Acid rain causes and consequences. How is acid rain formed?
Acid rain is commonly called any precipitation(rain, snow, hail) containing any amount of acid. The presence of acids leads to a decrease in pH levels. pH value
Acid rain is usually called any precipitation (rain, snow, hail) containing any amount of acid. The presence of acids leads to a decrease in pH levels. Hydrogen index (pH) is a value that reflects the concentration of hydrogen ions in solutions. The lower the pH level, the more hydrogen ions in the solution, the more acidic the environment.
For rainwater, the average pH value is 5.6. When the pH of precipitation is less than 5.6, it is referred to as acid rain. Compounds that lead to a decrease in the pH level of precipitation are oxides of sulfur, nitrogen, hydrogen chloride and volatile organic compounds(VOC).
Causes of acid rain
Acid rain, by nature of its origin, is of two types: natural (arising as a result of the activities of nature itself) and anthropogenic (caused by human activity).
Natural acid rain
Causes of acid rain naturally A little:
activity of microorganisms. A number of microorganisms, in the process of their life activity, cause the destruction of organic substances, which leads to the formation of gaseous sulfur compounds, which naturally enter the atmosphere. The amount of sulfur oxides formed in this way is estimated at about 30-40 million tons per year, which is approximately 1/3 of the total amount;
Volcanic activity supplies another 2 million tons of sulfur compounds into the atmosphere. Together with volcanic gases, sulfur dioxide, hydrogen sulfide, various sulfates and elemental sulfur enter the troposphere;
decomposition of nitrogen-containing natural compounds. Since all protein compounds are based on nitrogen, many processes lead to the formation of nitrogen oxides. For example, the breakdown of urine. It doesn't sound very pleasant, but that's life;
lightning discharges produce about 8 million tons of nitrogen compounds per year;
burning of wood and other biomass.
Anthropogenic acid rain
Since we are talking about anthropogenic impact, there is no need to have great mind, to guess that we will talk about the destructive influence of humanity on the state of the planet. A person is used to living in comfort, providing himself with everything he needs, but he’s not used to “cleaning up” after himself. Either he hasn’t grown out of the sliders yet, or he hasn’t matured enough in his mind.
The main cause of acid rain is air pollution. If thirty years ago as global causes, causing the appearance of compounds in the atmosphere that “oxidize” rain were called industrial enterprises and thermal power plants, today this list has been supplemented by road transport.
Thermal power plants and metallurgical enterprises “donate” about 255 million tons of sulfur and nitrogen oxides to nature.
Solid fuel rockets have also made and are making a significant contribution: the launch of one Shuttle complex results in the release of more than 200 tons of hydrogen chloride and about 90 tons of nitrogen oxides into the atmosphere.
Anthropogenic sources of sulfur oxides are enterprises producing sulfuric acid and refining oil.
Exhaust gases from motor vehicles account for 40% of nitrogen oxides entering the atmosphere.
The main source of VOCs in the atmosphere is, of course, chemical production, oil storage facilities, gas stations and gas stations, as well as various solvents used both in industry and in everyday life.
The final result is as follows: human activity supplies the atmosphere with more than 60% of sulfur compounds, about 40-50% of nitrogen compounds and 100% of volatile organic compounds.
From a chemical point of view, there is nothing complicated or incomprehensible about the formation of acid rain. Oxides entering the atmosphere react with water molecules, forming acids. Sulfur oxides, when released into the air, form sulfuric acid, and nitrogen oxides form nitric acid. One should also take into account the fact that in the atmosphere above major cities always contain particles of iron and manganese, which act as catalysts for reactions. Since there is a water cycle in nature, water in the form of precipitation sooner or later falls on the earth. Acid also gets in with the water.
Consequences of acid rain
The term "acid rain" first appeared in the second half of the 19th century and was coined by British chemists working on the pollution of Manchester. He noticed that significant changes in the composition of rainwater are caused by vapors and smoke entering the atmosphere as a result of the activities of enterprises. As a result of the research, it was discovered that acid rain causes discoloration of fabrics, metal corrosion, destruction of building materials and leads to the death of vegetation.
It took about a hundred years before scientists around the world sounded the alarm about harmful effects acid rain. This problem was first raised in 1972 at the UN conference on the environment.
