Causes of the Ozone Hole and the Threat It Carries to the Public Health

Nowadays, people very often raise the subject of the threat of the environment and the ways of preventing natural disasters. A so-called ozone hole (also known as ozone depletion) is also the topic of many discussions. Everybody knows that this phenomenon is worrying and it brings undesired effects. Unfortunately, not many people have the knowledge about the heart of the matter of the ozone hole.

As the name itself indicates, the ozone depletion occurs in the layer of ozone in atmosphere. This gas occurs just above the Earth’s surface, as well as from a few to about forty kilometers over it. In the first case, in troposphere, ozone is the anthropogenic gas and its presence unfavorably influences the environment, because it belongs to the group of greenhouse gases. The same gas, high in the stratosphere, fulfills a very important role, protecting our planet from the Sun’s excessive ultraviolet radiation. Talking about the dangerous phenomenon of ozone depletion, the scientists have on mind precisely the layer of ozone in the stratosphere вЂ" a so-called ozonosphere.

What exactly is the substance called ozone? The particles of this gas are built of three atoms of oxygen (O3). Its beneficial effect consists in, as I mentioned above, protecting against UV rays. The Sun sends from its inside the X-rays. However, before they reach the surface of the star, as a result of crashing on the material in the form of plasma, they lose a lot of energy and stop being the X-rays. From the Sun’s surface the visible and ultraviolet radiations travel towards the Earth. The first one, after reaching the Earth, is used by people and other living creatures. The high-energetic part of ultraviolet radiation is absorbed by nitrogen and oxygen in the atmosphere. Unfortunately, the lower-energetic part of that radiation is not engulfed by the mentioned gases. This radiation is blunted by the layer of ozone. Generally, all beams with higher energy than visible light have negative influence on our health, even though the UV radiation with the lowest energy enables the human organism to produce vitamin D. Thanks to the presence of ozone, the dose of radiation which reaches us is not so harmful any more.

In order to learn better the role of the ozone, it is indispensable to look closer at the transformations it surrenders. First of all, the gas being discussed by me, is not a durable variety of oxygen. Its disintegration happens very quickly and as a result of that the molecules of oxygen (O2) come into existence. This oxygen also gets divided into very reactive atoms (O), which attach themselves to the particles of oxygen, creating back the ozone (O3). All the processes absorb the energy of UV radiation and this way weaken it, that is they reduce its harmful effect. In natural conditions the chemical balance occurs and the amount of ozone stays on the permanent level. Unfortunately, some factors upsets the balance what causes problems.

Ozone’s concentration is measured in units called dobsons (it comes from the name of the constructor of measurement instruments). It is not dispersed evenly over the whole Earth’s surface. Its medium level amounts to 300 D, while above the equator there is only 250 D. If the stratospheric winds did not exist, there would be most ozone just about 30 over the equator. The winds, however, push the air expanded by ozone towards the poles. It falls closer to the surface of the planet and the biggest ozone condensation occurs approximately 25 kilometers above it. The Northern hemisphere receives more ozone than the Southern one does. When on the particular hemisphere the polar night ends, the transport of ozone is the largest.

The problem of the ozone hole began about the 1980s. In 1982, in the British scientific station “Halley Bay” in the Antarctic, the Dr. Joe Formana’s team discovered that a considerable portion of the ozone cover above the pole disappeared. Simultaneously, the measurements through the NASA’s satellite meteorological station were lead. Those researches did not indicate the similar condition of the ozonosphere. Later, it turned out that the computers rejected the possibility of so large disappearance of ozone, because earlier, programming them, nobody forecasted that such a situation might occur. In 1987, the amount of ozone above the pole was 50% smaller than before the hole was discovered. The researches indicated that the ozone’s condensation in the Earth’s atmosphere had been decreasing for a dozen or so years, on average 0.2% annually. The dropping of the amount of this gas is described as the extending of the ozone hole. This phenomenon is observed not only above the Antarctic, but also within other latitudes. In December 2000, the scientific press announced that the ozone hole over the Antarctic was gigantic and did not show tendencies to decreasing. It was acknowledged as an indirect effect of the unusually cold winter. Later the situation occurred above the Arctic.

Freons are the fundamental thread to the ozonosphere. These are the compounds of chlorine, fluorine and carbon (CFC). They are used in production of cooling devices. The were commonly used during the World War II to the production of spraying devices (this way they fought the mosquitoes вЂ" the carriers of malaria). They also found application in the production of varnishes, cosmetics, in medicine and in computer industry as cleaning supplies. From the beginning, freons seemed to be ideal compounds because of their inactiveness. They did not cause corrosion, dissolve in water, neither irritate the skin. Besides, they did not gather in the lower parts of atmosphere, where they possibly could threaten living organisms. It turned out, however, that the lightness and the chemical inactiveness of CFC compounds became a real torment. Pervading to the ozonosphere, they can stay in it for over hundred years.

In 1971, Prof. Sherwood Roland and Dr. Mario Molin, two chemicals, formulated a hypothesis about the negative influence of ferons to the ozone layer. CFC compounds under the influence of UV radiation fall apart into carbon, fluorine and chlorine. The carbon burns itself, fluorine and chlorine