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Air pollution

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  1. Air pollution Part B

  2. A Model of How Pollutants That Make Up Photochemicals Are Formed SMOG… • Is worse on hotter days • Increases as traffic increases • Is more common in cities with sunny, warm and dry climates with lots of cars like LA, Denver, Sydney (Australia), Mexico City, Jakarta (Indonesia) and Santiago (Chile)

  3. Several Factors Can Decrease Air Pollution Outdoor air pollution may be decreased by Settling of particles due to gravity Rain and snow Salty sea spray from the ocean Winds Chemical reactions ex. SO2 reacts with O2 in atmosphere to form SO3 which reacts with water vapor to form H2SO4-falls out as acid rain

  4. Outdoor air pollution may be increased by Urban buildings Hills and mountains High temperatures Emissions of VOCs from certain trees and plants –oaks, sweet gums, kudzu Grasshopper effect-volatile pollutants transported by evaporation and wind from tropical and temp. areas Temperature inversions Precipitation, wind Several Factors Can Increase Outdoor Air Pollution

  5. Look at the temperature inversion diagram in your text

  6. 18.3 Acid Deposition Is a Serious Regional Air Pollution Problem Acid deposition, acid rain Formation 1) sulfur dioxide (SO2) - forms H2SO4 (sulfuric acid) 2) nitrogen oxides (NOx) - forms HNO3 (nitric acid) In the U.S., ~ 2/3 of all SO2 and ~ 1/4 of all NOx comes from electric power generation that relies on burning fossil fuel Local versus regional problems-tall smokestacks Effects of prevailing winds: prevailing winds can blow acidic compounds over hundreds of miles a) wet deposition: acidic rain, fog, and snow b) dry deposition: acidic gases and particles Soils with limestone/calcium carbonate neutralize acid deposition Where is the worst acid deposition?Asia!! China is biggest emitter of SO2 In 1872, Robert Smith coined the term acid rain.

  7. Natural Capital Degradation: Acid Deposition, Acid Rain

  8. Acid Deposition Has a Number of Harmful Effects Human respiratory disorders Aquatic ecosystems affected: Leach metals such as Pb and Hg into water and can accumulate in tissues of fish. EX: Mercury (Hg) in fish Most fish cannot survive in water with pH < 4.5 Al+3 and Hg become more soluble Acid Shock - A sudden acidification of runoff waters from the spring melting of accumulated snow in the middle latitudes because of the winter deposition of acidic precipitation. Many lakes in Norway and Sweden have no fish

  9. Acid Deposition Has a Number of Harmful Effects • Harms crops by making soil too acidic (< 5.1) • Damage waxy coat on leaves • Impair germination • Leaches nutrients • Reduces plant productivity and the ability of soils to buffer acidic inputs • Synergistic effects

  10. Acid Deposition Has a Number of Harmful Effects • Affects forests by leaching plant nutrients such as Ca, Mg and releasing ions of Al, Pb, Cd and Hg which are toxic to trees) • promotes acid-loving mosses that kill trees. • Tree foliage damaged, making trees more susceptible to cold temps, diseases, insects, drought, fungi • Hubbard Brook Studies- found that trees do not suffer directly from acid rain, but from insufficient nutrients. In order for trees to recover, nutrients need to be replenished- this can take decades if left to nature.

  11. Damages exterior paint on cars and houses, deteriorates roofing, marble statues, historic buildings, stain glass windows- costs $5 billion/yr in US • Is a regional problem that affects areas that are downwind from large car-dominated cities and from polluting coal-burning facilities (acidic components remain in air for a few days)

  12. Acid Deposition Has a Number of Harmful Effects Damage to buildings, statues, and monuments effects of acid rain

  13. Natural Capital Degradation: Air Pollution Damage to Trees Emissions NOx SO2 H2O2 PANs Acid deposition O3 Others Increased susceptibility to drought, extreme cold, insects, mosses, and disease organisms Direct damage to leaves and bark Reduced photosynthesis and growth Tree death Soil acidification Release of toxic metal ions Leaching of soil nutrients Reduced nutrient and water uptake Root damage Acids Lake Groundwater Fig. 18-14a, p. 481

  14. We Know How to Reduce Acid Deposition Prevention approaches that reduce or eliminate emissions from SO2, nitrous oxide, and particulates. Remove S from coal before it is burned, use low-S coal, remove NOx from car exhaust. Tax emissions, improve energy efficiency. Reduce coal use? Expensive and cost passed on to consumers. Alternative energy sources? Areas affected are often far from sources. Clean up Add lime to neutralize acidified lakes and soil

  15. We Know How to Reduce Acid Deposition Prevention approaches that reduce or eliminate emissions from SO2, nitrous oxide, and particulates. Remove S from coal before it is burned, use low-S coal, remove NOx from car exhaust. Tax emissions, improve energy efficiency. Reduce coal use? Expensive and cost passed on to consumers. Alternative energy sources? Areas affected are often far from sources. Clean up Add lime to neutralize acidified lakes and soil

  16. 18-4 Indoor Air Pollution Is a Serious Problem Developing countries Indoor burning of wood, charcoal, dung, crop residues and coal Poor suffer the greatest risk Few, if any, regulations Is the most serious air pollution problem Developed countries Indoor air pollution poses a greater threat than outdoor air pollution.

