The main reason for acid rain is the presence in the atmosphere due to The main reason for acid rain is the presence in the atmosphere due to industrial emissions of sulfur and nitrogen oxides, hydrogen chloride and other acid-forming compounds. industrial emissions of sulfur and nitrogen oxides, hydrogen chloride and other acid-forming compounds.
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Acid rain Completed by 11th grade student Tanya Gorelova
What is it
Most often, acid rain is visually no different from normal rain. However, the results that result from its elimination clearly show this difference. To put it simply, acid rain is precipitation that contains acids (most often nitric and sulfuric). When falling on the leaves of trees, such precipitation not only changes their appearance (they gradually become dark brown), but also disrupts the natural processes occurring in the crown. When acid rain hits the ground, it changes it chemical composition. All this destroys trees from the inside.
Formation of acid rain and its impact on the environment
Causes of acid rain
The main reason for acid rain is the presence in the atmosphere of sulfur and nitrogen oxides, hydrogen chloride and other acid-forming compounds due to industrial emissions. As a result, rain and snow become acidified.
Approximate acidity of rainwater and some substances in pH units
What is the danger
There are several dangers caused by acid rain. The greatest danger is hidden in vegetation that has sprouted from soil saturated with acidic moisture. According to Swedish scientists, many animals die due to chemical changes in their bodies. Such changes are caused by the high content of molybdenum and other substances in the composition of plants. And this is a direct consequence of the effects of acid rain.
Another danger is the gradual extinction of forests and lakes, which are constantly exposed to acid. Harmful precipitation makes the conditions for life and reproduction of plants and animals completely unsuitable.
IN present moment The consequences of acid rain falling on the ground can be observed almost all over the world. Acid rain has a negative effect on bodies of water (rivers, lakes, ponds, bays), it increases their acidity to such a high level that fauna and flora die in the reservoirs.
If a person drinks water from reservoirs that have a high lead content, or if he eats fish that has a high mercury content, then he can develop very serious illnesses. It should be noted that acid rain negatively affects not only aquatic flora and fauna, it also destroys vegetation on land.
As for the effects of acid rain on people, it can significantly affect human health. For example, acid rain can cause respiratory diseases in humans. Regardless of how the harmful substances carried by acid rain enter the body (through food, drink or air), the consequence can be not only serious illness, but also death, and this applies to both adults and children.
What actions are being taken
Scientists have been calling on governments since the 1980s different countries reduce the amount of harmful substances released into the atmosphere. In general, such calls find a response. However, reducing emissions alone is far from enough. It is necessary to constantly monitor the state of the green forests of our planet. This includes a whole range of measures aimed, among other things, at restoring normal acidity of precipitation.
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Slide text: Chemistry teacher of the Stepninskaya Secondary School Elena Vitalievna Litvinova
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Slide text: Acid rain (acid rain), precipitation (snow, fog, dew) is called acidic only if the pH value of rainwater becomes less than 5.6.
Slide text: The term “acid rain” was introduced in 1872 by the English engineer Robert Smith in his book “Air and Rain: The Beginning of Chemical Climatology”
Slide text: The cause of acid rain is massive emissions of sulfur oxide (IV) SO2 and nitrogen oxides NO into the atmosphere. By interacting with atmospheric moisture they create an acidic environment.
Slide text: Natural (20 million tons per year) Anthropogenic (100 million tons per year) Technogenic (5707 million tons per year) Sources of SO2
Slide text: volcanoes forest fires Natural sources:
Slide text: Anthropogenic sources: Furnaces in the private sector Garbage dumps
Slide text: Combustion of coal and fuel oil at power and heating plants Metallurgical production Mechanical engineering Chemical technological processes Technogenic sources:
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Slide text: Natural (700 million tons per year) Anthropogenic Technogenic Sources of NO and NO2
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Slide text: Agriculture(mineral nitrogen fertilizers) Anthropogenic sources:
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Slide text: Motor transport and motor transport Energy Metallurgical industry Chemical industry Technogenic sources:
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Slide text: Content of a raindrop SO2 NO2 H2SO4 CO2 CO H2O HCl
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Slide text: They were first noted in Scandinavia and North America in the 50s (pH 4.5 - 3.7) The world record belongs to the Scottish city of Pitlochry, where in 1974 rain fell with a pH of 2.4.
