Ozone (O 3) is formed in the atmosphere from oxygen during electrical discharges during thunderstorms and under the influence of ultraviolet radiation from the Sun in the stratosphere. The ozone layer (ozone screen, ozonosphere) is located in the atmosphere at an altitude of 10-50 km with a maximum ozone concentration at an altitude of 20-25 km (above the poles it is thinner, like the entire atmosphere, and thicker above the equator). If the entire amount of ozone is collected under normal conditions (pressure 760 mm Hg and temperature 20 o C), then the thickness of this layer will be only 2.5 - 3 mm.
Importance of the ozone layer
The ozone screen delays the penetration of the most severe UV radiation from the Sun, the deadly “B-band”, which affects all living things, to the earth’s surface. A reduction in the ozone layer leads to a sharp increase in cancer (a decrease in the layer by 1% means an increase in ultraviolet radiation by 2% and leads to an increase in skin cancer by 5–6%), damage to the cornea and blindness, the development of mutations, and a decrease in the productivity of some plant species , and with a strong reduction - to the destruction of all living things.
Excess UV radiation disrupts the body's immune defense, contributing to the appearance of diseases in humans such as lupus (skin tuberculosis), erysipelas, smallpox, leishmaniasis, viral herpes, etc.
It has been established that a decrease in ozone content in the atmosphere can contribute to an increase in the greenhouse effect more significantly than an increase in carbon dioxide concentration.
Excessive flux of UV radiation is detrimental to phyto- and zooplankton, and the larvae of many fish.
A little history
Ozone holes most often appear over the poles, where the thickness of the atmosphere is less, and they reach their greatest values over Antarctica (where it is colder). This phenomenon began to be noted back in the 70s of the twentieth century, but it reached its maximum in the mid-80s.
Thus, in October 1985, reports appeared that the ozone concentration in the stratosphere over the English station Halley Bay (Antarctica) decreased by 40% from its minimum values, and over the Japanese one - almost 2 times... This phenomenon was named "ozone hole" Ozone holes of significant size over Antarctica appeared, as a rule, in the spring of 1987, 1992, 1997, when a decrease in the total content of stratospheric ozone (TO) by 40-60% was recorded. In the spring of 1998, the ozone hole over Antarctica reached a record area of 26 million square meters. km (3 times the territory of Australia). And at an altitude of 14-25 km in the atmosphere, almost complete destruction of ozone occurred.
Similar phenomena were observed in the Arctic (especially since the spring of 1986), but the size of the ozone hole here was almost 2 times smaller than over the Antarctic. In March 1995, the Arctic ozone layer was depleted by approximately 50%, and “mini-holes” formed over the northern regions of Canada and the Scandinavian Peninsula, the Scottish Islands (UK).
Ozone holes are not only observed over the poles. There are known cases where holes that spread to South America led to the blinding of livestock, mainly cattle. In the Kyrgyz Republic, the ozone hole was observed in May 1995 over high mountain areas. The size and duration (about 4-5 days) of its existence were insignificant, and it did not lead to any consequences.
Causes of ozone hole formation
Numerous international expeditions to study ozone holes in Antarctica to the Arctic have established that, in addition to various natural factors, the main one is the presence of a significant amount of CFCs (freons) in the atmosphere.
Freons (chlorofluorocarbons) - highly volatile, chemically inert substances near the earth's surface (synthesized in the 1930s), since the 1960s. have become widely used as refrigerants (refrigerators, air conditioners, refrigerators), aerosol foaming agents, etc. Freons, rising into the upper layers of the atmosphere, undergo photochemical decomposition, forming chlorine oxide, which intensively destroys ozone (each chlorine atom is capable of destroying 100,000 ozone molecules). The duration of stay of freons in the atmosphere is on average 50-200 years.
Security measuresozone layer
In 1985, the Vienna Convention for the Protection of the Ozone Layer was adopted.
In 1987, in Montreal, representatives of 36 countries signed the Protocol, under which they committed themselves to reducing the use and then eliminating the use of ozone-depleting substances (ODS) in industry and households. After 10 years, the number of countries that signed this Protocol increased to 163.
In a number of countries, in order to protect the ozone layer, alternative ozone-friendly substitutes for freons have been obtained, in particular, companies in Germany, Italy, Switzerland, and Great Britain began to use the refrigerant isobutane, which has zero ozone depletion potential. In many countries, environmentally friendly freon, a hydrocarbon propellant, has begun to be used in the production of aerosols (80% of all aerosols produced in the world).
