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AIR POLLUTION

AIR POLLUTION. Atmosphere. 78.08% Nitrogen (N 2 ) 20.95% Oxygen (O 2 ) 0-4% Water Vapor (H 2 O) 0.93% Argon (Ar) 0.036% Carbon Dioxide (CO 2 ) 0.002% Neon (Ne) 0.005%Helium (He) 0.002% Methane (CH 4 ) 0.00005% Hydrogen (H) 0.00003% Nitrous Oxide (N 2 O) 0.000004% Ozone (O 3 ).

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AIR POLLUTION

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  1. AIR POLLUTION

  2. Atmosphere • 78.08% Nitrogen (N2) • 20.95% Oxygen (O2) • 0-4% Water Vapor (H2O) • 0.93% Argon (Ar) • 0.036% Carbon Dioxide (CO2) • 0.002% Neon (Ne) • 0.005%Helium (He) • 0.002% Methane (CH4) • 0.00005% Hydrogen (H) • 0.00003% Nitrous Oxide (N2O) • 0.000004% Ozone (O3)

  3. EFFECTS OF AIR POLLUTION • 50,000 Americans die prematurely from air-pollution related illness • Residents of polluted cities are 15-17 times more likely to die from air pollution-related illness • In 2004, 159 million Americans breathe unhealthy air (EPA) • Half of all autopsies show some degree of lung degeneration • Heart attacks & immunological disorders more likely • Worldwide, 1.3 billion live in dangerously polluted areas

  4. Outdoor air pollution • Air pollutants = gases and particulate material added to the atmosphere • Can affect climate or harm people • Air pollution = the release of pollutants • Outdoor (ambient) air pollution = pollution outside • Has recently decreased due to government policy and improved technologies in developed countries • Developing countries and urban areas still have significant problems

  5. Types of outdoor air pollution • Air pollution can come from mobile or stationary sources • Point Sources = specific spots where large quantities of pollutants are discharged (power plants and factories) • Nonpoint Sources = more diffuse, consisting of many small sources (automobiles) • Primary Pollutants = directly harmful and can react to form harmful substances (soot and carbon dioxide) • Secondary Pollutants = form when primary pollutants interact or react with constituents or components of the atmosphere (tropospheric ozone and sulfuric acid)

  6. NATURAL SOURCES OF AIR POLLUTION • Wind erosion • Sulfur compounds • Volcanoes • Sulfur compounds • Acidic plumes • Caustic particulates • Waste from living organism • Sulfur compounds • Trees & bushes • VOC’s • Pollen • Forest fires – CO2 & particulates

  7. ANTHROPOGENIC SOURCES OF AIR POLLUTION • Categories • Primary Pollutants – harmful to humans in form initially released • Secondary Pollutants – nonharmful in form released, but become toxic or hazardous after exposed to other factors • Photochemical smog • Fugitive Emissions – no single point-source, but from many nonlocalized sources • Dust from soil or mining operations • Leaking pipes

  8. CRITERIA OR CONVENTIONAL AIR POLLUTANTS • Congress passed a series of laws starting in 1955 • Defined by the EPA (Environmental Protection Agency) Clean Air Act of 1970 • Sets standards for air quality, limits on emissions • Provides funds for pollution-control research • Allows citizens to sue parties violating the standards

  9. CRITERIA OR CONVENTIONAL AIR POLLUTANTS • The Clean Air Act of 1990 • Strengthens standards for auto emissions, toxic air pollutants, acidic deposition, stratospheric ozone depletion • Introduced emissions trading • Seven Pollutants • Legal limits or National Ambient Air Quality Standards (NAAQS) • Oxides of nitrogen • Oxides of sulfur • Oxides of carbon • Volatile Organic Compounds (VOC’s) • Particulate Matter • Metals and Halogens • Photochemical Oxidants

  10. The EPA sets standards • Environmental Protection Agency (EPA) sets nationwide standards for emissions of toxic pollutants • States monitor air quality and develop, implement, and enforce regulations within their borders • If a state’s plans for implementation are not adequate, the EPA can take over enforcement

  11. Areas in the U.S. fail air quality standards

  12. OXIDES OF NITROGEN (NOx) • Formed when atmospheric nitrogen is combusted at high temperatures (above 650C) to form nitrogen dioxide • See air pollution formulas • Nitrite and nitrate form when bacteria oxidize nitrogen from the atmosphere or ammonia as part of the nitrogen cycle • See air pollution formulas • React with water to form nitrous acid and nitric acid

