The Earth's atmosphere contains several layers located at different heights. One of the most important is the ozone layer, located in the stratosphere. In order to find out what the ozone hole is, you need to understand the function of this layer and the importance of its existence for life on the planet.
Description
The height of the ozone layer varies depending on the temperature regime of a particular area, for example, in the tropics it is in the range between 25 and 30 km, and at the poles - from 15 to 20 km. Ozone is a gas produced by the action of solar radiation on oxygen molecules. The process of ozone dissociation leads to the absorption of most of the dangerous ultraviolet radiation emitted by the Sun.
The thickness of the layer is usually measured in Dobson units, each of which is equal to an ozone layer of 10 micrometers, under the condition of normal pressure and temperature. The minimum thickness below which the layer ceases to exist is 220 units. Dobson. The presence of the ozone layer was established by the French physicists Charles Fabry and Henri Buisson at the beginning of the 20th century using spectroscopic analysis.
Ozone holes
There are many versions about what exactly provokes the thinning of the ozone layer of the planet. Some scientists blame anthropogenic factors for this, while others consider it a natural process. Ozone holes are the reduction or complete disappearance of a given gas from the stratosphere. For the first time this phenomenon was recorded in 1985, it was located on an area of about 1 thousand square kilometers in the Antarctic region.
The appearance of this hole was cyclical, it appeared in August and disappeared in December. At the same time, another slightly smaller hole appeared in the Arctic region. With the development of technology, it has become possible to record the formation of ozone layer breaks in real time, and now scientists can confidently say that there are several hundred of them on the planet. The largest are located at the poles. 
Causes and consequences of ozone holes
There is a theory that ozone holes occur for natural reasons. According to it, since the conversion of oxygen into ozone occurs as a result of exposure to solar radiation, then in its absence during the polar winter, this gas is not produced. During a long night, the already formed ozone, due to its large mass, descends into the lower layers of the atmosphere, where it is destroyed by pressure. This version perfectly explains the appearance of holes over the poles, but does not clarify the formation of their large-scale analogues over the territories of Kazakhstan and Russia, where polar nights are not observed.
Recently, the scientific community has agreed that there are both natural and man-made causes of ozone depletion. The anthropogenic factor includes an increase in the concentration of certain chemicals in the Earth's atmosphere. Ozone is destroyed by reactions with chlorine, hydrogen, bromine, hydrogen chloride, nitrogen monoxide, methane, as well as freon and its derivatives. The causes and consequences of ozone holes have not yet been fully established, but almost every year brings new discoveries in this area.
Why are ozone holes dangerous?
Ozone absorbs extremely dangerous solar radiation, preventing it from reaching the surface of the planet. When the layer of this gas becomes thinner, everything on Earth is exposed to ordinary radioactive irradiation. This provokes the growth of cancers, mainly localized on the skin. For plants, the disappearance of ozone is also detrimental; various genetic mutations and a general decrease in vitality occur in them. In recent years, humanity is becoming better aware of how dangerous ozone holes are for life on Earth.
Conclusion
Realizing the danger of ozone destruction, the international community has taken a number of measures aimed at reducing the negative impact on the atmosphere. In 1987, a protocol was signed in Montreal, which obliges to minimize the use of freon in industry, since it is this gas that provokes the appearance of holes outside the polar regions. However, it will take about a hundred years for the freon already released into the atmosphere to decompose, so the number of ozone holes in the Earth's atmosphere is unlikely to decrease in the near future.
“You can, perhaps, say that the purpose of man, as it were, is to destroy his kind, having previously made the globe uninhabitable.”
J. B. Lamarck.
Since the formation of a highly industrialized society, the dangerous human intervention in nature has increased dramatically, it has become more diverse and threatens to become a global danger to humanity. A real threat of a global ecological crisis, understood by the entire population of the planet, hangs over the world. The real hope for its prevention lies in continuous environmental education and enlightenment of people.
We can single out the main reasons leading to an ecological catastrophe:
pollution
environmental poisoning;
depletion of the atmosphere with oxygen;
Formation of ozone "holes".
This report summarizes some literature data on the causes and consequences of the destruction of the ozone layer, as well as ways to solve the problem of the formation of “ozone holes”.
Chemical and biological features of ozone
Ozone is an allotropic modification of oxygen. The nature of chemical bonds in ozone causes its instability (after a certain time, ozone spontaneously transforms into oxygen: 2O 3 → 3O 2) and high oxidizing ability. The oxidizing effect of ozone on organic substances is associated with the formation of radicals: RH + O 3 → RO 2. +OH.
These radicals initiate radical chain reactions with bioorganic molecules (lipids, proteins, nucleic acids), which leads to cell death. The use of ozone to sterilize drinking water is based on its ability to kill microbes. Ozone is not indifferent to higher organisms either. Prolonged exposure to an environment containing ozone (such as physiotherapy and quartz irradiation rooms) can cause severe damage to the nervous system. Therefore, ozone in large doses is a toxic gas. Its maximum permissible concentration in the air of the working area is 0.1 mg / m 3.