In the USA and Russia, research has already begun on active methods based on complex physical and chemical processes that help either reduce the rate of ozone destruction in the stratosphere or accelerate its formation. Thus, to tighten ozone holes over Antarctica, it is possible to use the method of injection (introducing) ethane (C 2 H b) or propane (C 3 H 8) into the stratosphere, which will bind atomic chlorine, which destroys ozone, into hydrogen chloride, which is passive to it. There are also physicochemical methods that accelerate the formation of ozone in the stratosphere, in particular methods of electromagnetic radiation, using electrical discharges (ozonizer principle) and laser radiation.
In addition, to prevent the release of CFCs from the many cooling devices available, recycling methods have been developed.
From oxygen under the influence of ultraviolet rays. The Earth's atmosphere has an ozone layer at an altitude of about 25 kilometers: a layer of this gas tightly surrounds our planet, protecting it from high concentrations of ultraviolet radiation. If not for this gas, the intense radiation could have killed all life on Earth.
The ozone layer is quite thin; it cannot completely protect the planet from the penetration of radiation, which has a detrimental effect on the condition and causes diseases. But for a long time it was enough to protect the Earth from danger.
In the 80s of the 20th century, it was discovered that there are areas in the ozone layer where the content of this gas is greatly reduced - the so-called ozone holes. The first hole was discovered over Antarctica by British scientists, they were amazed at the scale of the phenomenon - an area with a diameter of more than a thousand kilometers had almost no protective layer and was exposed to stronger ultraviolet radiation.
Later, other ozone holes were found, smaller in size, but no less dangerous.
Causes of ozone hole formation
The mechanism of formation of the ozone layer in the Earth's atmosphere is quite complex, and various reasons can lead to its disruption. At first, scientists proposed many versions: the influence of particles formed during atomic explosions, and the impact of the eruption of the El Chicon volcano; even opinions were expressed about the activities of aliens.
The reasons for the depletion of the ozone layer may be the lack of solar radiation, the formation of stratospheric clouds, polar vortices, but most often the concentration of this gas drops due to its reactions with various substances, which can be both natural and anthropogenic. Molecules are destroyed under the influence of hydrogen, oxygen, chlorine, and organic compounds. So far, scientists cannot say unambiguously whether the formation of ozone holes is mainly caused by human activity, or whether it is natural.
It has been proven that freons released during the operation of many devices cause ozone loss in middle and high latitudes, but they do not affect the formation of polar ozone holes.
It is likely that a combination of many human and natural factors led to the formation of ozone holes. On the one hand, volcanic activity has increased, on the other, people have begun to seriously influence nature - the ozone layer can be damaged not only by the release of freon, but also by collisions with failed satellites. Thanks to a decrease in the number of erupting volcanoes since the end of the 20th century and restrictions on the use of freons, the situation has begun to improve slightly: scientists recently recorded a small hole over Antarctica. A more detailed study of ozone depletion will make it possible to prevent the emergence of these areas.
Greenhouse effect
The greenhouse effect is an increase in the temperature of the planet's lower atmosphere due to the accumulation of greenhouse gases. Its mechanism is as follows: the sun's rays penetrate the atmosphere and heat the surface of the planet. Thermal radiation that comes from the surface should return to space, but the lower atmosphere is too dense for them to penetrate. The reason for this is greenhouse gases. Heat rays linger in the atmosphere, increasing its temperature.
History of greenhouse effect research
People first started talking about the phenomenon in 1827. Then an article by Jean Baptiste Joseph Fourier appeared, “A Note on the Temperatures of the Globe and Other Planets,” where he detailed his ideas about the mechanism of the greenhouse effect and the reasons for its appearance on Earth. In his research, Fourier relied not only on his own experiments, but also on the judgments of M. De Saussure. The latter conducted experiments with a glass vessel blackened from the inside, closed and placed in sunlight. The temperature inside the vessel was much higher than outside. This is explained by the following factor: thermal radiation cannot pass through the darkened glass, which means it remains inside the container. At the same time, sunlight easily penetrates through the walls, since the outside of the vessel remains transparent.
Causes
The nature of the phenomenon is explained by the different transparency of the atmosphere for radiation from space and from the surface of the planet. For the sun's rays, the planet's atmosphere is transparent, like glass, and therefore they easily pass through it. And for thermal radiation, the lower layers of the atmosphere are “impenetrable”, too dense for passage. That is why part of the thermal radiation remains in the atmosphere, gradually descending to its lowest layers. At the same time, the amount of greenhouse gases thickening the atmosphere is growing. Back in school we were taught that the main cause of the greenhouse effect is human activity. Evolution has led us to industry, we burn tons of coal, oil and gas, we get fuel, the roads are filled with cars. The consequence of this is the release of greenhouse gases and substances into the atmosphere. Among them are water vapor, methane, carbon dioxide, and nitric oxide. It's clear why they are named that way. The surface of the planet is heated by the sun's rays, but it necessarily “gives” some of the heat back. Thermal radiation that comes from the Earth's surface is called infrared. Greenhouse gases in the lower part of the atmosphere prevent heat rays from returning to space and trap them. As a result, the average temperature of the planet is increasing, and this leads to dangerous consequences. Is there really nothing that can regulate the amount of greenhouse gases in the atmosphere? Of course it can. Oxygen does this job perfectly. But the problem is that the planet’s population is growing inexorably, which means that more and more oxygen is being consumed. Our only salvation is vegetation, especially forests. They absorb excess carbon dioxide and release much more oxygen than humans consume.
