Mrs. Sealy APES

1. Ch. 17 Notes Air Pollution Mrs. Sealy APES

2. I. Air pollution detectors: • * canaries died in mines when there was too much methane • * lichens: fungi and alga living together that can live almost anywhere for long periods of time

3. II. Atmosphere - thin envelope of life-sustaining gases surrounding the earth (divided into several spherical layers) • 1.  Troposhere: innermost layer extending about 17 km above sea level • a.  contains about 75% of the mass of earth’s air • b.  weather occurs here • c.  78% nitrogen / 21% oxygen / 1% argon / 0.036% carbon dioxide • d.  average pressure exerted by gases in the atmosphere decreases with altitude because average density (mass of gases per unit of vol.) decreases with altitude

4. Atmosphere • 2. tropopause: top zone of the troposphere where temperature declines with altitude but then abruptly begins to rise

5. Atmospheric pressure (millibars) Temperature Pressure Mesopause Stratopause Tropopause 0 200 400 600 800 1,000 120 75 110 65 Thermosphere 100 90 55 80 Heating via ozone Mesosphere 45 70 60 Altitude (miles) Altitude (kilometers) 35 50 Stratosphere 40 25 30 15 Ozone “layer” 20 Heating from the earth Troposphere 10 5 Pressure = 1,000 millibars at ground level 0 Fig. 17.2, p. 418 –80 –40 0 40 80 120 (Sea Level) Temperature (˚C)

6. Atmosphere • 3. stratosphere: atmosphere’s 2nd layer extending from 17-48 km above earth’s surface • a. contains less matter than the troposphere but has similar composition • b. calm air, little mixing - good for flying planes • c. ozone: “global sunscreen” keeps about 99% of UV radiation out • i. allows humans and other life to exist • ii. helps protect humans from sunburn, cancer, cataracts, damage to immune system • iii. prevents oxygen in the troposphere from being converted to ozone, a harmful airpollutant which causes smog and damage to plants

7. Photochemical ozone 40 25 35 20 Stratosphere 30 25 Stratospheric ozone 15 Altitude (kilometers) Altitude (miles) 20 10 15 10 5 Troposphere 5 0 0 0 5 10 15 20 Fig. 17.3, p. 419 Ozone concentration (ppm)

8. III. Necessary natural processes in the atmosphere • Greenhouse effect: traps heat in the troposphere •  global warming: caused by the addition of heat-trapping chemicals to the atmosphere • ozone shield: part of the stratosphere which filters out most UV radiation • Ozone depletion: reduction of the concentration of ozone

9. IV. Disruption of Earth’s gaseous nutrient cycles • 1. Burning fossil fuels and clearing forests • a. disrupts ____________and can alter global climate and food-producing regions, cause huge heated air masses (heat islands) and dust domes over urban areas • b. disrupts _____________-nitrous oxides are converted to nitric acid which falls as acid rain • c. disrupts the sulfur cycle -sulfur dioxide from petroleum refining and burning of oil and coal causes acid rain NOx SOx

10. AIR Pollution • V. Air pollution: the presence of 1 or more chemicals in the atmosphere in quantities and duration that cause harm to humans, other forms of life, and materials

11. Types of pollutants • Primary pollutants: potential pollutants that have been directly added to the air by natural events or humans activities • Secondary pollutants: harmful chemicals formed in the atmosphere when a primary pollutant reacts with normal air components or other air pollutants

12. Types of Sources of Pollution • Stationary sources: power plants and factories •  mobile sources of pollution: cars ( responsible for 80-88% of air pollution) • Natural sources: volcanoes, erosion

13. 2 – SO4 NO3 – 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. 17.4, p. 422

14. Photochemical Smog • photochemical smog: (brown-air smog) a mixture of primary and secondary pollutants formed under the influence of sunlight • a. nitrogen and oxygen in air react at high temps found in automobile engines and boilers in industrial plants to produce colorless nitric oxide which reacts w/ oxygen to form nitrogen dioxide. Nitrogen dioxide causes the brownish haze over cities on sunny afternoons.

