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The Atmosphere and Air Pollution a. Origin of Modern Atmosphere original atmosphere surrounded the homogenous planet Earth and probably was composed of.

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Presentation on theme: "The Atmosphere and Air Pollution a. Origin of Modern Atmosphere original atmosphere surrounded the homogenous planet Earth and probably was composed of."— Presentation transcript:

1 The Atmosphere and Air Pollution a

2 Origin of Modern Atmosphere original atmosphere surrounded the homogenous planet Earth and probably was composed of H and He second atmosphere evolved from gases from molten Earth –H 2 O, CO 2, SO 2, CO, S 2, Cl 2, N 2, H 2, NH 3, and CH 4 –allowed formation of oceans and earliest life modern Atmosphere –evolved after Cyanobacteria started photosynthesizing –oxygen produced did not reach modern levels until about 400 million years ago

3 compared to the size of the Earth (10 4 km), the atmosphere is a thin shell (120 km). Earths Atmosphere

4 Exosphere Thermosphere (Ionosphere) Mesosphere Stratosphere Troposphere Atmosphere Layers

5 Troposphere 8 to 14.5 kilometers high (5 to 9 miles) most dense the temperature drops from about 17 to - 52 degrees Celsius almost all weather is in this region

6 Stratosphere extends to 50 kilometers (31 miles) high dry and less dense temperature in this region increases gradually to -3 degrees Celsius, due to the absorption of ultraviolet radiation ozone layer absorbs and scatters the solar ultraviolet radiation ninety-nine percent of "air" is located in first two layers every 1000-m 11% less air pressure

7 Composition Nitrogen (N 2, 78%)Nitrogen Oxygen (O 2, 21%)Oxygen Argon (Ar, 1%) myriad of other very influential components are also present which include the Water (H 2 O, 0 - 7%), "greenhouse" gases or Ozone (O 3, 0 - 0.01%), Carbon Dioxide (CO 2, 0.01-0.1%),WaterOzoneCarbon Dioxide

8 Importance of the Atmosphere Physicists – physical properties and processes that take place between the radiant energy and atmospheric gases Chemists – behavior of the chemical materials in the atmosphere the ways in which lightning causes the formation of substances chemistry of the ozone layer and of chemicals introduced from industrial processes

9 Astronomers and space scientists – the layer through which they must peer before entering the realms of space Meteorologists, climatologists and geographers –lower layers of the atmosphere predicting the weather investigating climatic regions examine the effects of climate and weather on human society

10 Outdoor Air Pollution

11 Primary Pollutants Secondary Pollutants Sources Natural Stationary CO CO 2 SO 2 NO NO 2 Most hydrocarbons Most suspended particles SO 3 HNO 3 H 2 SO 4 H2O2H2O2H2O2H2O2 O3O3O3O3PANs Most andsalts NO 3 – Mobile SO 4 2 –

12 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


14 54 million metric tons from mobile sources in 1990

15 Human Impact on Atmosphere Burning Fossil Fuels Using Nitrogen fertilizers and burning fossil fuels Refining petroleum and burning fossil fuels Manufacturing Adds CO 2 and O 3 to troposphere Global Warming Altering Climates Produces Acid Rain Releases NO, NO 2, N 2 O, and NH 3 into troposphere Produces acid rain Releases SO 2 into troposphere Releases toxic heavy metals (Pb, Cd, and As) into troposphere air/products.html

16 Criteria Air Pollutants EPA uses six "criteria pollutants" as indicators of air quality 1. Nitrogen Dioxide: NO 2 2. Ozone: ground level O 3 3. Carbon monoxide: CO 4. Lead: Pb 5. Particulate Matter: PM 10 (PM 2.5) 6. Sulfur Dioxide: SO 2 Volatile Organic Compounds: (VOCs) EPA established for each concentrations above which adverse effects on health may occur

