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Human Impact on the Atmosphere Human Impact on the Atmosphere Chapters 16 Air Pollution Advanced Placement Environmental Science.

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Presentation on theme: "Human Impact on the Atmosphere Human Impact on the Atmosphere Chapters 16 Air Pollution Advanced Placement Environmental Science."— Presentation transcript:

1 Human Impact on the Atmosphere Human Impact on the Atmosphere Chapters 16 Air Pollution Advanced Placement Environmental Science

2 Pollution Thorpe, 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 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 isn’t pollution that’s harming the environment. It’s the impurities in our air and water that are doing it.” Former U.S. Vice President Dan Quayle“It isn’t pollution that’s harming the environment. It’s the impurities in our air and water that are doing it.” Former U.S. Vice President Dan Quayle www.aqmd.gov/pubinfo/ 97annual.html

3 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

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 Pollutants Categories 1. Primary Pollutants- released directly from the source. 2. Secondary Pollutants: a) modified to a hazardous form after they enter the air or b) are formed by chemical reactions as components of the air mix and interact.

7 Pollution Categories 3. Fugitive Emissions are caused by soil erosion, strip mining, rock crushing and building construction. In US, fugitive dust adds up to 100 million metric tons/year.

8 Outdoor Air Pollution

9 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

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11 54 million metric tons from mobile sources in 1990

12 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 www.dr4.cnrs.fr/gif-2000/ air/products.html

13 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

14 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 @ higher temperatures, power plants, forest fires, volcanoes, bacteria in soil Class: Nitrogen oxides (NO x ) EPA Standard: 0.053 ppm

15 Mobile Source Emissions: Nitrogen Oxides

16 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

17 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

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 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

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

22 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)

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

24 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

25 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

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

28 Photochemical Smog Short Video

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

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

31 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–

32 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

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34 Air Pollution Results

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37 Indoor Air Pollution

38 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

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

40 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…”

41 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

42 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

43 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

44 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

45 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

46 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

47 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

48 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

49 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

50 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

51 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

52 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

53 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

54 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

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

56 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 http://www.epa.gov/iaq/radon/pubs/citguide.html#howdoes

57 Radon: Reducing the Risks Sealing cracks in floors and walls Simple systems using pipes and fans More information: http://www.epa.gov/iaq/radon/pubs/consguid.html#reductionte ch

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

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

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

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

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

63 Ventilation

64 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

65 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

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67 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

68 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

69 Air Pollution Prevention

70 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

71 Absorption

72 Adsorption

73 Combustion

74 Cyclone

75 Filtration

76 Electrostatic Precipitator

77 Liquid Scrubber

78 Sulfur Dioxide Control http://www.apt.lanl.gov/projects/cctc/factsheets/puair/adflugasdemo.html


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