1. Air Pollution
Chapter 18

2. The Asian Brown Cloud

3. Air Pollution in Shanghai, China, in 2004

4. The Atmosphere Consists of Several Layers
Atmosphere varies in
Density
Atmospheric pressure
Force, or mass, per unit area of a column of air

5. Air Movements in the Troposphere Play a Key Role in Earth’s Weather and Climate
75–80% of the earth’s air mass
Surface to 17 kilometers up
Closet to the earth's surface
Chemical composition of air
99% is nitrogen (78%) and oxygen (21%)
Rising and falling air currents: weather and climate
Involved in chemical cycling

6. The Stratosphere Is Our Global Sunscreen
Similar composition to the troposphere, with 2 exceptions
Much less water
O3, ozone layer, filters UV
Location
17 to 48 kilometers up

7. Natural Capital: The Earth’s Atmosphere Is a Dynamic System with Four Layers

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

9. Air Pollution Comes from Natural and Human Sources (2)
Human sources: mostly in industrialized and/or urban areas
Stationary sources
Power and industrial plants
Mobile sources
Motor vehicles

10. 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

11. Some Pollutants in the Atmosphere Combine to Form Other Pollutants
Primary pollutants
Are harmful chemicals emitted directly into the air from natural processes and human activities
Secondary pollutants
When a primary pollutant reacts with normal air components
Air quality improving in developed countries
Much more needs to be done in developing countries
Indoor pollution: big threat to the poor

12. Sources and Types of Air Pollutants

13. Indoor Air Pollution

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

15. 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)

16. What Are the Major Outdoor Air Pollutants? (3)
Particulates
Suspended particulate matter (SPM)
Consists of a variety of solid particles and liquid droplets small and light enough to remain suspended in the air for long periods
Fine
Most harmful
Less than 10 micrometers
Ultrafine
Diameter less than 2.5 micrometers
Sources
Dust, wild fires, sea salt
Coal-burning power and industrial plants, motor vehicles, plowed fields, road construction, unpaved roads, tobacco smoke
Human health and environmental impact
Mutations, reproductive problems, cancer
60,000 to 70,000 premature deaths a year

17. What Are the Major Outdoor Air Pollutants? (4)
Ozone (O3)
Sources
Human and environmental impact
Coughing, breathing problems, aggravate lung and heart diseases
Volatile organic compounds (VOCs)
Hydrocarbons and terpenes
Plants, wetlands, termites
Rice paddies, landfills, oil and natural gas wells, and cows
Leukemia, blood disorders

18. Chemical Reactions That Form Major Outdoor Air Pollutants

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

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

21. Burning Coal Produces Industrial Smog
Chemical composition of industrial smog
Sulfur dioxide, suspended droplets of sulfuric acid, and solid particles
Reduction of this smog in urban cities of the United States
Large boilers with good pollution control
Tall smokestacks
China and smog
Human deaths (358,000 per year)

22. How Pollutants Are Formed from Burning Coal and Oil, Leading to Industrial Smog

23. Sunlight Plus Cars Equals Photochemical Smog
Chemical composition
Mixture of primary and secondary pollutants formed under UV radiation
Sources
Commuter vehicles releasing NO and VOCs
VOCs + NO2 + Heat + Sunlight yields
Ground level O3 and other photochemical oxidants
Aldehydes
Other secondary pollutants
Human health and environmental impact

24. A Model of How Pollutants That Make Up Photochemicals Are Formed

25. Global Outlook: Photochemical Smog in Santiago, Chile

26. 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

27. 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
Occurs when volatile air pollutants are transported by evaporation and winds from tropical and temperate areas through the atmosphere to the earth’s polar areas
Temperature inversions

28. A Temperature Inversion

29. Acid Disposition Is a Serious Regional Air Pollution Problem
Acid deposition, acid rain
Formation
Excessive amounts of nitrogen oxides and sulfur dioxide to the atmosphere
Local versus regional problems
Effects of prevailing winds
Buffers
Where is the worst acid deposition?

