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Air and Air Pollution

Air and Air Pollution. Key Concepts. 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. The Atmosphere.

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Air and Air Pollution

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  1. Air and Air Pollution

  2. Key Concepts • 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. The Atmosphere Fig. 17-2 p. 419/ see also fig. 17-3 p. 420 • Troposphere: 75-80% of mass of the atmosphere • 78% N, 21% O, 1-4% H2O(v), 1% Ar and .037%CO2 • Stratosphere: much less H2O(v), and much more O3. • Ozone layer: Beneficial in the stratosphere damaging in the troposphere (smog). 8-17 km • Greenhouse effect: necessary for life

  4. Outdoor Air Pollution See Table 17-1 p. 420 See Table 17-2 p. 422 • Primary pollutants: from both natural and human (anthropogenic) sources • Secondary pollutants: from chemical reactions that occur in the atmosphere with the primary pollutants • Indoor Pollutants: Come from infiltration from outside polluted air and various chemicals used or produced inside buildings Fig. 17-4 p. 421

  5. Photochemical Smog Fig. 17-6 p. 424 Factors that influence: topography, population density, industry, fuels used, urbanization, high temperatures • Brown-air smog due to NO2 • Photochemicalreactions (see pg. 423-424) • Photochemicaloxidants (PAN’s, NO2, and O3 ) Oxidize compounds in air or lungs  Irritate lungs, damage plants

  6. Photochemical Smog At the high temperatures of the car's combustion chamber (cylinder), nitrogen and oxygen from the air react to form nitric oxide (NO): Step 1: N2 + O2 -----> 2NO Some of the nitric oxide (NO) reacts with oxygen to form nitrogen dioxide NO2): Step 2: 2NO + O2 -----> 2NO2 When the nitrogen dioxide (NO2) concentration is well above clean air levels and there is plenty of sunlight, then an oxygen atom splits off from the nitrogen dioxide molecule: Step 3: NO2 ---------->NO + O (sunlight) This oxygen atom (O) can react with oxygen molecules (O2) in the air to form ozone (O3): Step 4: O + O2 -----> O3 (ozone)

  7. Industrial Smog Fig. 17-8 p. 426 See pg. 423 • Gray-air smog: Suspended particles and soot • Industrial smog: largely due to burning of coal and release of sulfur impurities • Sulfuric acid • Sulfur dioxide • Particulates: < 10 micronsdangerous to health

  8. Temperature Inversions • Subsidence inversion:Warm air mass moves over a cold air mass and decreases vertical mixing Fig. 17-9 p. 427 • Radiation inversion:occurs at night, air near ground cools faster than air above. Sun rise heats up the air and usually diminishes by noon

  9. Regional Outdoor Air Pollution from Acid Deposition Fig. 17-10 p. 428 • Acid deposition: due to tall smokestacks pollution is decreased locally and increased regionally and transformed in the atmosphere as it is spread downwind and deposited as acid deposition • Dry deposition: acidic particles • Wet deposition: acid rain snow fog and cloud vapor

  10. Acid Deposition in the US Fig. 17-11 p. 429

  11. Acid Deposition and Humans • Respiratory diseases • Toxic metal leaching • Decreased visibility • Damage to structures, especially containing limestone • Decreased productivity and profitability of fisheries, forests, and farms

  12. Acid Deposition and Aquatic Systems Fig. 17-14 p. 431 • Fish declines • Undesirable species • Aluminum toxicity

  13. Acid Deposition, Plants, and Soil Fig. 17-15 p. 432 • Nutrient leaching • Heavy metal release • Weakens trees

  14. Figure 17-16Page 433 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 Tax emissions of SO2

  15. Indoor Air Pollution/Sick Building Syndrome Fig. 17-17 p. 434

  16. Radon Fig. 17-18 p. 436 • Radon-222 • 4 picocurie level • Occurs in certain areas based on geology • Associated with uranium and organic material in rock

  17. Effects of Air Pollution on Living Organisms and Materials • Damage to mucous membranes • Respiratory diseases (see Fig. 17-19 p. 438) • Damage to plant leaves and roots • Reduction in primary productivity • Deterioration of materials (See Table 17-3 p. 440)

  18. Solutions: Preventing and Reducing Air Pollution • Clean Air Act: passed 1970, 1977, and 1990 • National Ambient Air Quality Standards (NAAQS) • Primary and secondary standards: primary set to protect human health; secondary set to prevent environmental and property damage

  19. Emission Reduction Fig. 17-22 p. 441 Fig. 17-23a p. 442

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