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Slide text: In Russia, the foci of acid rain are: on the Kola Peninsula Norilsk Chelyabinsk (pH 3.4 - 3.1) Krasnoyarsk (pH 4.9 - 3.80) Kazan (4.8 - 3.3) St. Petersburg ( pH 4.8 - 3.7)
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Slide text: Specific feature of acid rains Transboundary nature, due to the transfer of acid-forming emissions by air currents over hundreds and thousands of kilometers. “The policy of high pipes” is a remedy against ground air pollution (the pipe of the Ekibastuz State District Power Plant-1 is 330 m high) Almost all countries simultaneously act as exporters of their own and importers of other people’s emissions.
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Slide text: Impact of acid rain on ecosystems
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Slide text: Damage caused by acid rain to nature Acidification of lakes in the world. In hundreds of lakes in Scandinavia, fish have disappeared for this reason. Acid rain promotes better solubility of dangerous metals such as aluminum, cadmium, mercury, lead from soils and bottom sediments, and this leads to illnesses for people who drink this water. Plants on land are also affected by acid rain. Exposure to acid rain reduces the resistance of forests to droughts, diseases, and natural pollution.
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Slide text: Measures to protect the atmosphere from acid-forming emissions Creation of treatment facilities and legal protection of the atmosphere. Liming of reservoirs and forests To protect cultural monuments, coatings made of silicones or derivatives of silicic acid esters are used. Replacing gasoline in cars with a mixture of alcohols. Use environmentally friendly energy resources (solar energy, wind, sea tides).
Presentation on the topic: Acid rain - current environmental problem
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The first mention of acid rain dates back to the middle of the 19th century. In 1872, the attention of English explorer Angus Smith was drawn to Victorian smog in Manchester. However, the global danger of the phenomenon was realized only in the 60s. XX century Scandinavian countries, Canada, the USA, Western Europe, etc. suffered from acid rain. Therefore, this problem was raised by Switzerland at the UN Conference on the Environment (Stockholm, 1972).
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Sources of acid-forming emissions Natural sources supply sulfur and nitrogen to the atmosphere (cycles in the biosphere, volcanic activity, etc.). However, anthropogenic factors play a major role. Emissions of these compounds from economic activity(fossil fuel power plants, metallurgical enterprises, etc.) amount to 255 million tons. In Europe alone, sulfur dioxide emissions in some years reach 20-40 million tons. In Russia, stationary sources released more than 7 million tons of acid-forming substances into the atmosphere. As a result of transboundary transfer, about 2 million tons of oxidized sulfur and nitrogen compounds entered the European part of the country.
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Sources of acid-forming emissions Solid fuel rockets Shuttle, Proton and Energia make a certain contribution to the formation of acid precipitation. Acid traces are formed from the combustion products of rocket fuel, consisting of particles of hydrogen chloride, nitrogen oxide, aluminum oxide, etc. Thus, during one launch of the Shuttle rocket complex, 225 tons of hydrogen chloride, about 88 tons of nitrogen oxides, and 310 tons of aluminum oxide enter the atmosphere.
