1. 1 Air Pollution

2. 2 Outline Natural Sources Human-Caused Air Pollution  Conventional Pollutants  Unconventional Pollutants  Indoor Air Pollution Climate and Topography Effects of Air Pollution Air Pollution Control Clean Air Legislation Current Conditions and Future Prospects

3. 3 THE AIR AROUND US Approximately 147 million metric tons of air pollution are released annually into the atmosphere in the U.S. by human activities.  Worldwide emissions total around 2 billion metric tons. Developed countries have been improving air quality, while air quality in developing world is getting worse.

4. 4 NATURAL SOURCES OF AIR POLLUTION Natural Fires - Smoke Volcanoes - Ash and acidic components Sea Spray - Sulfur Vegetation - Volatile organic compounds Bacterial Metabolism - Methane Dust  Pollen Viruses and Bacteria

5. 5 HUMAN-CAUSED AIR POLLUTION Primary Pollutants - Released directly from the source.  Aerosols, soot, smoke, CO Secondary Pollutants - Modified to a hazardous form after entering the air and mixing with other environmental components.  NO 2 and SO 2 mix with H 2 O to form nitric acid and sulfuric acid  Fugitive Emissions - Do not go through smokestack. - Dust from human-activities.

6. 6 Conventional Pollutants U.S. Clean Air Act designated seven major (conventional or criteria) pollutants for which maximum ambient air levels are mandated.  Sulfur Dioxide  Nitrogen Oxides  Carbon Oxides  Particulate Matter  Metals and Halogens  Volatile Organic Compounds

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8. 8 Conventional Pollutants Sulfur Compounds  Natural sources of sulfur in the atmosphere include evaporation from sea spray, volcanic fumes, and organic compounds.  Predominant form of anthropogenic (anthro – human, genic – creation) sulfur is sulfur- dioxide from fossil-fuel combustion. - Annual Emissions: 114 million metric tons

9. 9 Conventional Pollutants Nitrogen Compounds  Nitrogen oxides are reactive gases formed when nitrogen is heated above 650 o C in the presence of oxygen, or when nitrogen compounds are oxidized. - Annual Emissions: 230 million metric tons

10. 10 Conventional Pollutants Carbon Oxides  Predominant form of carbon in the air is carbon dioxide. - Increasing levels due to human activities. - Annual Emissions: 7-8 billion metric tons  Carbon monoxide is a colorless, odorless, toxic gas produced by incomplete fuel combustion. - Annual Emissions: 1 billion metric tons

11. 11 Conventional Pollutants Particulate Matter  Atmospheric aerosols (solid or liquid) - Respirable particles smaller than 2.5 micrometers are among most dangerous.  Anthropogenic particulate emissions amount to about 362 million metric tons annually.

12. 12 Conventional Pollutants Metals  Many toxic metals occur as trace elements in fuel. - Lead Emissions: 2 million metric tons.  Mercury - Bioaccumulation in aquatic ecosystems.  Nickel, beryllium, cadmium, arsenic… Halogens (Fluorine, Chlorine, Bromine)  CFC’s

13. 13 Conventional Pollutants Volatile Organic Compounds  Organic chemicals - Generally oxidized to CO and CO 2. - Plants are largest source. Photochemical Oxidants  Products of secondary atmospheric reactions driven by solar energy. - Ozone formed by splitting nitrogen dioxide.

14. 14 Air Toxins Hazardous Air Pollutants  Require special reporting and management as they remain in ecosystems for a long period of time, and tend to accumulate in animal tissues.  Toxic Release Inventory - Established 1986

15. 15 Unconventional Pollutants Aesthetic Degradation  Noise, odor, light pollution. - Reduce quality of life.

16. 16 Indoor Air Pollution EPA found indoor concentrations of toxic air pollutants are often higher than outdoor.  People generally spend more time indoors.  Smoking is the most important air pollutant in the U.S.. - 400,000 die annually from a disease related to smoking.  Associated costs are estimated at $100 billion annually.

17. 17 Indoor Air Pollution Less Developed Countries also suffer from indoor air pollution.  Organic fuels make up majority of household energy. - Often burned in smoky, poorly ventilated heating and cooking fires.

18. 18 Smog! Two types  Grey smog (aerosols from smoke, sulfur dioxide, sulfuric acid droplets)  Photochemical smog (brown smog) sunlight reacts with secondary pollutants creating a more toxic smog; Polyaromatic Hydrocarbons (PAH)

19. 19 Conditions conducive to smog Sunny, dry conditions Topography Population size Form of energy used Size of buildings Amount of precipitation Amount of industry and pollution controls

20. 20 CLIMATE AND TOPOGRAPHY Inversions  Temperature inversions occur when a stable layer of warm air overlays cooler air, reversing the normal temperature decline with increasing height, and preventing convection currents from dispersing pollutants. - Cold front slides under warm air mass. - Cool air subsides down slope.  Rapid nighttime cooling in a basin.

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22. 22 Dust Domes and Heat Islands Sparse vegetation and large amounts of concrete and glass create warm, stable air masses, heat islands, over large cities.  Concentrates pollutants in a “dust dome”. - Rural areas downwind from major industrial areas often have significantly decreased visibility and increased rainfall.

23. 23 Long-Range Transport or Transboundary Pollution Fine aerosols can be carried great distances by the wind.  Increasingly, sensitive monitoring equipment has begun to reveal industrial contaminants in places usually considered among the cleanest in the world. - Contaminants trapped by winds at the north pole, concentrate at high latitudes and eventually fall out as snow and ice and enter the food chain.

