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Air Pollution

Air Pollution. Chapter 19. Essential Question #1. What layers are found in the atmosphere and what are their altitudes?. The 4 Atmosphere Layers. Troposphere* Stratosphere* Mesosphere Thermosphere. Atmosphere Altitudes. Troposphere* 11 miles (17 km) above sea level Stratosphere*

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Air Pollution

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  1. Air Pollution Chapter 19

  2. Essential Question #1 What layers are found in the atmosphere and what are their altitudes?

  3. The 4 Atmosphere Layers • Troposphere* • Stratosphere* • Mesosphere • Thermosphere

  4. Atmosphere Altitudes • Troposphere* • 11 miles (17 km) above sea level • Stratosphere* • 11-30 miles (17-48 km) • Mesosphere • 30-50/53 miles (50-80/85 km) • Thermosphere • 50-311/621 miles (500-1000 km)

  5. Essential Question #2 What are the primary components of the troposphere and stratosphere?

  6. Troposphere • Closest to Earth • Responsible for weather & climate / chemical cycling • Temperature Decreases with Altitude (until the tropopause)

  7. Composition of Troposphere • 0.01 - 4% Water Vapor (H2O) • 0.93% Argon (Ar) • 0.038% Carbon Dioxide (CO2) • Trace amounts of Ozone, Methane, Nitrous Oxide, dust, soot, etc • 78% Nitrogen (N2) • 21% Oxygen (O2)

  8. Stratosphere • Similar composition to troposphere • Less H2O • Far more O3 • Temperature Increases with altitude • Ozone (O3) Layer

  9. Ozone Layer • 11-19 miles (17-30 km) • Filters 95% of UV light • UV light interacts with O2 in stratosphere producing ozone (O3) • Prevents oxygen in Troposphere from being converted into ozone (pollutant)

  10. Essential Question #3 What are the major outdoor air pollutants, where do they come from, and what are their impacts?

  11. Air Pollution High concentrations of chemicals in the troposphere that can harm organisms, ecosystems, materials, or alter the climate

  12. Outdoor Air Pollution • Natural Sources • Dust, forest fires, volcanoes, decay, VOC’s from some plants • Less harmful • Man-Made Sources • Industrial Revolution • Burning fossil fuels (coal, oil, gas, wood)

  13. Man-made Sources • Stationary sources • Mobile sources

  14. Outdoor Air Pollutant Categories • Primary Pollutants • Come directly from pollution source • Ex: soot, CO2, SO2, NO, etc • Secondary Pollutants • Primary pollutants react w/ other molecules to make new pollutants • Ex: O3, smog, acid rain components

  15. – 2 SO4 NO3 – Sources and Types of Air Pollutants Primary Pollutants CO CO2 Secondary Pollutants SO2 NO NO2 SO3 Most hydrocarbons HNO3 H2SO4 Most suspended particles H2O2 O3 PANs Most and salts Sources Natural Stationary Mobile Fig. 15-3, p. 348

  16. Carbon Oxides

  17. Nitrogen Oxides & Nitric Acid

  18. Sulfur Dioxide & Sulfuric Acid

  19. Particulates

  20. PM-10 / PM-2.5

  21. Ozone

  22. Volatile Organic Hydrocarbons (VOC’s)

  23. Radon

  24. Essential Question #4 What two types of smog, how are they formed, and what problems are associated with each?

  25. Industrial Smog(gray-air smog) • Develops from burning coal and oil that contain sulfur in factories • Common in industrialized countries with little pollution controls (China, Eastern Europe, India) • More common in winter months

  26. The Great London Fog • A period of cold weather, combined with anticyclone and windless conditions, collected airborne pollutants mostly from the use of coal to form a thick layer of smog over the city • December 5th-9th,1952 • Killed as many as 12,000 people!