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Formation of acid rain. Sulfur dioxide released into the atmosphere undergoes a series of chemical transformations leading to the formation of acids. Partially, sulfur dioxide as a result of photochemical oxidation is converted into sulfur oxide (VI) (sulfuric anhydride) SO3: 2 SO2 + O2 ↔ 2 SO3, which reacts with atmospheric water vapor, forming aerosols of sulfuric acid: SO3 + H2O → H2 SO4H2SO4 ↔ H+ + HSO4 -The main part of the emitted sulfur dioxide in humid air forms acidic polyhydrate SO2 nH2O, which is often called sulfurous acid H2 SO3:SO2 + H2O → H2 SO3H2SO3 ↔ H+ + HSO3 -Sulfurous acid in humid air is gradually oxidized to sulfuric acid: 2H2 SO3 + O2 → 2 H2 SO4 Aerosols of sulfuric and sulfurous acids condense in atmospheric water vapor and cause acid precipitation. They make up about 2/3 of acid precipitation. The rest is accounted for by aerosols of nitric and nitrous acids formed during the interaction of nitrogen dioxide with atmospheric water vapor: 2NO2 + H2O→ HNO3 + HNO2 HNO3 ↔ H+ +NO3-HNO2 ↔ H+ +NO2-
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Negative ecological and biological consequences of acid rain: Deterioration of atmospheric visibility Acidification of freshwater bodies and reduction of fish stocks Acidification of soils and reduction of their fertility Damage and death of forest formations Destruction of certain animal species Acceleration of corrosion of bridges, dams, metal structures Harm to human health Acceleration of destruction of world architectural monuments
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Acidification of lakes Freshwater lakes in Canada, the USA, Sweden, Norway, Finland, Russia and other countries have suffered from acid precipitation. Thus, in Canada, more than 14,000 lakes are acidified, in the eastern part of the USA - about 9,000, in Sweden - more than 6,500 reservoirs, in Norway - 5,000. In Russia, the lakes of Karelia and the Kola Peninsula were especially affected by acid precipitation. On the Kola Peninsula, 37% of the surveyed lakes are highly acidified, and about 30% of water bodies are at risk of acidification. In many lake ecosystems, an increase in water acidity (a decrease in pH value) has led to the degradation of fish populations and other aquatic organisms.
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Soil acidification Acid rain has a negative impact on soils: - Reduces soil fertility. At a pH value less than 5.0, a progressive decrease in their fertility begins, and at pH = 3, they become practically infertile. - Reduce the rate of decomposition of organic matter. Most bacteria and fungi prefer a neutral environment. At pH = 6.2, the number of bacteria in 1 g of soil is 13.6 x 106, and at pH = 4.8 - 4 x 106. - They wash out many nutrients from the soil. This leads to a decrease in the yield of agricultural crops (cotton, tomatoes, grapes, citrus fruits, etc.) by an average of 20-30%. Russia, which has more than 50 million hectares of acidified soils, annually loses agricultural yields in the amount of 16-18 million . tons in terms of grain.
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Impact on forest formations Due to precipitation: - plant growth has decreased and natural reforestation has deteriorated; - plant resistance to drought, frost and salinity has decreased; - the processes of transpiration, respiration and photosynthesis were disrupted. An increase in the area of damaged and dead forests was noted in Europe: in 1860 they occupied about 1000 hectares, now - over 50 million hectares. In Russia, outbreaks of pests and diseases annually cover up to 4 million hectares of forest formations. In Sweden, Spain, Austria, the share of degraded forests is 22-39%, in the Czech Republic, Slovakia, Greece, Great Britain, Norway - it reaches 49-71% of the total forest area. IN Western Europe especially suffer from acidification conifers(Norway spruce). The supply of sulfur and nitrogen compounds changes the chemical composition of soils and the nutritional regime of plants. Violation of the diet leads to discoloration and drying out of conifers. This process affected not only coniferous species, but also broad-leaved formations (oak, beech, sycamore, hickory, etc.).
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Harm to human health Aerosol particles from acid deposition pose a particular danger to human health. Large particles are retained in the upper respiratory tract. Small (less than 2 microns) droplets, consisting of a mixture of sulfuric and nitric acids, penetrate into the most remote areas of the lungs. With these aerosols, carcinogenic heavy metals (mercury, cadmium, lead) can enter the body. Thus, during the tragic London fog of 1952, more than 4,000 deaths were attributed to the increased content of sulfur oxides and sulfate particles in the humid air. In acidified lakes of the USA, Norway, and Finland, high concentrations of mercury in fish tissues were noted. The harm that eating such fish causes to the body is obvious; when consumed, it causes various diseases contaminated with acids (Minamata disease) in people. precipitation of water.