There is very little ozone, which smells so wonderful during a thunderstorm, in the atmosphere - 3-4 ppm (ppm) - (3-4) * 10 -4%. However, for the flora and fauna of the planet, its presence is extremely important. After all, the life that originated in the oceanic depths was able to “crawl out” onto land only after the ozone shield formed 600–800 million years ago. By absorbing biologically active solar ultraviolet radiation, it ensured its safe level on the surface of the planet. Life on Earth is unthinkable without the ozone layer, which protects all living things from the harmful ultraviolet radiation of the Sun. The disappearance of the ozonosphere would lead to unpredictable consequences - an outbreak of skin cancer, the destruction of plankton in the ocean, mutations of flora and fauna. Therefore, it is so important to understand the causes of the ozone "hole" over the Antarctic and the decrease in the ozone content in the Northern Hemisphere.
Ozone is formed in the upper stratosphere (40-50 km) during photochemical reactions involving oxygen, nitrogen, hydrogen and chlorine. Atmospheric ozone is concentrated in two areas - the stratosphere (up to 90%) and the troposphere. As for the layer of tropospheric ozone distributed at an altitude of 0 to 10 km, it is precisely due to uncontrolled industrial emissions that it is becoming more and more. In the lower stratosphere (10-25 km), where there is the most ozone, the main role in seasonal and longer-term changes in its concentration is played by the processes of air mass transfer.
The thickness of the ozone layer over Europe is declining at a rapid pace, which cannot but excite the minds of scientists. Over the past year, the thickness of the ozone "coating" has decreased by 30%, and the rate of deterioration of the natural protective layer has reached the highest level in the last 50 years. It has been established that chemical reactions that destroy ozone occur on the surface of ice crystals and any other particles that have fallen into the high stratospheric layers above the polar regions. What danger does this pose to humans?
The thin ozone layer (2-3 mm when distributed around the globe) is unable to prevent the penetration of short-wave ultraviolet rays, which cause skin cancer and are dangerous for plants. Therefore, today, due to the high activity of the sun, sunbathing has become less useful. In fact, centers of ecology should give recommendations to the population on how to act depending on the activity of the sun, but there is no such center in our country.
Climate change is associated with the depletion of the ozone layer. It is clear that changes will take place not only in the territory over which the ozone hole is “stretched”. The chain reaction will entail changes in many of the deep processes of our planet. This does not mean that rapid global warming will begin everywhere, as they scare us in horror films. Still, it is too complicated and lengthy process. But other cataclysms may arise, for example, the number of typhoons, tornadoes, hurricanes will increase.
It has been established that "holes" in the ozone layer occur over the Arctic and Antarctica. This is due to the fact that acid clouds form at the poles, destroying the ozone layer. It turns out that ozone holes do not arise from the activity of the sun, as is commonly believed, but from the daily activities of all the inhabitants of the planet, including us. Then the "acid gaps" are shifted, and most often to Siberia.
Using a new mathematical model, it was possible to link together data from ground-based, satellite and airborne observations with the levels of probable future emissions of ozone-depleting compounds into the atmosphere, the time of their transport to the Antarctic and the weather in southern latitudes. Using the model, a forecast was obtained according to which the ozone layer over Antarctica will recover in 2068, and not in 2050, as was thought.
It is known that at present the level of ozone in the stratosphere over territories remote from the poles is below the norm by about 6%. At the same time, in the spring period, the ozone content over the Antarctic can decrease by 70% relative to the average annual value. The new model makes it possible to more accurately predict the levels of ozone-depleting gases over the Antarctic and their temporal dynamics, which determines the size of the ozone "hole".
The use of ozone depleting substances is restricted by the Montreal Protocol. It was believed that this would lead to a rapid "tightening" of the ozone hole. However, new studies have shown that, in reality, the rate of its decrease will become noticeable only from 2018.
History of ozone
The first observations of ozone date back to 1840, but the problem of ozone developed rapidly in the 1920s, when special ground stations appeared in England and Switzerland.
Airborne soundings of atmospheric ozone and releases of ozone probes opened up an additional way to study the relationship between ozone transport and atmospheric stratification. The new era is marked by the appearance of artificial Earth satellites that observe atmospheric ozone and provide a vast amount of information.
In 1986, the Montreal Protocol was signed to limit the production and consumption of ozone-depleting substances that deplete the ozone layer. To date, 189 countries have acceded to the Montreal Protocol. The deadlines for the termination of production of other ozone-depleting substances have also been established. According to model forecasts, if the Protocol is observed, the level of chlorine in the atmosphere will decrease by 2050 to the level of 1980, which may lead to the disappearance of the Antarctic “ozone hole”.
Reasons for the formation of the “ozone hole”
In summer and spring, the concentration of ozone increases. It is always higher over the polar regions than over the equatorial ones. In addition, it changes according to an 11-year cycle, coinciding with the cycle of solar activity. All this was already well known in the 1980s. Observations have shown that a slow but steady decrease in the concentration of stratospheric ozone occurs over the Antarctic from year to year. This phenomenon was called the "ozone hole" (although, of course, there was no hole in the proper meaning of this word).
