Examination
What destroys the ozone layer. Destruction of the ozone layer. Causes of ozone depletion

What destroys the ozone layer. Destruction of the ozone layer. Causes of ozone depletion

Ozone layer depletion

The ozone layer is part of the stratosphere at an altitude of 12 to 50 km, in which, under the influence ultraviolet radiation In the sun, oxygen (O 2) is ionized, acquiring a third oxygen atom, and ozone (O 3) is obtained. The relatively high concentration of ozone (about 8 ml/m³) absorbs dangerous ultraviolet rays and protects everything living on land from harmful radiation. Moreover, if it were not for the ozone layer, life would not have been able to escape from the oceans at all and highly developed life forms such as mammals, including humans, would not have arisen. The highest density of ozone occurs at an altitude of 20 km, the largest part in the total volume is at an altitude of 40 km. If all the ozone in the atmosphere could be extracted and compressed under normal pressure, the result would be a layer covering the surface of the Earth only 3 mm thick. For comparison, the entire atmosphere compressed under normal pressure would constitute a layer of 8 km.

Ozone is an active gas and can have adverse effects on humans. Usually its concentration in the lower atmosphere is insignificant and it does not have a harmful effect on humans. Large amounts of ozone are formed in major cities with heavy traffic as a result of photochemical transformations of vehicle exhaust gases.

Ozone also regulates the harshness of cosmic radiation. If this gas is at least partially destroyed, then naturally the hardness of the radiation increases sharply, and, consequently, real changes in the flora and fauna occur.

It has already been proven that the absence or low concentration of ozone can or leads to cancer, which has the worst impact on humanity and its ability to reproduce.

Causes of ozone layer depletion

The ozone layer protects life on Earth from harmful ultraviolet radiation from the Sun. The ozone layer has been found to undergo a slight but constant weakening over some areas of the globe over many years, including densely populated areas in the mid-latitudes of the Northern Hemisphere. A vast ozone hole has been discovered over Antarctica.

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

Many reasons have been suggested for the weakening of the ozone shield.

Firstly, these are space rocket launches. Burning fuel “burns” large holes in the ozone layer. It was once assumed that these "holes" were closing. It turned out not. They have been around for quite a long time.

Secondly, airplanes. Especially those flying at altitudes of 12-15 km. The steam and other substances they emit destroy ozone. But, at the same time, aircraft flying below 12 km. They give an increase in ozone. In cities it is one of the components of photochemical smog. Thirdly, it is chlorine and its compounds with oxygen. A huge amount (up to 700 thousand tons) of this gas enters the atmosphere, primarily from the decomposition of freons. Freons are those that do not enter into any form at the surface of the Earth. chemical reactions gases that boil at room temperature, and therefore sharply increase their volume, which makes them good sprayers. Since their temperature decreases as they expand, freons are widely used in the refrigeration industry.

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

On February 9, 2004, news appeared on the website of the NASA Earth Institute that scientists at Harvard University had found a molecule that destroys ozone. Scientists called this molecule "chlorine monoxide dimer" because it is made up of two molecules of chlorine monoxide. The dimer only exists in the particularly cold stratosphere over the polar regions when chlorine monoxide levels are relatively high. This molecule comes from chlorofluorocarbons. The dimer causes ozone destruction by absorbing sunlight and breaking down into two chlorine atoms and an oxygen molecule. Free chlorine atoms begin to interact with ozone molecules, leading to a decrease in its amount.

Consequences of ozone layer depletion

The occurrence of “ozone holes” (a seasonal decrease in ozone content by half or more) was first observed in the late 70s over Antarctica. In subsequent years, the duration of existence and the area of ozone holes grew, and by now they have already captured the southern regions of Australia, Chile and Argentina. In parallel, although with some delay, the process of ozone depletion over the Northern Hemisphere developed. In the early 90s, a 20-25% decrease was observed over Scandinavia, the Baltic states and the northwestern regions of Russia. In latitudinal zones other than the subpolar ones, ozone depletion is less pronounced; however, even here it is statistically significant (1.5-6.2% over the last decade).

Depletion of the ozone layer can have a significant impact on the ecology of the world's oceans. Many of its systems are already stressed by existing levels of natural UV radiation, and increasing its intensity could be catastrophic for some of them. As a result of exposure to ultraviolet radiation in aquatic organisms, adaptive behavior (orientation and migration) is disrupted, photosynthesis and enzymatic reactions are suppressed, as well as the processes of reproduction and development, especially on early stages. Since the sensitivity to ultraviolet radiation of different components of aquatic ecosystems varies significantly, as a result of the destruction of stratospheric ozone, one should expect not only a decrease in the total biomass, but also a change in the structure of aquatic ecosystems. Under these conditions, beneficial sensitive forms can die and be displaced, and resistant, toxic to the environment, such as blue-green algae, can multiply.

Efficiency of aquatic food chains in decisive degree determined by their productivity entry level- phytoplankton. Calculations show that in the case of 25% destruction of stratospheric ozone, a 35% decrease in primary productivity in the surface layers of the ocean and a 10% decrease in the entire photosynthetic layer should be expected. The significance of the predicted changes becomes obvious if we take into account that phytoplankton utilizes more than half of carbon dioxide in the process of global photosynthesis, and only a 10th reduction in the intensity of this process is equivalent to doubling the emission of carbon dioxide into the atmosphere as a result of the combustion of minerals. In addition, ultraviolet radiation suppresses the production of dimethyl sulfide by phytoplankton, which plays an important role in the formation of clouds. The last two phenomena can cause long-term changes global climate and the level of the World Ocean.

From biological objects of secondary links in aquatic food chains, ultraviolet radiation can directly affect eggs and fry of fish, larvae of shrimp, oysters and crabs, as well as other small animals. In conditions of depletion of stratospheric ozone, the growth and death of commercial fish fry and, in addition, a decrease in catch as a result of a decrease in the primary productivity of the World Ocean are predicted.

Unlike aquatic organisms, higher plants can partially adapt to an increase in the intensity of natural ultraviolet radiation, however, under conditions of a 10-20% reduction in the ozone layer, they experience growth inhibition, a decrease in productivity, and changes in composition that reduce nutritional value. Sensitivity to ultraviolet radiation can vary significantly between plants different types, and in different lines of the same species. Cultures zoned in southern regions, more resistant compared to those zoned in temperate zones.

