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Human Impact on the Atmosphere
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  1. Human Impact on the Atmosphere Advanced Placement Environmental Science

  2. PollutionThorpe, Gary S., M.S., (2002). Barron’s How to prepare for the AP Environmental Science Advanced Placement Exam • The term “Smog” (smoke and fog) was first used in 1905 to describe sulfur dioxide emission • “It isn’t pollution that’s harming the environment. It’s the impurities in our air and water that are doing it.” FormerU.S. Vice President Dan Quayle www.aqmd.gov/pubinfo/ 97annual.html

  3. TheCleanAirAct Congress found: • Most people now live in urban areas • Growth results in air pollution • Air pollution endangers living things It decided: • Prevention and control at the source was appropriate • Such efforts are the responsibility of states and local authorities • Federal funds and leadership are essential for the development of effective programs

  4. Clean Air Act • Originally signed 1963 • States controlled standards • 1970 – Uniform Standards by Federal Govt. • Criteria Pollutants • Primary – Human health risk • Secondary – Protect materials, crops, climate, visibility, personal comfort

  5. Clean Air Act • 1990 version • Acid rain, urban smog, toxic air pollutants, ozone depletion, marketing pollution rights, VOC’s • 1997 version • Reduced ambient ozone levels • Cost $15 billion/year -> save 15,000 lives • Reduce bronchitis cases by 60,000 per year • Reduce hospital respiratory admission 9000/year

  6. Clean Air Act President George W. Bush signed rules amending Clean Air Act that allowed power plants and other industries to increase pollution significantly without adopting control measures

  7. http://www.cnn.com/2003/LAW/12/24/bush.clean.air.ap/index.htmlhttp://www.cnn.com/2003/LAW/12/24/bush.clean.air.ap/index.html Appeals court blocks Bush clean air changes Wednesday, December 24, 2003 Posted: 2:10 PM EST (1910 GMT) WASHINGTON (AP) --A federal appeals court on Wednesday blocked new Bush administration changes to the Clean Air Act from going into effect the next day, in a challenge from state attorneys general and cities that argued they would harm the environment and public health.

  8. Outdoor Air Pollution

  9. Primary Pollutants CO CO2 Secondary Pollutants SO2 NO NO2 SO3 Most hydrocarbons HNO3 H2SO4 Most suspended particles H2O2 O3 2 – NO3 and salts SO4 Most – Natural Sources Stationary Mobile

  10. Major Sources of Primary Pollutants Stationary Sources • Combustion of fuels for power and heat – Power Plants • Other burning such as Wood & crop burning or forest fires • Industrial/ commercial processes • Solvents and aerosols Mobile Sources • Highway: cars, trucks, buses and motorcycles • Off-highway: aircraft, boats, locomotives, farm equipment, RVs, construction machinery, and lawn mowers

  11. 54 million metric tons from mobile sources in 1990

  12. Human Impact on Atmosphere • Adds CO2 and O3 to troposphere • Global Warming • Altering Climates • Produces Acid Rain • Releases NO, NO2, and NH3 into troposphere • Produces acid rain • Releases SO2 into troposphere • Releases toxic heavy metals (Pb, Cd, and As) into troposphere • Burning Fossil Fuels • Using Nitrogen fertilizers and burning fossil fuels • Refining petroleum and burning fossil fuels • Manufacturing www.dr4.cnrs.fr/gif-2000/ air/products.html

  13. Criteria Air Pollutants EPA uses six "criteria pollutants" as indicators of air quality • Nitrogen Dioxide: NO2 • Ozone: ground level O3 • Carbon monoxide: CO • Lead: Pb • Particulate Matter • Sulfur Dioxide: SO2 • Volatile Organic Compounds: (VOCs) EPA established for each concentrations above which adverse effects on health may occur

  14. Nitrogen Dioxide (NO2) • Properties: reddish brown gas, formed as fuel burnt in car, strong oxidizing agent, forms Nitric acid in air • Effects: acid rain, lung and heart problems, decreased visibility (yellow haze), suppresses plant growth • Sources: fossil fuels combustion, power plants, forest fires, volcanoes, bacteria in soil • Class: Nitrogen oxides (NOx) • EPAStandard: 0.053 ppm