17 Nitrogen Dioxide (NO 2 ) 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 (NO x ) EPA Standard: 0.053 ppm

18 Mobile Source Emissions: Nitrogen Oxides

19 Ozone (O 3 ) Properties: colorless, unpleasant odor, major part of photochemical smog Effects: lung irritant, damages plants, rubber, fabric, eyes, 0.1 ppm can lower PSN by 50%, Sources: Created by sunlight acting on NO x and VOC, photocopiers, cars, industry, gas vapors, chemical solvents, incomplete fuel combustion products Class: photochemical oxidants

20 Ozone (O 3 ) 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

21 Mobile Source Emissions: Hydrocarbons – Precursors to Ozone

22 Carbon Monoxide (CO) Properties: colorless, odorless, heavier than air, 0.0036% of atmosphere Effects: binds tighter to Hb than O 2, mental functions and visual acuity, even at low levels Sources: incomplete combustion of fossil fuels 60 - 95% from auto exhaust Class: carbon oxides (CO 2, CO) EPA Standard: 9 ppm 5.5 billion tons enter atmosphere/year

23 Mobile Source Emissions - CO

24 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] Sources: particulates, smelters, batteries Class: toxic or heavy metals EPA Standard: 1.5 ug/m 3 2 million tons enter atmosphere/year

25 Suspended Particulate Matter (PM 10 ) Properties: particles suspended in air (<10 um) 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/m 3 (annual mean)

26 Mobile Source Emissions: Fine Particulate Matter (PM 2.5 )

27 Sulfur Dioxide (SO 2 ) Properties: colorless gas with irritating odor Effects: produces acid rain (H 2 SO 4 ), 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) Combines with water and NH 4 to increase soil fertility

28 VOCs (Volatile Organic Compounds) Properties: organic compounds (hydrocarbons) that evaporate easily, usually aromatic Effects: eye and respiratory irritants; carcinogenic; liver, CNS, 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

29 Other Air Pollutants Carbon dioxideCarbon dioxide ChloroFluoroCarbonsChloroFluoroCarbons FormaldehydeFormaldehyde BenzeneBenzene AsbestosAsbestos ManganeseManganese DioxinsDioxins CadmiumCadmium Others not yet fully characterizedOthers not yet fully characterized

30 Factors that increase and/or decrease pollution Local climate (inversions, air pressure, temperature, humidity)Local climate (inversions, air pressure, temperature, humidity) Topography (hills and mountains)Topography (hills and mountains) Population densityPopulation density Amount of industryAmount of industry Fuels used by population and industry for heating, manufacturing, transportation, powerFuels used by population and industry for heating, manufacturing, transportation, power Weather: rain, snow,windWeather: rain, snow,wind Buildings (slow wind speed)Buildings (slow wind speed) Mass transit usedMass transit used EconomicsEconomics

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

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

33 Pollution The term Smog (smoke and fog) was first used in 1905 to describe sulfur dioxide emissionThe term Smog (smoke and fog) was first used in 1905 to describe sulfur dioxide emission In 1952, severe pollution took the lives of 5000 people in LondonIn 1952, severe pollution took the lives of 5000 people in London It isnt pollution thats harming the environment. Its the impurities in our air and water that are doing it. Former U.S. Vice President Dan QuayleIt isnt pollution thats harming the environment. Its the impurities in our air and water that are doing it. Former U.S. Vice President Dan Quayle 97annual.html

34 Photochemical Smog Primary Pollutants NO 2 + Hydrocarbons Auto Emissions UV radiation H 2 O + O 2 Secondary Pollutants HNO 3 O 3 nitric acidozone Photochemical Smog

35 Solar radiation Ultraviolet radiation NO Nitric oxide P h o t o c h e m i c a l S m o g H 2 O Water NO 2 Nitrogen dioxide Hydrocarbons O 2 Molecular oxygen HNO 3 Nitric acid PANs Peroxyacyl nitrates Aldehydes (e.g., formaldehyde) O 3 Ozone O Atomic oxygen Photochemical Smog

