air pollution. primary pollutants: come from: natural sources (volcanoes) mobile sources (cars)...

Download Air Pollution. Primary Pollutants: Come from: Natural sources (volcanoes) Mobile sources (cars) Stationary sources (smoke stacks) Examples: Particle matter

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  • Slide 1
  • Air Pollution
  • Slide 2
  • Primary Pollutants: Come from: Natural sources (volcanoes) Mobile sources (cars) Stationary sources (smoke stacks) Examples: Particle matter or soot (PM 10 ) Nitric oxide (NO) Nitrogen dioxide (NO 2 ) Sulfur dioxide (SO 2 ) Carbon dioxide (CO 2 ) Carbon monoxide (CO) Secondary Pollutants: Result from chemical reactions of primary pollutants in the atmosphere Examples: Sulfur trioxide (SO 3 ) Sulfuric acid (H 2 SO 4 ) Ozone (O 3 )
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  • Major Air Pollutants Criteria air pollutants Set of pollutants that cause smog, acid rain, and other health hazards Emitted from industry, mining, transportation, power generation, and agriculture Include: ozone, particulate matter, carbon monoxide, sulfur dioxide, nitrogen oxides, and lead
  • Slide 4
  • Major Air Pollutants Nitrogen Dioxide (NO 2 ) Forms when fuels burn at high temperatures, from forest fires, volcanoes, and bacteria in soil Forms nitric acid in the air acid deposition When inhaled irritates the lungs Supresses plant growth May be a carcinogen Ozone (O 3 ) Formed by the reaction of sunlight and NOx and VOCs Causes: Lung irritation and damage Bronchial constriction Coughing Wheezing Eye irritation In high atmosphere forms ozone layer = good
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  • Major Air Pollutants Peroxyacyl Nitrates (PANs) Hydrocarbons + O 2 +NO 2 + light CH 3 COOONO 2 (PAN) Stable in the atmosphere transport unstable compounds far away from urban centers Cause eye irritation In high concentrations damage vegetation Sulfur Dioxide (SO 2 ) Produced by burning high- sulfur oil or coal, smelting of metals, and paper manufacturing Combines with water vapor to produce acid rain Acid rain causes: Reduction in plant productivity Breathing difficulties Destroys buildings Acidifies water supply
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  • Major Air Pollutants Suspended Particulate Matter (PM 10 ) Particles with a diameter of 1/7 of a human hair or less Include smoke, dust, diesel soot, lead, and asbestos Cause lung irriation and damage Are mutagens, teratogens (interfers with development), and carcinogens Reducing PM 10 would produce health benefits 10 times grater than reducing all other air pollutants combined Volatile Organic Compounds (VOCs) Include organic compounds that have a high vapor pressure Found in paints, aerosol sprays, dry-cleaning fluids, and industrial solvents Cause respiratory irritation and damage Most are carcinogens Cause liver, kidney, and central nervous system damage May be greater concentrations indoors than outdoors
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  • Measurement Units ppm (Parts per million) 1ppm means every 999,999 particles of air there is 1 particle of pollutant Others: ppb or nano: parts per billion ppt or pico: parts per trillion
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  • Smog Industrial: tends to be sulfur based Called grey-air smog Photochemical: nitrogen based Catalyzed by UV radiation Called brown-air smog
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  • Formation of industrial smog StepChemical Reaction 1. Carbon in coal or oil is burned in oxygen gas to produce carbon dioxide and carbon monoxide C + O CO 2 C + O CO 2. Unburned carbon ends up as soot or particulate matter C 3. Sulfur in oil and coal reacts with oxygen gas to produce sulfur dioxide S + O SO 2 4. Sulfur dioxide reacts with oxygen gas to produce sulfur trioxide SO 2 + O 2 SO 3 5. Sulfur trioxide reacts with water vapor in the air to form sulfuric acid SO 3 + H 2 O H 2 SO 4 6. Sulfuric acid reacts with atmospheric ammonia to form brown, solid ammonium sulfate H 2 SO 4 + NH 3 (NH 2 ) 2 SO 4
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  • Formation of photochemical smog Occurs during specific times of the day Net Result: NO + VOCs + O 2 + uv O 3 + PANs
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  • Formation of photochemical smog Time of day EventChemical Reactions 6 A.M. 9 A.M. People drive to work, concentrations of nitrogen oxides and VOCs increase N 2 + O2 2NO NO + VOCs NO 2 NO 2 + uv NO + O 9 A.M. 11 A.M. As traffic begins to decrease nitrogen oxides and VOCs react to form nitrogen dioxide 2NO + O 2NO 2
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  • Formation of photochemical smog cont. Time of dayEventChemical Reactions 11A.M. 4 P.M. As sunlight becomes more intentse, nitrogen dioxide is broken down and the concentration of ozone increaes NO 2 + uv NO + O O 2 + O O 3 Nitrogen dioxide reacts with water vapor to produce nitric acid and nitric oxide 3 NO 2 + H 2 O 2HNO 3 + NO Nitrogen dioxide can also react with VOCs released by vehicles, refineries, gas stations, and so on to produces toxic PANs NO 2 + VOCs PANs 4 P.M. Sunset Ozone production is halted
