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Acid Rain: The Problem Continues

Acid Rain: The Problem Continues. Contents. Definition Causes Formation Affected Areas Effects Preventive Measures. What Ever Happened to Acid Rain?. In the 1980’s, acid rain received a lot of media attention.

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Acid Rain: The Problem Continues

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  1. Acid Rain: The Problem Continues

  2. Contents • Definition • Causes • Formation • Affected Areas • Effects • Preventive Measures

  3. What Ever Happened to Acid Rain? • In the 1980’s, acid rain received a lot of media attention. • Although we don’t hear about acid rain as much these days, it is still a problem that deserves our attention. • Fortunately, acid rain is a problem that we can all help to solve.

  4. Definition of Acid Rain • Precipitation that has a pH of less than that of natural rainwater (which is about 5.6 due to dissolved carbon dioxide). • It is formed when sulphur dioxides and nitrogen oxides, as gases or fine particles in the atmosphere, combine with water vapour and precipitate as sulphuric acid or nitric acid in rain, snow, or fog.

  5. What is Acid Rain? How Does it Form? • “Acid rain” includes both wet and dry acidic deposits • Precipitation with a pH lower than 5.6 is considered acidic • Acid rain originates from sulfur dioxide and nitrogen oxide particles • Once these particles are emitted into the air they form sulfate and nitrate particles • These particles can travel long distances on wind currents • By combining with water vapor, these particles form acids which fall to the earth as acid rain.

  6. Where do Sulfur Dioxide (SO2) and Nitrogen Oxide (NOx) Particles Come From? • Sulfur dioxide and nitrogen dioxide particles are emitted from utility plants, especially coal-fed electric plants • Automobiles also emit acid rain causing pollution

  7. Causes of Acid Rain • Natural Sources • Emissions from volcanoes and from biological processes that occur on the land, in wetlands, and in the oceans contribute acid-producing gases to the atmosphere • Effects of acidic deposits have been detected in glacial ice thousands of years old in remote parts of the globe

  8. Causes of Acid Rain • The principal cause of acid rain is from human sources • Industrial factories, power-generating plants and vehicles • Sulphur dioxide and oxides of nitrogen are released during the fuel burning process (i.e. combustion)

  9. Formation of Acid Rain

  10. Formation of Acid Rain • When water vapour condenses, or as the rain falls, they dissolve in the water to form sulphuric acid (H2SO4) and nitric acid (HNO3). • While the air in cleaned of the pollutants in this way, it also causes precipitation to become acidic, forming acid rain

  11. Effects of Acid Rain • Harmful to vegetation • Increased acidity in soil • Leeches nutrients from soil, slowing plant growth • Leeches toxins from soil, poisoning plants • Creates brown spots in leaves of trees, impeding photosynthesis • Allows organisms to infect through broken leaves

  12. Effects of Acid Rain

  13. Effects of Acid Rain • Harmful to aquatic life • Increased acidity in water bodies • Stops eggs of certain organisms (e.g. fish) to stop hatching • Changes population ratios • Affects the ecosystem

  14. Lakes are also damaged by acid rain. Fish die off, and that removes the main source of food for birds. Acid rain can even kill fish before they are born when the eggs are laid and come into contact with the acid. Fish usually die only when the acid level of a lake is high; when the acid level is lower, they can become sick, suffer stunted growth, or lose their ability to reproduce. Also, birds can die from eating "toxic" fish and insects.

  15. Effects of Acid Rain • Affects human health • Respiratory problems, asthma, dry coughs, headaches and throat irritations • Leeching of toxins from the soil by acid rain can be absorbed by plants and animals. When consumed, these toxins affect humans severely. • Brain damage, kidney problems, and Alzheimer's disease has been linked to people eating "toxic" animals/plants.

  16. Buildings Acid rain dissolves the stonework and mortar of buildings (especially those made out of sandstone or limestone). It reacts with the minerals in the stone to form a powdery substance that can be washed away by rain.

  17. Transport Currently, both the railway industry and the aeroplane industry are having to spend a lot of money to repair the corrosive damage done by acid rain. Also, bridges have collapsed in the past due to acid rain corrosion.

  18. Affected Areas • Canada • Acid rain is a problem in Canada • Water and soil systems lack natural alkalinity such as lime base • Cannot neutralize acid • Canada consists of susceptible hard rock such as granite • Do not have the capacity to effectively neutralize acid rain

  19. Affected Areas • Industrial acid rain is a substantial problem in China, Eastern Europe and Russia and areas down-wind from them. • Acid rain from power plants in the Midwest United States has also harmed the forests of upstate New York and New England. • This shows that the effects of acid rain can spread over a large area, far from the source of the pollution

  20. Research carried out in North America in 1982, revealed that sulphur pollution killed 51,000 people and about 200,000 people become ill as a result of the pollution.

  21. More problems!!! • Acid rain can travel long distances. • Often it doesn’t fall where the gas is produced. High chimneys disperse (spread) the gases and winds blow them great distances before they dissolve and fall to Earth as rain. • Eg gases produced in England and Western Europe can result in acid rain in Scotland and Scandinavia.

  22. What else needs to be done about Acid Rain ? • In 1990, an amendment to the Clean Air Act called for reductions in sulfur emissions • This proved to be less effective than hoped, as acid rain still persists today • This is largely due to 2 reasons: • 1) reductions in sulfur emissions were not great enough and • 2) there were no reductions in nitrogen emissions which are also implicated in forming acid rain

  23. Preventive Measures • Flue Gas Desulphurisation (FGD) • Removes sulphur dioxide from flue gas (waste gases) • Consists of a wet scrubber and a reaction tower equipped with a fan that extracts hot smoky stack gases from a power plant into the tower • Lime or limestone (calcium carbonate) in slurry form is injected into the tower to mix with the stack gases and reacts with the sulphur dioxide present

  24. Preventive Measures • (continued) • Produces pH-neutral calcium sulphate that is physically removed from the scrubber • Sulphates can be used for industrial purposes Scrubber at work MSN Encarta

  25. Preventive Measures • Use other sources of electricity (i.e. nuclear power, hydro-electricity, wind energy, geothermal energy, and solar energy) • Issue of cost

  26. Reducing the effects of Acid Rain • Liming • Powdered limestone/limewater added to water and soil to neutralize acid • Used extensively in Norway and Sweden • Expensive, short-term remedy

  27. Can We Do Anything About Acid Rain? • YES! We can all take small actions to help solve the problem • We can help by: • using our cars less • conserving electricity • choosing electricity providers that emit lower amounts of air pollution emissions

  28. Bibliography • http://en.wikipedia.org/wiki/Acid_rain

  29. Thank You M. Panigrahy G.M.I.S.,Jakarta

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