Later, in the 90s of the last century, the same decrease began to occur over the Arctic. The phenomenon of the Antarctic "ozone hole" is not yet clear: whether the "hole" arose as a result of anthropogenic pollution of the atmosphere, or whether it is a natural geoastrophysical process.
Among the versions of the formation of ozone holes are:
· the influence of particles emitted during atomic explosions;
flights of rockets and high-altitude aircraft;
· reactions with ozone of some substances produced by chemical plants. These are primarily chlorinated hydrocarbons and especially freons - chlorofluorocarbons, or hydrocarbons in which all or most of the hydrogen atoms are replaced by fluorine and chlorine atoms.
Chlorofluorocarbons are widely used in modern household and industrial refrigerators (therefore they are called "freons"), in aerosol cans, as dry cleaning agents, for extinguishing fires in transport, as foaming agents, for the synthesis of polymers. The world production of these substances has reached almost 1.5 million tons/year.
Being highly volatile and fairly resistant to chemical attack, chlorofluorocarbons enter the atmosphere after use and can remain in it for up to 75 years, reaching the height of the ozone layer. Here, under the action of sunlight, they decompose, releasing atomic chlorine, which serves as the main "disturber" in the ozone layer.
The widespread use of fossil resources is accompanied by the release into the atmosphere of large masses of various chemical compounds. Most anthropogenic sources are concentrated in cities that occupy only a small part of the territory of our planet. As a result of the movement of air masses from the leeward side of large cities, a multi-kilometer plume of pollution is formed.
The source of air pollution are:
1) Road transport. It can be assumed that the contribution of transport to air pollution will increase with an increase in the number of cars.
2) Industrial production. The basic products of the main organic synthesis are ethylene (almost half of all organic substances are produced on its basis), propylene, butadiene, benzene, toluene, xylenes and methanol. Emissions from the chemical and petrochemical industries contain a wide range of pollutants: feedstock components, intermediate, by-products, and target synthesis products.
3) Aerosols. Fluorochlorohydrocarbons (freons) are widely used as volatile components (propellants) in aerosol packages. For these purposes, about 85% of freons were used and only 15% - in refrigeration and artificial climate installations. The specificity of the use of freons is such that 95% of their amount enters the atmosphere 1-2 years after production. It is believed that almost all the amount of freons produced must sooner or later enter the stratosphere and be included in the catalytic cycle of ozone destruction.
The earth's crust contains various gases in a free state, sorbed by various rocks and dissolved in water. Some of these gases reach the Earth's surface through deep faults and cracks and diffuse into the atmosphere. The existence of hydrocarbon respiration of the earth's crust is evidenced by the increased content of methane in the surface air above the oil and gas basins compared to the global background.
Studies have shown that the gases of volcanoes in Nicaragua contain significant amounts of HF. Analysis of air samples taken from the crater of the Masaya volcano also showed the presence of freons in them along with other organic compounds. Halogenated hydrocarbons are also present in the gases of hydrothermal sources. These data required evidence that the discovered fluorocarbons are not of anthropogenic origin. And such evidence was obtained. CFCs have been found in air bubbles of 2,000-year-old Antarctic ice. NASA experts undertook a unique study of air from a hermetically sealed lead coffin found in Maryland and reliably dated to the 17th century. Freons were also found in it. Another confirmation of the existence of a natural source of freons was “raised” from the seabed. CFCl 3 was found in water extracted in 1982 from a depth of more than 4000 meters in the equatorial part of the Atlantic Ocean, at the bottom of the Aleutian Trench and at a depth of 4500 meters off the coast of Antarctica.
Misconceptions about ozone "holes"
There are several widespread myths about the formation of ozone holes. Despite their unscientific nature, they often appear in the media - sometimes out of ignorance, sometimes supported by conspiracy theorists. Some of them are listed below.
1) Freons are the main destroyers of ozone. This statement is true for middle and high latitudes. In the rest, the chlorine cycle is responsible for only 15-25% of ozone loss in the stratosphere. It should be noted that 80% of chlorine is of anthropogenic origin. That is, human intervention greatly increases the contribution of the chlorine cycle. Before human intervention, the processes of ozone formation and its destruction were in equilibrium. But freons emitted by human activity have shifted this balance towards a decrease in ozone concentration. The mechanism of ozone destruction in the polar regions differs in principle from higher latitudes; the key stage is the conversion of inactive forms of halogen-containing substances into oxides, which occurs on the surface of particles of polar stratospheric clouds. And as a result, almost all ozone is destroyed in reactions with halogens (chlorine is responsible for 40-50% and bromine is about 20-40%).
2) Freons are too heavy to reach the stratosphere .