A very important, albeit mediocre, role in shaping the productivity of agricultural plants is played by soil microorganisms, which have a significant impact on soil fertility. In this sense, of particular interest are phototrophic cyanobacteria that live in the uppermost layers of soil and are capable of utilizing air nitrogen and then using it by plants in the process of photosynthesis. These microorganisms (especially in rice fields) are directly exposed to ultraviolet radiation. Radiation can inactivate the key enzyme of nitrogen assimilation - nitrogenase. Thus, as a result of the destruction of the ozone layer, a decrease in soil fertility should be expected. It is also very likely that other beneficial forms of soil microorganisms sensitive to ultraviolet radiation will be displaced and die off, and resistant forms will multiply, some of which may turn out to be pathogenic.

For humans, natural ultraviolet radiation is a risk factor even in the existing state of the ozone layer. Reactions to its impact are varied and contradictory. Some of them (formation by vitamins D, increase in general nonspecific resistance, therapeutic effect in some skin diseases) improve health, others (burns of the skin and eyes, skin aging, cataract and carcinogenesis) worsen it.

A typical reaction to eye overexposure is the occurrence of photokeratoconjunctivitis - acute inflammation of the outer membranes of the eye (cornea and conjunctiva). It usually develops under conditions of intense reflection sunlight from natural surfaces (snowy highlands, arctic and desert zones) and is accompanied by pain or the sensation of a foreign body in the eye, lacrimation, photophobia and spasm of the eyelids. An eye burn can occur within 2 hours in snowy areas and within 6 to 8 hours in a sandy desert.

Long-term exposure to ultraviolet radiation on the eye can cause cataracts, corneal and retinal degeneration, pterygia (growth of conjunctival tissue) and uveal melanoma. Although all of these diseases are very dangerous, the most common is cataracts, which usually develop without visible changes to the cornea. The increase in the incidence of cataracts is considered the main consequence of stratospheric ozone depletion in relation to the eye.

As a result of overexposure of the skin, aseptic inflammation, or erythema, develops, accompanied, in addition to pain, by changes in the thermal and sensory sensitivity of the skin, suppression of sweating and deterioration of the general condition. In temperate latitudes, erythema can be obtained in half an hour per open sun in the middle summer day. Typically, erythema develops with a latent period of 1–8 hours and persists for about a day. The value of the minimum erythema dose increases with increasing degree of skin pigmentation.

An important contribution to the carcinogenic effect of ultraviolet radiation is its immunosuppressive effect. Of the 2 existing types of immunity - humoral and cellular, only the latter is suppressed as a result of exposure to ultraviolet radiation. Factors of humoral immunity either remain indifferent or, in the case of chronic irradiation in small doses, are activated, contributing to an increase in general nonspecific resistance. In addition to reducing the ability to reject skin cancer cells (aggression against other types of cancer cells does not change), ultraviolet radiation-induced immunosuppression can suppress skin allergic reactions, reduce resistance to infectious agents, and also change the course and outcome of some infectious diseases.

Natural ultraviolet radiation is responsible for the bulk of skin tumors, the incidence of which in the white population is close to the total incidence of all other types of tumors combined. Existing tumors are divided into two types: non-melanoma (basal cell and squamous cell carcinomas) and malignant melanoma. Tumors of the first type predominate quantitatively, weakly metastasize and are easily cured. The frequency of melanomas is relatively low, but they grow quickly, metastasize early and have a high mortality rate. As with erythema, skin cancer is characterized by a clear inverse correlation between the effectiveness of irradiation and the degree of skin pigmentation. The frequency of skin tumors in the black population is more than 60 times lower, in the Hispanic population - 7 - 10 times lower than in the white population in the same latitudinal zone, with almost the same frequency of tumors other than skin cancer. In addition to the degree of pigmentation, risk factors for skin cancer include the presence of moles, age spots and freckles, poor tanning ability, blue eyes and red hair.

Ultraviolet radiation plays an important role in providing the body with vitamin D, which regulates the process of phosphorus-calcium metabolism. Vitamin D deficiency causes rickets and caries, and also plays an important role in the pathogenesis of the representative gland, which causes high mortality.

The role of ultraviolet radiation in providing the body with vitamin D cannot be compensated only by consuming it with food, since the process of biosynthesis of vitamin D in the skin is self-regulating and eliminates the possibility of hypervitaminosis. This disease causes calcium deposits in various tissues of the body with their subsequent necrotic degeneration.

If vitamin D deficiency occurs, a dose of ultraviolet radiation is required, amounting to approximately 60 minimum erythema doses per year to exposed areas of the body. For white people in temperate latitudes, this corresponds to half an hour of midday sun exposure every day from May to August. The intensity of vitamin D synthesis decreases with an increase in the degree of pigmentation in representatives of various ethnic groups may differ by more than an order of magnitude. As a result, skin pigmentation may be a cause of vitamin D deficiency in non-white immigrants in temperate and northern latitudes.

The currently observed increase in the degree of depletion of the ozone layer indicates the inadequacy of efforts being made to protect it.

Ways to solve the problem of ozone layer depletion

Awareness of the danger leads to the fact that the international community is taking more and more steps to protect the ozone layer. Let's look at some of them.

1) Creation of various organizations for the protection of the ozone layer (UNEP, COSPAR, MAGA)
2) Holding conferences.
a) Vienna Conference (September 1987). The Montreal Protocol was discussed and signed there:
- - the need for constant monitoring of the production, sale, and use of substances most dangerous to ozone (freons, bromine-containing compounds, etc.)
- - the use of chlorofluorocarbons compared to the 1986 level should be reduced by 20% by 1993 and halved by 1998.
b) At the beginning of 1990. scientists came to the conclusion that the restrictions of the Montreal Protocol were insufficient and proposals were made to completely stop production and emissions into the atmosphere already in 1991-1992. those freons that are limited by the Montreal Protocol.

The problem of preserving the ozone layer relates to global problems humanity. Therefore, it is discussed on many forums itself. different levels up to the Russian-American summit meetings.

We can only believe that a deep awareness of the danger threatening humanity will prompt the governments of all countries to take the necessary measures to reduce emissions of substances harmful to ozone.

Standardization of environmental quality. The purpose of rationing. Characteristics of sanitary and hygienic standards of the air environment.

The introduction of state standards for the quality of the natural environment and the establishment of a procedure for regulating the impact of economic and other activities on the environment are among the most important functions of state management of natural resources and environmental protection.