  15. Mobile Source Emissions: Nitrogen Oxides

  16. Ozone (O3) • Properties: colorless, unpleasant odor, major part of photochemical smog • Effects: lung irritant, damages plants, rubber, fabric, eyes, 0.1 ppm shows effects • Sources: Created by sunlight acting on NOx and VOC , photocopiers, cars, industry, gas vapors, chemical solvents, incomplete fuel combustion products • Class: photochemical oxidants

  17. Ozone (O3) • 10,000 to 15,000 people in US admitted to hospitals each year due to ozone-related illness • Children more susceptible • Airways narrower • More time spent outdoors

  18. Mobile Source Emissions: Hydrocarbons – Precursors to Ozone

  19. Carbon Monoxide (CO) • Properties:colorless, odorless, heavier than air, 0.0036% of atmosphere • Effects:binds tighter to Hb than O2, mental functions and visual acuity, even at low levels • Sources:incomplete combustion of fossil fuels 60 - 95% from auto exhaust • Class:carbon oxides (CO2, CO) • EPAStandard:9 ppm • 5.5 billion tons enter atmosphere/year

  20. Mobile Source Emissions - CO

  21. Lead (Pb) • Properties: grayish metal • Effects: accumulates in tissue; affects kidneys, liver and nervous system (children most susceptible); mental retardation; possible carcinogen; 20% of inner city kids have high lead levels • Sources: particulates, smelters, batteries • Class:toxic or heavy metals • EPAStandard: 1.5 ug/m3 • 2 million tons enter atmosphere/year

  22. Suspended Particulate Matter (PM10) • Properties: particles suspended in air (<10 um) (1/1000000th of a meter) • Effects: lung damage, mutagenic, carcinogenic, teratogenic • Sources:burning coal or diesel, volcanoes, factories, unpaved roads, plowing, lint, pollen, spores, burning fields • Class: SPM: dust, soot, asbestos, lead, PCBs, dioxins, pesticides • EPA Standard: 50 ug/m3 (annual mean)

  23. Mobile Source Emissions: Fine Particulate Matter (PM2.5)

  24. Sulfur Dioxide (SO2) • Properties: colorless gas with irritating odor • Effects: produces acid rain (H2SO4), breathing difficulties, eutrophication due to sulfate formation, lichen and moss are indicators • Sources:burning high sulfur coal or oil, smelting or metals, paper manufacture • Class: sulfur oxides • EPA Standard: 0.3 ppm (annual mean)

  25. VOCs (Volatile Organic Compounds) • Properties: organic compounds (hydrocarbons) that evaporate easily, usually aromatic • Effects: eye and respiratory irritants; carcinogenic; liver, or kidney damage; damages plants; lowered visibility due to brown haze; global warming • Sources:vehicles(largest source),evaporation of solvents or fossil fuels, aerosols, paint thinners, dry cleaning • Class: HAPs (Hazardous Air Pollutants) • Methane • Benzene • Chlorofluorocarbons (CFCs), etc. • Concentrations indoors up to 1000x outdoors • 600 million tons of CFCs

  26. Other Air Pollutants • Carbon dioxide • ChloroFluoroCarbons • Formaldehyde • Benzene • Asbestos • Manganese • Dioxins • Cadmium • Others not yet fully characterized

  27. Formation & Intensity Factors • Local climate (inversions, air pressure, temperature, humidity) • Topography (hills and mountains) • Population density • Amount of industry • Fuels used by population and industry for heating, manufacturing, transportation, power • Weather: rain, snow,wind • Buildings (slow wind speed) • Mass transit used • Economics

  28. Thermal Inversion cool air Pollutants cool air warm air (inversion layer) warm air • surface heated by sun • warm air rises (incl. pollutants) • cools off, mixes with air of equal density & disperses • surface cools rapidly (night) • a layer of warm air overlays surface • polluted surface air rises but cannot disperse ⇒ remains trapped

  29. Smog Forms ...when polluted air is stagnant (weather conditions, geographic location) Los Angeles, CA

  30. Photochemical Smog UV radiation H2O + O2 Primary Pollutants NO2 + Hydrocarbons Secondary Pollutants HNO3 O3 nitric acid ozone Photochemical Smog Auto Emissions

