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Global Change: Air Pollution and Climate Change

Global Change: Air Pollution and Climate Change. I. The Atmosphere. A. Definition: Thin envelope of air-atmosphere- divided into spherical layers characterized by a abrupt changes in temperature, pressure and composition

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Global Change: Air Pollution and Climate Change

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  1. Global Change: Air Pollution and Climate Change

  2. I. The Atmosphere A. Definition: Thin envelope of air-atmosphere- divided into spherical layers characterized by a abrupt changes in temperature, pressure and composition Contains 78% nitrogen, 21% oxygen, Remaining is H2O vapor, Ar, CO2, CH4, O3, N2O • Troposphere: Layer closest to Earth’s surface; 11 miles up at equator/5 at poles. This is 75-80% of Earth’s mass. This is where weather occurs, chemical cycling of many nutrients • Stratosphere: Second layer-extends 11-30 miles above surface. Much smaller concentration of water vapor; contains O3 in higher amount.

  3. B. Global Processes in Atmosphere • Greenhouse Effect Troposphere Traps Heat H2O primary GHG/CO2 greatly influenced by human activities • Ozone Shield-”Global Sunscreen” Stratosphere Filters UV radiation O3 Chlorofluorocarbons and halogens destroy ozone

  4. II. Urban Outdoor Air Pollution From Smog • Air Pollution: Presence of chemicals in the troposphere in concentrations high enough to harm organisms, ecosystems, materials or alter climate. • Primary Pollutants: substances emitted directly into air. • Secondary Pollutants: created when primary react with basic components of air to form new, harmful pollutants. • Stationary Sources: Non-moving /fixed-site producers of pollution such as power plants, chemical plants, oil refineries, manufacturing facilities • Mobile Sources: air toxics emitted from highway vehicles and non-road equipment

  5. Fig. 19-3, p. 442

  6. Common Criteria Air Pollutants (NOSCLP) Regulated by Clean Air Act NO2, O3, SO2, CO, Lead, Particulates • VOC: Volatile Organic Chemicals: organic compounds that exist as gases. Most are hydrocarbons and include methane, benzene, vinyl chloride, formaldehyde

  7. Carbon Oxides Carbon monoxide (CO):2C +O2 2CO • colorless, odorless, highly toxic • forms from incomplete combustion of hydrocarbons • Sources are auto exhaust, burning forests, fossil fuel power plants and industry Carbon Dioxide C + O2 CO2 • Colorless odorless, not directly harmful to humans • 93% in atmosphere result of natural carbon cycle-the rest from human activities (burning FF and clearcutting) • Causing climate change which is impacting human health

  8. Nitrogen oxides and nitric acid Nitric Oxide: N2 + O2 2NO • Colorless, odorless, forms when nitrogen and oxygen react under high-combustion in autos and coal plants • Also produced by lightening and by bacteria during N-cycle. • NO reacts with O2 to form Nitrogen dioxide (NO2- a red-brown toxic gas that causes irritation to the eyes and respiratory system) • Collectively known as NOx  Nitric Acid: HNO3 • Further reaction of nitrogen dioxide with water can produce nitric acid, a component of acid rain • At high enough levels, nitrogen oxides can irritate eyes, nose and throat, aggravate lung ailments such as asthma and bronchitis, suppress plant growth and reduce visibility when converted to nitric acid and nitrate salts.

  9. Sulfur Dioxide and sulfuric acid Sulfur Dioxide: S + O2 SO2 • Colorless gas with irritating odor. • About 1/3 from natural sources of S-cycle / 2/3 from human sources like combustion of sulfur containing coal, oil refining and smelting of sulfur ores • In atmosphere SO2 converted to aerosols which consist of microscopic suspended droplets of sulfuric acid. • Cause reduced visibility and aggravate breathing problems. Damage crops, trees, aquatic life, and corrode buildings and statues.

  10. Particulates • Suspended particulate Matter (SPM) solid particles and liquid droplets • From burning coal burning and industrial plants • Irritate throat, damage lungs, toxic particulates can cause genetic mutations, reproductive problems and cancer Ozone • Colorless, highly reactive gas, major component of photochemical smog • Cause breathing problems, aggravate lung and heart disease, damage plants

  11. Volatile Organic Compounds (VOCs) • Organic compounds that exist as gases or evaporate and become gases • Methane-potent GHG from plants, wetlands and termites as well as human sources such as rice paddies, landfills, cows. Other VOCs are benzene and industrial solvents, gasoline and plastics Lead • heavy metal that is mostly a problem from leaded gasoline and paint and incineration in developing world.

  12. Photochemical and Industrial Smog • Industrial Smog : consists of sulfur dioxide, suspended droplets of sulfuric acid and suspended solid particulates.

  13. Industrial Smog in India

  14. Photochemical Smog • Nitrogen oxides are formed by nitrogen and oxygen in the air reacting together under high temperature such as in the exhaust of fossil fuel-burning engines in cars, trucks, coal power plants, and industrial manufacturing factories. ground level O3 aldeyhydes VOCs + NOx + heat + sunlight other secondary pollutants • Nitrogen reacts with oxygen ( N2 + 02 2NO) or ( N2 +2 02 2NO2) 2. Nitrogen dioxide absorbs UV energy and splits to form nitric oxide and atomic oxygen:NO2 NO + O 3. Then, in sunlight, the atomic oxygen combines with oxygen gas to form tropospheric ozone (O3): O+ O2 O3

  15. All of these chemicals are usually highly reactive and oxidizing. It is present in all modern cities, but it is more common in cities with sunny, warm, dry climates and a large number of motor vehicles.Because it travels with the wind, it can affect sparsely populated areas as well. • http://money.cnn.com/galleries/2012/real_estate/1204/gallery.polluted-cities/8.html