It is sometimes argued that since Freon molecules are much heavier than nitrogen and oxygen, they cannot reach the stratosphere in significant quantities. However, atmospheric gases are mixed completely, rather than stratified or sorted by weight. Estimates of the required time for diffusional separation of gases in the atmosphere require times of the order of thousands of years. Of course, this is not possible in a dynamic atmosphere. Therefore, even such heavy gases as inert or freons are evenly distributed in the atmosphere, reaching, among other things, the stratosphere. Experimental measurements of their concentrations in the atmosphere confirm this. If the gases in the atmosphere did not mix, then such heavy gases from its composition as argon and carbon dioxide would form a layer several tens of meters thick on the Earth's surface, which would make the Earth's surface uninhabitable. Fortunately, this is not the case.
3) The main sources of halogens are natural, not anthropogenic
Sources of chlorine in the stratosphere
It is believed that natural sources of halogens, such as volcanoes or oceans, are more significant for the process of ozone depletion than man-made ones. Without questioning the contribution of natural sources to the overall balance of halogens, it should be noted that they generally do not reach the stratosphere due to the fact that they are water-soluble (mainly chloride ions and hydrogen chloride) and are washed out of the atmosphere, falling as rain on the ground.
4) The ozone hole must be located above the sources of freon
Dynamics of changes in the size of the ozone hole and ozone concentration in the Antarctic over the years.
Many do not understand why the ozone hole is formed in the Antarctic, when the main emissions of freons occur in the Northern Hemisphere. The fact is that freons are well mixed in the troposphere and stratosphere. In view of their low reactivity, they are practically not consumed in the lower layers of the atmosphere and have a lifetime of several years or even decades. Therefore, they easily reach the upper atmosphere. The Antarctic "ozone hole" does not exist permanently. It appears in late winter - early 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 the polar vortex. The air inside this vortex moves mostly in closed paths around the South Pole. At this time, the polar region is not illuminated by the Sun, and ozone does not occur there. With the advent of summer, the amount of ozone increases and again reaches its previous norm. That is, fluctuations in ozone concentration over the Antarctic are seasonal. However, if we trace the dynamics of changes in the ozone concentration and the size of the ozone hole averaged over the course of a year over the past decades, then there is a strictly defined trend towards a decrease in the ozone concentration.
5) Ozone only breaks down over Antarctica
The evolution of the ozone layer over Arosa, Switzerland
This is not true, the ozone level is also falling in the entire atmosphere. This is shown by the results of long-term measurements of the ozone concentration in different parts of the planet. You can look at the graph of ozone concentration over Arosa (Switzerland).
Problem Solving Ways
To start a global recovery, it is necessary to reduce the access to the atmosphere of all substances that destroy ozone very quickly and are stored there for a long time. People should understand this and help nature turn on the process of restoring the ozone layer, in particular, new forest plantations are needed.
To restore the ozone layer, it needs to be fed. At first, for this purpose, it was supposed to create several ground-based ozone factories and "throw" ozone into the upper atmosphere on cargo planes. However, this project (probably it was the first project to "treat" the planet) was not implemented. Another way is proposed by the Russian consortium "Interozone": 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. If this experiment turns out to be successful, in the future it is planned to use the experience of the Russian orbital station "Mir" and create several space platforms with energy sources and lasers at an altitude of 400 km. Laser beams will be directed to the central part of the ozone layer and will constantly feed it. The energy source can be solar panels. Astronauts on these platforms will only be required for periodic inspections and repairs.
Whether the grandiose peace project will come true, time will tell.
Given the urgency of the situation, it seems necessary:
To expand the complex of theoretical and experimental studies on the problem of preserving the ozone layer;
Establish an International Fund for the Preservation of the Ozone Layer by active means;
Organize an International Committee to develop a strategy for the survival of mankind in extreme conditions.
Bibliography
1. (ru -).
2. ((cite web - | url = http://www.duel.ru/200530/?30_4_2 - | title = "Duel" Is it worth it? - | accessdate = 3.07.2007 - | lang = ru - ) )
3. I.K.Larin. The ozone layer and the Earth's climate. Mistakes of the mind and their correction ..
4. National Academy of Sciences Halocarbons: Effects on Stratospheric Ozone. - 1976.
5. Babakin B. S. Refrigerants: history of appearance, classification, application.
6. Journal "Ecology and Life". Article by E.A. Zhadina, Candidate of Physical and Mathematical Sciences.
Kazan National Research Technological University
Essay on the destruction of the ozone layer
Completed by: student gr.5111-41 Garifullin I.I. Checked by: Fatykhova L.A.
Kazan 2015
1. Introduction
2.Main part:
a) Determination of ozone
b) Causes of "ozone holes"
c) The main hypotheses of the destruction of the ozone layer
d) Ecological and biomedical consequences of ozone depletion
3.Conclusion
4. List of used literature
Introduction.
In the 21st century among the many global environmental problems of the biosphere, the problem of the destruction of the ozone layer and the associated increase in biologically dangerous ultraviolet radiation on the earth's surface remains very relevant. In the future, this may develop into an irreversible catastrophe that is detrimental to humanity. In recent decades, numerous studies have established a steady trend towards a decrease in the ozone content in the atmosphere. According to the World Health Organization (WHO), every 1% decrease in ozone in the atmosphere (and, accordingly, an increase in UV radiation by 2%) leads to a 5% increase in the number of oncological diseases.