30. Natural Capital Degradation: Acid Deposition, Acid Rain

31. Current and Possible Future Acid Rain Problem Areas

32. Acid Deposition Has a Number of Harmful Effects (1)
Human respiratory disorders
Aquatic ecosystems affected
Release of toxic metals
Acid allows metals (lead and mercury) to leach out into lakes used as water supplies

33. Acid Deposition Has a Number of Harmful Effects (2)
Leaching of soil nutrients
Allows essential nutrients to leach out and harmful metals to take their place
Loss of crops and trees
Damage to buildings, statues, and monuments

34. Natural Capital Degradation: Air Pollution Damage to Trees in North Carolina, U.S.

35. 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

36. 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 indoors

37. Indoor Air Pollution Is a Serious Problem (3)
Who are at greatest risk from indoor air pollution?
Children under 5 and the elderly
Sick
Pregnant women
People with respiratory disorders or heart problems
Smokers
Factory workers

38. Indoor Air Pollution Is a Serious Problem (4)
Four most dangerous indoor air pollutants
Tobacco smoke
Formaldehyde
Radioactive radon-222 gas
Very small particles
Sources of these pollutants
Radon comes from radioactive decay of uranium, phosphate, granite, and shale
Human health risks

39. Indoor Air Pollution Is a Serious Problem (5)
Other possible indoor air pollutants
Pesticide residue
Pb particles
Living organisms and their excrements
E.g., Dust mites and cockroach droppings
Airborne spores of molds and mildews
Sick-building syndrome
Studies have linked various air pollutants found in buildings to a number of health effects

40. Some Important Indoor Air Pollutants

41. Science: Magnified View of a Household Dust Mite in a Dust Ball

42. Science: Sources and Paths of Entry for Indoor Radon-222 Gas

43. Your Body’s Natural Defenses against Air Pollution Can Be Overwhelmed
Respiratory system protection from air pollutants
Role of cilia, mucus, sneezing, and coughing
Effect of smoking and prolonged air pollution exposure
Chronic bronchitis
Emphysema

44. Air Pollution Is a Big Killer
3 Million deaths per year world-wide
Mostly in Asia
Main causes
EPA: proposed stricter emission standards for diesel-powered vehicles
Link between international trade and air pollution
Cargo ships and pollution

45. Premature Deaths from Air Pollution in the U.S.

46. Laws and Regulations Can Reduce Outdoor Air Pollution (1)
United States
Clean Air Acts: 1970, 1977, and 1990
Enforced by states and major cities
EPA
National ambient air quality standards (NAAQs) for 6 outdoor criteria pollutants
CO, NO, SO2, suspended particulate matter, ozone, and lead
Primary standards were set to protect human health
Secondary standards were set to prevent environmental and property damage
National emission standards for 188 hazardous air pollutants (HAPs)
Toxic Release Inventory (TRI)

47. Laws and Regulations Can Reduce Outdoor Air Pollution (2)
Good news in U.S.
Decrease in emissions
Use of low-sulfur diesel fuel
Cuts pollution
Developing countries
More air pollution
Still a major problem

48. Case Study: U.S. Air Pollution Laws Can Be Improved (1)
Rely on cleanup more than prevention of pollution
Raise fuel-efficiency for cars, SUVs, and light trucks
Far behind European Union, Japan, and China
Better regulation of emissions of motorcycles and two-cycle gasoline engines
Regulate air pollution for oceangoing ships in American ports

49. Case Study: U.S. Air Pollution Laws Can Be Improved (2)
Why are airports exempt from many regulations?
Regulate greenhouse gas emissions
Ultrafine particles are not regulated
Urban O3 levels too high

50. Case Study: U.S. Air Pollution Can Be Improved (3)
What about indoor air pollution?
Better enforcement of the Clean Air Acts
Local governments are not getting the federal funding required to enforce these regulations
Is intense pressure needed from citizens to make improvements?

51. We Can Use the Marketplace to Reduce Outdoor Air Pollution
Emission trading or cap-and-trade program
Mixed reactions to program
SO2 emissions down significantly
NO2 will be tried in the future

52. There Are Many Ways to Reduce Outdoor Air Pollution
1980 –2006
SO2 emissions from U.S. electric power plants decreased by 66%
NOx emissions by 41%
Particulate emissions by 28%
Older plants not governed by the same regulations
New cars have better emissions

53. Reducing Indoor Air Pollution Should Be a Priority
Greater threat to human health than outdoor pollution
What can be done?
Prevention
Cleanup

54. We Need to Put More Emphasis on Pollution Prevention
Output approaches
What can we do about the air pollutants we produce?
New shift to preventing outdoor and indoor pollution
Pressure from citizens