Outdoor Air Pollution

1. AP Environmental Science Mr. Grant Lesson 46 Outdoor Air Pollution

2. Do you know your stuff? What is the most common gas in the atmosphere? Charles What role does ozone play in the stratosphere? David … in the troposphere? Trade winds blow which way?Emma Explain atmospheric convection. Wilson

3. Objectives: • Define the term Montreal Protocol. • Identify major pollutants, outline the scope of outdoor air pollution, and assess potential solutions. • Explain stratospheric ozone depletion and identify steps taken to address it. • Define acidic deposition and illustrate its consequences.

4. Define the term Montreal Protocol. Montreal Protocol

5. Identify major pollutants, outline the scope of outdoor air pollution and assess potential solutions. • Natural sources such as windblown dust, volcanoes, and fires pollute the atmosphere, but human activity can worsen some of these phenomena. • Human-emitted pollutants include primary and secondary pollutants from point and non-point sources. • To safeguard public health under the Clean Air Act, the U.S. EPA and state governments monitor ambient concentrations of six criteria pollutants (carbon monoxide, sulfur dioxide, nitrogen dioxide, tropospheric ozone, particulate matter and lead). • Agencies monitor emissions of these pollutants and of volatile organic compounds. • Emissions in the United States have decreased substantially since the Clean Air Act of 1970, and ambient air quality is much improved in most respects.

6. Identify major pollutants, outline the scope of outdoor air pollution and assess potential solutions. • Emissions of 188 toxic air pollutants are also declining, but they still pose health risks. • Industrializing nations such as China and India are experiencing some of the world’s worst air pollution today. • Rural areas suffer air pollution from feedlots and other sources. • Industrial smog produced by fossil fuel combustion is still a problem in urban and industrial areas of many developing nations. • Photochemical smog like that which affects Los Angeles, Tehran, and other cities today is created by chemical reactions of pollutants in the presence of sunlight. It impairs visibility and human health in urban areas.

7. Outdoor air pollution

8. Natural sources pollute: volcanoes Volcanoes are one source of natural air pollution, as shown by the Mount Saint Helens eruption in 1980

9. Natural sources pollute: fires In 1997, unprecedented forest fires sickened 20 million and caused a plane to crash

10. Natural sources pollute: dust storms Phoenix, Arizona, 2012

11. We create outdoor air pollution

12. Pollutants exert local and global effects

13. Legislation addresses pollution The Clean Air Act of 1970 / The Clean Air Act of 1990

14. The EPA sets standards

15. Criteria pollutants: CO and SO2 • Carbon monoxide(CO) = • Sulfur dioxide (SO2) =

16. Criteria pollutants: NO2 • Nitrogen dioxide (NO2) =

17. Criteria pollutants: tropospheric ozone • Tropospheric ozone (O3) =

18. Criteria pollutants: particulate matter andlead • Particulate matter • Lead

19. Areas in the U.S. fail air quality standards Many Americans live in areas with unhealthy levels of criteria pollutants

20. Agencies monitor emissions

21. U.S. air pollution In 2008, the U.S. emitted 123 million tons of the six monitored pollutants The average U.S. driver emits 6 metric tons of CO2/yr as well as other pollutants!

22. We have reduced air pollution

23. We reduced emissions and improved theeconomy Coal Electrical Plant Scrubber

24. Toxic substances pose health risks • Toxic air pollutants = substances that cause: • Cancer, reproductive defects • Neurological, developmental, immune system, or respiratory problems

25. U.S. health risks vary geographically Non-cancerous respiratory ailments Nationwide cancer risks

26. Industrializing and developing nations suffer increasing pollution More people own cars

27. Air pollution in China

28. Air quality is a rural issue, too

29. Smog: our most common air quality problem Smog = an unhealthy mixture of air pollutants over urban areas Smog in Donora killed 21 people and sickened 6,000

30. Photochemical (brown air) smog High levels of NO2cause photochemical smog to form a brown haze over cities

31. Creation of industrial and photochemical smog Industrial smog Photochemical smog

32. We can reduce smog

33. Explain stratospheric ozone depletion and identify steps taken to address it. • CFCs and other persistent human-made compounds destroy stratospheric ozone, and thinning ozone concentrations pose dangers to life because they allow more ultraviolet radiation to each Earth’s surface. • Ozone depletion is most severe over Antarctica, where an “ozone hole” appears each spring. • The Montreal Protocol and its follow-up agreements have proven remarkably successful in reducing emissions of ozone-depleting substances. • The long residence time of CFCs in the atmosphere accounts for a time lag between the protocol and the full restoration of stratospheric ozone.

34. Synthetic chemicals deplete stratospheric ozone

35. CFCs destroy ozone One chlorine atom can destroy 100,000 ozone molecules

36. The Antarctic ozone hole

37. The Montreal Protocol Montreal Protocol = 196 nations agreed to cut CFC production in half by 1998

38. Protecting the ozone layer International agreements reduced ozone-depleting substances The hole in the ozone has stopped growing

39. Define acidic deposition and illustrate its consequences. • Acidic deposition results when pollutants such as SO2 and NO react in the atmosphere to produce strong acids that are deposited on Earth’s surface. • Acidic deposition may be wet (e.g., “acid rain”) or dry, and it may occur a long distance from the source of pollution. • Water bodies, soils, trees, animals, and ecosystems all experience negative impacts from acidic deposition. • Regulation, cap-and-trade programs, and technology are all helping to reduce acid deposition in North America, yet more needs to be done, and industrializing nations will need to tackle the problem as well.

40. Acid deposition… another transboundary issue

41. Burning fossil fuels produces acid rain

42. Impacts of acid deposition

43. pH of precipitation in the U.S. • The acid-neutralizing capacity of soil, rock, or water impacts the severity of acid rain’s effects Many regions of acidification are downwind of major sources of pollution

44. We have begun to address acid deposition