The modern oxygen atmosphere of the Earth is a unique phenomenon among the planets of the solar system, and this feature is associated with the presence of life on our planet.
The problem of ecology for people is undoubtedly the most important now. The destruction of the Earth's ozone layer points to the reality of an ecological catastrophe. Ozone - a triatomic form of oxygen, is formed in the upper atmosphere under the influence of hard (short-wavelength) ultraviolet radiation from the Sun.
Today, ozone worries everyone, even those who previously did not suspect the existence of an ozone layer in the atmosphere, and believed only that the smell of ozone is a sign of fresh air. (No wonder ozone in Greek means "smell".) This interest is understandable - we are talking about the future of the entire biosphere of the Earth, including man himself. At present, there is a need to take certain binding decisions for all that would make it possible to preserve the ozone layer. But for these decisions to be correct, we need complete information about the factors that change the amount of ozone in the Earth's atmosphere, as well as about the properties of ozone, about how it reacts to these factors. Therefore, I consider the topic I have chosen relevant and necessary for consideration.
Main part: Ozone determination
It is known that ozone (Oz) - a modification of oxygen - has a high chemical reactivity and toxicity. Ozone 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 10-15 km with a maximum concentration of ozone at an altitude of 20-25 km. The ozone screen delays the penetration to the earth's surface of the most severe UV radiation (wavelength 200-320nm), which is detrimental to all living things. However, as a result of anthropogenic influences, the ozone "umbrella" has become leaky and ozone holes with a noticeably reduced (up to 50% or more) ozone content began to appear in it.
Causes of the "ozone holes"
Ozone (ozone) holes are only part of the complex environmental problem of the depletion of the Earth's ozone layer. In the early 1980s a decrease in the total ozone content in the atmosphere was noted over the area of scientific stations in Antarctica. So, in October 1985. There were reports that the ozone concentration in the stratosphere over the British station Halley Bay decreased by 40% of its minimum values, and over the Japanese station - by almost 2 times. This phenomenon has been called the "ozone hole". Significant ozone holes over Antarctica arose in the spring of 1987, 1992, 1997, when a decrease in the total stratospheric ozone (TO) by 40 - 60% was recorded. In the spring of 1998, the ozone hole over Antarctica reached a record area - 26 million square meters. km (3 times the size of Australia). And at an altitude of 14 - 25 km, almost complete destruction of ozone occurred in the atmosphere.
Similar phenomena were noted 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. March 1995 the ozone layer of the Arctic was depleted by about 50%, and "mini-holes" were formed over the northern regions of Canada and the Scandinavian Peninsula, the Scottish Isles (UK).
Currently, there are about 120 ozonometric stations in the world, including 40 that appeared since the 1960s. 20th century on Russian territory. Observation data from ground-based stations indicate that in 1997 a calm state of the total ozone content was noted over almost the entire controlled territory of Russia.
To elucidate the reasons for the emergence of powerful ozone holes, it was in the circumpolar spaces at the end of the 20th century. studies were carried out (using flying laboratory aircraft) of the ozone layer over Antarctica and the Arctic. It has been established that, in addition to anthropogenic factors (emissions into the atmosphere of freons, nitrogen oxides, methyl bromide, etc.), natural influences play a significant role. So, in the spring of 1997, in some regions of the Arctic, a drop in the ozone content in the atmosphere to 60% was recorded. Moreover, over a number of years, the rate of depletion of the ozonosphere over the Arctic increased even in conditions when the concentration of chlorofluorocarbons (CFCs), or freons, remained constant in it. According to the Norwegian scientist K. Henriksen, an ever-expanding funnel of cold air has formed in the lower layers of the Arctic stratosphere over the past decade. It created ideal conditions for the destruction of ozone molecules, which occurs mainly at a very low temperature (about -80 * C). A similar funnel over Antarctica is the cause of the ozone holes. Thus, the cause of the ozone-depleting process in high latitudes (Arctic, Antarctica) can be largely caused by natural influences.
Recently, more and more often the public is concerned about environmental issues - protecting the environment, animals, reducing the amount of harmful and hazardous emissions. Surely everyone has also heard about what an ozone hole is, and that there are a lot of them in the modern stratosphere of the Earth. And there is.
Modern anthropogenic activity and technical development endanger the existence of animals and plants on Earth, as well as the very life of people.
The ozone layer is the protective shell of the blue planet, which is located in the stratosphere. Its height is about twenty-five kilometers from the earth's surface. And this layer is formed from oxygen, which, under the influence of solar radiation, undergoes chemical transformations. The local decrease in ozone concentration (in the common people this is the well-known "hole") is currently caused by many reasons. First of all, this, of course, is human activity (both industrial and everyday household). There are, however, opinions that the ozone layer is destroyed under the influence of exclusively natural phenomena not related to people.
Anthropogenic influence
Having understood what the ozone hole is, it is necessary to find out what kind of human activity contributes to its appearance. First of all, these are aerosols. Every day we use deodorants, hairsprays, eau de toilette with spray bottles and often do not think about the fact that this adversely affects the protective layer of the planet.
