The ozonosphere is the layer of our planet's atmosphere that blocks the hardest part of the ultraviolet spectrum. Some types of sunlight have a detrimental effect on living organisms. Periodically, the ozonosphere becomes thinner, gaps of various sizes appear in it. Dangerous rays can freely penetrate through the holes that have appeared on the surface of the Earth. Where is the ozone layer located? What can be done to save it? The proposed article is devoted to the discussion of these problems of geography and ecology of the Earth.
What is ozone?
Oxygen on Earth exists in the form of two simple gaseous compounds, is part of water and a very large number of other common inorganic and organic substances (silicates, carbonates, sulfates, proteins, carbohydrates, fats). One of the more well-known allotropic modifications of the element is the simple substance oxygen, its formula is O2. The second modification of atoms is O (ozone). The formula for this substance is O3. Triatomic molecules are formed when there is an excess of energy, for example, as a result of lightning discharges in nature. Next, we will find out what the ozone layer of the Earth is, why its thickness is constantly changing.
Ozone under normal conditions is a blue gas with a sharp, specific aroma. The molecular weight of the substance is 48 (for comparison - Mr(air)=29). The smell of ozone is reminiscent of a thunderstorm, because after this natural phenomenon, there are more O3 molecules in the air. The concentration increases not only where the ozone layer is located, but also close to the Earth's surface. This chemically active substance is toxic to living organisms, but quickly dissociates (breaks down). In the laboratory and industry, special devices have been created - ozonizers - for passing electrical discharges through air or oxygen.
What is the ozone layer?
O3 molecules have high chemical and biological activity. The attachment of the third atom to diatomic oxygen is accompanied by an increase in the energy reserve and the instability of the compound. Ozone easily decomposes into molecular oxygen and an active particle, which vigorously oxidizes other substances and kills microorganisms. But more often, questions related to the smelling compound concern its accumulation in the atmosphere above the Earth. What is the ozone layer and why is its destruction harmful?
There is always a certain amount of O3 molecules near the surface of our planet, but the concentration of the compound increases with height. The formation of this substance occurs in the stratosphere due to the ultraviolet radiation of the Sun, which carries a large supply of energy.
Ozonesphere
There isa region of space above the Earth where there is much more ozone than at the surface. But in general, the shell, consisting of O3 molecules, is thin and discontinuous. Where is the ozone layer of the Earth or the ozonosphere of our planet located? The variability in the thickness of this screen has repeatedly confused researchers.
A certain amount of ozone is always present in the Earth's atmosphere, there are significant fluctuations in its concentration with height and over the years. We will look into these problems after we find out the exact location of the protective screen of molecules O3.
Where is the Earth's ozone layer?
A noticeable increase in the content of ozone molecules begins at a distance of 10 km and persists up to 50 km above the Earth. But the amount of matter that is present in the troposphere is not yet a screen. As you move away from the earth's surface, the density of ozone increases. The maximum values fall on the stratosphere, its region at an altitude of 20 to 25 km. There are 10 times more O3 molecules here than at the surface of the Earth.
But why is the thickness, integrity of the ozone layer of concern to scientists and ordinary people? A boom over the state of the protective screen erupted in the past century. Researchers have found that the ozone layer of the atmosphere over Antarctica has become thinner. The main cause of the phenomenon was established - the dissociation of O3 molecules. Destruction occurs as a result of the combined effect of a number of factors, the leading among them is anthropogenic, associated with the activities of mankind.
Ozone holes
In the last 30-40 years, scientists have noted the appearance of gaps in the protective screen above the Earth's surface. The scientific community has been alarmed by reports that the ozone layer, the Earth's shield, is rapidly degrading. All the media in the mid-1980s printed reports of a "hole" over Antarctica. The researchers noticed that this gap in the ozone layer increases in the spring. The main reason for the growth of damage was named artificial and synthetic substances - chlorofluorocarbons. The most common groups of these compounds are freons or refrigerants. More than 40 substances belonging to this group are known. They come from many sources because applications include the food, chemical, perfume and other industries.
