1. Chapter 15 Air Pollution and Stratospheric Ozone Depletion

2. Air Pollution  Air pollution- the introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter ecosystems.  Ground level pollution is also called tropospheric pollution.

3. Major Air Pollutants  Sulfur Dioxide  Nitrogen Oxides  Carbon Oxides  Particulate Matter  Lead  Ozone  Mercury  Volatiles Organic Compounds

5. Sulfur Dioxide (SO 2 )  A corrosive gas that comes primarily from combustion of coal and oil.  Respiratory irritant  Also released during volcanic eruptions and forest fires. S + O  SO 2

6. Nitrogen Oxide (NO x )  Can be either:  NO Nitrogen oxide: a colorless odorless gas  NO2 Nitrogen dioxide: pungent, reddish-brown gas  Primary anthropogenic sources- motor vehicles and stationary fossil fuel combustion.  Natural sources: Forest fires, lightning, microbial action in soil.

7. Carbon Oxides  Carbon monoxide (CO): colorless, odorless gas formed in the incomplete combustion of most matter  Ex. Vehicle exhaust, natural gas heaters, cooking with charcoal or kerosene  Carbon dioxide (CO2): colorless odorless gas that forms during the complete combustion of most matter, including fossil fuels and biomass

8. Particulate Matter Particulate Matter (PM): solid or liquid particles suspended in air. Also called particulates or particles.  Produced from the combustion of wood, animal manure, coal, oil, gasoline, volcanoes, road dust, rock crushing, forest fires and dust storms.  Diesel vehicles give off more black smoke than do gasoline vehicles.  Particulate matter smaller than 10  m (PM 10 )are not filtered by the nose and can be deposited in the respiratory tract.  Particulate matter 2.5  m or smaller (PM 2.5 ) are of deep concern, they deposit deeper in the respiratory tract and are composed of more toxic substance.

9. Haze: reduced visibility caused primarily when particulate matter from air pollution scatters light.

10. Photochemical Oxidants Photochemical oxidants are a class of air pollutants formed as a result of sunlight acting on compounds such as nitrogen oxides and sulfur dioxide.  Oxides remove electrons from other substances.  harmful to plant tissue, human respiratory tissue  Smog: mixture of oxidants and particulates

11. Photochemical Oxidants Photochemical smog: dominated by ozone  also called Los Angeles-type smog or brown smog  Occurs when sunlight acts on vehicle pollutants

12. Photochemical Oxidants Sulfurous smog dominated by sulfur dioxide and sulfate compounds  also called London-type smog or gray smog.  Occurs where coal is burned and the atmosphere is humid.

13. Volatile Organic Compounds VOC’s are organic compounds that become vapors at typical atmospheric temperatures. Anthropogenic o Emissions (Hydrocarbons) o Industrial solvents: trichlorethylene (TCE), benzene and vinyl chloride Natural o Ethylene, terpene

14. Primary Pollutants  Primary pollutants- polluting compounds that come directly out of the smoke-stack, exhaust pip, or natural emission source.  Examples: CO, CO2, SO2, NOx, and most suspended particulate matter.

15. Secondary Pollutants  Secondary pollutants- pollutants that have undergone transformation in the presence of sunlight, water, oxygen, or other compounds.  Examples: ozone, sulfate and nitrate

16. Natural Sources of Air Pollution  Volcanoes  Lightning  Forest fires  Plants

17. Anthropogenic Sources of Air Pollution  On-road vehicles  Power plants  Industrial processes  Waste disposal

19. Check 1: _________________ are the largest source of carbon monoxide and nitrogen oxides. Vehicles (transportation)

20. Check 2: Electricity generation is almost 50% fueled by ________. Coal

21. Check 3: Electricity generation is the major source of anthropogenic ______________. Sulfur dioxide

22. Check 4: What is the difference between a primary and a secondary pollutant? Primary- come directly from the source. Transformation to secondary requires sunlight, water and/or temp.

23. Check 5: Identify 4 primary pollutants? CO, CO 2, SO 2, NO x, VOC’s

24. Check 6: Identify 2 secondary pollutants? Ozone, SO 3, H 2 SO 4, HNO 3, H 2 O 2

25. Check 7: What are the major natural sources of air pollution? Volcanoes, lightning, forest fires, plants (living and dead)

26. Check 8: Identify the pollutants released by a volcano. SO 2, particulate matter, CO, NO x

27. Check 9: Identify the pollutants created by lightning. NO x

28. Check 10: Identify the pollutants released by forest fires. particulate matter, CO and NO x

29. Check 11: Identify the VOC’s released by living plants. Ethylene, turpene These can give rise to smog and photochemical oxidant pollution… hence the name Smoky Mountains.

30. Check 12: Identify an anthropogenic source of particulate matter. Road dust, industrial processes, farming, combustion of coal, oil and gasoline.

