The presence in the air of foreign particles that are endanger health and cause discomfort to people, of substances that affect fauna and flora, are certain signs of pollution. The air we take into our lungs is part of the gaseous blanket that covers our dear earth. This cover protects us from merciless radiations from the sun. The air influences our health and in its composition there should be: 78.09% nitrogen, 2.095% oxygen, 0.92% argon, 0.03% carbon. This entire mixture represents 99.99% of the air composition. The rest is made up of other gases like: neon, helium, methane, krypton, ozone, hydrogen and radon. Various proportions of water vapors add to this amalgam. Unfortunately, the last 200 years brought about a deep depreciation in the composition of air. Combustion of coal and methane produced enormous quantities of carbon dioxide. To make the things worse, the discovery of automobiles increased the amount of toxic gases. The incredible and fast developments in agriculture lead to important accumulations of methane and nitrate oxides in the atmosphere. Moreover, increasing deforestations diminish the level of oxygen in the atmosphere. The oxygen is responsible for maintaining a pressure in the lung alveolus. It helps alteration of gas changes (oxygen and carbon dioxide) and it oxygenates the blood. The carbon dioxide that exists in the atmosphere in proportion of 0.03% does not influence negatively, as long as it does not impede the gas to pass from blood into lung alveolus and when it is released through the air breathed. The carbon dioxide and other gases that are responsible for the well-known greenhouse effect reduce the heat and keep it trapped inside the Earth’s atmosphere. In case the greenhouse gases increase, it will create harmful problems, of which the scariest would be the depletion of the atmosphere. We, the only inhabitants endowed with reasoning, have insensibly increased carbon dioxide emissions. That results in faster warming. The more we use vehicles and power factories, the greater our contribution to global warming is. Temperatures are expected to increase by 1.4 to 5.8 degrees till 2100.
The polluting substances responsible for poisoning the atmosphere fall into the following categories:
1.The toxic gases- are the ones that would impede tissues in our body to get oxygenated. The most ordinary is the carbon oxide, which together with the hemoglobin forms a stable compound- carboxyl-hemoglobin. This would block the oxygen to be assimilated in blood.
2.The urban pollution is known under the name of smog. The smog is a mixture of carbon monoxide and organic compounds which result from incomplete combustion of fossil fuels such as coal. While the smog interacts with the oxygen in the air, the organic and sulphuric acids condense and turn into watery drops that thicken the fog.
3.The irritants- they have harmful effects upon the ocular membrane as well as upon the respiratory system. Into this group we find: non-toxic powders, gases and vapors such as the sulphur dioxide, nitrogen dioxide, chlorine, hydrogen nitride, etc.
4.The polluters that cause modifications in the fiber of the respiratory system. Among them, the most common are: the silicon dioxide, asbestos and iron dioxides. These are known to be more aggressive, especially in exceptional conditions of air pollution.
5.The allergens – have been known for a long time. They are directly responsible for a wide range of respiratory or skin allergies.