The composition of freons, in addition to carbon and hydrogen, includes halogens: fluorine, chlorine, sometimes bromine. A large number of such substances are used as refrigerants in refrigerators and air conditioners. Freons themselves are stable, but at high temperatures and in the presence of active chemical agents, they enter into oxidation reactions. The reaction products may include compounds that are toxic to living organisms.
Freons and ozone screen
Chlorofluorocarbons interact with O3 molecules and destroy the protective layer above the Earth's surface. At first, the thinning of the ozonosphere was taken as a natural fluctuation in its thickness, which happens all the time. But over time, holes like the "hole" over Antarctica were noticedthroughout the Northern Hemisphere. The number of such gaps has increased since the first observation, but they are smaller in size than over the icy continent.
Initially, scientists doubted that it was CFCs that caused the process of ozone destruction. These are substances with a large molecular weight. How can they reach the stratosphere, where the ozone layer is located, if it is much heavier than oxygen, nitrogen and carbon dioxide? Observations of upward flows in the atmosphere during a thunderstorm, as well as experiments, have proved the possibility of penetration of various particles with air to a height of 10–20 km above the Earth, where the boundary of the troposphere and stratosphere is located.
Variety of ozone depleters
The ozone shield also receives nitrogen oxides resulting from the combustion of fuel in the engines of supersonic aircraft and various types of spacecraft. Complement the list of substances from which the atmosphere, the ozone layer, and emissions from terrestrial volcanoes are destroyed. Sometimes the streams of gases and dust reach a height of 10-15 kilometers and spread over hundreds of thousands of kilometers.
Smog over large industrial centers and megacities also contributes to the dissociation of O3 molecules in the atmosphere. The reason for the increase in the size of ozone holes is also considered to be an increase in the concentrations of so-called greenhouse gases in the atmosphere, where the ozone layer is located. Thus, the global environmental problem of climate change is directly related to the issues of ozone depletion. The fact is that greenhouse gases containsubstances that react with O3 molecules. Ozone dissociates, oxygen atom causes other elements to oxidize.
Danger of losing the ozone shield
Were there gaps in the ozonosphere before space flights, the appearance of freons and other atmospheric pollutants? The above questions are debatable, but one conclusion suggests itself: the ozone layer of the atmosphere must be studied and preserved from destruction. Our planet without a screen of molecules O3 loses its protection from hard cosmic rays of a certain length, absorbed by the active substance layer. If the ozone shield is thin or absent, then the basic life processes on Earth are endangered. Excessive ultraviolet radiation increases the risk of mutations in the cells of living organisms.
Protection of the ozone layer
The lack of data on the thickness of the protective screen in the past centuries and millennia makes forecasts difficult. What happens if the ozonosphere collapses completely? For several decades, physicians have noted an increase in the number of people affected by skin cancer. This is one of the diseases caused by excessive ultraviolet radiation.
In 1987, several countries joined the Montreal Protocol, which provided for the reduction and total ban on the production of chlorofluorocarbons. This was just one of the measures that will help preserve the ozone layer - the Earth's ultraviolet shield. But freons are still produced by industry and enter the atmosphere. However, compliance with the MontrealProtocol led to the reduction of ozone holes.
What can everyone do to save the ozonosphere?
Researchers suggest that the complete restoration of the protective screen will take several more decades. This is in the event that its intensive destruction stops, which raises many doubts. Greenhouse gases continue to enter the atmosphere, rockets and other spacecraft are launched, and the fleet of aircraft in different countries is growing. This means that scientists have yet to develop effective ways to protect the ozone shield from destruction.
At the everyday level, everyone can also contribute. Ozone will be less decomposed if the air becomes cleaner, contains less dust, soot, and toxic vehicle emissions. To protect the thin ozonosphere, it is necessary to stop the burning of waste, to arrange their safe disposal everywhere. Transport should be switched to more environmentally friendly fuels, and various types of energy resources should be saved everywhere.