15. b. Reaction: •  *  photochemical oxidants: NO2, O3 and PANs (peroxyacyl nitrates) • a. react with (oxidize) certain compounds in the atmosphere that normally aren’t oxidized by reaction with oxygen   • b. irritate the respiratory tract, damage plants

16. O Atomic oxygen Solar radiation Ultraviolet radiation NO Nitric oxide O2 Molecular oxygen NO2 Nitrogen dioxide H2O Water Hydrocarbons PANs Peroxyacyl nitrates O3 Ozone Aldehydes (e.g., formaldehyde) HNO3 Nitric acid Photochemical smog Fig. 17.5, p. 424

17. 40 Nitric oxide Nitrogen dioxide Ozone 30 20 Parts per million 10 0 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 A.M. Noon P.M. Time Fig. 17.6, p. 424

18. Industrial Smog • Industrial Smog: gray-air smog) consists of sulfur dioxide, suspended droplets of sulfuric acid, and a variety of suspended solid particles and droplets • a. when burned, carbon in coal & oil is converted to CO2 and CO. Unburned carbon ends up in the atmosphere as suspended particulate matter (soot). Sulfur dioxide (colorless, suffocating gas) and sulfur trioxide (SO3) cause sulfuric acid • b. rarely a problem in today’s developed countries but bad in countries where large quantities of coal are burned with inadequate pollution controls

19. VI. Factors influencing the formation of photochemical and industrial smog •  local climate and______________, population density, amt. of industry, and the fuels used in industry, heating, and transportation • hills, mountains, and cities reduce air flow and allow pollutants to build up at ground level

20. VI. Factors influencing the formation of photochemical and industrial smog • temperature/ thermal inversion: a layer of dense, cool air trapped under a layer of dense, warm air preventing upward-flowing air currents from developing • a. prolonged inversions cause air pollution in the trapped layer to build up to harmful levels • b. L.A. is the air-pollution capital of the US because they have ideal conditions for photochemical smog and frequent inversion layers

21. Increasing altitude Decreasing temperature Warmer air Inversion layer Cool layer Mountain Mountain Valley Fig. 17.8a, p. 426

22. Descending warm air mass Sea breeze Increasing altitude Decreasing temperature Inversion layer Mountain range Fig. 17.8b, p. 426

23. How to tell if your shoes are causing air pollution.

24. VII. Acid Deposition • 1. “dilution solution” to air-pollution: to reduce local air pollution and meet government standards without having to add expensive pollution control devices, most coal-burning plants, ore smelters, etc. use taller smokestacks to emit sulfur dioxide high into atmosphere • 2.    increases pollution downwind

25. VII. Acid Deposition • 3. chemicals reach ground:  • a. Wet: acid rain, snow, fog, cloud vapor • b. Dry:acidic particles • c. mixture causes acid deposition (acid rain)

26. VII. Acid Deposition • 4. pH: a numerical measure of the concentration of hydrogen ions in a solution (1 digit change equals 10X change in acidity) • a. levels less than 7 - acid (natural precipitation) • b. levels greater than 7 - Base • c. typical rain in east US is now about 10 times more acidic (pH 4.3)

27. 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. 17.9, p. 428

28. 5. What areas are most affected by acid deposition? • occurs on a local rather than global basis b/c acidic components only remain in the air for a few days • areas downwind from coal and oil burning power plants, industrial plants and urban areas • ecosystems containing acidic soils without natural buffering of bases • growing problem in China (40% of its land), former Soviet Union, India, Nigeria, Brazil, Venezuela, Columbia

29. 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. 17.11, p. 429

30. 0 Miles 1,000 0 Kilometers 1,600 China Iran Pakistan Saudi Arabia India Myanmar Arabian Sea Thailand Bay of Bengal Ethiopia Indian Ocean Equator Percentage of direct sunlight intercepted Very heavy 35%–45% Heavy 20%–35% Medium 10%–20% Fig. 17.12a, p. 429

31. 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 Fig. 17.13, p. 430 pH

32. 6. What are the effects of acid deposition? •  medium-risk ecological problem, high-risk to human health • human respiratory diseases (bronchitis, asthma), damages statues, buildings, metals, plastics and paints • damages tree foliage, makes trees more susceptible to cold temps, disease, insects, drought, fungi • harmful to aquatic species

33. Effects of Weather Emissions Dry weather Low precipitation SO2 NOX Acid deposition Increased susceptibility to frost, pests, fungi, mosses, and disease H2O2 O3 Increased evapotranspiration PANs Others Direct damage to leaves and needles Dead leaves or needles Increased transpiration Water deficit Reduced photosynthesis and growth Bark damage Nutrient deficiency Soil acidification Damage to tree crown Tree death Kills certain essential soil microorganisms Sulfate Acids Nitrate Calcium Aluminum Magnesium Potassium Release of toxic metal ions Leaching of soil nutrients Disturbance of nutrient uptake Damage to fine roots Acids and soil nutrients Disturbance of water uptake Lake Groundwater Fig. 17.14, p. 432

34. Fig. 17.10, p. 428

35. D. What can be done to reduce acid deposition? • prevention • 1) reducing energy use & thus air-pollution by improving energy efficiency • 2) switching from coal to cleaner-burning natural gas • 3) removing sulfur from coal before it is burned • 4) burning low-sulfur coal • 5) removing SO2 particles, particulates, and nitrogen oxides from smokestack gases • 6) removing nitrogen oxides from combustion engines