31. Check 13: Identify the number 1 source of anthropogenic CO On-road vehicles

32. Check 14: Identify the number 1 source of anthropogenic NOx On-road vehicles

33. Check 15: Identify the number 1 source of anthropogenic SO 2 Electricity generation

34. Check 16: Identify two compounds that bioaccumulate DDT and mercury

35. Check 17: Identify a point source of CO. Vehicle emissions

36. Check 18: Identify a point source pollution of SOx. Volcanic eruptions, forest fires, car exhaust

37. Check 19: Identify point source pollution of NOx. motor vehicles, stationary fossil fuel combustion, Forest fires, lightning, microbial action in soil.

38. http://www.cnn.com/2014/03/25/health/wh o-air-pollution- deaths/?sr=fb032514airpollution7pstory

39. Photochemical Smog

40. Thermal Inversions  Thermal Inversion- when a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below.  The warm inversion layer traps emissions that then accumulate beneath it.

41. Acid Deposition  Acid deposition- occurs when nitrogen oxides and sulfur oxides combine with atmospheric oxygen and water. These form the secondary pollutants nitric acid and sulfuric acid.  These secondary pollutants further break down into nitrate and sulfate which cause the acid in acid deposition.

42. Effects of Acid Deposition  Lowering the pH of lake water  Decreasing species diversity of aquatic organisms  Mobilizing metals that are found in soils and releasing these into surface waters  Damaging statues, monuments, and buildings… acid rain eats through stone and metal

43. Acid Deposition

44. Ways to Prevent Air Pollution  Removing sulfur dioxide from coal by fluidized bed combustion  Catalytic converters on cars  Scrubbers on smoke stacks  Baghouse filters  Electrostatic precipitators

45. Fluidized bed combustion  Removes sulfur dioxide from coal exhaust during combustion.  Coal is burned in close proximity to calcium carbonate (CaCO 3 )  CaCO 3 absorbs SO2 producing calcium sulfate (CaSO 4 )  CaSO 4 is used to make gypsum wallboard (sheetrock)

46. Control of NO x emissions  Reduce burn temperatures and control amount of oxygen can reduce NOx… can result in less complete combustion, more CO and particulates produced.  Catalytic converters on cars reduce NO and CO, as well as unleaded gas.

47. Control of Particulate Matter  A common means of pollution control  Each uses energy, generating additional pollution  Baghouse filter  Electrostatic precipitator  Scrubber

48. Baghouse filter  Fabric filter  Can remove almost 100% of PM emissions.

49. Electrostatic Precipitator  Uses an electric charge to make particles coalesce

50. Scrubber  Uses water and air to separate and remove particles.

51. Stratospheric Ozone  The stratospheric ozone layer exists roughly 45- 60 kilometers above the Earth.  Ozone has the ability to absorb ultraviolet radiation and protect life on Earth.

52. Formation and Breakdown of Ozone  First, UV-C radiation breaks the bonds holding together the oxygen molecule, leaving two free oxygen atoms: O2 + UV-C  2O  Sometimes the free oxygen atoms result in ozone: O2 + O  O3  Ozone is broken down into O2 and free oxygen atoms when it absorbs both UV-C and UV-B ultraviolet light: O3 + UV-B or UV-C  O2 + O

53. Anthropogenic Contributions to Ozone Destruction  Certain chemicals can break down ozone, particularly chlorine.  The major source of chlorine in the stratosphere is a compound known as chlorofluorocarbons (CFCs)  CFCs are used in refrigeration and air conditioning, as propellants in aerosol cans and as “blowing agents” to inject air into foam products like Styrofoam.

54. Anthropogenic Contributions to Ozone Destruction  When CFCs are released into the troposphere they make their way to the stratosphere.  The ultraviolet radiation present has enough energy to break the bond connecting chlorine to the CFC molecule.  which can then break apart the ozone molecules.

55. Anthropogenic Contributions to Ozone Destruction  First, chlorine breaks ozone’s bonds and pulls off one atom of oxygen, forming a chlorine monoxide molecule and O2: O3 + Cl  ClO + O2  Next, a free oxygen atoms pulls the oxygen atom from ClO, liberating the chlorine and creating one oxygen molecule: ClO + O  Cl + O2  One chlorine atom can catalyze the breakdown of as many as 100,000 ozone molecules before it leaves the stratosphere.

56. Depletion of the Ozone Layer  Global Ozone concentrations had decreased by more than 10%.  Depletion was greatest at the poles  Decreased stratospheric ozone has increased the amount of UV-B radiation that reaches the surface of Earth.

57. Indoor Air Pollutants  Wood, animal manure or coal used for cooking and heating in developing countries.  Asbestos  Carbon Monoxide  Radon  VOCs in home products