Environmental quality standards are established to assess the state of atmospheric air, water, and soil according to chemical, physical and biological characteristics. This means that if in atmospheric air, water or soil, the content of, for example, a chemical substance does not exceed the corresponding standard for its maximum permissible concentration, then the state of the air or soil is favorable, i.e. not posing a danger to human health and other living organisms.

The role of standards in the formation of information about the quality of the natural environment is that they provide an assessment of the environment ecological environment, others limit the sources of harmful effects on it.

According to the Law “On Environmental Protection,” environmental quality regulation aims to establish scientifically based maximum permissible standards for environmental impact, guaranteeing environmental safety and protecting public health, ensuring the prevention of environmental pollution, reproduction and rational use of natural resources.

The introduction of environmental standards allows us to solve the following problems:

1) Standards allow us to determine the degree of human impact on the environment. Environmental monitoring is based not only on observing nature. This observation must be objective; it must, using technical indicators, determine the degree of pollution of air, water, etc.
2) Standards allow government agencies to exercise control over the activities of natural resource users. Environmental control is manifested in analyzing the level of environmental pollution and determining its permissible value in accordance with established standards.
3) Environmental standards serve as the basis for the application of liability measures in cases of exceeding them. Often, environmental standards serve as the only criterion for bringing the guilty party to justice.

Standards in the field of environmental protection are established standards for environmental quality and standards for permissible impact on it, the observance of which ensures the sustainable functioning of natural ecological systems and biodiversity is preserved. It is carried out for the purpose of state regulation of the impact of economic and other activities on the environment, guaranteeing the preservation of a favorable environment and ensuring environmental safety.

Standardization in the field of environmental protection consists of establishing:

1) environmental quality standards - standards that are established in accordance with physical, chemical, biological and other indicators for assessing the state of the environment and, if observed, ensure a favorable environment;
2) standards for permissible impact on the environment when carrying out economic and other activities - standards that are established in accordance with the indicators of the impact of economic and other activities on the environment and in which environmental quality standards are observed;
3) other standards in the field of environmental protection, such as:
- * standards for permissible anthropogenic load on the environment - standards that are established in accordance with the magnitude of the permissible cumulative impact of all sources on the environment and (or) individual components of the natural environment within specific territories and (or) water areas, and when observed, sustainable operation is ensured natural ecological systems and conserve biological diversity;
- * standards for permissible emissions and discharges of chemical substances, including radioactive, other substances and microorganisms (standards for permissible emissions and discharges of substances and microorganisms) - standards that are established for economic and other entities in accordance with the mass indicators of chemical substances, including radioactive and other substances and microorganisms that are permissible for release into the environment from stationary, mobile and other sources in the established mode and taking into account technological standards, and in compliance with which environmental quality standards are ensured;
- * technological standard - a standard for permissible emissions and discharges of substances and microorganisms, which is established for stationary, mobile and other sources, technological processes, equipment and reflects the permissible mass of emissions and discharges of substances and microorganisms into the environment per unit of output;
- * standards for maximum permissible concentrations of chemical substances, including radioactive, other substances and microorganisms - standards that are established in accordance with the indicators of the maximum permissible content of chemical substances, including radioactive, other substances and microorganisms in environment and non-compliance with which may lead to environmental pollution and degradation of natural ecological systems;
- * standards for permissible physical impacts - standards that are established in accordance with the levels of permissible impact physical factors on the environment and, subject to compliance with which, environmental quality standards are ensured.

In addition, regulation of environmental quality is carried out using technical regulations, state standards and other regulatory documents in the field of environmental protection.

Standards and regulatory documents in the field of environmental protection are developed, approved and put into effect on the basis of modern achievements of science and technology, taking into account international rules and standards in the field of environmental protection.

Standards and methods for their determination are approved by environmental authorities and sanitary and epidemiological supervision authorities. As production, science and technology develop, regulation in ecology develops and improves. When developing regulations, international environmental norms and standards are taken into account.

If quality standards are violated, emissions, discharges and other harmful impacts may be limited, suspended, or terminated. Instructions for this are given by state authorities in the field of environmental protection and sanitary and epidemiological supervision.

Sanitary and hygienic standards.

To take into account the influence chemical pollution Various international and national standards, or regulations, have been introduced on human health. The pollution standard is the maximum concentration of a substance in the environment allowed regulations. Sanitary and hygienic standards are a set of indicators of the sanitary and hygienic state of environmental components (air, water, soil, etc.), determined by the magnitude of their pollution levels, the non-exceeding of which ensures normal living conditions and health safety.

Federal Law dated March 30, 1999. No. 52-FZ (as amended on December 22, 2008) “On the sanitary and epidemiological welfare of the population” established that sanitary rules and regulations are mandatory for everyone government agencies, public associations, business entities, officials and citizens. Sanitary and epidemiological rules apply throughout Russia.

Sanitary and hygienic pollution standards are used to manage environmental quality, which helps reduce their impact on human health and morbidity to an acceptable level.

WHO standards are the most widespread in the world. In our country, maximum permissible concentrations (MACs), which determine the maximum level of presence of chemical pollutants in air, water or soil, have received the status of state standards in this area.

Maximum permissible concentration (MAC) is a sanitary and hygienic standard, defined as the maximum concentration of chemicals in air, water and soil, which, with periodic exposure or throughout life, does not have a harmful effect on the health of a person and his offspring. There are maximum one-time and average daily maximum permissible concentrations, maximum permissible concentrations for a work area (premises) or for a residential area. Moreover, the maximum permissible concentration for a residential area is set less than for a working area.

Standards for maximum permissible levels of noise, vibration, magnetic fields and other physical impacts are established at a level that ensures the preservation of people’s health and ability to work, the protection of flora and fauna, favorable conditions labor.

Sanitary standards for the permissible noise level in residential areas establish that it should not exceed 60 decibels, and at night - from 23 to 7 o'clock - 45 decibels. For sanatorium and resort areas, these standards are 40 and 30 decibels, respectively.

For residential areas, the sanitary and epidemiological service authorities have substantiated and approved permissible levels of vibration and electromagnetic influences.

Other regulated physical effects include thermal effects. Its main sources are energy, energy-intensive industries, and household services. In the adopted Rules of Protection surface waters from wastewater pollution, standards for thermal impact on water bodies have been established. In the source of household, drinking and cultural water supply, the summer water temperature should not exceed the temperature of the hottest month by more than 3° Celsius, in fishery reservoirs - be no more than 5° Celsius above the natural water temperature.