Oxidation water resources. Rivers and lakes are the most sensitive. Fish die. Despite the fact that some species of fish can withstand slight acidification of water, they also die due to the loss of food resources. In those lakes where the pH level was less than 5.1, not a single fish was caught. This is explained not only by the fact that adult fish die - at a pH of 5.0, most cannot hatch fry from the eggs, as a result there is a reduction in the numerical and species composition fish populations.
Harmful effects on vegetation. Acid rain affects vegetation directly and indirectly. The direct impact occurs in high mountain areas, where tree crowns are literally immersed in acidic clouds. Excessively acidic water destroys leaves and weakens plants. The indirect impact occurs due to a decrease in the level nutrients in the soil and, as a result, an increase in the proportion of toxic substances.
Destruction of human creations. Building facades, cultural and architectural monuments, pipelines, cars - everything is exposed to acid rain. Many studies have been conducted, and they all say one thing: acid rain exposure has increased significantly over the past three decades. As a result, not only marble sculptures and stained glass windows of ancient buildings are under threat, but also leather and paper products of historical value.
Human health. Acid rain itself does not have a direct impact on human health - if you get caught in such rain or swim in a reservoir with acidified water, you do not risk anything. Compounds that form in the atmosphere due to the entry of sulfur and nitrogen oxides into it pose a threat to health. The resulting sulfates are transported by air currents over considerable distances, are inhaled by many people, and, as studies show, provoke the development of bronchitis and asthma. Another point is that a person eats the gifts of nature; not all suppliers can guarantee the normal composition of food products.
Solution
Since this problem is global character, then it can only be solved together. The real solution will be to reduce emissions from enterprises, both into the atmosphere and into water. There are only two solutions: stopping the activities of enterprises or installing expensive filters. There is a third solution, but it is only in the future - the creation of environmentally friendly industries.
The words that every person should be aware of the consequences of their actions have long been set on edge. But you can’t argue with the fact that the behavior of society is made up of the behavior of individual individuals. The difficulty is that people are accustomed to separating themselves from humanity in environmental matters: the air is polluted by enterprises, toxic waste gets into the water due to unscrupulous firms and companies. They are them, and I am me.
Household aspects and individual solutions to the problem
Strictly follow the rules for disposing of solvents and other substances containing toxic and harmful chemical compounds.
Give up cars. Maybe? - hardly.
Influence the installation of filters, implementation alternative ways Not everyone can produce, but compliance ecological culture and raising the younger generation to be environmentally literate and culturally aware is not only possible, it should become the norm of behavior for every person.
No one is surprised by the many books and films devoted to the results of man’s technogenic impact on nature. The films depict the dead surface of the planet, the struggle for survival and various mutant life forms in a colorful and frighteningly realistic manner. Fairy tale, fiction? - a very real prospect. Think about it, not so long ago space flights seemed like fiction, engineer Garin’s hyperboloid (modern laser systems) seemed like science fiction.
When thinking about the future of planet Earth, it is worth thinking not about what awaits humanity, but about the kind of world in which children, grandchildren and great-grandchildren will live. Only personal interest can motivate a person to take real steps.
Acid rain is a serious environmental problem caused by pollution environment. Their frequent appearance frightens not only scientists, but also ordinary people, because such precipitation can have an impact Negative influence on human health. Acid rain is characterized by a low pH level. For normal precipitation, this figure is 5.6, and even a slight violation of the norm is fraught with serious consequences for living organisms caught in the affected area.
With a significant shift, the reduced level of acidity causes the death of fish, amphibians, and insects. Also, in the area where such precipitation is observed, you can notice acid burns on the leaves of trees and the death of some plants.
Negative consequences of acid rain also exist for humans. After a rainstorm, toxic gases accumulate in the atmosphere, and inhaling them is highly discouraged. A short walk in acid rain can cause asthma, heart and lung diseases.
Acid rain: causes and consequences
The problem of acid rain has long been global in nature, and every inhabitant of the planet should think about their contribution to this a natural phenomenon. All harmful substances that enter the air during human activity do not disappear anywhere, but remain in the atmosphere and sooner or later return to the earth in the form of precipitation. Moreover, the consequences of acid rain are so serious that it sometimes takes hundreds of years to eliminate them.
