Air and Air Pollution

1. Air and Air Pollution G. Tyler Miller, Jr.’s Environmental Science 10th Edition Chapter 12

2. Key Concepts- Chapter Overview • Structure and composition of the atmosphere • Types and sources of outdoor air pollution • Types, formation, and effects of smog • Sources and effects of acid deposition • Effects of air pollution • Prevention and control of air pollution

3. When is a Lichen Like a Canary? • Mine canaries • Lichens • Detectors of air pollution • Lake Superior • Chernobyl Fig. 12-1, p. 255

4. Earth’s Atmosphere • Troposphere • 78% N, 21% O • Stratosphere • Ozone layer Fig. 12-2 p. 256

5. Average Distribution and Concentration of Ozone 40 25 35 20 Stratosphere 30 25 Stratospheric ozone 15 Altitude (kilometers) Altitude (miles) 20 10 15 10 5 Troposphere 5 Photochemical ozone 0 0 0 5 10 15 20 Ozone concentration (ppm) Fig. 12-3, p. 257

6. Beneficial vs. Harmful Ozone Located in Stratosphere Global Sunscreen Blocks 95% of sun’s UV Protection from sunburn, skin eye cancer, cataracts, immune system damage Prevents formation of photochemical ozone in troposphere “ozone hole” created by human activities Located in Troposphere Secondary pollutant- photochemical ozone Damages plants, lung tissue, materials Major component of photochemical smog

7. Outdoor Air Pollution 2 – SO4 NO3 – • Primary pollutants • Secondary pollutants Primary Pollutants CO CO2 Secondary Pollutants SO2 NO NO2 SO3 Most hydrocarbons HNO3 H2SO4 Most suspended particles H2O2 O3 PANs Most and salts Natural Sources Stationary Mobile Fig. 12-4, p. 258 Fig. 12-4 p. 258 Also refer to Tables 12-1 p. 258 and 12-2 p. 259

8. Photochemical Smog • Photochemical reactions Fig. 12-5, p. 260 • Photochemicalsmog • Brown-air smog • Common in Cities with sunny, warm, dry climateswith lots of vehicles- L.A., Denver, Salt Lake,..

9. Photochemical Smog Clear day Smoggy day Fig. 12-6b, p. 261

10. Industrial Smog • “Gray-air smog” • Sulfur dioxide- from coal • Aerosols- suspended particles & droplets • Sulfuric acid • No longer a problem in most MDCs Fig. 12-7, p. 261

11. Factors Influencing Smog Formation • Local climate- rain,snow salt spray and winds cleanse air • Topography-hills reduce air flow • Types and amount of air pollutants • Urban buildings- slow wind speed • High temperatures- promote chemical rxns

12. How Nature Removes Air Pollution • Precipitation • Sea spray • Wind

13. Temperature Inversions • Radiation temperature inversion Fig. 12-8a, p.263

14. Temperature Inversions Descending warm air mass Inversion layer Sea breeze Increasing altitude Mountain range Decreasing temperature Fig. 12-8b, p. 263 • Subsidence temperature inversion

15. Regional Outdoor Air Pollution from Acid Deposition (“Acid Rain”) Wind Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3) Windborne ammonia gas and particles of cultivated soil partially neutralize acids and form dry sulfate and nitrate salts Wet acid deposition (droplets of H2SO4 and HNO3 dissolved in rain and snow) Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Sulfur dioxide (SO2) and NO Nitric oxide (NO) Acid fog Farm Ocean Lakes in shallow soil low in limestone become acidic Lakes in deep soil high in limestone are buffered Fig. 12-9, p. 264 • Acid deposition • Dry acid deposition • Wet acid deposition Fig. 20-8 p. 444

16. Acid Deposition in the US In Eastern US most precipitation has pH of 4.2 - 4.7 (10X higher than normal- 5.6) Some forests in E. US and near L.A. bathed in fog and dews as acidic as lemon juice (2.3)

17. Areas Affected and Threatened by Acid Deposition 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. 12-10, p. 265

18. Acid Deposition and Humans • Respiratory diseases • Toxic metal leaching • Damage to structures and property • Decreased visibility • Decreased productivity and profitability of fisheries, forests, and farms • Damage to scenic tourist areas

19. Acid Deposition and Aquatic Systems • Declines in fish populations- • Loss of all fish below pH 4.5 • Aluminum toxicity- suffocates fish by clogging gills • Acid shock- sudden runoff after snow melt

20. Sensitivity of Aquatic Organisms to Acidic Conditions 4.0 Water boatman Whirligig Yellow perch Lake trout Brown trout Salamander (embryonic) Mayfly Smallmouth bass Mussel 6.5 6.0 5.5 5.0 4.5 4.0 3.5 pH Fig. 12-11, p. 266

21. Effects of Acid Deposition on Plants and Soils • Direct damage • Nutrient leaching • Metal release • Moss growth • Weakens trees • Mountain trees Fig. 12-12, p. 267

22. Prevention Cleanup Reduce air pollution by improving energy efficiency Add lime to neutralize acidified lakes Add phosphate fertilizer to neutralize acidified lakes Reduce coal use Increase natural gas use Increase use of renewable resources Burn low-sulfur coal Remove SO2 particulates, and NOx from smokestack gases Remove NOx from motor vehicular exhaust Fig. 12-13, p. 268 Tax emissions of SO2 Solutions to Acid Deposition

23. “Sick Building Syndrome” Pollutants found in buildings linked to dizziness, headaches, coughing, sneezing, nausea, burning eyes, chronic fatigue and flu-like symptoms New buildings more commonly “sick” 17% of commercial buildings in US considered sick

24. 4 Most Dangerous Indoor Air Pollutants • Formaldehyde • Radioactive radon-222 • Cigarette smoke • Ultrafine particles

25. Indoor Air Pollution Fig. 12-14, p. 269

26. Indoor Air Pollutants

27. Radon • Radioactive radon-222 • Lung cancer threat • Occurs in certain areas based on geology • Associated with uranium in rocks and soils Fig. 12-15, p. 270

28. Effects of Air Pollution on People • Respiratory diseases (see Fig. 12-17, p. 272) • Asthma • Lung cancer • Chronic bronchitis • Emphysema • Premature death

29. Solutions: Preventing and Reducing Air Pollution • U.S. Clean Air Acts • U.S. National Ambient Air Quality Standards (NAAQS) • Further possible improvements • Emissions trading

30. Emissions Reduction Fig. 12-18, p. 275

31. Motor Vehicle Air Pollution Prevention Cleanup Mass transit Emission control devices Bicycles and walking Less polluting engines Less polluting fuels Car exhaust Inspections twice a year Improve fuel efficiency Get older, polluting cars off the road Give buyers tax write-offs for buying low-polluting, energy-efficient vehicles Restrict driving in polluted areas Stricter emission standards Fig. 12-20, p. 276

32. Reducing IndoorAir Pollution Fig. 12-21, p. 277

33. Outdoor Air Pollution Indoor Air Pollution Improve energy efficiency to reduce fossil fuel use Rely more on lower-polluting natural gas Rely more on renewable energy (especially solar cells, wind, and solar- produced hydrogen) Transfer technologies for latest energy efficiency, renewable energy, and pollution prevention to developing countries Reduce poverty Distribute cheap and efficient cookstoves to poor families in developing countries Reduce or ban indoor smoking Develop simple and cheap tests for indoor pollutants such as particulates, radon, and formaldehyde Ways for Us to Prevent Air Pollution Fig. 12-22, p. 278