The fact is that the compounds that are present in the cans we are used to (including bromine and chlorine) readily react with oxygen atoms. Therefore, the ozone layer is destroyed, turning after such chemical reactions into completely useless (and often harmful) substances.
Destructive compounds for the ozone layer are also present in air conditioners that save in the summer heat, as well as in cooling equipment. The widespread industrial activity of man also weakens earthly defenses. It is oppressed by industrial water (some of the harmful substances evaporate over time), pollute the stratosphere and cars. The latter, as statistics show, is becoming more and more every year. negatively affects the ozone layer and
natural influence
Knowing what an ozone hole is, you must also have an idea of how many of them are above the surface of our planet. The answer is disappointing: there are many gaps in earthly protection. They are small and often do not represent a hole, but a very thin remaining layer of ozone. However, there are also two huge unprotected spaces. This is the Arctic and Antarctic ozone hole.
The stratosphere above the Earth's poles contains almost no protective layer at all. What is it connected with? After all, there are no cars and industrial production. It's all about natural influence, the second reason. Polar vortices occur when warm and cold air flows collide. These gas formations contain nitric acid in large quantities, which, under the influence of very low temperatures, reacts with ozone.
Environmentalists began to sound the alarm only in the twentieth century. Destructive, which make their way to the ground without stumbling upon an ozone barrier, can cause skin cancer in humans, as well as the death of many animals and plants (primarily marine). Thus, almost all compounds that destroy the protective layer of our planet have been banned by international organizations. It is believed that even if humanity abruptly stops any negative impact on ozone in the stratosphere, the holes that currently exist will not disappear very soon. This is due to the fact that freons that have already made their way up are able to exist independently in the atmosphere for decades.
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MINISTRY OF TRANSPORT OF THE RUSSIAN FEDERATION
FGOUVPO ULYANOVSK HIGHER AVIATION SCHOOL
CIVIL AVIATION (INSTITUTE)
FACULTY OF FLIGHT OPERATION AND AIR TRAFFIC CONTROL
DEPARTMENT PASOP
ESSAY
on the topic:Ozone holes: causesandeffects
Completed by: Bazarov M.A.
Head: Morozova M.M.
Ulyanovsk 2012
Introduction
1. Reasons
2. Consequences
3. Geographic location
4. The role of civil and military aviation in the formation of ozone holes
5. Ways to solve problems
Conclusion
Introduction
With the advent of human civilization, a new factor appeared that influenced the fate of living nature. He has attained great strength in this century and especially in recent times. 5 billion of our contemporaries have the same impact on nature in terms of scale that Stone Age people could have if their number was 50 billion people, and the amount of energy released by the earth received from the sun.
Since the emergence of a highly industrialized society, dangerous human intervention in nature has increased dramatically, the scope of this intervention has expanded, it has become more diverse and now threatens to become a global danger to humanity.
The consumption of non-renewable raw materials is increasing, more and more arable land is leaving the economy, as cities and factories are built on them. The Earth's biosphere is currently undergoing increasing anthropogenic impact. At the same time, several of the most significant processes can be distinguished, none of which improves the state of the airspace of our planet.
The accumulation of carbon dioxide in the atmosphere is also progressing. Further development of this process will strengthen the undesirable trend towards an increase in the average annual temperature on the planet.
As a result, a dilemma arose before society: either thoughtlessly roll towards its inevitable death in an impending ecological catastrophe, or consciously turn the mighty forces of science and technology created by the genius of man from a weapon previously turned against nature and man himself, into a tool for their protection and prosperity, into a tool rational environmental management.
A real threat of a global ecological crisis, understood by the entire population of the planet, hangs over the world, and the real hope for its prevention lies in continuous environmental education and enlightenment of people.
The World Health Organization has determined that human health is 20% dependent on heredity, 20% on the environment, 50% on lifestyle and 10% on medicine. In a number of regions of Russia, by 2005, the following dynamics of factors affecting human health is expected: the role of ecology will increase to 40%, the effect of the genetic factor will increase to 30%, the ability to maintain health due to lifestyle will decrease to 25%, and the role of medicine will decrease to 5%. .
Characterizing the current state of ecology as critical, one can single out the main causes that lead to an ecological catastrophe: pollution, poisoning of the environment, depletion of the atmosphere with oxygen, ozone holes.
The purpose of this work was to summarize the literature data on the causes and consequences of the destruction of the ozone layer, as well as ways to solve the problem of the formation of “ozone holes”.
ozone layer hole ecological
1. Causes
Ozone hole - a local drop in the concentration of ozone in the 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 of the anthropogenic factor in the form of the release of chlorine- and bromine-containing freons led to a significant thinning of the ozone layer.
According to another hypothesis, the process of formation of "ozone holes" can be largely natural and is not associated solely with the harmful effects of human civilization.