In order to find out what the consequences of acid rain can be, you need to understand the very concept of the natural phenomenon in question. So scientists agree that this definition is too narrow to describe global problem. Only rain cannot be taken into account - acid hail, fog and snow are also carriers of harmful substances, since the processes of their formation are largely identical. In addition, toxic gases or dust clouds may appear during dry weather. They are also a type of acid precipitation.
Causes of acid rain formation
The cause of acid rain lies largely in the human factor. Constant air pollution with acid-forming compounds (sulfur oxides, hydrogen chloride, nitrogen) leads to imbalance. The main “suppliers” of these substances into the atmosphere are large enterprises, in particular those working in the field of metallurgy, processing of oil-containing products, burning coal or fuel oil. Despite the presence of filters and cleaning systems, the level modern technology still does not completely eliminate the negative impact of industrial waste.
Acid rain is also associated with an increase in vehicles on the planet. Exhaust gases, although in small proportions, also contain harmful acidic compounds, and in terms of the number of cars, the level of pollution becomes critical. Thermal power plants also contribute, as well as many household items, such as aerosols, cleaning products, etc.
In addition to human influence, acid rain can also occur due to certain natural processes. Thus, their appearance is caused by volcanic activity, during which large amounts of sulfur are released. In addition, it produces gaseous compounds during the breakdown of certain organic substances, which also leads to air pollution.
How is acid rain formed?
All harmful substances released into the air react with solar energy, carbon dioxide or water, resulting in acidic compounds. Together with drops of moisture, they rise into the atmosphere and form clouds. As a result, acid rain occurs, snowflakes or hailstones form, which return all absorbed elements to the earth.
In some regions, deviations from the norm of 2-3 units were noticed: the permissible acidity level is 5.6 pH, but in China and the Moscow region there was precipitation with values of 2.15 pH. At the same time, it is quite difficult to predict where exactly acid rain will appear, because the wind can carry the formed clouds quite far from the place of pollution.
Composition of acid rain
The main elements in acid rain are sulfuric and sulfurous acids, as well as ozone, which is formed during thunderstorms. There is also a nitrogen variety of sediments, in which the main core is nitric and nitrous acids. Less commonly, acid rain can be caused by high levels of chlorine and methane in the atmosphere. Also, other harmful substances may get into precipitation, depending on the composition of industrial and household waste that enter the air in a particular region.
Consequences: acid rain
Acid rain and its effects are a constant subject of observation for scientists around the world. Unfortunately, their forecasts are very disappointing. Precipitation with a low acidity level is dangerous for flora, fauna, and humans. In addition, they can lead to more serious environmental problems.
Once in the soil, acid rain destroys many nutrients that are necessary for plant growth. At the same time, they also draw toxic metals to the surface. Among them are lead, aluminum, etc. With a sufficiently concentrated acid content, precipitation leads to the death of trees, the soil becomes unsuitable for growing crops, and it takes years to restore it!
The same thing happens with reservoirs. The composition of acid rain disrupts the balance of the natural environment, which leads to the death of fish, as well as a slowdown in the growth of algae. Thus, an entire body of water may cease to exist for a long time.
Before reaching the ground, acid rain travels through air masses, leaving particles of toxic substances in the air. This has an extremely adverse effect on the health of animals and people, and also causes significant damage to buildings. Many paints and cladding materials, metal structures simply begin to dissolve when drops hit them! As a result, the appearance of a house, monument or car will be forever damaged.
Global environmental problems that can be caused by acid precipitation:
- Changes in the ecosystem of water bodies, as a result - the death of their animals and flora. Such sources cannot be used for drinking, since the content of heavy metals in them will be many times higher than the norm.
- Significant damage to the foliage and roots of trees, which will deprive them of protection from frost and many diseases. The problem is especially pressing in the case of coniferous trees, which “keep awake” even in severe cold.
- Contamination of soil with toxic substances. All plants located in the contaminated area of soil will certainly weaken or die altogether. All harmful elements will arrive along with useful ones. Unfortunately, there will be very few of the latter left.
Effect of acid rain on humans
Studying acid precipitation, the causes and consequences of their loss, scientists care not only about nature, but also about human lives. Death of livestock commercial fish, crops - all this significantly affects the standard of living and economic situation in any country.
