The earth’s atmosphere is made up of 5 layers: troposphere, stratosphere, mesosphere, thermosphere, exosphere. Between 20 and 40 km in height there is the ozonosphere which represents the lowest part of the stratosphere.
Ozone is a molecule made up of three oxygen atoms (O3). It is a blue gas, formed by the natural activities of algae, which, during their life cycle, release oxygen. Over time, ozone molecules have deposited in the upper atmosphere of our planet, creating a protective layer that absorbs the most dangerous ultraviolet solar radiation. The ozone layer in the atmosphere is called the ozonosphere, thinner above the equator and thicker above the poles. Thanks to a photochemical reaction between the oxygen molecules and the sun’s rays, new atmospheric ozone is continuously formed which keeps the thickness of the ozone layer in constant equilibrium. This filter has allowed life to leave marine life to conquer the land, starting the evolution of terrestrial species: if there had not been the ozone layer to protect our planet, today there would not even be man since it protects living organisms from the most energetic UV rays of the sun. The ozonosphere therefore represents a protective shell for the Earth and its inhabitants. A hole in this layer exposes humans and living beings on the planet to a whole series of negative effects, as well as being among the causes of global warming. The ozone hole is therefore a thinning of this “shell”, or a progressive decrease in the concentration of ozone present in the stratosphere in some areas of our planet. Especially near the North Pole and the South Pole. This reduction is in fact due to causes attributable to humans. This phenomenon is caused by chlorofluorocarbons, gases composed of fluorine, chlorine and carbon, widely used in spray cans, refrigerators, as well as in a whole other series of industrial activities. The molecules emitted by these products reach the stratosphere and, once they enter it, due to the effect of ultraviolet rays, they break, releasing chlorine. The main cause of the accentuation of the ozone hole is therefore attributable to man. Many countries have made efforts to limit the problem and reverse course. This international agreement led to the Montreal Protocol of 1987. Thanks to this agreement, products that cause the ozone hole to widen have been banned. There are also serious consequences to the expansion of the ozone hole: as regards man, lacking the ozone filter present in the atmosphere, he would be exposed directly to the dangerous ultraviolet rays produced by the sun, causing cancer of the skin, as well as causing several DNA mutations. The environment would also be significantly affected: harmful UV rays have a negative effect on the chlorophyll photosynthesis of plants, which are prevented from doing so.
In these days when social isolation, due to this epidemic, forces us to stay home, the planet is breathing. The images of empty streets, ports and airports full of those vehicles that, instead, should have crowded the sea and the sky, of wild animals walking undisturbed through the streets of the cities, were emblematic. Good news in the midst of a stormy sea of data reporting a dramatic situation, positives that increase every day, all over the world, and people who do not survive this invisible and devious enemy. I think this should serve as a lesson … on Earth we are guests and for this reason we should learn to live with flora and fauna, rather than trying at all costs to become the absolute masters.