The Federal Law "On Environmental Protection" requires the determination of maximum permissible impact standards for each source of pollution. Definition of MPC is an expensive and long-term medical-biological and sanitary-hygienic procedure. Currently, the total number of substances for which MPCs have been determined exceeds one thousand, while harmful substances, with which a person deals throughout his life, is an order of magnitude greater.

We all live on earth under the rays of the warm sun, but do we know everything about the impact of these rays on human body?

All life on Earth directly depends on the energy of the Sun. It is ultraviolet that is the source of this invaluable energy. However, the impact of ultraviolet radiation on living organisms often leads to inevitable damage to structures nucleic acids and proteins, and, as a result, leads to cell death.

Nature itself has created a reliable defense - the Earth, which serves as a barrier to harmful gases. The air at an altitude of 20-50 km contains a huge amount of ozone, which creates a kind of shield that protects the entire biosphere and humanity.

The human body knows how to defend itself through the synthesis of a dark pigment (melanin), which we call nothing more than tanning. But at the same time, in the spring, when the skin contains a small amount of melanin, a person cannot stay long time in the sun: the skin may quickly turn red, and after a few hours the general body temperature may rise and appear headache.

Everyone has long known that scientists are observing the systematic destruction of the ozone layer. The ozone content in the atmosphere has decreased significantly; moreover, a so-called “hole” has been discovered, which is located above Antarctica. Unfortunately, the area of this hole is increasing every year, and today its area exceeds Antarctica itself in size.

The destruction of the ozone layer does not go unnoticed by humanity; for example, in countries that are in close proximity to the mainland, an increase in diseases is observed. These are mainly diseases associated with increased UV exposure, such as cataracts, skin cancer, etc.

Military activity also contributes to the destruction of our “shield”. The engines of ballistic missiles, which are used by the military, emit a huge amount of harmful emissions into the atmosphere. Each launch of one such rocket into space creates a huge “hole” in the ozone layer. After only a few hours, such a “hole” heals.

Back in the 70s, over a remote and deserted island, the American military scattered in the stratosphere chemical substances, which contributed to the formation of a “hole” that healed only after many hours. The destruction of the ozone layer over the island led to the fact that a significant part of the island's land inhabitants was simply destroyed. Animals, plants, microorganisms - all died. Only a few large turtles were able to survive, thanks to their thick bony shell. However, these turtles became blind because their retinas were burned by ultraviolet light.

The sun's molecular oxygen) dissociates into atoms, which then combine with other O2 molecules to form ozone (O3). The relatively high concentration of ozone (about 8 ml/m³) absorbs dangerous ultraviolet rays and protects everything living on land from harmful radiation

Stages of ozone layer destruction:

1) Emissions: as a result of human activity, as well as as a result of natural processes on Earth, gases containing halogens (bromine and chlorine) are emitted (released), i.e. substances that destroy the ozone layer.

2) Accumulation (emitted gases containing halogens accumulate (accumulate) in the lower atmospheric layers, and under the influence of wind and air flows move to regions that are not in direct proximity to the sources of such gas emissions).

3) Movement (accumulated gases containing halogens move into the stratosphere with the help of air flows).

4) Transformation (most of the gases containing halogens, under the influence of ultraviolet radiation from the Sun in the stratosphere, are converted into easily reacting halogen gases, as a result of which the destruction of the ozone layer occurs relatively more actively in the polar regions of the globe).

5) Chemical reactions (easily reacting halogen gases cause the destruction of stratospheric ozone; a factor promoting reactions is polar stratospheric clouds).

6) Removal (under the influence of air currents, easily reacting halogen gases return to the troposphere, where, due to the humidity and rain present in the clouds, they are separated, and thus completely removed from the atmosphere).

Reasons for OS destruction:

Firstly , are launches of space rockets. Burning fuel “burns” large holes in the ozone layer. It was once assumed that these “holes” were closing. It turned out not. They have been around for quite a long time. Secondly , airplanes flying at altitudes of 12-15 km. The steam and other substances they emit destroy ozone. But at the same time, planes flying below 12 km give an increase in ozone. In cities it is one of the components of photochemical smog . Third - nitrogen oxides. They are ejected by the same airplanes, but most of them are released from the soil surface, especially during the decomposition of nitrogen fertilizers.

Consequences:

This negatively affects not only all living beings: people, animals, plants, tropical forests, but also on objects. For example, if the ozone layer becomes too thin, the rubber used on the farm will last much less. Aquatic organisms living in the upper layers of water will cease to exist. The fauna of the Amazon jungle with pythons and parrots will finally die. Fishing catches and agricultural yields will be significantly reduced. Undoubtedly, the destruction of the ozone layer will affect people. Humanity will become sick twice as often because the immune system will weaken significantly. Your risk of developing skin cancer and cataracts will increase.

Scientists suggest that a 1% decrease in the ozone layer will lead to the active spread of diseases. For example, cases of skin cancer will increase by 10 thousand times, and eye cataracts - by 100 thousand. A person’s tendency to develop diseases of the respiratory tract and lungs will increase rapidly.

Scientists are searching for ways to restore the ozone layer. Initially, for this purpose, it was proposed to create factories for the production of ozone, and then deliver it by plane into the atmosphere. Another option is to create balloons equipped with lasers, powered by solar panels, which will use oxygen to create ozone. The most realistic way out of this situation is is a reduction in deforestation and an increase in green spaces.

On July 10, 1976, in the small Italian town of Seveso, an incident occurred. terrible disaster. An accident at a local chemical plant producing trichlorophenol released a huge toxic cloud containing more than 2 kg into the air. dioxins are one of the most toxic substances on earth. (This amount of dioxins can kill more than 100 thousand people). The cause of the accident was a failure in the production process, the pressure and temperature in the reactor sharply increased, the explosion-preventing valve operated, and a deadly gas leaked. The leak lasted two to three minutes; the resulting white cloud began to spread to the southeast with the wind and stretched over the city. Then it began to descend and cover the ground with fog. Tiny particles of chemicals fell from the sky like snow, and the air was filled with an acrid, chlorine-like smell. Thousands of people experienced attacks of coughing, nausea, severe pain in the eyes and headaches. The plant management believed that there was only a small release of trichlorophenol, which is a million times less toxic than dioxins (no one imagined that they could be contained there).
Plant managers provided a detailed report on the incident only on July 12. Meanwhile, all this time, unsuspecting people continued to eat vegetables and fruits, as it turned out later, from areas contaminated with dioxins.

