ENVIRONMENTAL SCIENCE

1. 13e ENVIRONMENTALSCIENCE CHAPTER 15:Air Pollution, Climate Change, and Ozone Depletion

2. Fig. 15-1, p. 368

3. Asian Brown Cloud • http://www.youtube.com/watch?v=qYYK-2sDN4U • http://www.youtube.com/watch?v=v-SEJfpQLSI&NR=1&feature=fvwp

4. Core Case Study: South Asia’s Massive Brown Cloud (1) • Asian Brown Cloud • India to Bangladesh to China’s Pacific coast • Pollutants from fires, cars, industry • Skies permanently gray or brown

5. Core Case Study: South Asia’s Massive Brown Cloud (2) • Changing weather patterns • 700,000 premature deaths per year • Has traveled to the west coast of the U.S. • Made worse by global warming

6. 15-1 What is the Nature of the Atmosphere? • Concept 15-1 The two innermost layers of the atmosphere are the troposphere, which supports life, and the stratosphere, which contains the protective ozone layer.

7. Earth’s Atmosphere • Troposphere • Extends upward 5-11 miles above earth’s surface • Makes up 75–80% earth’s air mass • 78% N2, 21% O2 • Weather and climate • Stratosphere • Ozone layer

8. Stratosphere • Stratosphere • Extends from 11-30 miles above Earth’s surface • Volume of water vapor less than Troposphere • Concentration of ozone much higher • Ozone Layer • Global sunscreen, keeps 95% of harmful UV radiation from reaching Earth’s surface

9. Atmospheric pressure (millibars) 75 65 55 45 35 25 15 5 0 200 400 600 800 1,000 120 110 100 90 80 70 60 50 40 30 20 10 0 Temperature Thermosphere Mesopause Mesosphere Altitude (kilometers) Altitude (miles) Stratopause Stratosphere Tropopause Ozone layer Troposphere Pressure (Sea Level) Pressure = 1,000 Millibars at ground level –80 –40 0 40 80 120 Temperature (°C) Fig. 15-2, p. 370

10. 15-2 What Are the Major Air Pollution Problems? (1) • Concept 15-2A Three major outdoor air pollution problems are industrial smog from burning coal, photochemical smog from motor vehicle and industrial emissions, and acid deposition from coal burning and motor vehicle exhaust.

11. 15-2 What Are the Major Air Pollution Problems? (2) • Concept 15-2B The most threatening indoor air pollutants are smoke and soot from wood and coal fires (mostly in developing countries) and chemicals used in building materials and products.

12. Air pollution • http://www.youtube.com/watch?v=Hx_yWFQvJT4&feature=related

13. Outdoor Air Pollution • What is air pollution? • Presence of chemicals in atmosphere in concentrations that are high enough to be harmful • Stationary and mobile sources • Primary pollutants-harmful chemicals emitted directly into the air • Secondary pollutants- formed when primary pollutants react with one another and with other components of air to form new harmful chemicals

14. Types of Major Air Pollutants • Carbon oxides (CO, CO2) • Nitrogen oxides and nitric acid (NO, NO2, HNO3) • Sulfur dioxide and sulfuric acid (SO2, H2SO4) • Particulates (SPM) • Ozone (O3) • Volatile organic compounds (VOCs)

15. Carbon Oxides Carbon monoxide (CO) colorless, odorless and highly toxic gas that forms during incomplete combustion of carbon-containing materials • Major sources: motor vehicle exhaust, burning of forests and grasslands, tobacco smoke, open fires/inefficient stoves for cooking • Reacts with Hb in RBCs to decrease ability of blood to transport O2 to body cells and tissues

17. Carbon dioxide (CO2) • Colorless, odorless gas • 93% of atmospheric CO2 result of natural carbon cycle • Rest from burning fossil fuels, clearing forests and grasslands • Now classified as air pollutant due to role in climate change

18. Nitrogen oxides and nitric acid • Nitric oxide (NO) colorless gas forms when N and O react at high combustion temps in auto engines and coal-burning power/industrial plants • In air NO reacts with O to form Nitrogen dioxide (NO2), reddish brown gas • Collectively NO and NO2 called Nitrogen oxides (NOx)

19. Some NO2 reacts with water vapor to form nitric acid (HNO3) and nitrate salts (NO3-), components of acid deposition • Both NO and NO2 play role in formation of photochemical smog: a mixture of chemicals formed under influence of sunlight in cities with heavy traffic

