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Environment

Environment. Environment – “ Surroundings” Consists of Atmosphere, Lithosphere Hydrosphere Biosphere Atmosphere – Above earth – “ Gaseous Mantle” Mixture of Gases. POLLUTION.

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Environment

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  1. Environment • Environment – “ Surroundings” Consists of Atmosphere, Lithosphere Hydrosphere Biosphere • Atmosphere – Above earth – “ Gaseous Mantle” Mixture of Gases

  2. POLLUTION Any addition to air, water, soil or food that threatens the health, survival or activities of human or other living organisms

  3. What are pollutants?Any substance which causes pollution is called a pollutant. • Environmental Pollutants • The various principal pollutants which pollute our air, water, land are as follows : • Deposited matter – soot, smoke, tar, dust, grit etc. • Gases – Oxides of nitrogen (NO, NO2), sulphur (SO2), CO, halogens, • Acids droplets – sulphruric, acid nitric acid etc. • Fluorides • Metals – Mercury, lead, iron, zinc, nickel, tin, cadmium, • chromium • Agrochemicals – Biocides, and fertilizers. • Complex organic substances – Benzene, ether, benzpyrenes . • Photochemical oxidants – Photochemical smog, ozone, PAN, PBzN • Radioactive waste • Noise

  4. Major Environmental Pollutions Air Pollution Water Pollution Land Pollution/ Degradation

  5. Air Pollution • Global climate change – global warming • Ozone depletion • Acid rain • Urban air pollution - Noise pollution • Indoor air pollution

  6. Natural composition of the air GasVolume (%) • Oxygen 20.92 • Nitrogen 78.10 • Argon 0.9325 • Carbon dioxide 0.03 • Hydrogen 0.01 • Neon 0.0018 • Helium 0.0005 • Krypton 0.0001

  7. Sources of pollutants • Methane • Nitrogen compounds • CO2 • SO2 • CFC • O3, PAN, H2O2 • Radioactive substances • Suspended particles

  8. Sources of atmospheric CH4

  9. Atmospheric methane and nitrous oxide pollution

  10. Smoke • A suspension of fine solid particles (usually < 1 µm in diameter) in the air. • Due to incomplete combustion of a fuel. • The smoke from coal consists of carbon, oil  unburned hydrocarbons, silica, Al, Pb, sulphuric acid and organic compounds. • Smoke affects earth's energy budget by disrupting the flow of both incoming and outgoing radiation.

  11. Fog • A suspension of water droplets in the lower atmosphere which reduces visibility • It is caused by condensation when moist air is cooled below the dewpoint.

  12. Smog • A combination of smoke and fog which creates air pollution. • Originally applied to pollution containing acid smoke from burning coal (London smog 1952). • Used also to describe the photochemical pollution of cities such as Los Angeles.

  13. Photochemical smog/ oxidising smog • The hydrocarbons and oxides of nitrogen (NOx) undergo continuing chemical change by the energy from solar radiation. • A variety of toxic chemicals such as Ozone (O3), aldehydes and peroxyacetyl nitrate (PAN) are produced • reducing visibility, causing eye and skin irritation and plant damage. • Photochemical smog development is greatest in early afternoons.

  14. London smog or reducing smog • Heavy smog for 5 days - 4000 deaths • Peak SO2 concentration was 1.3 ppm and smoke 4 mg/M3 • SO2 H2SO4 vapours in the atmosphere • Because of exceptionally high concentrations of sulfur oxides and particulate matter industrial smog or sulfurous smog.

  15. London smog • Industrial smog is caused by combustion of fossil fuels (coals) in power plants, smelters etc. • Causes of deaths were bronchitis, pneumonia and allied respiratory troubles.

  16. Bhopal gas tragedy The poisonous gas, methyl isocyanate (MIC) leakage in the pesticide manufacturing plant of Union Carbide of India Ltd., (UCIL), Bhopal, Madhya Pradesh on December 3, 1984. 46 tons of MIC was released spreading to 40 km. Effects : About 65,000 people suffered from various disorders in eyes, lungs, stomach, heart, etc.

  17. Bhopal gas tragedy • The immediate symptom is bronchospasm which causes coughing, chest pain and abdominal pain. • Breathing troubles and eye ache and also cyanide generation in the body which ultimately turns fatal. • Nearly 3000 people died within a short span on time. 1600 domestic animals died, crop yields were reduced etc.

  18. This vapour was a highly toxic cloud of methyl isocyanate. • 2,000 died immediately • 3,00,000 were injured • 7,000 animals were injured, 1000 were killed.

  19. Darkening effect of TajMahal • Taj Mahal is a white marble stone mausoleum. • walls of Taj Mahal has become darkened and disfigured due to air pollution from nearby Mathura Oil refinery. • H2O + SO2  H2SO3 • SO2 + O2  SO3; SO3 + H2O  H2SO4. • The acid rain reacts with marble stone (CaCO3) to produce calcium sulphate, causing darkening and disfigurement.

  20. TCDD accident • TCDD accident at seveso, Italy (July, 1976). • Explosion in a chemical plant manufacturing herbicide 2, 4 5 trichlorophenoxy acetate. • A poisonous gas consisting of TCDD came out and engulfed the poisonous for man. • Building ground and soil were contaminated. • Skin diseases, liver troubles. 1% babies born after the accident were deformed and also premature.

  21. Chernobyl disaster Worst nuclear accident occurred at Chernobyl, Ukraine (USSR) on 28th April, 1986. Explosion from nuclear reaction

  22. Map of projected 2020 emissions by continent of SO2, NOx and NH3

  23. Effects of acid rain • Aquatic ecosystem drastically affected • Soil acidification • Toxic metals are made available • Damage the foliage of plants and weaken trees • Enhances UV radiation penetration • Causes lesions and burns in agricultural crops • Lower reproductive potential of animals and birds • Causes respiratory ailments in humans • Linked to Alzheimer’s disease • Damages monuments, metals

  24. Prevention of acid rain • Emission control technologies • Burn less high sulfur fossil fuel • Alternatives such as natural gas, wind or solar energy • Use of catalytic converter in vehicles • Energy efficient technologies

  25. Dust pollution World – 140 million t / year dust particle emission cement factories, cotton indudstries, thermal tations 200 kg cement production – 20-30 kg dust emission For 1 Mw electricity - 2.5 t Flyash emission up to 8-10 km deposition of dust particles Land, Plant, Man and Animal health affected

  26. Management of Air Pollution • Source Correction: • Collection of pollutants: • Cooling: • Treatment • Setting chambers • Cyclones • Bag filters • Wet collectors. • Electrostatic precipitators • Absorption • Incineration • Catalytic combustion • 5. Dispersion

  27. Let’s make this a cleaner world to live in

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