The tragic consequences of what happened began to fully manifest themselves on July 14. Hundreds of people who were seriously poisoned ended up in hospitals. The victims' skin became covered with eczema, scars and burns, and they suffered from vomiting and severe headaches. In pregnant women, there was an extremely high rate of miscarriages. And doctors, relying on the company's information, treated patients for poisoning with trichlorophenol, which is a million times less toxic than dioxins. Started mass death animals. They received lethal doses of poison much faster than humans due to the fact that they drank rainwater and ate grass, which contained large doses of dioxins. On the same day, a meeting of the mayors of Seveso and nearby Meda was held, at which a priority action plan was adopted. The next day, it was decided to burn all the trees, as well as the fruits and vegetables harvested from the contaminated area.

Only 5 days later, a chemical laboratory in Switzerland found that as a result of the leak, a large amount of dioxins was released into the atmosphere. All local doctors were notified about the contamination of the area with dioxins, and a ban was established on eating foods from the contaminated region.
On July 24, the evacuation of residents from the most contaminated areas began. This area was fenced with barbed wire and police cordons were placed around it. After that, people in protective overalls entered there to destroy the remaining animals and plants. All vegetation in the most contaminated area was burned, and in addition to the 25 thousand dead animals, another 60 thousand were killed. Healthy human existence is still impossible in these areas.

Scientists from the University of Milan conducted a study to study the incidence of cancer in the population of settlements nearby the city of Seveso.
More than 36 thousand people were monitored and a significantly higher incidence of cancer was detected in them. From 1976 to 1986, about 500 people died from cancer in the disaster area. In 1977, 39 cases of congenital deformities were recorded there, which is significantly more than before the disaster.

The largest Hungarian industrial and environmental disaster occurred on October 4, 2010 at an aluminum production plant (Ajkai Timfoldgyar Zrt) near the city of Ajka (150 km from Budapest). An explosion occurred at the plant, destroying a platform that held a container containing toxic waste. As a result, 1,100,000 cubic meters of highly alkaline red mud leaked. The territories of the regions of Vas, Veszprem and Gyor-Moson-Sopron were flooded. There are 10 known victims of the accident (one more is considered missing); in total, more than 140 people received chemical burns and injuries due to the accident. Most of the local flora and fauna died. Toxic waste has entered many local rivers, significantly affecting their ecosystems.

Chronology of events:

October 4 at 12.25 – dam destruction. Leakage of 1.1 million cubic meters of toxic chemical - red mud.

October 7 – the norm for alkali content in the Danube was exceeded (according to the Hungarian Water Resources Control Service). A threat is created to the entire Danube ecosystem.

October 9 – the evacuation of the population of the affected city of Kolontar begins due to the existing threat of a repeated sludge spill.

October 12 – a decision was made to nationalize the company that owns the plant. All victims will receive compensation. According to monitoring data, the amount of toxic substances in the soil is decreasing, although their level still remains at a dangerous level

Perhaps the most important environmental problem of the Nile River is the overpopulation of the countries located on the river. The life of the population of these countries completely depends on the Nile. Every year people's needs are growing. The river provides the people with water and electricity resources. Many wars in the old days were fought over oil, but in the modern world they can be fought over water. It is the Nile, the great river of the world, which has passed through the history of mankind through its streams, that will find itself at the epicenter of the conflict.

Fresh running water has always nourished life on our planet, but now its value is greater than ever. It is expected that over the next 20 years, the amount of water available to each person will be reduced by three times. We are talking about Egypt. Since Egypt is located downstream from Ethiopia, the issue of rational use water resources Nila, has a conflicting nature. The situation is extremely serious and Egypt has already announced the possibility of war, referring to Ethiopia.

The Nile in Egypt flows almost all the time through the desert, not counting the narrow strips of green irrigated lands bordering the river on both banks, the entire territory of the country is a homeless desert. In the struggle for survival in this desert, the river plays a key role.

Giant platinums were built upstream of the Nile in order to satisfy the need for electricity, but they also began to delay the flow of the river and ruined the lives of Egyptian peasants. This country used to have some of the best soil in the world, but the construction of dams has disrupted the silt deposition that has naturally enriched the land for many thousands of years. Now the fields are producing an extremely meager harvest.

As a direct result modern methods the construction of dams - there was a decline in agriculture in Egypt for the first time in history. The peasants are forced to abandon the way of life that has supported the nation for many thousands of years. As the river approaches the southernmost point of Egypt's border, it becomes difficult not to notice that this people is rapidly modernizing and that tourism is displacing agriculture as the mainstay of the Egyptian economy, while the old way of life is gradually becoming a thing of the past.

The construction of a giant dam in Ethiopia can solve many problems for the population of this poor country, including providing full electricity. If the outcome of this project is positive, it is planned to build several more dams, which in turn will reduce the flow of water resources located downstream in Egypt by approximately half.

Undoubtedly, every country wants to use the priceless wealth of the Nile to the maximum. If a compromise is not found, the future fate of the Nile will be sad. Be that as it may, the river acquired such a specific environmental problem due to population growth, its modernization and increased needs.

The open nature of the atmosphere as a system makes it possible for it to be closely connected with the underlying surface, the biosphere and the Cosmos. The influence of cosmic, solar, and ultraviolet rays appears throughout the entire thickness of the atmosphere, but most of all in the ozone layer. The ozone layer is a layer of the atmosphere (stratosphere), within which the concentration of ozone molecules (03) is ten times higher than at the Earth's surface.

Ozone means "fragrant" in Greek. This name was given to it by the German chemist Christian Friedrich Schonbein, who worked in Switzerland almost all his life and was a professor at the University of Basel. In 1839, he described chemical methods for producing ozone. The ozone layer itself was discovered in 1913 by Charles Fabry and Henri Buison. In the 20s of the XX century. Oxford University professor Gordon Dobson9 was actively involved in research into the ozone layer, in whose honor the unit of measurement for the thickness of the ozone layer, the Dobson unit, was named. The researcher established a worldwide network for monitoring the ozone layer, which has been in operation since 1928. Until now.