If you forget for a while about damage to property or economic problems and think directly about health, then the picture also emerges as depressing. Any disease associated with the human respiratory system will worsen if the patient enters the affected area during or after acid rain.
Also dangerous are fish and animals that can be eaten, living in this area. They may contain toxic compounds of mercury, lead, manganese, and aluminum. Acid rain itself always contains heavy metal ions. Once in the human body, they cause intoxication, serious illnesses kidneys and liver, blockage of nerve canals, blood clots. Some of the effects of acid rain may take a generation to manifest themselves, so protecting yourself from toxic substances is also important for the sake of your descendants.
How to protect yourself from acid rain and prevent its occurrence
Today, the United States, Russia and China are at risk for acid rain. It is on the territory of these countries that the largest number of coal processing plants and metallurgical enterprises are located. However, danger also looms over Japan and Canada, where acid rain can simply be blown by the wind. According to some studies, if no action is taken preventive measures, then this list will be supplemented with dozens more countries in the very near future.
It is practically useless to combat the problem of acid rain locally. To change the situation in better side Comprehensive measures are needed, which are possible only through the interaction of several states. Scientists continue to work on new purification systems, trying to minimize the release of harmful substances into the atmosphere, however, the percentage of acid precipitation is only increasing.
To protect yourself from negative consequences acid rain, be sure to use an umbrella and raincoat in wet weather. The worst thing is for drops to get on exposed skin. It should be understood that it is impossible to distinguish acid rain from normal rain with the naked eye, so precautions must be taken at all times.
If you hear that acid precipitation will fall in your region, then try not to go outside at the indicated time. Also, stay at home for a few hours after rain, snow or hail, tightly closing windows and doors to prevent toxic substances in the air from entering the room.
IN Lately Quite often you can hear about acid rain. It occurs when nature, air and water interact with various pollutants. Such precipitation gives rise to a number of negative consequences:
- diseases in humans;
- death of agricultural plants;
- reduction of forest areas.
Acid rain occurs due to industrial emissions chemical compounds, combustion of petroleum products and other fuels. These substances pollute the atmosphere. Ammonia, sulfur, nitrogen and other substances then react with the moisture, causing the rain to become acidic.
For the first time in human history, acid rain was recorded in 1872, and by the twentieth century this phenomenon had become very common. Acid rain causes the most damage to the United States and European countries. In addition, ecologists have developed a special map that shows the areas most exposed to dangerous acid rain.
Causes of acid rain
The causes of toxic rain are man-made and natural. As a result of the development of industry and technology, plants, factories and various enterprises began to emit huge amounts of nitrogen and sulfur oxides into the air. So, when sulfur enters the atmosphere, it interacts with water vapor and forms sulfuric acid. The same thing happens with nitrogen dioxide; nitric acid is formed and falls out along with precipitation.
Another source of air pollution is exhaust gases from motor vehicles. Once in the air, harmful substances oxidize and fall to the ground in the form of acid rain. Nitrogen and sulfur are released into the atmosphere as a result of the combustion of peat and coal at thermal power plants. Huge amounts of sulfur oxide enter the air during metal processing. Nitrogen compounds are released during the production of building materials.
Some of the sulfur in the atmosphere is natural origin For example, after a volcanic eruption, sulfur dioxide is released. Nitrogen-containing substances can be released into the air as a result of the activity of certain soil microbes and lightning discharges.
Consequences of acid rain
There are many consequences of acid rain. People caught in such rain can ruin their health. Given atmospheric phenomenon causes allergies, asthma, cancer. Rain also pollutes rivers and lakes, making the water unfit for consumption. All residents of water areas are in danger; huge populations of fish may die.
Acid rain, falling on the ground, pollutes the soil. This depletes the fertility of the land and the number of harvests decreases. Since precipitation falls over large areas, it negatively affects trees, which contributes to their drying out. As a result of influence chemical elements, metabolic processes in trees change, and root development is inhibited. Plants become sensitive to temperature changes. After any acid rain, trees can suddenly shed their leaves.
One of the less dangerous consequences toxic precipitation is the destruction of stone monuments and architectural objects. All this can lead to collapse public buildings and houses of a large number of people.
The problem of acid rain needs to be seriously considered. This phenomenon directly depends on human activities, and therefore the amount of emissions that pollute the atmosphere should be significantly reduced. When air pollution is reduced to a minimum, the planet will be less susceptible to harmful precipitation such as acid rain.