  13. OXIDES OF NITROGEN - SOURCES • More than ½ are anthropogenic • Power generation • Internal combustion engines (cars, trucks, planes, trains) • Feedlots & use of fertilizer

  14. OXIDES OF NITROGEN - EFFECTS • Responsible for 30% of all acid deposition • Acid rain damages waterways and wildlife, forests, plants, buildings and people • Destruction of forests leads to soil erosion • Eutrophication • Nitrate and nitrites and acids of nitrogen are essential plant nutrients • Promote photosynthesis, feeds oxygen-demanding, decomposing organisms • Reduction of DO (dissolved oxygen) • Nutrients are oxygen-demanding wastes

  15. OXIDES OF NITROGEN - REMEDIATION • Reduction • Combustion at lower temperatures • Staged burner • 1st – high temp, no oxygen • 2nd – low temp, oxygen-rich • Use pure oxygen instead of air • Catalytic converter

  16. OXIDES OF SULFUR • Sulfur dioxide is corrosive, damages tissue • Reacts with water to form sulfurous or sulfuric acid • See pollution formulas

  17. OXIDES OF SULFUR - SOURCES • Coal combustion by electric power generation stations • Coal from organic breakdown of plant material • Plants contain protein which contain sulfur • Once burned, sulfur combines with oxygen to form sulfur dioxide • Sulfur dioxide combines with water to form sulfuric or sulfurous acid • Sulfur also emitted from volcanoes

  18. OXIDES OF SULFUR - EFFECTS • Cause breathing difficulties • Combines with other ions to form particulates • Irritates lungs • Combines with water vapor to form acid rain • Responsible for 70% of acid deposition • See pollution equations

  19. OXIDES OF SULFUR - REMEDIATION • Use low sulfur coal • Use other fuel sources • Fluidized bed combustion • Coal & limestone combined • Sulfur dioxide combines with calcium & forms solid • Produces calcium sulfite CaSO3, calcium sulfate (CaSO4) and gypsum (CaSO4∙2H2O) • Flue gas desulfurization or wet scrubbing • Post-combustion gas sprayed with liquid suspension of limestone • Messy, exchanges air pollution problem with solid waste one

  20. OXIDES OF CARBON • Carbon dioxide and carbon monoxide are colorless, odorless gasses

  21. OXIDES OF CARBON - SOURCES • Produced from the combustion of carbon • Carbon monoxide results from incomplete combustion of wood or hydrocarbons • Carbon dioxide also from respiration

  22. OXIDES OF CARBON - EFFECTS • Increased amount of CO2 most probably led to global warming • CO is toxic to humans • Binds more readily to oxygen-carrying hemoglobin • Prevents transport of oxygen to tissues

  23. VOLATILE ORGANIC COMPOUNDS (VOCs) • Easily vaporized or have high vapor pressure • React to form ground-level ozone (a strong irritant)

  24. VOC’s - SOURCES • Evaporation of crude oil • Air conditioning fluids • Dry cleaning solvents • Paints • Adhesives • Building materials • Other sources

  25. VOC’s - EFFECTS • Carcinogens • Irritants • Neurotoxins • Liver and kidney toxins • Largest category of most highly toxic air pollutants

  26. VOC’s – REMEDIATION • Isolate so gas unable to escape • Adjust carburetors so less gasoline escapes • Install afterburners for more complete combustion • More complete combustion forms CO2 & H2O • Tradeoff – production of more NOx’s

  27. PARTICULATE MATTER (PM) • aka aerosols – solid or liquid particles suspended in the atmosphere • Particles small enough to be held up by the kinetic energy of the surrounding gas molecules • Includes ash (from fires or fly-ash from coal-fired power plants), dust, smoke, pollen, mildew spores, acid droplets

  28. PM - SOURCES • Erosion & desertification • Combustion of fossil fuels • Incineration • Diesel engines • Wood burning stoves & fireplaces • Volcanoes • Pollen

  29. PM - EFFECTS • Visibility reduction • Irritates lungs • Particles <2.5 µm in diameter particularly dangerous • Smaller particles more likely to be deeply inhaled and affect lung tissue • Exacerbates lung and heart disease • Linked to heart attacks, asthma, bronchitis, lung cancer and abnormal fetal development

  30. PM - REMEDIATION • Bag filters • Filter catches particles disposed of as solid waste • Electrostatic precipitators • Charged particles stick to charged plates