Ozone is observed in the layer of air from earth's surface to an altitude of about 70 km, but its main quantity is concentrated at an altitude of 20-55 km. The total ozone content in the atmosphere, if brought to normal pressure (1013.2 hPa) at a temperature of 0 ° C, ranges from 1 to 6 mm. This value is usually called the reduced thickness of the ozone layer or its total amount. This gas, despite its extremely small amount, plays a very important role in physical processes upper layers atmosphere (stratosphere and mesosphere). Atmospheric ozone is considered the most important energy source in the stratosphere. It absorbs about 1% of all solar radiation falling on the Earth. Due to this, at these altitudes the air temperature increases to values approaching zero. Vertical and horizontal temperature distribution in the stratosphere, as well as the pressure field, wind regime and, in particular, jet streams are directly related to atmospheric ozone.

From an environmental point of view, it is equally important that ozone determines the ultraviolet climate of our planet. It limits the short-wavelength part of the solar spectrum (as well as a similar part of the spectrum of stars and the Cosmos) and does not allow radiation shorter than 290 nm to pass through to the Earth’s surface, if it passed through life on Earth in the modern protein form would be impossible. When this radiation penetrates the earth's surface, it suppresses photosynthesis in plants, causes burns to the skin and retina, destroys blood cells and DNA molecules, promotes the growth of malignant tumors, and the like. And if humans, as well as animals and organisms not associated with photosynthesis, do not immediately suffer from increased ultraviolet radiation, then terrestrial plants are absolutely defenseless against it, and their death will disrupt ecological food chains, which will lead to irreparable losses for the entire biosphere. Ozone is a kind of protective screen for all life on Earth.

Almost all atmospheric ozone is concentrated in the lower stratosphere, and general content it is subject to periodic and non-periodic changes. An increase in ozone content in the stratosphere helps to reduce the influx of solar radiation to the earth's surface, since it absorbs solar radiation not only in the ultraviolet, but also in the visible and near-visible infrared parts of the spectrum. There is no doubt that an increase in ozone content in the stratosphere leads to an increase in its heating. At the same time, the temperature, pressure and circulation of the troposphere also experience corresponding changes. The climate responds sensitively to even minor changes in solar radiation. So, ozone can be associated with both natural and artificial climate changes, as well as the dependence of the climate on solar activity. Artificial climate change is the consequences of changes in the ozone content in the atmosphere (so far, unfortunately, only in the direction of its decrease).

Ozone is the cause blue color sky. In the atmosphere, ozone forms the ozonosphere - the most important part of the atmosphere, which affects the climate and protects all living things from ultraviolet radiation. The maximum ozone concentration is at an altitude of 18-5 km. We are protected from the aggressive effects of ultraviolet radiation, since most of it (99%) is absorbed by the ozone layer in the stratosphere at an altitude of about 20-25 km from the earth's surface. This layer is called the ozone shield.

In 1985, specialists from the British Antarctic Atmospheric Research Service reported a completely unexpected fact: spring content ozone in the atmosphere above the Halley Way station in Antarctica decreased by 40% between 1977 and 1984. This was soon confirmed by other researchers who proved that the region of low ozone content extends beyond Antarctica and covers a layer from 12 to 24 km in height, that is, a significant part of the lower stratosphere. In September and October, about 70% of ozone is lost over Antarctica, accounting for about 3% of all atmospheric ozone. The very space in which the ozone layer over Antarctica was carefully studied was the international Airplane Antarctic Ozone Experiment. During the experiment, scientists from four countries climbed into the low ozone region several times and collected detailed data on the size of the “hole” and chemical processes that are happening there. At first

In the 80s, according to measurements from the Nimbus-7 satellite, a similar “hole” was discovered in the Arctic, although it covered a much smaller area and the decrease in ozone levels in it was not so significant - about 9%. On average on Earth from 1979 to 1990, ozone decreased by 5%.

Several hypotheses have been put forward to explain the occurrence of the "ozone hole" and several expeditions have been sent to weed out incorrect hypotheses. The first hypothesis is atmospheric circulation. The circulation pattern could gradually change so that air flows over Antarctica rush upward. As a result, stratospheric air enriched with ozone was mixed with air from the troposphere - the lower ten-kilometer layer containing little ozone. But measurements, on the contrary, showed that in fact the air that fills the “ozone hole” comes from the higher layers, where there is usually a lot of ozone.

The second hypothesis is chemical reactions. One of the first such hypotheses was that nitrogen compounds, which are the most important agents in the destruction of ozone, may be present around the “ozone hole” in elevated concentrations. The reason for the increase in concentration was considered solar Activity and atmospheric circulation. There is an alternative that is more reliable chemical theory, according to which the formation of the “ozone hole” occurs as a result of the action of chlorine compounds entering the atmosphere mainly from anthropogenic chlorofluorocarbons (CFCs). These inert compounds, used as refrigerants for air conditioners and refrigerators, as chemical agents for the production of foam plastics, can be stored in the atmosphere for 50 to 100 years. When they reach the middle of the stratosphere, located at an altitude of about 30 km, ultraviolet radiation breaks them apart. Chlorine, released from CFC molecules, first exists as free chlorine or reacts with ozone to form chlorine oxide CN. Both forms enter into further reactions, forming stable compounds - chlorine reservoirs. They consist of various shapes of hydrochloric acid HCl, formed by the reaction of free chlorine with components such as methane and chlorine nitrate. Chlorine tanks do not destroy ozone - in such compounds the chlorine remains inert and cannot react with ozone. Early computer models showed that CFCs would not significantly affect the ozone layer, meaning that some free chlorine would only destroy a small portion of the ozone. Obviously, the mechanism for releasing chlorine from the tanks.

So, chlorine is a catalyst for the decomposition of ozone. Having completed the cycle once, chlorine repeats it many times until it leaves the stratosphere or is turned off. Scientists have calculated that during a long stay in the stratosphere, each chlorine atom destroys almost 100 thousand ozone molecules, and thereby transmits the same number of ultraviolet photons to the earth's surface. Freons (chlorofluoromethanes) of technogenic origin, entering the stratosphere, accumulate there and also destroy ozone. This destructive force is accompanied by nitrogen fertilizers and the synthesis of nitro compounds nuclear explosions. Of particular danger are the explosions of neutron bombs, which can destroy ozone screen over entire regions (ecological wars). The importance of this problem was recognized by UN units, in particular, the UN Environment Program (UNEP) began to deal with this problem.

So, the “ozone hole” is a local decrease in ozone concentration in the stratosphere by 10-40%, associated with the action of freons, a decrease in the amount of oxygen during launches spaceships and jet flights (Fig. 5.4). It manifests itself clearly at extremely low temperatures. The growth in the second half of the 20th century led to a significant decrease in the thickness of the ozone layer. anthropogenic load in the form of constant release of chlorine and bromine freons (BFC). According to another hypothesis, the process of formation of "ozone holes" is largely natural and is not associated solely with harmful effects human civilization.

