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Air Pollution

Air Pollution. Chapter 18. Core Case Study: South Asia’s Massive Brown Cloud. Asian Brown Cloud Causes Chemical composition Areas impacted Air pollution connects the world Steps taken in China and India to reduce air pollution. The Asian Brown Cloud.

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Air Pollution

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  1. Air Pollution Chapter 18

  2. Core Case Study: South Asia’s Massive Brown Cloud • Asian Brown Cloud • Causes • Chemical composition • Areas impacted • Air pollution connects the world • Steps taken in China and India to reduce air pollution

  3. The Asian Brown Cloud

  4. Air Pollution in Shanghai, China, in 2004

  5. 18-1 What Is the Nature of the Atmosphere? • Concept 18-1 The atmosphere is structured in layers, including the troposphere, which supports life, and the stratosphere, which contains the protective ozone layer.

  6. The Atmosphere Consists of Several Layers • Atmosphere varies in • Density • Atmospheric pressure

  7. Air Movements in the Troposphere Play a Key Role in Earth’s Weather and Climate • Troposphere • 75–80% of the earth’s air mass • Closet to the earth's surface • Chemical composition of air • Rising and falling air currents: weather and climate • Involved in chemical cycling

  8. The Stratosphere Is Our Global Sunscreen • Stratosphere • Similar composition to the troposphere, with 2 exceptions • Much less water • O3, ozone layer, filters UV • Location

  9. Atmospheric pressure (millibars) 1,000 200 0 400 600 800 120 75 Temperature 110 65 Thermosphere 100 90 55 Mesopause 80 Mesosphere 45 70 Altitude (kilometers) Altitude (miles) 60 Stratopause 35 50 Stratosphere 40 25 30 Tropopause 15 Ozone layer 20 10 Pressure Troposphere 5 (Sea level) 0 Pressure = 1,000 millibars at ground level –80 80 40 120 –40 0 Temperature (˚C) Fig. 18-3, p. 470

  10. 18-2 What Are the Major Outdoor Pollution Problems? • Concept 18-2 Pollutants mix in the air to form industrial smog, mostly the result of burning coal, and photochemical smog, caused by motor vehicle, industrial, and power plant emissions.

  11. Air Pollution Comes from Natural and Human Sources (1) • Air pollution • Natural sources • Dust blown by wind • Pollutants from wildfires and volcanoes • Volatile organics released by plants • Withdrawing groundwater

  12. Case Study: Air Pollution in the Past: The Bad Old Days (1) • Discovery of fire • Middle Ages • Industrial Revolution • London, England • 1850s • 1952: yellow fog • Clean Air Act of 1956

  13. Case Study: Air Pollution in the Past: The Bad Old Days (2) • United States • 1948: Donora, PA; first U.S. air pollution disaster • 1963: New York City • Global problem

  14. Some Pollutants in the Atmosphere Combine to Form Other Pollutants • Primary pollutants • Secondary pollutants • Air quality improving in developed countries • Much more needs to be done in developing countries • Indoor pollution: big threat to the poor

  15. Primary Pollutants Secondary Pollutants CO CO2 SO2 NO NO2 SO3 Most hydrocarbons HNO3 H2SO4 Most suspended particles H2O2 O3 PANs Most NO3− and SO42− salts Sources Natural Stationary Mobile Fig. 18-4, p. 472

  16. What Are the Major Outdoor Air Pollutants? (1) • Carbon oxides • Carbon monoxide (CO) • Carbon dioxide (CO2) • Sources • Human health and environmental impact

  17. What Are the Major Outdoor Air Pollutants? (2) • Nitrogen oxides (NO) and nitric acid (HNO3) • Sources • Acid deposition • Photochemical smog • Human health and environmental impact • Sulfur dioxide (SO2) and sulfuric acid (H2SO4) • Sources • Human health and environmental impact

  18. What Are the Major Outdoor Air Pollutants? (3) • Particulates • Suspended particulate matter (SPM) • Fine • Ultrafine • Sources • Human health and environmental impact

  19. What Are the Major Outdoor Air Pollutants? (4) • Ozone (O3) • Sources • Human and environmental impact • Volatile organic compounds (VOCs) • Hydrocarbons and terpenes • Sources • Human and environmental impact

  20. Chemical Reactions That Form Major Outdoor Air Pollutants

  21. Stepped Art Table 18-1, p. 473

  22. Statue Corroded by Acid Deposition and Other Forms of Air Pollution, RI, U.S.

  23. Science Focus: Detecting Air Pollutants • Chemical instruments • Satellites • Nanotechnology • Biological indicators • Lichens

  24. Natural Capital: Lichen Species, Vulnerability to Air Pollutants

  25. Case Study: Lead Is a Highly Toxic Pollutant (1) • Does not break down in the environment • Sources • Human health and environmental impact • Most vulnerable

  26. Case Study: Lead Is a Highly Toxic Pollutant (2) • Reduction of lead (Pb) • Unleaded gasoline • Unleaded paint • Still problems • 2007: toys with Pb paint recalled • Global ban on lead in gasoline and paint

  27. SOLUTIONS Lead Poisoning Prevention Control Replace lead pipes and plumbing fixtures containing lead solder Phase out leaded gasoline worldwide Phase out waste incineration Remove leaded paint and lead dust from older houses and apartments Ban use of lead solder Sharply reduce lead emissions from incinerators Ban use of lead in computer and TV monitors Remove lead from TV sets and computer monitors before incineration or land disposal Ban lead glazing for ceramicware used to serve food Test for lead in existing ceramicware used to serve food Ban candles with lead cores Test existing candles for lead Test blood for lead by age 1 Wash fresh fruits and vegetables Fig. 18-7, p. 476