36 Indoor Air Pollution

37 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

38 Exposure Time spent in various environments in US and less-developed countries

39 House of Commons Select Committee Enquiry on Indoor Air Pollution (1991) [There is] evidence that 3 million people have asthma in the UK… and this is increasing by 5% per annum. Overall there appears to be a worryingly large number of health problems which could be connected with indoor pollution and which affect very large numbers of the population. [The Committee recommends that the Government] develop guidelines and codes of practice for indoor air quality in buildings which specifically identify exposure limits for an extended list of pollutants…

40 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 moulds Outdoor air

41 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

42 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 kitchens can readily exceed WHO and EPA standards

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

44 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

45 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 aetiology of multiple chemical sensitivity; also implicated in sick building syndrome

46 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

47 Health Effects Fungi and bacteria Dampness and mould-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

48 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

49 Health Effects Fine particles Consistent evidence that exposure to small airborne particles (e.g. PM10) 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

50 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

51 Radon Risk: Non-Smoker Radon Level (pCI/L) If 1000 people who did not smoke were exposed to this level over a lifetime.. About X would get lung cancer This risk of cancer from radon exposure compares to … What to do: 208Being killed in a violent crime Fix your home 104Fix your home 8310x risk of dying in a plane crash Fix your home 42Risk of drowningFix your home 2<1Risk of dying in a home fire Fix your home 1.3<1Average indoor radon levelFix your home 0.4<1Average indoor radon levelFix your home If you are a former smoker, your risk may be higher

52 Radon Risk: Smoker Radon Level (pCI/L) If 1000 people who smoke were exposed to this level over a lifetime.. About X would get lung cancer This risk of cancer from radon exposure compares to … What to do: Stop smoking and … 20135100x risk of drowningFix your home 1071100x risk of dying in a home fire Fix your home 857Fix your home 429100x risk of dying in a plane crash Fix your home 2152x the risk of dying in a car crash Fix your home 1.39Average indoor radon levelFix your home 0.43Average indoor radon levelFix your home If you are a former smoker, your risk may be lower

53 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

54 (From: Zone pCi/L 1 >4 2 2 - 4 3 <2

55 Radon: How it Enters Buildings Cracks in solid floors Construction joints Cracks in walls Gaps in suspended floors Gaps around service pipes Cavities inside walls The water supply

56 Radon: Reducing the Risks Sealing cracks in floors and walls Simple systems using pipes and fans More information: ech

57 Sick Building Syndrome (SBS) vs Building Related Illness (BRI)

58 Sick Building Syndrome A persistent set of symptoms in > 20% population Causes(s) not known or recognizable Complaints/Symptoms relieved after exiting building

59 Complaints/Symptoms Headaches Fatigue Reduced Mentation Irritability Eye, nose or throat irritation Dry Skin Nasal Congestion Difficulty Breathing Nose Bleeds Nausea

60 Building Related Illness Clinically Recognized Disease Exposure to indoor air pollutants Recognizable Causes

61 Clinically Recognized Diseases –Pontiac Fever – Legionella spp. –Legionnaire's Disease –Hypersensitivity Pneumonitis –Humidifier Fever –Asthma –Allergy –Respiratory Disease Chronic Obstructive Pulmonary Disease

62 Ventilation

63 Movement of Air Into / Out of Homes Amount of air available to dilute pollutants –important indicator of the likely contaminant concentration Indoor air can mix with outside air by three mechanisms –infiltration –natural ventilation –forced ventilation

64 Movement of Air Into / Out of Homes Infiltration –natural air exchange that occurs between a building and its environment when the doors and windows are closed –leakage through holes or openings in the building envelope –pressure induced due to pressure differentials inside and outside of the building especially important with cracks and other openings in wall

65 Movement of Air Into / Out of Homes Infiltration –Temperature induced (stack effect) driven by air movement through holes in floors, ceilings in winter, warm air in a building wants to rise, exits through cracks in ceiling and draws in