An ozone hole with a diameter of over 1000 km was first discovered in 1985, in the Southern Hemisphere, over Antarctica, by a group of British scientists: J. Shanklin (English), J. Farman (English), B. Gardiner (English), who published the corresponding article in the journal Nature. Every August it appeared, and in December-January it ceased to exist. Another hole was forming over the Northern Hemisphere in the Arctic, but smaller. At this stage in the development of mankind, world scientists have proved that there are a huge number of ozone holes on Earth. But the most dangerous and largest is located above the Antarctic.
A combination of factors leads to a decrease in the concentration of ozone 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), whose surface 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 lack of a continental surface, the temperature is several degrees higher than in the Antarctic, and PSOs are less common, and they also tend to break up in early autumn. Being reactive, ozone molecules can react with many inorganic and organic compounds. The main substances contributing to the destruction of ozone molecules are simple substances (hydrogen, oxygen atoms, chlorine, bromine), inorganic (hydrogen chloride, nitrogen monoxide) and organic compounds (methane, fluorochlorine and fluorobromofreons, which emit chlorine and bromine atoms). Unlike, for example, hydrofluorofreons, which decompose to fluorine atoms, which, in turn, quickly react with water to form stable hydrogen fluoride. Thus, fluorine does not participate in ozone decay reactions. Iodine also does not destroy stratospheric ozone, since iodine-containing organic substances are almost completely consumed even in the troposphere. The main reactions that contribute to the destruction of ozone are given in the article about the ozone layer.
Chlorine "eats" both ozone and atomic oxygen due to rather fast reactions:
O3 + Cl = O2 + ClO
СlO + O = Cl + O2
Moreover, the last reaction leads to the regeneration of active chlorine. Chlorine is thus not even consumed, destroying the ozone layer.
In summer and spring, the concentration of ozone increases. It is always higher over the polar regions than over the equatorial ones. In addition, it changes according to an 11-year cycle, coinciding with the cycle of solar activity. All this was already well known in the 1980s. Observations have shown that a slow but steady decrease in the concentration of stratospheric ozone occurs over the Antarctic from year to year. This phenomenon was called the "ozone hole" (although, of course, there was no hole in the proper meaning of this word).
Later, in the 90s of the last century, the same decrease began to occur over the Arctic. The phenomenon of the Antarctic "ozone hole" is not yet clear: whether the "hole" arose as a result of anthropogenic pollution of the atmosphere, or whether it is a natural geoastrophysical process.
Among the versions of the formation of ozone holes are:
the influence of particles emitted in atomic explosions;
flights of rockets and high-altitude aircraft;
reactions with ozone of certain substances produced by chemical plants. These are primarily chlorinated hydrocarbons and especially freons - chlorofluorocarbons, or hydrocarbons in which all or most of the hydrogen atoms are replaced by fluorine and chlorine atoms.
Chlorofluorocarbons are widely used in modern household and industrial refrigerators (therefore they are called "freons"), in aerosol cans, as dry cleaning agents, for extinguishing fires in transport, as foaming agents, for the synthesis of polymers. The world production of these substances has reached almost 1.5 million tons/year.
Being highly volatile and fairly resistant to chemical attack, chlorofluorocarbons enter the atmosphere after use and can remain in it for up to 75 years, reaching the height of the ozone layer. Here, under the action of sunlight, they decompose, releasing atomic chlorine, which serves as the main "disturber" in the ozone layer.
2. Effects
The ozone hole poses a danger to living organisms, since the ozone layer protects the Earth's surface from excessive doses of ultraviolet radiation from the sun. The weakening of the ozone layer increases the flow of solar radiation to the earth and causes an increase in the number of skin cancers in people. Plants and animals also suffer from increased levels of radiation.
Ozone in the stratosphere protects the Earth from damaging ultraviolet, solar radiation. The destruction of the ozone layer will allow more solar radiation to reach the Earth's surface.
Every percent of stratospheric ozone lost results in a 1.5 to 2 percent increase in exposure to ultraviolet, solar radiation, according to the US Environmental Protection Agency. For humans, an increase in the intensity of ultraviolet radiation, primarily dangerous, is the effect of solar radiation on the skin and eyes.
Radiation with a wavelength in the spectrum from 280 to 320 nanometers - UV rays, which are partially blocked by ozone - can cause premature aging and an increase in skin cancers, as well as damage to plants and animals.
Radiation with a wavelength of more than 320 nanometers, the UV spectrum, is practically not absorbed by ozone and is actually necessary for a person to form vitamin D. UV radiation with a wavelength in the spectrum of 200 - 280 nanometers can cause serious consequences for biological organisms. However, the radiation of this spectrum is almost completely absorbed by ozone. Thus, the "Achilles' heel" of terrestrial life is the radiation of a rather narrow spectrum of UV waves with a length of 320 to 280 nanometers. With a reduction in wavelength, their ability to harm living organisms and DNA increases. Fortunately, the ability of ozone to absorb ultraviolet radiation increases in proportion to the reduction in the wavelength of radiation.
· Increasing incidence of skin cancer.
Suppression of the human immune system.
· Damage to the eyes.