  28. Burning Coal Produces Industrial Smog • Chemical composition of industrial smog • Reduction of this smog in urban cities of the United States • China and smog • Human deaths

  29. Ammonium sulfate [(NH4)2SO4] Ammonia (NH3) Sulfuric acid (H2SO4) Carbon monoxide (CO) and carbon dioxide (CO2) Water vapor (H2O) Sulfur trioxide (SO 3 ) Oxygen (O2) Sulfur dioxide (SO2) Burning coal and oil Oxygen (O2) Carbon (C) in coal and oil Sulfur (S) in coal and oil Stepped Art Fig. 18-8, p. 476

  30. Sunlight Plus Cars Equals Photochemical Smog • Photochemical Smog • Chemical composition • Sources • VOCs + NO2 + Heat + Sunlight yields • Ground level O3 and other photochemical oxidants • Aldehydes • Other secondary pollutants • Human health and environmental impact

  31. PANS and other pollutants Volatile organic compounds (VOCs) Ozone (O3) Oxygen (O2) Nitric oxide (NO) + Oxygen atom (O) Water vapor (H2O) Hydrocarbons UV radiation Peroxyacyl nitrates (PANs) Nitrogen dioxide (NO2) Oxygen (O2) Nitric oxide (NO) Oxygen (O2) Burning fossil fuels Nitrogen (N) in fossil fuel Fig. 18-9, p. 477

  32. Global Outlook: Photochemical Smog in Santiago, Chile

  33. Denver’s Brown Cloud: http://www.infrastructurist.com/wp-content/uploads/brown-cloud.jpg

  34. Several Factors Can Decrease or Increase Outdoor Air Pollution (1) • Outdoor air pollution may be decreased by • Settling of particles due to gravity • Rain and snow • Salty sea spray from the ocean • Winds • Chemical reactions

  35. Several Factors Can Decrease or Increase Outdoor Air Pollution (2) • Outdoor air pollution may be increased by • Urban buildings • Hills and mountains • High temperatures • Emissions of VOCs from certain trees and plants • Grasshopper effect • Temperature inversions

  36. Descending warm air mass Warmer air Inversion layer Inversion layer Sea breeze Increasing altitude Decreasing temperature Fig. 18-11, p. 478

  37. 18-3 What Is Acid Deposition and Why Is It a Problem? • Concept 18-3 Acid deposition is caused mainly by coal-burning power plant and motor vehicle emissions, and in some regions, threatens human health, aquatic life and ecosystems, forests, and human-built structures.

  38. Acid Disposition Is a Serious Regional Air Pollution Problem • Acid deposition, acid rain • Formation • Local versus regional problems • Effects of prevailing winds • Buffers • Where is the worst acid deposition?

  39. Wind Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3) Windborne ammonia gas and some soil particles partially neutralize acids and form dry sulfate and nitrate salts Wet acid depostion (droplets of H2SO4 and HNO3 dissolved in rain and snow) Nitric oxide (NO) Sulfur dioxide (SO2) and NO Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Acid fog Lakes in shallow soil low in limestone become acidic Lakes in deep soil high in limestone are buffered Fig. 18-12, p. 479

  40. Potential problem areas because of sensitive soils Potential problem areas because of air pollution: emissions leading to acid deposition Current problem areas (including lakes and rivers) Fig. 18-13, p. 480

  41. Acid Deposition Has a Number of Harmful Effects (1) • Human respiratory disorders • Aquatic ecosystems affected • Release of toxic metals

  42. Acid Deposition Has a Number of Harmful Effects (2) • Leaching of soil nutrients • Loss of crops and trees • Damage to buildings, statues, and monuments

  43. Emissions NOx SO2 H2O2 PANs Acid deposition O3 Others Increased susceptibility to drought, extreme cold, insects, mosses, and disease organisms Direct damage to leaves and bark Reduced photosynthesis and growth Tree death Soil acidification Release of toxic metal ions Leaching of soil nutrients Reduced nutrient and water uptake Root damage Acids Lake Groundwater Fig. 18-14a, p. 481

  44. Science Focus: Hubbard Brook Study Effects of Acid Rain • White Mountains, NH, U.S. • Experimentation supports: • Trees do not suffer from direct contact with acid rain • Nutrients are leached out of the soil • Effect of Ca2+ on regrowth of the forest

  45. We Know How to Reduce Acid Deposition • Prevention approaches • Clean up • Add lime to neutralize acidified lakes and soil • Add phosphate fertilizer to neutralize acidified lakes

  46. SOLUTIONS Acid Deposition Prevention Cleanup Reduce coal use Add lime to neutralize acidified lakes Burn low-sulfur coal Increase natural gas use Add phosphate fertilizer to neutralize acidified lakes Increase use of renewable energy resources Remove SO2 particulates and NOx from smokestack gases Remove NOx from motor vehicular exhaust Tax emissions of SO2 Reduce air pollution by improving energy efficiency Fig. 18-15, p. 483

  47. Indoor Air Pollution

  48. 18-4 What Are the Major Indoor Air Pollution Problems? • Concept 18-4 The most threatening indoor air pollutants are smoke and soot from wood and coal cooking fires (a hazard found mostly in developing countries) and chemicals used in building materials and products.

  49. Indoor Air Pollution Is a Serious Problem (1) • Developing countries • Indoor burning • Poor suffer the greatest risk • Developed countries • Indoor air pollution is greater than outdoor air pollution

  50. Indoor Air Pollution Is a Serious Problem (2) • Why? • 11 of the common air pollutants higher inside than outside • Greater in vehicles than outside • Health risks magnified: people spend 70–98% of their time is indoors

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