  16. III. Several Factors can Decrease or Increase Outdoor Air Pollution Five Natural factors Reduce • Particles heavier than air settle out • Rain and snow partially cleanse air • Salty sea spray washes out many pollutants from air that flows from land over oceans • Winds sweep pollutants away and mix w/clean air (dilute) • Some pollutants removed from air by chem reactions

  17. Five Factors Increase Outdoor Pollution • Urban buildings slow wind speed and reduce dilution • Hills and mountains reduce flow of air in valleys below them/pollutants build up at ground level. • High temperatures promote chemical reactions • Grasshopper effect-occurs when pollutants are transported at high altitudes by evaporation and winds from tropical and temperature areas through the atmosphere to polar areas • Temperature inversions: when a layer of warm air temporarily lies atop layer of cold air and traps pollutants.

  18. Urban Heat Island Effect • The term "heat island" describes built up areas that are hotter than nearby rural areas. The annual mean air temperature of a city with 1 million people or more can be 1.8–5.4°F (1–3°C) warmer than its surroundings. Microclimate • Causes The principal reason for the nighttime warming is that buildings block surface heat from radiating into the relatively cold night sky. Changes in the thermal properties of surface materials: concrete, asphalt Lack of evapotranspiration (for example through lack of vegetation) in urban areas.

  19. IV. Indoor Air Pollution • http://www.epa.gov/iaq/pubs/insidest.html • Greater Threat than Outdoor Air Pollution-LDC indorr burning of wood, charcoal, dung, coal in unvented or poorly vented stoves • Asbestos: Pipe insulation, , floor tiles. Causes lung disease/cancer • Formaldehyde: furniture stuffing, foam insulation, particle board. Causes irritation of eyes, throat, skin, lungs. Dizziness and nausea • Radon -222: naturally occurring colorless and odorless radioactive gas (from decay of U-238) found in soil and rock that can seep into homes and buildings. Can cause lung cancer. Seal cracks in foundation and vent basement. • Carbon Monoxide • Respiratory system works as a natural defense. • Sick Building Syndrome

  20. V. What is global warming? • Increase in concentration of GHG caused rise in temps. CO2, CH4, H2O, N2O are natural GHG’s Halocarbons (CFC’s), O3 are man-made • H2O most potent GHG; CO2 the GHG humans most influence http://www.ucar.edu/learn/1_3_1.htm http://www.ucsusa.org/global_warming/science_and_impacts/science/emissions-of-heat-trapping.html • Global Climate Change: changes in all aspects of the earth’s climate including temperature, precipitation, storm intensity and patterns • No one any longer disagrees that planet is warming and industrial pollutants are at least in part to blame.

  21. Global Warming • History • http://www.nytimes.com/interactive/2009/12/07/science/20091207_CLIMATE_TIMELINE.html • French mathematician describes greenhouse effect-planet like a glass vessel • First proposed in 1840-Thoreau and George Marsh (congressman from Vermont who noticed effects of clear cutting forests and compared it to Turkey where he was ambassador and saw effects –temp swings, loss of soil fertility, less rain and failed civilizations. • 1896-Swedish chemist states we are evaporating our coal mines into atmosphere • Rachel Carson 1962 silent spring-business tried to convince us that technological obstacles to control pollution were insurmountable and unaffordable. EXAMPLE: auto industry and lead free gas • 1969: Global warming phrase first appears in a NY Times article • 1970: First earth day/ EPA Formed • 1985-Hole in ozone • 1997-Kyoto Protocol-signed by Clinton-never submits to senate • 2005-Kyoto takes effect without US participation

  22. The Goldilocks Principle

  23. Average mean global temp has increased .6oC since 1860.

  24. Global Warming/Climate Change Milankovitch cycles: Periods of normal warming and cooling due to changes in orbit every 26,000 years Causes • Causes: burning fossil fuels, clearing forests, inorganic fertilizers (N2O) Evidence • Ice Core data http://www.classzone.com/books/earth_science/terc/content/investigations/es2105/es2105page01.cfm http://www.pbs.org/wgbh/nova/earth/profile-thompson.html http://www.pbs.org/wgbh/nova/earth/extreme-ice.html http://media.hhmi.org/hl/12Lect4.html (start at 30 minutes) CO2 can stay around for 100 years • CO2 at highest levels ever-400 ppm-what happens if we go to 450, 550 or 750 in next 50 years

  25. Impacts of Global Warming • Rising Sea Levels-Thermal Expansion http://marketplace.publicradio.org/display/web/2010/04/12/pm-new-york-rising-currents-exhibition-q/ • Alteration of Ocean Currents • Melting Ice Caps: positive feedback loop • Coastal Flooding • Forest Fires • Grassland Dust Bowls-Loss of food production • Increased frequency and severity of storms • Spread of infectious disease • Ecosystem Collapse

  26. Solutions To Global Warming • Efficiency • Fuel Emission standards • Renewable Resources • Forestry • Smart Growth-Condensed land use in growth areas-Public transport • Upgrade power plants • Carbon Sequestering: Large towers to suck CO2 (NaOH) and store it in depleted oil and natural gas fields, deep ocean • http://www.youtube.com/watch?v=OtfuYlhDjw4&NR=1 • Emissions Trading (Cap and Trade):Administrative approach. Each manufacturing plant has a strict pollution limit (credits). If plant A is able to cut emissions cheaply and does more than law requires, it can sell to plant B, which cannot economically reduce its emissions so it can buy them from A. Used in European Union. Has been effective for SOx reduction in US

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