Solving the environmental problem of acid rain
The problem of acid rain is global in nature. In this regard, it can only be solved if we combine the efforts of a huge number of people. One of the main methods to solve this problem is to reduce harmful industrial emissions into water and air. All enterprises must use cleaning filters and facilities. The most long-term, expensive, but also the most promising solution to the problem is the creation of environmentally friendly enterprises in the future. All modern technologies should be used taking into account the assessment of the impact of activities on the environment.
Modern modes of transport cause a lot of harm to the atmosphere. It is unlikely that people will give up cars anytime soon. However, today new environmentally friendly technologies are being introduced vehicles. These are hybrids and electric cars. Cars such as Tesla have already gained recognition in different countries peace. They operate on special batteries. Electric scooters are also gradually gaining popularity. In addition, we should not forget about traditional electric transport: trams, trolleybuses, metro, electric trains.
We should not forget that air pollution is caused by people themselves. You don’t need to think that someone else is to blame for this problem, and it doesn’t depend on you specifically. This is not entirely true. Of course, one person is not capable of releasing toxic and chemicals into the atmosphere in large quantities. However, regular use passenger cars leads to the fact that you regularly release exhaust gases into the atmosphere, and this subsequently becomes the cause of acid rain.
Unfortunately, not all people are aware of such an environmental problem as acid rain. Today, there are many films, articles in magazines and books about this problem, so everyone can easily fill this gap, recognize the problem and begin to act to solve it.
Normal rainwater has a slightly acidic reaction, since the air where moisture particles are formed contains carbon dioxide. But if the atmosphere has an increased content of pollutants emitted as a result of the operation of cars, metallurgical enterprises, power plants and other human activity, then the water reacts with these compounds and its pH decreases. It contains sulfuric, nitrogenous, sulfurous, nitric and other acids. And when they fall on the ground in the form of rain, snow or other types of precipitation (including fog), these substances interact with the environment and have a detrimental effect on it.
Consequences of acid rain
If acid rain is observed in the area of reservoirs - over rivers, lakes, seas, then the water in them also gradually begins to oxidize, although with small impacts it actively resists changes in pH. But if acid rain occurs regularly, then this resistance decreases, as a result ecological state reservoirs are deteriorating. With a high concentration of acids in water, the creatures living in it, most often insects, begin to die. For example, mayflies cannot live at a pH greater than 5.5. Fish are more resistant to such pollution, but if the insects die, the chain is inevitably broken: for example, trout that feed on these are faced with a lack of food. As a result, the number of fish in the reservoir also decreases.
Some fish can exist in acidic water, but cannot raise offspring in it, which also leads to the death of the population.
If acid rain falls on forests, the leaves of the trees are destroyed and fall off. Most often these are affected tall trees, which end up in acid clouds. Light rainfall with high acidity destroys forests more slowly and imperceptibly: they gradually reduce soil fertility and saturate it with toxins, plants begin to get sick and slowly die out.
Cars that cause air pollution then begin to suffer from them: acid precipitation destroys their protective coatings. Such rains are no less dangerous for structures created by man: buildings and monuments made of marble or limestone are literally corroded, as calcite is washed out of them.
Granite and sand rocks are more resistant to acids.
Acid rain also poses a threat to human health. Outwardly, they are impossible to distinguish, they look like ordinary rain, do not have a specific smell or taste and do not lead to unpleasant sensations on the skin. You can be exposed to acids not only during precipitation, but also while swimming in a river or lake. This leads to an increased risk of cardiovascular diseases and respiratory diseases - asthma, bronchitis, sinusitis.
The term “acid rain” refers to all types of meteorological precipitation - rain, snow, hail, fog, sleet, the pH of which is less than the average pH of rainwater (the average pH for rainwater is 5.6). Sulfur dioxide (SO2) and nitrogen oxides (NOx) released during human activity are transformed in the atmosphere into acid-forming particles. These particles react with atmospheric water, turning it into acid solutions, which lower the pH of rainwater. Sulfur dioxide and various nitrogen oxides are emitted into the atmosphere by motor vehicles, as a result of the activities of metallurgical enterprises and power plants, as well as by the combustion of coal and wood. Reacting with atmospheric water, they turn into solutions of acids - sulfuric, sulfurous, nitrous and nitric. Then, along with snow or rain, they fall to the Earth.
