiate the ideas of “global environmental chauvinism” and the guilt of progress in this.
As G. Kruchenitsky points out, A. Khrgian, Russia's leading ozone specialist, was practically the first to draw attention to the fact that the formation and disappearance of ozone holes in the northern hemisphere correlates with atmospheric-dynamic, and not chemical processes. The ozone content can change by several tens of percent within two to three days. That is, the issue is not in ozone-depleting substances, but in the dynamics of the atmosphere itself.
E. Borisenkov, a prominent specialist in the field of atmospheric studies, based on processing data from nine Western European stations over twenty-three years, established a correlation between 11-year cycles of solar activity and changes in ozone in the Earth's atmosphere.
The causes of ozone holes are mostly associated with anthropogenic sources of compounds penetrating into the stratospheric layer of the Earth's atmosphere. However, there is one catch. It lies in the fact that the main sources of ozone-depleting compounds are not located in the polar (southern and northern) latitudes, but are concentrated closer to the equator and are almost entirely located in the northern hemisphere. While the most frequent phenomena of thinning the thickness of the ozone layer (the actual appearance of ozone holes) are observed in Antarctica (southern hemisphere) and less often in the Arctic zone.
That is, sources of ozone-depleting compounds must be quickly and well mixed in the Earth's atmosphere. At the same time, they quickly leave the lower layers of the atmosphere, where their reactions with the participation of ozone should also be observed. To be fair, it should be noted that there is significantly less ozone in the troposphere than in the stratosphere. In addition, the “lifetime” of these compounds can reach several years. Therefore, they can reach the stratosphere under conditions of dominant vertical movements of air masses and heat. But here comes the difficulty. Since the main movements associated with heat and mass transfer (heat + transferred air mass) take place precisely in the troposphere. And since the air temperature is already constant at an altitude of 11-10 km and is about -50? C, then this heat and mass transfer from the tropospheric layer to the stratospheric layer should be slowed down. And the participation of anthropogenic sources that destroy the ozone layer may not be as significant as is still believed.
The next fact that can reduce the role of the anthropogenic factor in the destruction of the Earth's ozone layer is the appearance of ozone holes, mostly in spring or winter. But this, firstly, contradicts the assumption about the possibility of rapid mixing of ozone-depleting compounds in the Earth’s atmosphere and their penetration into the stratospheric layer of high ozone concentration. Secondly, the anthropogenic source of ozone-depleting compounds is constantly active. Consequently, it is difficult to explain the reason for the appearance of ozone holes in spring and winter, and even in polar latitudes, by an anthropogenic cause. But the presence of polar winters and the natural decrease in solar radiation in winter satisfactorily explains the natural cause of the occurrence of ozone holes over Antarctica and the Arctic. For example, ozone concentrations in the Earth's atmosphere in summer vary from 0 to 0.07%, and in winter from 0 to 0.02%.
In Antarctica and the Arctic, the mechanism of ozone destruction is fundamentally different from higher latitudes. Here, the conversion of inactive forms of halogen-containing substances into oxides mainly occurs. The reaction takes place on the surface of particles of polar stratospheric clouds. As a result, almost all ozone is destroyed in reactions with halogens. At the same time, chlorine is responsible for 40-50% and bromine is responsible for about 20-40%.
With the arrival of the polar summer, the amount of ozone increases and returns to its previous level. That is, fluctuations in ozone concentration over Antarctica are seasonal. Everyone admits this. But if, nevertheless, earlier supporters of anthropogenic sources of ozone-depleting compounds were inclined to claim that a steady dynamics of decrease in ozone concentration was observed during the year, then later this dynamics turned out to be the opposite. Ozone holes have begun to shrink. Although, in their opinion, restoration of the ozone layer should take several decades. Since it was believed that a huge volume of freons from anthropogenic sources had accumulated in the atmosphere, which have a lifetime of tens, and even hundreds of years. Therefore, the ozone hole should not be expected to close until 2048. As we see, this forecast did not come true. But drastic efforts were made to reduce freon production volumes.
organism ultraviolet ozone marine
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 large 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 has 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)
It is no secret that our planet Earth is unique in the solar system, since it is the only planet on which life exists. And the origin of life on Earth was possible thanks to a special protective ball of ozone, which covers our planet at an altitude of 20-50 km. What is ozone and why is it needed? The word “ozone” itself is translated from Greek as “smelling”, because it is its smell that we can feel after. Ozone is a blue gas consisting of triatomic molecules, essentially even more concentrated oxygen. The importance of ozone is enormous, since it is what protects the Earth from the harmful effects of ultraviolet rays coming from the Sun. Unfortunately, we people do not appreciate what was created by nature (or God) over billions of years, and one of the results of destructive human activity was the appearance of ozone holes, which we will talk about in today’s article.