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  • Case Study Great Smog of 52 A period of cold weather combined with windless conditions to collect airborne pollutants (most form coal) to produce a thick layer of grey smog over London December 5 9 1952 Dispersed quickly after a change in weather 100,000 people became ill 12,000 died
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  • Catalytic Converters Converts toxic chemicals in engine exhaust to less noxious substances Inside a catalyst stimulates a chemical reaction in which noxious by-products of combustion are converted to less toxic substances
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  • Catalytic Converters 3 way converter: Reduction of nitrogen dioxides to nitrogen and oxygen Oxidation of carbon monoxide to carbon dioxide Oxidation of unburned hydrocarbons to carbon dioxide and water.
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  • Catalytic converters Pros Remove hydrocarbons and other harmful emissions Cons Do not reduce carbon dioxide emissions Release nitrous oxide which contributes to climate change
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  • Types of Acid Deposition Wet: Acid rain Acid fog Acid snow Water flows over the ground and affects plants and animals Dry Acid gases Acid particles Particles fall out of atmosphere and onto buildings, cars, trees, etc. Rain can wash particles off features in the environment contributing to acid rain
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  • Acid depositions Due to: Sulfur dioxide Nitrogen oxides Environmental effects: Acidify streams Damage forests soils through nitrogen saturation Acid shock (rapid melting of snow pack with acid particles) Leaches essential plant nutrients from the soil
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  • Heat Islands Occur in metropolitan areas Urban air is 10 F (6 C) warmer than surrounding environment
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  • Heat Islands Causes: Buildings reduce radiation of heat to the atmosphere Thermal properties of surface material (asphalt, bricks, concrete) store heat longer Lack of vegetation and standing water increase temperatures Human activities (automobiles, industry, etc.) Effects: Combined with high levels of pollution leads to a localized green house effect Excessive temperatures can lead to deaths Meteorological effects: Alter local wind patterns Alter the development of clouds and fog Alter number of lighting strikes Change precipitation patterns
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  • Wind and Urban Heat Islands
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  • Combating urban heat islands Increasing amount of landscaping in parks and on top of buildings Increasing the amount of light or reflective material
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  • Smart Cities
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  • Temperature Inversions Occur when air temperature increases with height above the ground Usually occur at night when the surface cools, cooling the air above it Can lead to smog being trapped near the ground human health problems (asthma, emphysema, and increase in lung cancer)
  • Slide 25
  • Case Study- Donora, PA 1948 Smog from the local zinc and steel smelting plants settled in the valley where Donora was located 20 people asphyxiated and 7,000 went to the hospital (total population of the town was 14,000) Four days later, wind cleared the toxins from the town Led to first meaningful federal and state laws to control air pollution
  • Slide 26
  • Indoor Air Pollution Indoor air pollution is 25% to 60% greater than outdoor pollution Sick Building Syndrome (SBS) describes a combination of ailments associated with a place of work or residence Common Pollutants: Mold Bacteria Carbon monoxide Radon Allergens Asbestos Tobacco smoke Formaldehyde VOCs
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  • SBS symptoms Headaches Breathing difficulties Allergies Asthma Cancer Emphysema Nerve disorders
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  • Air Pollution Remediation and Reduction Strategies 1. Emphasizing tax incentives for pollution control rather than fines and penalties 2. Setting legislative standards for energy efficiency 3. Increasing funding for research into renewable energy resources 4. Incorporating incentives for reducing air pollution into trade policies 5. Distributing solar cook stoves to developing countries to replace coal and firewood
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  • Air Pollution Remediation and Reduction Strategies 6. Phasing out two-cycle gasoline engines 7. For issues involving SBS a. Modify building codes to control materials used in construction b. Replace and repair areas that have received water damage to control for mold c. Use paints, adhesives, solvents, cleaning products, and pesticides in well-ventilated areas and during non- occupancy d. Increase the number of complete air exchanges in buildings e. Ensure proper maintenance of HVAC systems 8. Providing incentives to use mass transit
  • Slide 30
  • Combating Acid Rain Design more efficient engines to reduce emissions Reduce


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