Rice. 5.4.

This discovery worried both scientists and the general public because it meant that the layer of ozone that covers our planet was in greater danger than previously thought. The thinning of this layer can lead to serious consequences for humanity. A decrease in ozone concentration by only 1% leads to an increase in the intensity of hard ultraviolet radiation at the Earth's surface by an average of 2%. This conclusion is confirmed by measurements taken in Antarctica. In terms of its effect on living organisms, hard ultraviolet radiation is similar to ionizing radiation, however, due to its longer wavelength than y-radiation, it is not able to penetrate deep into tissues, and therefore affects only superficial organs. Harsh ultraviolet light has enough energy to destroy DNA and other organic molecules, causing skin cancer, especially transient malignant melanoma, cataracts and immune deficiency. Naturally, hard ultraviolet radiation can cause ordinary burns to the skin and cornea. Already today, the incidence of skin cancer has noticeably increased throughout the world, but many other factors (for example, the popularity of tanning) do not allow us to unequivocally state that this was only due to a decrease in ozone levels.

Hard ultraviolet (UV) radiation is poorly absorbed by water and is therefore very dangerous for marine ecosystems. Experiments have shown that plankton, which live in the surface layer of water, can be seriously damaged and even die when the intensity of hard UV increases. Plankton is the basis of the food chains of all marine ecosystems, so there is a threat that all life in the surface layers of the seas and oceans may disappear. Plants are less sensitive to hard UV, but if the dose is increased, they may also suffer. If the ozone content in the atmosphere decreases significantly, humanity will easily find a means of protection from harsh UV, but at the same time risks dying of starvation.

The stratospheric ozone screen is very sensitive to modern man-made impacts, which have reached alarming proportions. It is believed that 500 supersonic transport aircraft, if they regularly fly at altitudes of maximum ozone levels throughout the year, can reduce its total ozone content by half. Launches of space rockets for any purpose create “holes” in the ozonosphere with a diameter of hundreds of kilometers. 85 such launches over the course of a year are enough to obtain the same result in ozone destruction.

The absolute values of ozone content are the largest in high latitudes with significant monthly averages. The ozone content in the atmosphere of continental mid-latitudes is subject to frequent and significant extreme deviations. Negative anomalies, that is, “holes,” are especially repeated here. Most often, significant extremes for the ozone layer were observed over Moscow and Budapest, somewhat less so over Canada, Norway, Denmark, the Czech Republic, as well as St. Petersburg, Kiev, and Tbilisi.

The idea of the danger of ozone layer destruction was first expressed back in the late 1960s. At that time, it was believed that the main danger to atmospheric ozone was emissions of water vapor and nitrogen oxides (g40x) from the engines of supersonic transport aircraft and rockets. However, supersonic aviation developed at a much less rapid pace than expected. Today, only Concorde is used for commercial purposes, making several flights a week between America and Europe; almost only supersonic strategic bombers and reconnaissance aircraft of the EK-71 type fly from military aircraft in the stratosphere. Such a load is unlikely to pose a serious threat to the ozone layer. . Emissions of nitrogen oxides from the Earth's surface as a result of the combustion of fossil fuels, mass production and use of nitrogen fertilizers are also harmful to the ozone layer in some ways, but nitrogen oxides are unstable and easily destroyed in the lower atmosphere. Rocket launches also do not occur very often, however, chlorate solid fuels of modern space systems, for example, in the solid rocket boosters of the Space Shuttle and Ariane, can cause serious local damage to the ozone layer in the launch area.

In 1974. Scientists University of California concluded that chlorofluorocarbons can destroy ozone. Since then, the so-called chlorofluorocarbon problem has become one of the main problems in air pollution research. CFCs have been used for more than 60 years as a “coolant” in refrigerators and air conditioners, propellants for aerosol mixtures, foaming agents in fire extinguishers, cleaners for electronic devices, dry cleaning of clothing, and in the production of foam plastics. When seen as ideal for practical application chemicals because they are very stable and inactive and therefore non-toxic. But it is precisely the inertness of these compounds that makes them dangerous to atmospheric ozone. CFCs do not break down quickly in the troposphere, as do most nitrogen oxides, and eventually enter the stratosphere. When CFC molecules rise to an altitude of approximately 25 km, where ozone concentration is maximum, they are exposed to intense ultraviolet radiation, which does not penetrate below due to the shielding effect of ozone. Ultraviolet light destroys CFC molecules that are stable under normal conditions; they break down into highly reactive components, in particular, atomic chlorine. Thus, CFCs transport chlorine from the Earth's surface through the troposphere and lower atmosphere into the stratosphere, the altitude where ozone concentrations are highest.

As a result, 1 chlorine atom can destroy up to 100 thousand ozone molecules before it is turned off or returns to the troposphere. Today, emissions of CFCs into the atmosphere are estimated at millions of tons, but it should be noted that even if the production and use of CFCs are completely stopped, immediate results will not be achieved: the effects of CFCs that have already entered the atmosphere will continue for at least several more decades.

Despite this, many countries have begun to take measures to reduce the production and use of CFCs. Since 1978 The use of CFCs in aerosols has been banned in the United States. Unfortunately, their use in other industries has not been limited. 1987 23 of the most developed countries in the world signed a convention in Montreal obliging them to reduce the consumption of CFCs by 1999. To half the level of 1986. For use as a propellant in aerosols, a substitute for CFCs has already been found - a propane-butane mixture, which with physical parameters of almost not inferior to freons, but, unlike them, flammable. Such aerosols are already used in many countries around the world. It is more difficult with refrigeration units - the second largest consumer of freons. Indeed, due to their polarity, CFC molecules have a high heat of evaporation, which is very important for the working fluid in refrigerators and air conditioners. The best known substitute for freons today is ammonia, but it is toxic and still inferior to CFCs in terms of physical parameters. Good results from the use of fluorinated hydrocarbons. In many countries, new substitutes are being developed and good practical results have already been achieved, but this problem has not yet been completely solved.

The use of freons continues and the level of CFCs in the atmosphere has not yet stabilized. Thus, according to the Global Climate Change Monitoring Network, in background conditions - on the shores of the Pacific and Atlantic Oceans and on islands far from industrial and densely populated areas- freon concentration is growing at a rate of 5-9% per year. The content of photochemically active chlorine compounds in the stratosphere today is 2-3 times higher compared to the level of the 50s of the 20th century, at the beginning of intensive production of freons.