What are ozone holes?
First, let’s define the very concept of an “ozone hole” and what it is. The fact is that many people mistakenly imagine the ozone hole as some kind of hole in the atmosphere of our planet, a place in which the ozone sphere is completely absent. In fact, this is not entirely true, it’s not that it is completely absent, it’s just that the concentration of ozone at the site of the ozone hole is several times lower than it should be. As a result, it is easier for ultraviolet rays to reach the surface of the planet and exert their destructive effect precisely in the areas of ozone holes.
Where are the ozone holes?
Well, in this case, the natural question will be about the location of the ozone holes. The first ozone hole in history was discovered in 1985 over Antarctica; according to scientists, the diameter of this ozone hole was 1000 km. Moreover, this ozone hole has a very strange behavior: it appears every time in August and disappears by the beginning of winter, only to appear again in August.
A little later, another ozone hole, albeit of a smaller size, was discovered over the Arctic. Nowadays, many small ozone holes have been discovered in different places, but the ozone hole over Antarctica ranks first in size.
Photo of the ozone hole over Antarctica.
How do ozone holes form?
The fact is that at the poles, due to the low temperature there, stratospheric clouds containing ice crystals are formed. When these clouds come into contact with molecular chlorine entering the atmosphere, a whole series of chlorine gases occurs, the result of which is the destruction of ozone molecules, reducing its amount in the atmosphere. And as a result, an ozone hole is formed.
Causes of ozone holes
What are the causes of ozone holes? There are several reasons for this phenomenon, and the most important of them is environmental pollution. Many factories, factories, flue gas power plants emit into the atmosphere, including the ill-fated chlorine, and it, already entering into chemical reactions, makes a boom in the atmosphere.
Also, the appearance of ozone holes was greatly facilitated by nuclear tests conducted in the last century. During nuclear explosions, nitrogen oxides enter the atmosphere, which, entering into chemical reactions with ozone, also destroy it.
Airplanes flying in clouds also contribute to the appearance of ozone holes, since each of their flights is accompanied by the release of the same nitrogen oxide into the atmosphere, which is destructive to our protective ozone ball.
Consequences of ozone holes
The consequences of the expansion of ozone holes, of course, are not the most rosy - due to increased ultraviolet radiation, the number of people with skin cancer may increase. In addition, a person’s general immunity decreases, which leads to many other diseases. However, not only people can suffer from increased ultraviolet radiation passing through the ozone hole, but also, for example, inhabitants of the upper layers of the ocean: shrimp, crabs, algae. Why are ozone holes dangerous for them? All the same problems with immunity.
How to deal with ozone holes
Scientists have proposed the following solution to the problem of ozone holes:
- Begin regulating the release of ozone-depleting chemicals into the atmosphere.
- Start to restore individually the amount of ozone at the site of ozone holes. To do this in this way, using aircraft at an altitude of 12-30 km to spray piece ozone into the atmosphere. The disadvantage of this method is the need for significant economic costs, and, unfortunately, it is impossible to spray a significant amount of ozone into the atmosphere at a time with modern technologies.
Ozone holes, video
And finally, an interesting documentary about ozone holes.
One of the most remarkable "green" myths is the claim that the ozone holes above the Earth's poles are caused by emissions of certain substances produced by humans into the atmosphere. Thousands of people still believe in it, even though any schoolchild who hasn’t skipped chemistry and geography classes can debunk this myth.
The myth that human activity is causing the so-called ozone hole to grow is remarkable in many ways. Firstly, it is extremely plausible, that is, it is based on real facts. Such as the presence of the ozone hole itself and the fact that a number of substances produced by humans can destroy ozone. And if so, then a non-specialist has no doubt that it is human activity that is to blame for the depletion of the ozone layer - just look at the graphs of the hole’s growth and the increase in emissions of relevant substances into the atmosphere.
And here another feature of the “ozone” myth emerges. For some reason, those who believe the above-mentioned evidence completely forget that the mere coincidence of two graphs does not mean anything. After all, it may just be an accident. In order to have undeniable evidence of the anthropogenic theory of the origin of ozone holes, it is necessary to study not only the mechanism of ozone destruction by freons and other substances, but also the mechanism of subsequent restoration of the layer.