  17. Indoor Air Pollution Is a Serious Problem Why? We spend up to 70-98% of our time indoors or inside our cars! 11 of the common air pollutants are at higher levels inside than outside Greater inside vehicles than outside Health risks magnified because pollutants are magnified indoors.

  18. Indoor Air Pollution Is a Serious Problem Who is at greatest risk from indoor air pollution? Children under 5 and the elderly Sick Pregnant women People with respiratory disorders or heart problems Smokers Factory workers

  19. Indoor Air Pollution Is a Serious Problem Four most dangerous indoor air pollutants Tobacco smoke Formaldehyde(CH2O) – found in plywood, particle board, paneling, drapes, furniture, carpet and wallpaper adhesives Estimated that 1/5,000 people who live in manufactured homes for more than 10 an lead to Lou Gehrig’s disease (kills nerve cells) Radioactive radon-222 gas- colorless, odorless, radioactive gas that is produced by the natural radioactive decay of U-238. Very small particles

  20. Sources of these pollutants-brought in on shoes, pesticides, paints, sprays, living organisms (bugs), mold • Human health risks-sore throat, headache, chronic breathing problems, rash (flu-like systems)

  21. Indoor Air Pollution Is a Serious Problem Other possible indoor air pollutants Pesticide residue Pb particles Living organisms and their excrements E.g., Dust mites and cockroach droppings Airborne spores of molds and mildews Sick-building syndrome

  22. What exactly is a sick building? • Term that refers to a building in which a number of people report adverse health effects that they believe are related to the time they spend in the building • A building in which occupants suffer persistent symptoms that disappear when they go outside • A building which contains unhealthy levels of indoor air pollutants

  23. How do you know if a building is really “sick”? • When people report relief of symptoms when they go outside • When 20% or more of the occupants report some adverse health effect when inside the building • When occupants report any of the following symptoms: chronic respiratory problems, sinus infection, sore throat, asthma, shortness of breath, depression, forgetfulness, headaches, eye irritation

  24. What type of building can be sick? • Old • Asbestos and lead • New • Formaldehyde or VOC’s • Houses with wood-burning stoves • Carbon monoxide

  25. Some Important Indoor Air Pollutants

  26. Radioactive Radon Gas Colorless, odorless, radioactive gas Sources: natural radioactive decay of Uranium-238 (rocks and soil) Human health risks-damage to lung tissue-cancer Testing for radon - detectors Correcting a radon problem: Sealing cracks in walls and foundation, increase ventilation

  27. Sources and Paths of Entry for Indoor Radon-222 Gas It’s a fantastic house with the exception of the radon gas.

  28. Your Body’s Natural Defenses against Air Pollution Can Be Overwhelmed Respiratory system protection from air pollutants Role of cilia, mucus, sneezing, and coughing Effect of smoking and prolonged air pollution exposure Chronic bronchitis Emphysema 6% of people in US suffer from asthma

  29. Major Components of the Human Respiratory System Lung Attack

  30. Air Pollution Is a Big Killer 3 Million deaths per year world-wide Mostly in Asia Main causes-indoor air pollution In US, more than 150,000 die each year from air pollution EPA: proposed stricter emission standards for diesel-powered vehicles Reduce emission by 90% Car makers hope they can delay Link between international trade and air pollution Cargo ships and pollution

  31. Premature Deaths from Air Pollution in the U.S.

  32. Laws and Regulations Can Reduce Outdoor Air Pollution United States Clean Air Acts: 1970, 1977, and 1990 EPA National ambient air quality standards (NAAQs) for 6 outdoor criteria pollutants Carbon monoxide, nitric oxides (NOx), sulfur dioxide, ozone, lead, and suspended particulate matter (SPM) Primary Standard-Human health Secondary Standard-environmental and property damage

  33. National emission standards for 188 hazardous air pollutants (HAPs) • Mainly toxic metals, VOCs, and chlorinated hydrocarbons • Toxic Release Inventory (TRI)-for power plants, refineries which requires by law for release of info about chemical releases and waste management

  34. Good news in U.S. Decrease in emissions 49% from 1980-2006 Use of low-sulfur diesel fuel Cuts pollution Developing countries More air pollution Laws and Regulations Can Reduce Outdoor Air Pollution

  35. We Can Use the Marketplace to Reduce Outdoor Air Pollution Emission trading or cap-and-trade program “Pollution Credits” Mixed reactions to program SO2 emissions down significantly NO2 will be tried in the future Mercury from coal plants-does not break down-must set limits

  36. There Are Many Ways to Reduce Outdoor Air Pollution 1980 –2006 SO2 emissions from U.S. electric power plants decreased by 66% NOx emissions by 41% Particulate emissions by 28% Older plants not governed by the same regulations New cars have better emissions

  37. Reducing Indoor Air Pollution Should Be a Priority Greater threat to human health than outdoor pollution What can be done? Prevention Cleanup

  38. We Need to Put More Emphasis on Pollution Prevention Output approaches New shift to preventing outdoor and indoor pollution Pressure from citizens

  39. Air Pollution… • Global climate change, ozone depletion, acid rain, photochemical smog, and indoor air pollution are some of the most significant environmental problems faced by humanity. All of these problems/issues emphasize how important a healthy atmosphere is.

  40. ON THE AP EXAM… • Don’t just state something “causes pollution”. At least state that the activity causes “air pollution” or “water pollution”. Most likely, though, graders will want more specific information such as “this activity releases sulfur dioxide into the atmosphere”.