Acid rain for the most part observed in areas with developed industry. Although water droplets are quickly removed from the atmosphere, they still spread hundreds of kilometers from heat-emitting stations, industrial plants, etc.
Among the harmful substances contained in the air of cities are: large group, which has carcinogenic activity. This is primarily benzo(a)pyrene and others aromatic hydrocarbons, coming from boiler houses of industrial enterprises and with exhaust gases from vehicles.
Consequences of acid precipitation.
In the 70s in rivers and lakes Scandinavian countries fish began to disappear, the snow in the mountains turned grey colour, leaves from the trees covered the ground ahead of time. Very soon the same phenomena were noticed in the USA, Canada, and Western Europe. In Germany, 30% and in some places 50% of forests were damaged. And all this happens far from cities and industrial centers. It turned out that the cause of all these troubles is acid rain.
The pH value varies in different bodies of water, but in undisturbed natural environment the range of these changes is strictly limited. Natural waters and soils have buffering capabilities, they are able to neutralize a certain part of the acid and preserve the environment. However, it is obvious that nature’s buffering capacity is not unlimited.
In water bodies affected by acid rain, new life can inhale small amounts of phosphate fertilizers, they help plankton absorb nitrates, which leads to a decrease in water acidity. Phosphate is less expensive to use than lime, and phosphate also has less impact on water chemistry.
The land and plants, of course, also suffer from acid rain: soil productivity decreases, the supply of nutrients decreases, and the composition of soil microorganisms changes.
Acid rain causes enormous damage to forests. Forests are drying out, and dryness is developing over large areas.
Acid increases the mobility of aluminum in soils, which is toxic to small roots, and this leads to oppression of foliage and needles, and brittleness of branches. Coniferous trees are especially affected because needles are replaced less frequently than leaves, and therefore accumulate more harmful substances over the same period. Coniferous trees They turn yellow, their crowns become soft, and small roots are damaged. But also deciduous trees The color of the leaves changes, the foliage falls off prematurely, part of the crown dies, and the bark is damaged. Natural regeneration of conifers and deciduous forests not happening.
Specialists from the American University of North Carolina studied the effects of acid rain on plants during the period of their maximum susceptibility to environmental factors. Under the influence of acid rain immediately after pollination, fewer grains were formed in corn cobs than with irrigation clean water. Moreover, the more acid the rainwater contained, the fewer grains were formed on the cobs. However, it turned out that acid rain that occurred before pollination did not have a noticeable effect on the formation of grains.
Acid rain not only kills wildlife, but also destroy architectural monuments. Durable, hard marble, a mixture of calcium oxides (CaO and CO2), reacts with a solution of sulfuric acid and turns into gypsum (CaSO4). Temperature changes, rain and wind destroy this soft material. Historical monuments of Greece and Rome, standing for millennia, in last years are destroyed right before our eyes. The same fate threatens the Taj Mahal, a masterpiece of Indian architecture of the Mughal period, and in London the Tower and Westminster Abbey. At St. Paul's Cathedral in Rome, a layer of Portland limestone has been eroded by an inch. In Holland, the statues at St. John's Cathedral are melting like candy. The royal palace on Dam Square in Amsterdam is corroded by black deposits. More than 100 thousand valuable stained glass windows decorating the cathedrals in Tabernacle, Conterbury, Cologne, Erfurt, Prague, Bern, and other European cities may be completely lost in the next 15-20 years. Having studied new data on the acidity of precipitation falling in different regions Western Europe, and about their impact on buildings and structures, employees of the University of Dublin (Ireland) revealed that the most catastrophic situation occurred in the center of Manchester (UK), where in 20 months acid precipitation dissolved more than 120 g per 1 sq. m. m. stone (sandstone, marble or limestone). The city suffered greatly, although total precipitation during the observed period of time was extremely low there. Obviously, their degree of acidity was too high.
Manchester is followed by Liphun (Hampshire in the UK) and Antwerp (Belgium), where every stone is under open air lost 100g from Q1. m. Even cities known for atmospheric pollution, such as Athens, Copenhagen and Amsterdam, suffered acid destruction to a much lesser extent. People who are forced to consume also suffer from acid rain. drinking water, contaminated with toxic metals - mercury, lead, cadmium, etc.
