Acid rain is called any precipitation (rain, snow, hail) containing any number of acids. The presence of acids leads to a decrease in pH. Hydrogen indicator (pH) is the value showing the concentration of hydrogen ions in solutions. The lower the pH, the more hydrogen ions in solution, the more acidic is the medium.
For rainwater the average pH equal to 5.6. In the case where the pH of precipitation is less 5,6 – talk about acid rains. Compounds that lower the pH of precipitation are oxides of sulphur, nitrogen, hydrogen chloride and volatile organic compounds (VOCS).
The causes of acid rain
Acid rain, on the nature of their origin are of two types: natural (result from the activities of nature) and anthropogenic (caused by human activity).
Natural acid rain
The causes of acid rain in a natural way a bit:
the activity of microorganisms. The number of microorganisms in the course of their life causes the destruction of organic substances, which leads to the formation of gaseous sulfur compounds that are naturally released to the atmosphere. The number formed in this way sulfur oxides is estimated in the order of 30-40 million tons per year, which is approximately 1/3 of the total number;
volcanic activity supplies the atmosphere additional 2 million tons of sulfur compounds. Together with the volcanic gases in the troposphere are sulfur dioxide, hydrogen sulfide, various sulfates, and elemental sulfur;
the decay of nitrogen-containing natural compounds. As the basis of all protein compounds contain nitrogen, many of the processes leading to the formation of nitrogen oxides. For example, the breakup of urine. Sounds pleasant, but that's life;
lightning discharges produce about 8 million tons of nitrogen per year;
burning of wood and other biomass.
Anthropogenic acid rain
Since we are talking about the anthropogenic impact, it is not necessary to have a great mind to guess what we will focus on the harmful impact of humanity upon the planet. People used to live in comfort, to provide themselves with everything necessary, except that "remove" is not used. Either of the sliders has not increased, whether the mind is not Mature enough.
The main cause of acid rain is air pollution. If thirty years ago as global causes in the atmosphere compounds, "oxidizing" rain, called the industrial enterprises and thermal power plants, today this list was supplemented with road transport.
Thermal power plants and metallurgical enterprises "give" nature, about 255 million tons of oxides of sulphur and nitrogen.
Solid-fuel rockets also have made and are making a significant contribution: the launch of a complex space Shuttle leads to the release into the atmosphere of over 200 tons of hydrogen chloride, approximately 90 tons of nitrogen oxides.
Anthropogenic sources of sulphur oxides are enterprises producing sulfuric acid and processing oil.
The exhaust gases of motor transport – 40% of nitrogen oxides into the atmosphere.
The main source of VOCS in the atmosphere are chemical manufacturing, oil terminals, petrol filling stations and gas stations, as well as various solvents used in industry and in everyday life.
The final result of the following: human activity into the atmosphere supplies more than 60% of sulfur compounds, about 40-50% of the nitrogen and 100% volatile organic compounds.
From the point of view of chemistry that formed acid rains, nothing complicated and incomprehensible is not. Oxides entering the atmosphere react with water molecules forming acid. Sulfur oxides into the air, forming sulfuric acid, oxides of nitrogen and nitrogen. It should take into account the fact that in the atmosphere above major cities are always contained particles of iron and manganese that act as catalysts for the reactions. As in nature there is the water cycle, water as rain sooner or later hits the ground. Along with water and acid.
The consequences of acid rain
The term "acid rain" first appeared in the second half of the XIX century and was introduced into use by the British chemists involved in pollution of Manchester. It was observed that significant changes in the composition of rainwater is called with smoke and fumes into the atmosphere by the activities of enterprises. As a result of studies it was found that acid rain caused the discoloration of fabrics, the corrosion of the metal, the destruction of materials and lead to the destruction of vegetation.
It took about a hundred years before scientists around the world sounded the alarm, speaking about the harmful effects of acid rain. This problem was first raised in 1972 at the UN conference on environment.
The oxidation of water resources. Be the most sensitive rivers and lakes. There is a destruction of fish. Despite the fact that some species of fish can withstand a slight acidification of the water, they also die because of loss of forage resources. In those lakes where the pH was 5.1 at least, was not caught no fish. This is explained not only by the fact that die adult specimens of fishes at pH equal to 5.0, most can't get fry from the eggs, resulting in a reduction of numerical and species composition of fish populations.
Harmful effects on vegetation. Acid rain act on vegetation directly and indirectly. A direct impact occurs in the highlands where the trees are literally immersed in the acid clouds. Overly acidic water destroys the leaves and weakens plants. The indirect effect is due to the decrease in the level of nutrients in the soil and, as a consequence, an increase in the proportion of toxic substances.
The destruction of human creations. The facades of buildings, monuments of culture and architecture, piping, machine is exposed to acid rain. There have been many studies and they all say one thing: for the past three decades, the impact of acid rain has increased significantly. The result is threatened not only marble sculpture, stained glass, old buildings, but also products made of leather and paper of historical value.
Human health. Themselves acid rain does not have a direct impact on human health is coming under the rain or after a swim in the reservoir with the acidified water, the man risks nothing. The threat to health are compounds that are formed in the atmosphere due to leakage of sulphur and nitrogen oxides. The resulting sulfates are carried by air currents for considerable distances, and inhaled by many people, and studies show that provoke the development of bronchitis and asthma. Another point is that a person eats the gifts of nature, to guarantee the normal composition of the food may not all suppliers.
The solution to the problem
Since this is a global issue, and it can be solved only together. The real solution would be the emission reduction activities of enterprises, both in atmosphere and in water. Solutions are only two: the termination of enterprise activity either the installation of expensive filters. There is a third solution, but it is only in the long term – creation of ecologically safe production.
Words that every person should be aware of the consequences of their actions, are ridden to death. But with the fact that the behavior of the society consists of the behavior of individuals, do not argue. The difficulty is that people in the environmental issues used to separate himself from mankind: the air polluting enterprises toxic waste into the water supply due to unscrupulous firms and companies. They're them and I'm me.
Consumer aspects and individual problem solutions
Strictly observe the rules of recycling of solvents and other substances that contain toxic and harmful chemicals.
To abandon the car. Possible? – hardly.
Affect the installation of filters, introduction of alternative production methods can not everyone, but the respect for ecological culture and education of the younger generation of ecologically literate and cultural – not only possible, it should become the norm of behavior of each person.
No surprise a lot of books and movies devoted to the results of anthropogenic impact on nature. In the films vividly and with frightening realism brought a dead planet's surface, fighting for survival and different mutant forms of life. Tale of fiction? is a very real possibility. Think about it, not so long ago flights into space seemed like a fiction, the hyperboloid of engineer Garin (modern laser systems) – fiction.
Thinking about the future of planet Earth, should not think about what awaits humanity, and about what kind of world the children will live and grandchildren. Only personal interest can drive a person to real steps.