Well, here comes the fun part. As soon as an interested non-specialist begins to study all these mechanisms (for which you do not need to sit in the library for days - just remember a few paragraphs from school textbooks on chemistry and geography), he immediately understands that this version is nothing more than a myth. And remembering the impact this myth had on the world economy by limiting the production of freons, he immediately understands why it was created. However, let's look at the situation from the very beginning and in order.
We remember from the chemistry course that ozone is an allotropic modification of oxygen. Its molecules contain not two O atoms, but three. Ozone can be formed in different ways, but the most common in nature is this: oxygen absorbs a portion of ultraviolet radiation with a wavelength of 175-200 nm and 280-315 nm and is converted into ozone. This is exactly how the ozone protective layer was formed in ancient times (somewhere 2-1.7 billion years ago), and this is how it continues to form to this day.
By the way, from the above it follows that almost half of the dangerous UV radiation is actually absorbed by oxygen, not ozone. Ozone is only a “by-product” of this process. However, its value lies in the fact that it also absorbs part of the ultraviolet - that whose wavelength is from 200 to 280 nm. But what happens to the ozone itself? That's right - it turns back into oxygen. Thus, in the upper layers of the atmosphere there is a certain cyclic equilibrium process - ultraviolet of one type promotes the conversion of ozone into oxygen, and it, absorbing UV radiation of another type, again turns into O 2.
A simple and logical conclusion follows from all this - in order to completely destroy the ozone layer, we need to deprive our atmosphere of oxygen. After all, no matter how much human-produced freons (hydrocarbons containing chlorine and bromine, used as refrigerants and solvents), methane, hydrogen chloride and nitrogen monoxide destroy ozone molecules, ultraviolet irradiation of oxygen will again restore the ozone layer - after all, these substances are “turned off” unable! As well as reducing the amount of oxygen in the atmosphere, since trees, grasses and algae produce hundreds of thousands of times more of it than humanity - the aforementioned ozone destroyers.
So, as you can see, not a single substance created by people is able to destroy the ozone layer as long as oxygen is present in the Earth’s atmosphere and the Sun emits ultraviolet radiation. But why then do ozone holes occur? I want to say right away that the term “hole” itself is not entirely correct - we are talking only about the thinning of the ozone layer in certain parts of the stratosphere, and not about its complete absence. However, to answer the question, you just need to remember where exactly on the planet the largest and most persistent ozone holes exist.
And here there is nothing to remember: the largest of the stable ozone holes is located directly above Antarctica, and the other, slightly smaller one, is located above the Arctic. All other ozone holes on Earth are unstable; they form quickly, but are “darned” just as quickly. Why does the thinning of the ozone layer persist for quite a long time in the polar regions? Yes, simply because in these places the polar night lasts for six months. And during this time, the atmosphere over the Arctic and Antarctic does not receive enough ultraviolet light to convert oxygen into ozone.
Well, O 3, in turn, left without “replenishment”, begins to quickly collapse - after all, it is a very unstable substance. That is why the ozone layer over the poles is thinning considerably, although the process occurs with some delay - a visible hole appears at the beginning of summer and disappears by mid-winter. However, when the polar day arrives, ozone begins to be produced again and the ozone hole is slowly mended. True, not completely - all the same, the time of intense receipt of UV radiation in these parts is shorter than the period of its deficiency. That's why the ozone hole doesn't disappear.
But why, in this case, was the myth created and replicated? The answer to this question is not only simple, but very simple. The fact is that the presence of a permanent ozone hole over Antarctica was first proven in 1985. And at the end of 1986, specialists from the American company DuPont (that is, DuPont) launched the production of a new class of refrigerants - fluorocarbons that do not contain chlorine. This greatly reduced the cost of production, but the new substance still had to be promoted to the market.
And here DuPont finances the dissemination in the media of a myth about evil freons that spoil the ozone layer, which was created by a group of meteorologists on its order. As a result, a frightened public began to demand that the authorities take action. And these measures were taken at the end of 1987, when a protocol was signed in Montreal to limit the production of substances that deplete the ozone layer. This led to the ruin of many companies that produced freons, and also to the fact that DuPont became a monopolist in the refrigerant market for many years.
By the way, it was precisely the speed with which DuPont management made the decision to use the ozone hole for its own purposes that led to the fact that the myth turned out to be so unfinished that it could be exposed by an ordinary schoolchild who did not skip chemistry and geography classes. If they had more time, you see, they would have composed a more convincing version. Nevertheless, even what the scientists eventually “gave birth” at the request of DuPont was able to convince many people.