  31. Solar radiation Photochemical Smog Ultraviolet radiation NO Nitric oxide O Atomic oxygen O2 Molecular oxygen NO2 Nitrogen dioxide H2O Water Hydrocarbons PANs Peroxyacyl nitrates Aldehydes (e.g., formaldehyde) O3 Ozone HNO3 Nitric acid P h o t o c h e m i c a l S m o g

  32. Indoor Air Pollution

  33. Why is indoor air quality important? • 70 to 90% of time spent indoors, mostly at home • Many significant pollution sources in the home (e.g. gas cookers, paints and glues) • Personal exposure to many common pollutants is driven by indoor exposure • Especially important for susceptible groups – e.g. the sick, old and very young

  34. Exposure • Time spent in various environments in US and less-developed countries

  35. Sources of Indoor Air Pollutants • Building materials • Furniture • Furnishings and fabrics • Glues • Cleaning products • Other consumer products • Combustion appliances (cookers and heaters) • Open fires • Tobacco smoking • Cooking • House dust mites, bacteria and molds • Outdoor air

  36. Important Indoor Air pollutants • Nitrogen dioxide • Carbon monoxide • Formaldehyde • Volatile Organic Compounds (VOCs) • House dust mites (and other allergens, e.g. from pets) • Environmental tobacco smoke • Fine particles • Chlorinated organic compounds (e.g. pesticides) • Asbestos and man-made mineral fibres • Radon

  37. Health Effects Nitrogen dioxide • Respiratory irritant • Elevated risk of respiratory illness in children, perhaps resulting from increased susceptibility to respiratory infection; inconsistent evidence for effects in adults • Concentrations in houses can readily exceed WHO and EPA standards

  38. Health Effects Carbon monoxide • An asphyxiant and toxicant • Hazard of acute intoxication, mostly from malfunctioning fuel-burning appliances and inadequate or blocked flutes • Possibility of chronic effects of long-term exposure to non- lethal concentrations, particularly amongst susceptible groups

  39. Health Effects Formaldehyde • Sensory and respiratory irritant and sensitizer • Possible increased risk of asthma and chronic bronchitis in children at higher exposure levels • Individual differences in sensory and other transient responses • Caution over rising indoor concentrations

  40. Health Effects Volatile Organic Compounds (VOCs) • Occur in complex and variable mixtures • Main health effects relate to comfort and well-being, but benzene (and other VOCs) are carcinogenic • Concern about possible role of VOCs in the development of multiple chemical sensitivity; also implicated in sick building syndrome

  41. Health Effects House dust mites • House dust mites produce Der p1 allergen, a potent sensitizer • Good evidence of increased risk of sensitization with increasing allergen exposure, but this does not necessarily lead to asthma • Small reductions in exposure will not necessarily lead to reduced incidence and/or symptoms • Indoor humidity is important

  42. Health Effects Fungi and bacteria • Dampness and mold-growth linked to self-reported respiratory conditions, but little convincing evidence for association between measured airborne fungi and respiratory disease • Insufficient data to relate exposure to (non-pathogenic) bacteria to health effects in the indoor environment

  43. Health Effects Environmental tobacco smoke (ETS) • Sudden infant death syndrome • Lower respiratory tract illness • Middle ear disease • Asthma 12 million children exposed to secondhand smoke in homes

  44. Health Effects Fine particles • Consistent evidence that exposure to small airborne particles in ambient air can impact on human health; mechanisms uncertain • Chronic Obstructive Pulmonary Disease and Cardiovascular Disease patients and asthmatics probably at extra risk • Relative importance of indoor sources is unknown

  45. Health Effects Radon • Can cause lung cancer • Estimated that 7,000 to 30,000 Americans die each year from radon-induced lung cancer • Only smoking causes more lung cancer deaths • Smokers more at risk than non-smokers

  46. Radon Risk: Non-Smoker If you are a former smoker, your risk may be higher

  47. Radon Risk: Smoker If you are a former smoker, your risk may be lower

  48. Radon • 55% of our exposure to radiation comes from radon • colorless, tasteless, odorless gas • formed from the decay of uranium • found in nearly all soils • levels vary

  49. (From: http://www.epa.gov/iaq/radon/zonemap.html) Zone pCi/L 1 >4 2 2 - 4 3 <2