20. Nitrous oxide (N2O) greenhouse gas, emitted from fertilizers and animal wastes and produced by burning fossil fuels • Nitrogen oxides can irritate eyes, nose, throat; aggravate lung ailments, suppress plant growth, and reduce visibility

21. Sulfur dioxide and sulfuric acid • Sulfur dioxide (SO2) colorless gas with irritating odor • 1/3 from natural sources, 2/3 from human sources such as combustion of sulfur containing coal and oil refining and smelting • Can be converted to aerosols, microscopic suspended droplets of sulfuric acid (H2SO4) and suspended particles of sulfate (SO4) salts that return to Earth as component of acid deposition • SO2, H2SO4 droplets, and suspended particles of sulfate reduce visibility; aggravate breathing problems; also damage crops, trees, soils and aquatic life, corrode metals, damage stone on buildings and statues • Major component of Asian Brown Cloud

24. Particulates • Suspended particulate matter (SPM) • Variety of solid particles and liquid droplets small and light enough to remain suspended in air for long periods • 38% from human sources such as coal burning plants, motor vehicles, road construction, and tobacco smoke • Major component of Asian Brown Cloud • These particles can irritate nose, throat; damage lungs; aggravate asthma and bronchitis, and shorten life • Also contains toxic particulates; can lead to mutations, reproductive problems, cancer • Reduce visibility, corrode metals, discolor clothes and paints

25. Ozone • Ozone (O3), colorless, highly reactive gas, major ingredient of photochemical smog • Can cause coughing, breathing problems, aggravate lung and heart disease, reduce resistance to colds/ pnuemonia, irritate eyes, nose, throat • damages plants, rubber in tires, fabrics, paints

26. Ozone in troposphere near ground level “bad ozone” • Ozone in stratosphere “good ozone” b/c protects us from the sun’s harmful UV radiation • Same chemical • Human activities decreasing “good ozone” increasing “bad ozone”

27. Volatile organic compounds (VOCs) • VOC’s are organic compounds that exist as gases in the atmosphere or that evaporate into the atmosphere • Ex. hydrocarbons emitted by leaves of many plants and methane(CH4) a greenhouse gas 20 times more effective per molecule than CO2 is at warming atmosphere • 1/3 from natural sources, 2/3 human sources; rice paddies, landfills, oil and natural gas wells, cows • Other VOCs are liquids that evaporate into atmosphere ex. Benzene and other industrial solvents, dry cleaning fluids, components of gasoline, plastics, and other products

28. 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 NO3– and SO42– salts Sources Natural Stationary Mobile Fig. 15-3, p. 371

29. In Class • List the major outdoor air pollutants, describe, and give their harmful effects.

31. Industrial Smog • Burning coal • Sulfur dioxide, sulfuric acid, suspended particles (gray air smog) • Coal-burning a major contributor to Asian Brown Cloud • Developed versus developing countries • Air pollution control in the U.S. and Europe • China, India, Ukraine

32. Photochemical Smog • Photochemical reactions: chemical rxn activated by sunlight • Photochemical smog: mixture of primary and secondary pollutants formed under the influence of UV radiation from the sun • Brown-air smog (contains NO2) • Sources • Health effects • Urban areas

33. Photochemcial smog in Santiago, Chile Fig. 15-4, p. 373

34. Natural Factors That Reduce Air Pollution • Particles heavier than air • Rain and snow • Salty sea spray from oceans • Winds • Chemical reactions

35. Natural Factors That Increase Air Pollution • Urban buildings • Hills and mountains • High temperatures • VOC emissions from certain trees and plants • Grasshopper effect • Temperature inversions

36. http://www.lchs.wolfcreek.ab.ca/lcsweb/Staff/sschultz/Sci30/007DA42D-000F810F.5/Grasshopper%20effect.jpghttp://www.lchs.wolfcreek.ab.ca/lcsweb/Staff/sschultz/Sci30/007DA42D-000F810F.5/Grasshopper%20effect.jpg

37. http://www.airquality.utah.gov/Public-Interest/Current-Issues/cache-valley-PM/Images/Inversion.jpghttp://www.airquality.utah.gov/Public-Interest/Current-Issues/cache-valley-PM/Images/Inversion.jpg

38. Acid Deposition • Sulfur dioxides and nitrogen oxides • Wet and dry deposition • Acid rain • Regional air pollution • Midwest coal-burning power plants • Prevailing winds