The greenhouse effect and the Earth's climate
When we talk about the consequences of the greenhouse effect, we understand its impact on the Earth's climate. First of all, it is global warming. Many people equate the concepts of “greenhouse effect” and “global warming”, but they are not equal, but interrelated: the first is the cause of the second. Global warming is directly related to the oceans. Here is an example of two cause-and-effect relationships. The average temperature of the planet is rising, liquid begins to evaporate. This also applies to the World Ocean: some scientists are afraid that in a couple of hundred years it will begin to “dry up.” At the same time, due to high temperatures, glaciers and sea ice will begin to actively melt in the near future. This will lead to an inevitable rise in sea levels. We are already observing regular floods in coastal areas, but if the level of the World Ocean rises significantly, all nearby land areas will be flooded and crops will perish.
Impact on people's lives
Do not forget that an increase in the average temperature of the Earth will affect our lives. The consequences can be very serious. Many areas of our planet, already prone to drought, will become absolutely unviable, people will begin to migrate en masse to other regions. This will inevitably lead to socio-economic problems and the outbreak of the third and fourth world wars. Lack of food, destruction of crops - this is what awaits us in the next century. But does it have to wait? Or is it still possible to change something? Can humanity reduce the harm from the greenhouse effect? Wetlands can prevent the greenhouse effect, the largest swamp in the world, Vasyugan.
Actions that can save the Earth
Today, all the harmful factors that lead to the accumulation of greenhouse gases are known, and we know what needs to be done to stop it. Don't think that one person won't change anything. Of course, only all of humanity can achieve the effect, but who knows - maybe a hundred more people are reading a similar article at this moment? Forest conservation Stop deforestation. Plants are our salvation! In addition, it is necessary not only to preserve existing forests, but also to actively plant new ones. Every person should understand this problem. Photosynthesis is so powerful that it can provide us with huge amounts of oxygen. It will be enough for the normal life of people and the elimination of harmful gases from the atmosphere. Use of electric vehicles Refusal to use fuel-powered vehicles. Every car emits a huge amount of greenhouse gases each year, so why not make a healthier choice for the environment? Scientists are already offering us electric cars - environmentally friendly cars that do not use fuel. The minus of a “fuel” car is another step towards eliminating greenhouse gases. All over the world they are trying to speed up this transition, but so far the modern developments of such machines are far from perfect. Even in Japan, where such cars are used the most, they are not ready to completely switch to their use. Alternative to hydrocarbon fuels Invention of alternative energy. Humanity doesn't stand still, so why are we stuck using coal, oil and gas? Burning these natural components leads to the accumulation of greenhouse gases in the atmosphere, so it's time to switch to an environmentally friendly form of energy. We cannot completely abandon everything that emits harmful gases. But we can help increase oxygen in the atmosphere. Not only a real man should plant a tree - every person must do this! What is the most important thing in solving any problem? Don't close your eyes to her. We may not notice the harm from the greenhouse effect, but future generations will definitely notice it. We can stop burning coal and oil, preserve the natural vegetation of the planet, abandon a conventional car in favor of an environmentally friendly one - and all for what? In order for our Earth to exist after us
Ozone holes
Ozone hole - a local drop in ozone concentration in the Earth's ozone layer
Everyone knows that our planet is enveloped in a fairly dense ozone layer, located at an altitude of 12–50 km above the earth’s surface. This air gap is a reliable protection for all living things from dangerous ultraviolet radiation and allows you to avoid the harmful effects of solar radiation.
It was thanks to the ozone layer that microorganisms were once able to get out of the oceans onto land and contributed to the emergence of highly developed life forms. However, since the beginning of the 20th century, the ozone layer began to collapse, as a result of which ozone holes began to appear in some places in the stratosphere.
What are ozone holes?
Contrary to popular belief that the ozone hole is a gap in the sky, it is actually an area of significant decline in ozone levels in the stratosphere. In such places, it is easier for ultraviolet rays to penetrate to the surface of the planet and have their destructive effect on everything living on it.
Unlike places with normal ozone concentrations, the hole content of the “blue” substance is only about 30%.