66 Movement of Air Into / Out of Homes Natural ventilation –air exchange that occurs when windows or doors are opened to increase air circulation Forced ventilation –mechanical air handling systems used to induce air exchange using fans and blowers Trade-offs –cut infiltration to decrease heating and cooling costs vs. indoor air quality problems

67 Movement of Air Into / Out of Homes Infiltration rates –Influenced by how fast wind is blowing, pressure differentials temperature differential between inside and outside of house location of leaks in building envelope

68 Air Pollution Prevention

69 The Clean Air Act 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

70 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

71 Clean Air Act 1990 version –Acid rain, urban smog, toxic air pollutants, ozone depletion, marketing pollution rights, VOCs 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

72 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

73 Clean Air Act Title I - Air Pollution Prevention and Control –Part A - Air Quality and Emission Limitations –Part B - Ozone Protection (replaced by Title VI) –Part C - Prevention of Significant Deterioration of Air Quality –Part D - Plan Requirements for Nonattainment Areas Title II - Emission Standards for Moving Sources –Part A - Motor Vehicle Emission and Fuel Standards –Part B - Aircraft Emission Standards –Part C - Clean Fuel Vehicles Title III - General Title IV - Acid Deposition Control Title V - Permits Title VI - Stratospheric Ozone Protection

74 Specific Air Pollution Treatment Technology Traditional –Move factory to remote location –Build taller smokestack so wind blows pollution elsewhere New –Biofiltration : vapors pumped through soil where microbes degrade –High-energy destruction: high-voltage electricity –Membrane separation: diffusion of organic vapors through membrane –Oxidation: High temperature combustor

75 Absorption

76 Adsorption

77 Combustion

78 Cyclone

79 Filtration

80 Electrostatic Precipitator

81 Liquid Scrubber

82 Sulfur Dioxide Control

83 Air Pollution Results


85 Comparison of 1970 and 1999 Emissions




89 Number of People Living in Counties with Air Quality Concentrations Above the Level of the National Ambient Air Quality Standards (NAAQS) in 1999

90 Trends in Sulfur Dioxide Emissions Following Implementation of Phase I of the Acid Rain Program: Total State-level Utility SO2 (1980, 1990, 1999)

91 Fifty Years of Air Pollution Figures are in millions of metric tons per year

92 Mobile Sources: The Last Ten Years -10% -29% -8% -85% -3% -24% VOCs CO NO x PM 10 SO x Lead Percent reductions shown are based on estimates of tons/year from mobile sources over the 1981 - 1990 time period

93 Who is Affected by Air Pollution? 63 22 9 19 1 5 Ozone CO NO 2 PM 10 SO 2 Lead Millions of people living in counties with air quality that exceeds each NAAQS (1990 data) Over 74 million people are subjected to high levels of at least one of these pollutants

94 Milestones in the Control of Automotive Emissions 1952 - Autos linked to air pollution 1963 - Original CAA, PCV valves 1968 - HC & CO exhaust controls 1970 - CAA amendments, EPA formed 1971 - Evaporative controls 1972 - First I/M Program 1973 - NOx exhaust controls 1975 - First catalytic converters 1981 - New cars meet statutory limits 1989 - Volatility limits on gasoline 1990 - New CAA Amendments

95 1987 Montreal Protocol: CFC emissions should be reduced by 50% by the year 2000 (they had been increasing 3% per year.) 1990 London amendments: production of CFCs, CCl4, and halons should cease entirely by 2000. 1992 Copenhagen agreements: phase- out accelerated to 1996.

96 Goals of Kyoto Protocol Reduction of greenhouse gases to below 1990 levels: 5.2% world wide reduction on average by 2008- 2012 6% for Canada by 2008-2012 When sufficient countries ratify the Protocol (at least 55 countries comprising at least 55% of emissions), Protocol comes into effect USA - 25% of emissions

97 Kyoto Emissions Agreement

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