39. Acid deposition: consists of rain, snow, dust, or gas with pH less than 5.6 Wind Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3) Windborne ammonia gas and some soil particles partially neutralize acids and form dry sulfate and nitrate salts Wet acid deposition (droplets of H2SO4 and HNO3 dissolved in rain and snow) Nitric oxide (NO) Sulfur dioxide (SO2) and NO Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Acid fog Lakes in shallow soil low in limestone become acidic Lakes in deep soil high in limestone are buffered Fig. 15-5, p. 374

40. Regions where acid deposition is now a problem and regions with the potential to develop this problem 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. 15-6, p. 375

41. Harmful Effects of Acid Deposition • Structural damage • Respiratory diseases in humans • Toxic metal leaching • Kills fish and other aquatic organisms • Leaches plant nutrients from soil • Acid clouds and fog at mountaintops

42. Solutions Acid Deposition Prevention Cleanup Reduce coal use Add lime to neutralize acidified lakes Burn low-sulfur coal Increase natural gas use Add phosphate fertilizer to neutralize acidified lakes Increase use of renewable energy resources Remove SO2 particulates and NOx from smokestack gases Remove NOx from motor vehicular exhaust Tax emissions of SO2 Reduce air pollution by improving energy efficiency Fig. 15-7, p. 376

43. Indoor Air Pollution • According to WHO indoor air pollution is world’s most serious air pollution problem especially for poor people • Developing countries • Indoor cooking and heating • Often higher concentration in buildings and cars • Most time is spent indoors or in cars • EPA – top cancer risk

44. Major Indoor Air Pollutants • Tobacco smoke • Formaldehyde • Radioactive radon-222 gas • Very small particles

45. Chloroform Source: Chlorine-treated water in hot showers Possible threat: Cancer Para-dichlorobenzene Source: Air fresheners, mothball crystals Threat: Cancer Tetrachloroethylene Source: Dry-cleaning fluid fumes on clothes Threat: Nerve disorders, damage to liver and kidneys, possible cancer Formaldehyde Source: Furniture stuffing, paneling, particleboard, foam insulation Threat: Irritation of eyes, throat, skin, and lungs; nausea; dizziness 1,1,1-Trichloroethane Source: Aerosol sprays Threat: Dizziness, irregular breathing Styrene Source: Carpets, plastic products Threat: Kidney and liver damage Nitrogen oxides Source: Unvented gas stoves and kerosene heaters, woodstoves Threat: Irritated lungs, children's colds, headaches Benzo-α-pyrene Source: Tobacco smoke, woodstoves Threat: Lung cancer Particulates Source: Pollen, pet dander, dust mites, cooking smoke particles Threat: Irritated lungs, asthma attacks, itchy eyes, runny nose, lung disease Radon-222 Source: Radioactive soil and rock surrounding foundation, water supply Threat: Lung cancer Tobacco smoke Source: Cigarettes Threat: Lung cancer, respiratory ailments, heart disease Asbestos Source: Pipe insulation, vinyl ceiling and floor tiles Threat: Lung disease, lung cancer Carbon monoxide Source: Faulty furnaces, unvented gas stoves and kerosene heaters, woodstoves Threat: Headaches, drowsiness, irregular heartbeat, death Methylene chloride Source: Paint strippers and thinners Threat: Nerve disorders, diabetes Fig. 15-8, p. 377

46. Air Pollution and the Human Respiratory System • Natural protective system; hairs in nose filter out large particles, mucus captures particles, cilia (tiny mucus coated, hair-like structures) transport pollutants they trap • Lung cancer, chronic bronchitis, emphysema, asthma • Premature deaths • Air pollution kills 2.4 million people prematurely every year worldwide

47. Major components of respiratory system Epithelial cell Cilia Nasal cavity Goblet cell (secreting mucus) Oral cavity Pharynx (throat) Mucus Trachea (windpipe) Bronchioles Bronchus Alveolar duct Right lung Bronchioles Alveoli Alveolar sac (sectioned) Fig. 15-9, p. 378

48. Deaths per 100,000 adults per year Premature deaths from air pollution in US <1 1–5 5–10 10–20 20–30 30+ Fig. 15-10, p. 378

49. 15-3 How Should We Deal with Air Pollution? • Concept 15-3 Legal, economic, and technological tools can help clean up air pollution, but the best solution is to prevent it.

50. U.S. Outdoor Air Pollution Control Laws • Clean Air Acts 1970, 1977, 1990 • Air-quality standards for 6 major outdoor pollutants • Carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), SPM, ozone (O3), and lead • Levels of these 6 pollutants have fallen dramatically between 1980 and 2008