Where are the ozone holes?
The first large ozone hole was discovered over Antarctica in 1985. Its diameter was about 1000 km, and it appeared every year in August, and disappeared by the beginning of winter. Then the researchers determined that the ozone concentration over the mainland was reduced by 50%, and its greatest decrease was recorded at altitudes from 14 to 19 km.
Subsequently, another large hole (smaller in size) was discovered over the Arctic, but now scientists know hundreds of similar phenomena, although the largest one is still the one that appears over Antarctica.
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 destroy 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.
An ozone hole is a local drop in ozone concentration in the Earth's ozone layer. Initially, experts suggested that ozone concentration tends to change due to particles that are emitted during any atomic explosion.
For a long time, high-altitude aircraft and spacecraft flights were considered to be the culprits for the appearance of ozone holes in the Earth’s atmosphere.
However, numerous studies and experiments have shown that ozone levels can vary qualitatively due to certain naturally occurring nitrogen-containing air pollutants.
The main causes of ozone holes
It has long been established that the bulk of natural ozone is found at an altitude of 15 to 50 kilometers above the Earth’s surface - in the stratosphere. Ozone brings the greatest benefit by absorbing a significant amount of ultraviolet solar radiation, which would otherwise be destructive to living organisms on our planet. A decrease in ozone concentration in a certain location may be due to two types of air pollution. These include:
- Natural processes that cause air pollution.
- Anthropogenic pollution of the Earth's atmosphere.
Degassing processes are constantly taking place in the Earth's mantle, resulting in the release of a variety of organic compounds. Mud volcanoes and hydrothermal vents can generate these types of gases.
In addition, in the earth's crust there are certain gases that are in a free state. Some of them are able to reach the earth's surface and diffuse into the atmosphere through cracks in the earth's crust. Therefore, the surface air over oil and gas basins often contains elevated levels of methane. These types of pollution can be classified as natural – occurring in connection with natural phenomena.
Anthropogenic air pollution can be caused by space rocket launches and supersonic jet flights. Also, a large number of various chemical compounds are released into the atmosphere during the extraction and processing of numerous minerals from the bowels of the earth.
Large industrial cities, which are unique anthropogenic sources, also play a significant role in air pollution. The air masses in such areas are polluted through the extensive flow of road transport, as well as due to emissions from various industrial enterprises.
The history of the discovery of ozone holes in the atmosphere
The ozone hole was first discovered in 1985 by a group of British scientists led by Joe Farman. The diameter of the hole was more than 1000 kilometers, and it was located above Antarctica - in the Southern Hemisphere. Appearing annually in August, this ozone hole disappeared between December and January.
The year 1992 was marked for scientists by the fact that another ozone hole, with a much smaller diameter, had formed over the Northern Hemisphere in Antarctica. And in 2008, the diameter of the first ozone phenomenon discovered in Antarctica reached its maximum record size - 27 million square kilometers.
Possible consequences of expanding ozone holes
Since the ozone layer is designed to protect the surface of our planet from an excess of ultraviolet solar radiation, ozone holes can be considered a really dangerous phenomenon for living organisms. A decrease in the ozone layer significantly increases the flow of solar radiation, which can influence the sharp increase in the number of skin cancers. The appearance of ozone holes is no less destructive for plants and animals on Earth.
Thanks to public attention, the Vienna Convention for the Protection of the Ozone Layer was adopted in 1985. Then came the so-called Montreal Protocol, adopted in 1987 and defining a list of the most dangerous chlorofluorocarbons. At the same time, the producing countries of these air pollutants pledged to limit their release, and by 2000, to stop them altogether.
Hypotheses about the natural origin of the ozone hole
But Russian scientists have published confirmation of the hypothesis about the natural origin of the Antarctic ozone hole. In 1999, at Moscow State University, NPO Typhoon published a scientific work in which, according to calculations by geophysicists A.P. Kapitsa and A.A. Gavrilova, the Antarctic ozone hole existed before it was discovered by direct experimental methods in 1982, which, according to Russian scientists, confirms the hypothesis of the natural origin of the ozone hole over Antarctica.
The authors of this scientific work were A.P. Kapitsa (Corresponding Member of the Russian Academy of Sciences) and A.A. Gavrilov (Moscow State University). These two scientists were able to establish that the number of facts contradicting the anthropogenic hypothesis of the origin of the Antarctic ozone hole is constantly growing, and after proving that the data of anomalously low values of total ozone content in Antarctica in 1957-1959 are correct, it became obvious that the cause of ozone holes is different from anthropogenic.
The results of the research by Kapitsa and Gavrilov were published in Reports of the Academy of Sciences, 1999, volume 366, no. 4, p. 543-546