  27. China’s Air-pocalypse • US Embassy in Beijing tweeted regular Air Quality Index (AQI) readings. • Reached as high as 750+

  28. Asian Brown Cloud

  29. Photochemical Smog(brown-air smog) • Develops from a reaction involving nitrogen oxides (NOx), VOCs, UV light, and heat • Generates Ozone, nitric acid, aldehydes, PAN’s & other secondary pollutants • More common in cities with many cars, sunny, warm and dry (Los Angeles / Atlanta)

  30. Factors Influencing Smog Formation Reduce Air Pollution • Rain & Snow • Salty Sea Spray • Winds • Gravity • Chemical Reactions Increase Air Pollution • Urban Buildings • Hills & Mountains • High Temperatures • promote chemical reactions • Grasshopper Effect • pollution rises & settles near poles • VOC Emissions • From certain plants (sweet gum, poplar, kudzu) • Temperature Inversions

  31. Temperature Inversion • A warm air mass that is resting on a cold air mass • Prevents pollutants from rising & dispersing • Seen in valleys surrounded by mountains & coastal cities surrounded by mountains (LA)

  32. Essential Question #5 What is acid deposition, what are the harmful effects of it, and how can it be reduced?

  33. Acid Deposition • Mixture of: • Wet Deposition • precipitation with a pH under 5.6 • Dry Deposition • acidic particles – mostly nitrate & sulfate • Natural precipitation has a pH of 5.6, so anything lower is considered acid rain

  34. Regional Problem • Usually a regional problem in areas downwind of a coal plant or big city.

  35. Current and Potential Problems with Acid Deposition 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. 15-8, p. 355

  36. Causes & Harmful Effects • Causes: • Burning Coal  SO2 and NO • Burning Gasoline  NO • Chemicals react with H20 vapor forming acid deposition • Harmful Effects: • Respiratory problems • Damages metal & stone objects • Reduces visibility • Kills aquatic plants & animals • Harms forests & crops • Leaches nutrients from soil

  37. Reducing Acid Deposition • Improve energy efficiency (less pollution) • Use less coal • Use renewable energy (solar, wind) • Remove SO2 and NO from exhaust of cars and factories • Tax pollution • Add limestone to affected lakes to neutralize the acid

  38. Solutions Acid Deposition Prevention Cleanup Reduce air pollution by improving energy efficiency Add lime to neutralize acidified lakes Reduce coal use Add phosphate fertilizer to neutralize acidified lakes Increase natural gas use Increase use of renewable energy resources Burn low-sulfur coal Remove SO2 particulates & NOx from smokestack gases Remove NOx from motor vehicular exhaust Tax emissions of SO2 Fig. 19-10, p. 452

  39. Essential Question #6 What are some common indoor air pollutants and how can indoor air pollution pose a greater threat to human health than outdoor air pollution?

  40. Indoor Air Pollution • Pollutants often at higher concentrations indoors • Usually poses much greater human health risk • especially in developing countries • indoor burning of wood, coal, and charcoal in poorly ventilated homes

  41. Para-dichlorobenzene Chloroform Tetrachloroethylene Formaldehyde 1, 1, 1- Trichloroethane Styrene Nitrogen Oxides Benzo-a-pyrene Particulates Tobacco Smoke Radon-222 Asbestos Carbon Monoxide Methylene Chloride Fig. 19-11, p. 453

  42. 4 Most Dangerous Indoor Air Pollutants (Developed Countries) • Tobacco smoke • Formaldehyde • Used in manufacturing furniture, building materials, etc • Radon • Seeps into homes from soil & rocks below • Very fine particles

  43. Sick Building Syndrome • Describes situations in which building occupants experience acute health & comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. • Causes: • Inadequate ventilation • Indoor chemical contaminants • Chemical contaminants from outdoor sources • Biological contaminants

  44. EPA Headquarters • 1st official recorded incident of “sick building syndrome” in 1988 after new carpet installation.

  45. Essential Question #7 What are the harmful effects of air pollutants?

  46. General Effects of Pollution

  47. Harmful Effects • Respiratory diseases such as: • asthma • lung cancer • chronic bronchitis • emphysema

  48. Damage of Particulate Pollution

  49. Developing vs. Developed • Developing countries problems are from indoor pollution caused by cooking and heating • Developed countries problems come from coal-burning power plants & industry

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