Ultraviolet radiation can damage the cornea of the eye, the connective membrane of the eye, the lens and the retina of the eye. Ultraviolet radiation can cause photokeratosis (or snow blindness), similar to sunburn of the cornea or connective tissue of the eye. Increased human exposure to ultraviolet radiation due to ozone depletion will increase the number of people with cataracts, according to the authors of How to Save Our Skin. A cataract blocks the lens of the eye, reducing visual acuity and can cause blindness.
· Destruction of crops.
3. Geographic location
The thinning of the ozone layer began to be recorded in the 70s. It decreased especially significantly over Antarctica, which led to the appearance of the common expression “ozone hole”. Small holes are also fixed in the northern hemisphere - over the Arctic, in the region of the Plesetsk and Baikonur cosmodromes. In 1974, two scientists from the University of California, Mario Molina and Sherwood Rowland, hypothesized that freon gases used in the refrigeration and perfume industries are the main factor in the destruction of ozone. Less significant ozone-depleting factors are flights of rockets and supersonic aircraft.
The location of "ozone holes" tends to localize positive World magnetic anomalies. In the Southern Hemisphere, this is the Antarctic, and in the Northern Hemisphere, the East Siberian World Magnetic Anomaly. Moreover, the power of the Siberian anomaly is growing so strongly that even in Novosibirsk the vertical component of the geomagnetic field is growing annually by 30 gamma (nanotesla).
The loss of the ozone layer over the Arctic Basin was so significant this year that for the first time in the history of observations, one can speak of the emergence of an "ozone hole" similar to the Antarctic one. At altitudes above 20 km, ozone losses amounted to about 80%. The probable cause of this phenomenon is the unusually long persistence of relatively low temperatures in the stratosphere at these latitudes.
4. The role of the civil and military aviation in educationozone holes
The destruction of the ozone layer is facilitated not only by freons released into the atmosphere and entering the stratosphere. Nitrogen oxides, which are formed during nuclear explosions, are also involved in the destruction of the ozone layer. But nitrogen oxides are also formed in the combustion chambers of high-altitude aircraft turbojet engines. Nitrogen oxides are formed from the nitrogen and oxygen that are there. The rate of formation of nitrogen oxides is the greater, the higher the temperature, i.e., the greater the engine power.
Not only is the engine power of an aircraft important, but also the altitude at which it flies and releases ozone-destroying nitrogen oxides. The higher the oxide or nitrous oxide is formed, the more destructive it is for ozone.
The total amount of nitrogen oxide emitted into the atmosphere per year is estimated at 1 billion tons. About a third of this amount is emitted by aircraft above the average tropopause level (11 km). As for aircraft, the most harmful emissions are military aircraft, the number of which is in the tens of thousands. They fly mainly at the heights of the ozone layer.
5. Problem Solving Ways
To start a global recovery, it is necessary to reduce the access to the atmosphere of all substances that destroy ozone very quickly and are stored there for a long time.
Also, we - all people should understand this and help nature turn on the process of restoring the ozone layer, we need new forest plantations, stop cutting down forests for other countries that for some reason do not want to cut down their own, but make money from our forests.
To restore the ozone layer, it needs to be fed. At first, for this purpose, it was supposed to create several ground-based ozone factories and "throw" ozone into the upper atmosphere on cargo planes. However, this project (probably it was the first project to "treat" the planet) was not implemented.
Another way is proposed by the Russian consortium "Interozone": 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.
If this experiment turns out to be successful, in the future it is planned to use the experience of the Russian orbital station "Mir" and create several space platforms with energy sources and lasers at an altitude of 400 km. Laser beams will be directed to the central part of the ozone layer and will constantly feed it. The energy source can be solar panels. Astronauts on these platforms will only be required for periodic inspections and repairs.
Conclusion
The possibilities of human impact on nature are constantly growing and have already reached a level where it is possible to cause irreparable damage to the biosphere. This is not the first time that a substance that has long been considered completely harmless turns out to be extremely dangerous. Twenty years ago, hardly anyone could have imagined that an ordinary aerosol can could pose a serious threat to the planet as a whole. Unfortunately, it is far from always possible to predict in time how this or that compound will affect the biosphere. However, in the case of CFCs, there was such a possibility: all chemical reactions describing the process of CFC ozone destruction are extremely simple and have been known for a long time. But even after the CFC problem was formulated in 1974, the only country that took any action to reduce the production of CFCs was the United States and these measures were completely insufficient. It took a strong enough demonstration of the dangers of CFCs for serious action to be taken on a global scale. It should be noted that even after the discovery of the ozone hole, the ratification of the Montreal Convention was at one time under threat. Perhaps the problem of CFCs will teach with great attention and caution to all substances that enter the biosphere as a result of human activities.
The problem of historical and modern climate change turned out to be very complex and cannot be solved in the schemes of one-factor determinism. In addition, with increasing carbon dioxide concentration, changes in the ozonosphere associated with the evolution of the geomagnetic field play an important role. The development and testing of new hypotheses is a necessary condition for understanding the patterns of the general circulation of the atmosphere and other geophysical processes affecting the biosphere.
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