Meaning of Ozone Layer
The notion of layer can be used to name something that covers something else or that area that overlaps with others to form a unit. The ozone, on the other hand, is a substance that consists of three oxygen atoms per molecule.
The so-called ozone layer is part of the atmosphere. The atmosphere is called the set of gases that surround the planet: ozone, oxygen, carbon dioxide, nitrogen and others. The atmosphere is divided into successive layers that go from the troposphere (the closest to Earth) to the exosphere (the farthest).
Ozone is found in the stratosphere, which develops between 10 and 50 kilometers high. This ozone is essential for life as it is responsible for absorbing ultraviolet rays emitted by the sun.
The ozone layer, whose thickness varies, filters this radiation, minimizing its arrival at the earth’s surface. A reduction in the ozone layer, therefore, favors ultraviolet radiation reaching the Earth, a situation that can generate many problems for humans.
The use of various chemical compounds present in aerosols, fungicides, refrigerants and other products generates an increase in the concentration of bromine and chromium in the stratosphere, affecting the ozone layer. When the ozone layer is reduced, its ability to filter radiation also decreases: the increased arrival of ultraviolet rays to the surface, in turn, increases the cases of skin cancer, cataracts and other health disorders.
Although there is often talk of an ozone hole, in reality there is no such hole in the ozone layer. What the experts have detected is an abnormal decrease in the thickness of the mentioned layer, more noticeable in certain regions.
Substances that threaten the ozone layer
At the end of the 1980’s, the Montreal Protocol was signed, a treaty in which it was agreed not to use those chemicals that could destroy the ozone layer, and thus began a slow and long road to recovery. However, since new substances have been used since that time, which were not included in the document, in 2017 new threats to the integrity of the layer were discovered that could delay regeneration by three decades.
The study carried out in 2017 showed that the use of chlorine chemicals had increased considerably in recent times, both for making plastics and for removing paint. The treaty of 87 does not regulate the use of these compounds, most of which come from Chinese industry.
Since the signing of the agreement, hydrochlorofluorocarbons and chlorofluorocarbons that caused anomalous depletion of the ozone layer have ceased to be used in several countries. The substances that generated concern thirty years later are those that have a short life span; one of them is dichloromethane, used as an industrial solvent. From 2007 to 2017, the percentage of dichloromethane found in the atmosphere increased by 60%.
The second of the compounds of concern is 1,2-dichloroethane, used to make PVC. Although until not long ago it was believed that the decomposition of these substances occurred before reaching the ozone layer, samples obtained in recent years have proven just the opposite.
The research also showed that cold winds carry these substances to the Eastern Pacific from factories located in China, and that is where the air rises to the atmosphere at high speed; if its release had taken place in other parts of the planet, the impact would have been considerably less.