  31. METALS & HALOGENS • Metals enter as volatile gases (mercury), oxides or particulates • Lead and mercury are neurotoxins • Halogens are very reactive non-metals • Chlorine, fluorine, bromine, iodine • Chlorinated and fluorinated hydrocarbons (CFC’s) migrate to stratosphere and convert atmospheric O3 into O2 • Destroys ozone layer

  32. METALS & HALOGENS - SOURCES • Lead from gasoline • Mercury from coal-fired power plants & waste incinerators • Mercury switches in thermostats emit low levels of mercury vapor • CFC’s from propellants, coolants, foams, dry cleaning solvents

  33. METALS & HALOGENS - EFFECTS • Lead & mercury – decreased neurological function, permanent debilitation & death • Lead – reduced ability to metabolize food • Mercury is metabolized by microorganisms into highly toxic methyl mercury – a neurotoxin • Methyl mercury is fat-soluble, persistent, bioaccumulates & biomagnifies • Reduced ozone – skin cancer & long term biological effects

  34. METALS & HALOGENS - REMEDIATION • Unleaded gasoline • Mercury removed with electrostatic precipitation (then becomes solid waste) • Mercury will be released as long as we use coal as a source of fuel

  35. PHOTOCHEMICAL OXIDANTS • Secondary pollutants that are synthesized with the aid of solar energy • Smog – occurs in warm sunny areas with large numbers of automobiles • Most common is ozone • Produced when O splits from NO2 and joins with O2 • See air pollution formulas

  36. PHOTOCHEMICAL OXIDANTS – SOURCES & REMEDIATION • NOx’s critical to creation of ozone • Sources & remediation of photochemical oxidants same as NOx

  37. Burning fossil fuels produces industrial smog • Smog = unhealthy mixtures of air pollutants over urban areas • Industrial (gray air) smog = industries burn coal or oil • Occurs in cooler, hilly areas • Government regulations in developed countries reduced smog • Coal-burning industrializing countries face significant health risks

  38. Photochemical (brown air) smog • Produced by a series of reactions • Hot, sunny cities surrounded by mountains • Light-driven reactions of primary pollutants and normal atmospheric compounds • Morning traffic exhaust releases pollutants • Irritates eyes, noses, and throats • Vehicle inspection programs in the U.S. have decreased smog

  39. 17.16 Industrial smog Photochemical smog

  40. PHOTOCHEMICAL OXIDANTS - EFFECTS • Highly reactive and caustic to painted surfaces and lung tissue

  41. Air quality is a rural issue, too • Airborne pesticides from farms • Industrial pollutants drifting from cities, factories and powerplants • Feedlots, where cattle, hogs, or chickens are raised in dense concentrations • Voluminous amounts of methane, hydrogen sulfide, and ammonia • People living or working nearby have high rates of respiratory problems

  42. HAZARDOUS AIR POLLUTANTS (HAPs) • Cause cancer, birth defects, mutation • Neurotoxins, immunotoxins, endocrine disruptors • EPA requires companies to make public Toxic Release Inventory for any toxic materials released over the minimum amount in a year

  43. EFFECT OF GEOGRAPHY ON AIR POLLUTION • Temperature inversions in valleys • Cold air traps polluted air, cannot escape become worse with time • Increased photochemical smog

  44. EFFECT OF GEOGRAPHY ON AIR POLLUTION • Urban heat islands • Lack of cooling green vegetation & increased concrete • Concrete absorbs heat & reradiates at night • More heat from less infiltration (cities paved) • Heat holds in pollutants, especially dust & particulates • Heat deflects weather the would disperse pollutants • Global atmospheric circulation distributes pollution regionally

  45. NOISE POLLUTION • Any unwanted or undesirable anthropogenically created sound • Increases aggression & blood pressure • Includes congested traffic, loud music, airport traffic • Deafness from chronic exposure • Reduces human quality of life • May interfere with animal behavior – migration, courtships, circadian rhythms

  46. EARTH AT NIGHT

  47. LIGHT POLLUTION • Misdirected or misused light... generally resulting from an inappropriate application of exterior lighting products. • Light Pollution comes in several forms: • Sky Glow - light wastefully escaping into the night sky and causing a glow over urban/suburban areas • Glare - light shining dangerously out into peoples eyes as they walk or drive by • Light Trespass - unwanted light shining onto a neighbors property or into their home • It can confuse animal navigation, alter competitive interactions, change predator-prey relations, and cause physiological harm

  48. INDOOR AIR POLLUTION • 4 general types • Asthma triggers • Toxic building materials • Radon gas • Carbon monoxide

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