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Damage to world architectural monuments Due to acid precipitation, the Colosseum and St. Peter's Cathedral in Rome, St. Mark's Cathedral in Venice, Delphi (the sanctuary of Apollo), temples and tombs in industrial areas of Japan, etc. are destroyed. The huge stone obelisk of Cleopatra, transported from Egypt to Great Britain, suffered more severe damage due to acid precipitation during its 85 years in London than in 3,000 years in Alexandria. The leader in the impact of acid rain on buildings and architectural structures in Western Europe is Manchester, where in 20 months. acid precipitation dissolved more than 120 g of stone (sandstone, marble, limestone) from 1 m2 of structures. Next come Antwerp (Netherlands) - losses of more than 100 g/m2 - and cities such as Athens, Amsterdam, Copenhagen, where acid rain dissolved 20-40 g of stone from every 1 m2 of construction. (According to the University of Dublin (Ireland)
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Today, no one doubts that acid rain is one of the causes of the death of life in water bodies, forests, crops, and vegetation. In addition, acid rain destroys buildings and cultural monuments, pipelines, renders cars unusable, reduces soil fertility and can lead to toxic metals seeping into aquifers.
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Acid precipitation
causes and consequences
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Acid precipitation is precipitation whose acidity is higher than normal. A measure of acidity is the pH value (hydrogen value). The pH value scale goes from 0 (extremely high acidity), through 7 (neutral environment, i.e. pure water) to 14 (alkaline environment). The lower the pH value, the higher the acidity. If the acidity of the water is below 5.5, then the precipitation is considered acidic. Over vast areas of the industrialized countries of the world, precipitation falls, the acidity of which exceeds normal by 10 - 1000 times (pH = 5-2.5). The term “acid rain” was first introduced in 1872 by the English scientist Robert Smith in his book Air and Rain: The Beginning of Chemical Climatology. The smog in Manchester caught his attention.
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Causes
Even normal rainwater is slightly acidic due to the presence of carbon dioxide in the air. And acid rain is formed as a result of a reaction between water and pollutants such as sulfur oxide and various nitrogen oxides. These substances are emitted into the atmosphere by road transport, as a result of the activities of metallurgical enterprises and thermal power plants. Combining with atmospheric water, they turn into solutions of acids - sulfuric, sulfurous, nitrous and nitric. Then, along with snow or rain, they fall to the ground.
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Consequences
The consequences of acid rain are observed in the USA, Germany, the Czech Republic, Slovakia, the Netherlands, Switzerland, Australia, the republics of the former Yugoslavia and many other countries around the globe. Death of reservoirs and aquatic inhabitants; Forest degradation; Soil erosion; Release of Al, Hg and Cu from rocks and minerals.
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Measures to prevent acid precipitation
To combat acid rain, efforts must be directed toward reducing emissions of acid-forming substances from coal-fired power plants. And for this it is necessary: the use of low-sulfur coal or its removal of sulfur; installation of filters for purification of gaseous products; use of alternative energy sources.
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The ancient buildings of the Acropolis in Athens suffered more from air pollution during the period from 1960 to 1980 than in the previous two and a half millennia. What explains this? City of El Tajin (Mexico) 6th century BC. Ancient temples of Greece
For the same reason, several years ago, all original marble statues, which are works of art, were removed from the Summer Garden in St. Petersburg and replaced with copies.
Acid rain
Key Questions 1. What is “acid rain”? 2. How does human activity affect the formation of “acid rain”? Main sources of pollution. 3. What effect does acid rain have on the environment? 4. Can humans prevent air pollution?
Scheme of formation of “acid rain”
The main sources of air pollution are oil refineries, chemical plants, metallurgical plants, thermal power plants, road transport, textile and food factories.
How acids are formed SO2 + H2O = H2SO3 2 SO2 + O2 = 2 SO3 SO3 + H2O = H2SO4 4NO2 + O2 + 2 H2O = 4HNO3
Experimental results Reagents Water Liquid from the flask Violet flowers No changes Color change Chalk or marble No changes Intense gas release Magnesium Very weak gas release Intense gas release
How you can prevent air pollution Installing purification devices Replacing high-sulfate fuels Controlling automobile emissions Using environmentally friendly fuels
Conclusions Acid rain is the result of air pollution Acid rain destroys not only buildings and cultural monuments, but also destroys all living things Preventing acid rain is the work of man
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