36. D. What can be done to reduce acid deposition? • reducing coal use is economically & politically difficult • clean-up approaches are expensive and mask symptoms w/ out treating causes • acidified lakes can be neutralized by treating them or the surrounding soil with large amounts of limestone or lime. This is an expensive and temporary remedy

37. 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 from NOx motor vehicular exhaust Fig. 17.15, p. 433 Tax emissions of SO2

38. Ultra Fine Particles Fine Particles Large Particles Sea salt nuclei Fly ash Carbon black Pollens Paint pigments Tobacco smoke Cement dust Milled flour Combustion nuclei Coal dust Oil smoke Metallurgical dust and fumes Photochemical smog Insecticide dusts Fig. 17.7, p. 425 0.001 0.01 2.5 10.0 100.0 Average particle diameter (micrometers or microns)

39. VIII. Indoor air-pollution • levels of 11 common pollutants are generally 2-5 times higher inside homes and commercial buildings than outdoors •  health risks high b/c people spend 70-98% of their time indoors •  source of cancer risk • greatest risk people - smokers, infants & children under 5, the old, the sick, pregnant women, people with respiratory or heart problems, factory workers causes dizziness, headaches, coughing, sneezing, nausea, burning eyes, chronic fatigue,

40. Para-dichlorobenzene Tetrachloroethylene Chloroform 1, 1, 1- Trichloroethane Formaldehyde Benzo-a-pyrene Nitrogen Oxides Styrene Tobacco Smoke Asbestos Radon-222 Methylene Chloride Carbon Monoxide Fig. 17.16, p. 435

41. Indoor Air Pollution • Sick building syndrome - flu-like symptoms from indoor pollution • a. a building is “sick” when at least 20% of its occupants suffer persistent symptoms that stop when they go outside new buildings are more commonly sick b/c of reduce air exchange, chemicals from building materials • b. costs about 100 billion per yr. in absenteeism, reduced productivity, and health costs • c. caused by mineral fibers, fiberglass, formaldehyde(extremely irritating gas)   • d. burning of wood, dung and crop residues in open fires in developing countries is responsible for many respiratory illnesses

42. IX. What should be done about asbestos? • Asbestos: several different fibrous forms of silicate minerals widely used since the 1940s for fireproofing and thermal insulation • if breathed they can remain in the lungs for years • used for fireproofing, soundproofing, insulation of heaters & pipes, brake linings, etc cause asbestosis: a chronic, sometimes fatal disease that eventually makes breathing nearly impossible • causes mesothelioma an inoperable cancer of the chest cavity lining cause lung cancer those affected - asbestos miners, insulators, pipe fitters, shipyard employees, workers in asbestos-producing factories most asbestos factories have gone out of business or moved to other countries

43. X. Is your home contaminated with radon gas? • Radon: a colorless, odorless, tasteless, naturally occurring radioactive gas produced by the radioactive decay of uranium-238 • if inhaled can expose lung tissue to large amounts of ionizing radiation • lifetime exposure in a home responsible for 13,600 deaths a yr.

44. Radon levels in the US

45. Outlet vents for furnaces and dryers Open window Open window Openings around pipes Openings around pipes Cracks in wall Cracks in wall Slab joints Wood stove Cracks in floor Clothes dryer Furnace Sump pump Radon-222 gas Uranium-238 Slab Radium-222 Soil Fig. 17.17, p. 436

46. XI. How is human health harmed by air pollutants? • 1) lung cancer • 2) asthma: typically and allergic reaction causing sudden episodes of acute shortness of breath   • 3) chronic bronchitis: persistent inflammation and damage to the cells lining the bronchi and bronchioles, causing mucus buildup, painful coughing and shortness of breath • 4) emphysema: irreversible damage to air sacs or alveoli leading to abnormal dilation of air spaces, loss of lung elasticity, and acute shortness of breath CO reduces the ability of blood to carry oxygen which impairs perception, things, causes headaches, dizziness, nausea, and can trigger heart attacks, damage fetuses http://kidshealth.org/kid/health_problems/allergy/asthma.html

47. Nasal cavity Oral cavity Pharynx (throat) (see figure 17.18b) Trachea (windpipe) Bronchus Right lung Bronchioles (see figure 17.18c) Fig. 17.18a, p. 437

48. Epithelial cell Cilia Mucus Fig. 17.18b, p. 437

49. Bronchiole Alveolar sac (sectioned) Alveolar duct Alveoli Fig. 17.18c, p. 437

50. How many people die prematurely from air pollution? • a. outdoor pollution deaths : 65,000 - 200,000 / yr • b. total pollution deaths : 150,000 - 350,000 / yr