It is necessary to save nature from oxidation. To do this, it will be necessary to sharply reduce emissions of sulfur and nitrogen oxides into the atmosphere, but primarily sulfur dioxide, since it is sulfuric acid and its salts that account for 70-80% of the acidity of rain that falls at large distances from the site of industrial emissions. Natural sediments have different acidity, but on average pH = 5.6. Acid precipitation with pH< 5,6 представляют серьезную угрозу, особенно если величина рН падает ниже 5,1. Ниже перечислю основные последствия выпадения кислотных осадков:
- - Damage to statues, buildings, metals and car trim;
- - Death of fish, aquatic plants and microorganisms in lakes and rivers;
- - Reduced reproductive ability of salmon and trout at pH
- - Death and decreased productivity of many species of phytoplankton when pH
- - Weakening or death of trees, especially conifers growing on high altitudes, due to the leaching of calcium, sodium and other nutrients from the soil;
- - Damage to tree roots and death of many fish species due to the release of aluminum, lead, mercury and cadmium ions from soils and bottom sediments;
- - Weakening of trees and increasing their susceptibility to diseases, insects, droughts, fungi and mosses that thrive in an acidic environment;
- - Slow growth cultivated plants, such as tomatoes, soybeans, beans, tobacco, spinach, carrots, broccoli and cotton;
- - Population growth of 81 Agola, a protozoan that causes a serious intestinal infection that affects rock climbers and mountaineers, drinking water from seemingly clear mountain streams;
- - The emergence and exacerbation of many diseases respiratory system human, premature death.
Acid precipitation illustrates the threshold effect. Most soils, lakes and rivers contain alkaline chemical substances, which can interact with some acids, neutralizing them. However, regular long-term exposure to acids depletes most of these oxidation-inhibiting substances. Then it suddenly starts mass death trees and fish in lakes and rivers. When this happens, it is too late to take any measures to prevent serious damage. The delay is 10-20 years.
Acid precipitation is already a serious problem in Northern and Central Europe, in the northeastern United States, southeastern Canada, parts of China, Brazil and Nigeria. All big threat they are beginning to represent in the industrial regions of Asia, Latin America and Africa and in some places in the western United States (mainly due to dry precipitation). Acid precipitation also occurs in a number of tropical areas where industry is practically undeveloped, mainly due to the release of nitrogen oxides during the combustion of biomass. Most of the acid-forming substances produced in one country are carried by prevailing surface winds to another. More than three-quarters of the acid deposition in Norway, Switzerland, Austria, Sweden, the Netherlands and Finland is carried into these countries by wind from the industrial areas of Western and of Eastern Europe. More than half of the acid deposition in densely populated areas of southeastern Canada and the eastern United States comes from emissions from highly concentrated coal and oil energy and industrial plants in seven Central and upper Midwest states—Ohio, Indiana, Pennsylvania, Illinois, Missouri, West Virginia, and Tennessee. (Figure V). The acidity level of precipitation over most of Eastern North America is 4.0-4.2. This is 30-40 times more acidic than normal precipitation that fell in these places several decades ago. States that throw away greatest number acid-forming substances are California, Indiana, Ohio and Texas.
About 75% of the acid deposition that falls in Canada is blown from the United States, and only 15% of the acid deposition that falls in the northeastern states comes from emissions within Canada. This large positive balance of acid deposition transport between the United States and Canada led to strained relations between the two countries. Canadian scientists and officials and many US scientists have criticized the US government for not moving quickly enough to reduce harmful emissions from industrial plants and power plants by at least 50%. The Ontario Ministry of Environment estimates that acid deposition threatens 48,000 Canadian lakes and their $1.1 billion-a-year sport fishing and $10-billion-a-year tourism industries. Canadians are also concerned that acid deposition is harming forestry and related industries, which employ one in 10 people in the country and generate $14 billion a year. At the rate National Academy Sciences estimate that the cost of acid deposition in the United States is already at least $6 billion a year and will rise sharply if immediate action is not taken.
The cost of reducing these pollutants will range from $1.2 billion to $20 billion, depending on the degree of treatment and the technology used.