1. Air Pollution
Chapter 18

2. What Is the Nature of the Atmosphere?
The atmosphere is structured in layers, including the troposphere, which supports life, and the stratosphere, which contains the protective ozone layer.

3. Troposphere – “Weather Breeder”
- 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

4. The Stratosphere Is Our Global Sunscreen
Similar composition to the troposphere, with 2 exceptions
Much less water
O3, ozone layer, filters UV
Location – 11 – 30 miles up

5. What is Air Pollution and What Are the Major Outdoor Pollution Problems?
Air pollution – presence of chemicals in the atmosphere high enough to harm organisms, ecosystems or materials & to alter climate
Natural sources
Dust blown by wind
Pollutants from wildfires
and volcanoes
Volatile organics released
by plants
Withdrawing groundwater
Human (Anthropogenic) sources:
mostly in industrialized and/or urban areas
Stationary sources – examples include industry and power plants
Mobile sources – examples include motor vehicles

6. Some Pollutants in the Atmosphere Combine to Form Other Pollutants
Primary pollutants – released directly into atmosphere
Secondary pollutants – formed by chemical reactions in air

7. What Are the Major Outdoor Air Pollutants?
Carbon oxides
Carbon monoxide (CO)
Carbon dioxide (CO2)
Sources - incomplete combustion of carbon-containing materials
Human health and environmental impact
CO reduces ability of blood to transport O2
CO2  Do you need to ask? ;-)
Primary Pollutant

8. What Are the Major Outdoor Air Pollutants?
Nitrogen oxides (NO) and nitric acid (HNO3)
Sources – automobile engines & coal burning power plants
Human health and environmental impact – greenhouse gas, acid deposition, irritation to eyes, nose, aggravated asthma, etc
Photochemical smog (makes harmful O3) – more later
Sulfur dioxide (SO2) and sulfuric acid (H2SO4)
Sources – coal burning power plants & smelting
Human health and environmental impact – acid deposition

9. What Are the Major Outdoor Air Pollutants?
Particulates
Suspended particulate matter (SPM)
Sources – natural sources, plowed fields, construction, unpaved roads, tobacco smoke, coal burning power plants, cars
Human health and environmental impact –
Irritate nose, throat, aggravate asthma, some can accumulate in body (lead, PCB’s)

10. What Are the Major Outdoor Air Pollutants?
Ozone (O3)
Sources - photochemical smog
Human and environmental impact – same as others, also damages plants, rubber in tires, etc.
Volatile organic compounds (VOCs)
Hydrocarbons, terpenes, methane
Sources – natural sources, landfills, solvents, rice paddies, natural gas wells, etc.
Human and environmental impact – greenhouse gas (CH4), damage plants, can cause cancer

11. Burning Coal Produces Industrial Smog
Chemical composition of industrial smog (grey)
Reduction of this smog in urban cities of the United States
China and smog
Human deaths

12. Sunlight Plus Cars Equals 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

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

14. Several Factors Can Decrease or Increase Outdoor Air Pollution
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
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

15. A Temperature Inversion

16. What Is Acid Deposition and Why Is It a Problem?
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.

17. 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?

18. Natural Capital Degradation: Acid Deposition, Acid Rain

19. Current and Possible Future Acid Rain Problem Areas

20. Acid Deposition Has a Number of Harmful Effects
Human respiratory disorders
Aquatic ecosystems affected
Release of toxic metals
Leaching of soil nutrients
Loss of crops and trees
Damage to buildings, statues, and monuments

21. Solutions: Acid Deposition, Prevention and Cleanup

22. What Are the Major Indoor Air Pollution Problems?
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.
Developing countries
Indoor burning
Poor suffer the greatest risk
Developed countries
Indoor air pollution is greater than outdoor air pollution!!! WHY????

23. Indoor Air Pollution Is a Serious Problem
You asked 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
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

24. Indoor Air Pollution Is a Serious Problem
Four most dangerous indoor air pollutants
Tobacco smoke
Formaldehyde
Radioactive radon-222 gas
Very small particles
Sources of these pollutants
Human health risks

25. Indoor Air Pollution Is a Serious Problem
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 – Let’s watch TWC - SICK BUILDINGS!

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

27. What Are the Health Effects of Air Pollution?
Air pollution can contribute to asthma, chronic bronchitis, emphysema, lung cancer, heart attack, and stroke.

28. 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

29. Normal Human Lungs and the Lungs of a Person Who Died of Emphysema

30. 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

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

32. How Should We Deal with Air Pollution?
Legal, economic, and technological tools can help to clean up air pollution, but much greater emphasis should be focused on preventing air pollution. - SOUND FAMILIAR???

33. Laws and Regulations Can Reduce Outdoor Air Pollution
United States
Clean Air Acts: 1970, 1977, and 1990
EPA
National ambient air quality standards (NAAQs) for 6 outdoor criteria pollutants
National emission standards for 188 hazardous air pollutants (HAPs)
Toxic Release Inventory (TRI)

34. Laws and Regulations Can Reduce Outdoor Air Pollution
Good news in U.S.
Decrease in emissions
Use of low-sulfur diesel fuel
Cuts pollution
Developing countries
More air pollution

35. 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

36. Solutions: Stationary Source Air Pollution

37. Solutions: Motor Vehicle Air Pollution, Prevention and Cleanup

38. Solutions: Indoor Pollution, Prevention and Cleanup or Dilution