In addition to refrigerants, methyl bromide is also a particularly dangerous “enemy” of the atmosphere. This gas is used in agriculture as a plant protection agent. But methyl bromide destroys not only pests in the soil, but also ozone in the atmosphere, even in higher layers than freons. It is estimated that the destructive power of a bromine atom is 80 times greater than that of a chlorine atom. Bromine contained in methyl bromide is much more dangerous for stratospheric ozone than chlorine from freon gases. In Germany, farmers widely used methyl bromide when growing potatoes and sugar beets, and in 1982 its use was banned, not because of the threat of ozone layer destruction (this was not yet known), but because of the danger to groundwater.

The European Union has almost completely phased out the use of methyl bromide. The only exceptions are Spain and Italy, where the cultivation of greenhouse crops, in particular tomatoes and cucumbers, is very common. In the USA, methyl bromide is used mainly on flower and strawberry plantations in California and Florida. As is known, Agriculture The USA is distinguished by its monoculture, that is, a farmer who has, for example, strawberry plantations in Florida, grows only them, and, moreover, for many years in a row. The problem is that a huge number of pests that specialize in certain crops multiply in the soil. In such cases, methyl bromide is used, which is a very aggressive poison. Abandoning methyl bromide practically means abandoning monoculture farming, and for farmers this is associated with risk and financial losses. Fierce competition in the market does not allow interruptions in production.

So, forecasts that assumed that, while maintaining the current level of CFC emissions, by the middle of the 21st century. Ozone levels in the stratosphere could fall by half, may have been very pessimistic. Firstly, the “hole” over Antarctica is largely a consequence of meteorological processes. Ozone formation is possible only in the presence of ultraviolet radiation, that is, it does not occur during the polar night. In winter, a persistent vortex forms over Antarctica, preventing the flow of ozone-rich air from mid-latitudes, so by spring, even a small amount of active chlorine can cause serious damage to the ozone layer. There is almost no such vortex over the Arctic, so in the Northern Hemisphere the decrease in ozone concentration is much less. Many researchers believe that the process of ozone destruction is influenced by polar stratospheric clouds. These high-altitude clouds, which are much more common over Antarctica than over the Arctic, form in winter when there is no sunlight, and in Antarctic conditions the temperature in the stratosphere drops below -80 ° C. It can be assumed that nitrogen compounds condense, freeze and remain bound to cloud particles, respectively, they are deprived of the opportunity to react with chlorine. All this indicates that CFCs are capable of causing a significant decrease in ozone concentration only in the specific atmospheric conditions of Antarctica, and for a noticeable effect in mid-latitudes, the concentration of active chlorine must be much higher. Secondly, when the ozone layer is destroyed, hard ultraviolet radiation will begin to penetrate deeper into the atmosphere. This means that ozone formation will continue to occur, but only slightly lower, in the area with high content oxygen.

Although the first pessimistic estimates have been revised, this in no way means that there is no problem. Rather, it became clear that there was no need for a “catastrophic” danger. Even the most optimistic estimates predict, at the current level of CFC emissions into the atmosphere, serious biosphere disturbances in the second half of the 21st century. Therefore, it is still necessary to reduce the use of CFCs.

Due to its chemical activity, ozone (O3) molecules can react with many inorganic and organic compounds. The main substances that contribute to the destruction of ozone molecules:

Simple substances - hydrogen (H2), oxygen atoms (O), chlorine (Cl), bromine (Br)

Inorganic compounds - hydrogen chloride (HCl), nitrogen monoxide (NO)

Organic compounds - methane (CH4), fluorochlorine and fluorobromine freons, which release chlorine and bromine atoms.

Nitrogen oxides play an important role in ozone depletion reactions in the middle stratosphere. Despite the fact that there is more nitrogen in the atmosphere than any other gas, the formation of its oxides directly from molecular nitrogen is insignificant, since the N2 molecule is very stable, in fact inert. Its decay requires a lot of energy, for example, a lightning discharge or very hard radiation, solar protons or galactic radiation. This is not the case in the stratosphere, so the main source of nitrogen oxides (NO x) is nitrous oxide (N20), which is formed on the Earth's surface and in the oceans mainly as a result of bacterial activity. But the human “contribution” to this process today amounts to almost a third of the total amount of nitrous oxide.

In connection with these problems, already in 1975 the World Meteorological Organization for the first time made a statement on the impact of human activities and its impact on the ozone layer. possible consequences and adopted the “Global Ozone Study and Monitoring” project, which was also supported by the International Commission on Atmospheric Ozone. And in 1977 At the initiative of UNEP, a special meeting of ozone experts was held, which adopted the World Ozone Action Plan. The first international treaty regulating this issue was the Vienna Convention for the Protection of the Ozone Layer, which was signed in 1985 in Vienna (Austria); it entered into force on September 22, 1988. This international legal document obliges participating states to conduct research and systematic observations of chemical and physical processes, which can affect the ozone layer, the impact of changes in the state of the ozone layer on human health, climate change, etc. The implementation of the Vienna Convention is monitored by the Conference of the Parties to the convention.

1987 An international agreement was signed in Montreal to reduce and subsequently phase out the production of substances that deplete the ozone layer. The Montreal Protocol on Substances that Deplete the Ozone Layer is international treaty, created to protect the ozone layer by stopping or limiting the production of certain substances that were thought to cause ozone depletion. The agreement entered into force on January 1, 1989. After this, the participants held eight more meetings at which additions to the agreement were adopted; in 1989 (Helsinki), 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal) and 1999 (Beijing). The treaty was almost universally accepted and effectively implemented, with then UN Secretary-General Kofi Annan calling it "perhaps one of the most successful international agreements to date."

The Montreal Protocol is an invariable companion to the Vienna Convention for the Protection of the Ozone Layer. The norms of this document are more specific and clarifying than the norms of the Vienna Convention. It contains a list of substances and products that destroy the ozone layer. These include air conditioners in cars and trucks, refrigerators, freezers, ice makers, aerosol products, fluoropolymers and the like. Implementation of the Vienna Convention and the Montreal Protocol in Western Europe ended successfully. There, the use of ozone-depleting substances was reduced even faster than envisaged in the Protocol. Unfortunately, the length of time that these substances remain in the atmosphere means that even at this accelerated rate of withdrawal, the ozone layer may not fully recover until after 2050.