24. 24 Long-Range Transport

25. 25 Pollution and Progress Dark or medium green; highly developed Pea green – developing Other colors - underdeveloped

26. 26 Ways to Combat Pollution in Developing and Underdeveloped Countries Give them the advanced technology in exchange for  Carbon cap and trade allowances  Exchange of goods or resources/purchasing from developed countries

27. 27 Stratospheric Ozone Discovered in 1985 that stratospheric ozone levels were dropping rapidly during September and October.  Occurring since at least 1960. At ground-level, ozone is a pollutant, but in the stratosphere it screens UV radiation.  A 1% decrease in ozone results in a 2% increase in UV rays reaching the earth.

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29. 29 Stratospheric Ozone Circumpolar vortex isolates Antarctic air and allows stratospheric temperatures to drop and create ice crystals at high altitudes.  Absorb ozone and chlorine molecules. - When sun returns in the spring, energy liberates the chlorine allowing the depletion process to proceed rapidly.  CFCs believed to be main culprit.  Persist for decades.  Production eliminated in 1996.

30. 30 CFC’s or Chlorofluorcarbons Propellants added to spray cans to help move the wanted chemical out Found in ALL spray cans up until 1986

31. 31 Destruction of Stratospheric Ozone http://www.nasa.gov/vision/earth/environment/ozone_hole101.html

32. 32 Ground Level Ozone How ozone is formed http://airnow.gov/index.cfm?action=movie.ma in http://airnow.gov/index.cfm?action=movie.ma in

33. 33 Air Pollution Trends, 1990-2000 Rising levels of pollution Lack of laws to curb emissions

34. 34 EFFECTS OF AIR POLLUTION Human Health  EPA estimates each year 50,000 U.S. citizens die prematurely from illnesses related to air pollution. - Likelihood of suffering ill health is related to intensity and duration of exposure.  Inhalation is the most common route, but absorption through the skin and consumption via food can also occur.

35. 35 Global Distribution of Deaths from Air Pollution

36. 36 Human Health Bronchitis  Persistent inflammation of airways in the lung that causes mucus build-up and muscle spasms constricting airways. - Can lead to emphysema - irreversible chronic obstructive lung disease in which airways become permanently constricted and alveoli are damaged or destroyed. - http://airnow.gov/index.cfm?action=movi e.main Air Aware video http://airnow.gov/index.cfm?action=movi e.main

37. 37 Human Health Asthma  Chronic condition where trachea and bronchioles swell, reducing air volume to lungs  Highest rates seen among inner city minorities due to home location near industry (industrial racism)

38. 38 Plant Pathology Chemical pollutants can directly damage plants, or can cause indirect damage by disrupting normal growth and development patterns.  Certain environmental factors have synergistic effects in which the injury caused by the combination is more than the sum of the individual exposures. - Pollutant levels too low to cause visible effects may still be damaging. Synegy – simultaneous joint action of separate substances/factions/factors which, together, have greater total effect than the sum of their individual effects.

39. 39 Acid Deposition pH and Atmospheric Acidity  pH scale ranges from 0-14. - 7 = Neutral; 7 = Basic  Unpolluted rain generally has ph of 5.6. - Carbonic acid from atmospheric CO 2.  In industrialized areas, anthropogenic acids in the air often outweigh natural sources of acid.

40. 40 Acid Precipitation

41. 41 Acid Deposition Aquatic Effects  Thin, acidic soils and oligotrophic lakes* of southern Norway and Sweden have been severely affected by acid deposition. - Generally, reproduction is the most sensitive stage in fish life cycles.  In early 1970’s, evidence began to accumulate suggesting air pollutants are acidifying many N.A. lakes. *lakes are clear and blue, with very low levels of nutrients and algae

42. 42 Acid Deposition Forest Damage  Air pollution and depositions of atmospheric acids are believed to be important causes of forest destruction in many areas. Buildings and Monuments  Limestone and marble are destroyed by air pollution at an alarming rate.  Corroding steel in reinforced concrete weakens buildings, roads, and bridges.

43. 43 AIR POLLUTION CONTROL Reducing Production  Particulate Removal - Remove particles physically by trapping them in a porous mesh which allows air to pass through but holds back solids. - Electrostatic Precipitators - Fly ash particles pick up electrostatic charge as they pass between large electrodes in waste stream, and accumulate on collecting plate.

44. 44 AIR POLLUTION CONTROL Reducing Production  Particulate Removal - Remove particles physically by trapping them in a porous mesh which allows air to pass through but holds back solids.  Sulfur Removal - Switch from soft coal with a high sulfur content to low sulfur coal. - Change to another fuel (natural gas).

45. 45 Air Pollution Control Nitrogen Oxides  Best method is to prevent creation. - Staged Burners - Selective Catalysts Hydrocarbon Control  Use closed systems to prevent escape of fugitive emissions.

46. 46 Scrubbers Dry scrubber rods electronically attract dry aerosols Sulfur scrubbers remove sulfuric acid and sulfur compounds from smoke Wet scrubbers spray the dirty air to remove particles from the bottom

47. 47 Modern Automobile Emission-Control System

48. 48 CLEAN AIR LEGISLATION Clean Air Act (1963) - First national air pollution control. Clean Air Act (1970) rewrote original.  Identified critical pollutants.  Established ambient air quality standards. - Primary Standards - Human health - Secondary Standards - Materials, environment, aesthetic and comfort.

49. 49 Clean Air Act Revision (1990) - Included provision for:  Acid Rain  Urban Smog  Toxic Air Pollutants  Ozone Protection  Marketing Pollution Rights  Volatile Organic Compounds  Ambient Ozone  No x Emissions Revision (1997) - Stricter standards Latest revision (2007) – ruling by Supreme Court mandates inclusion of carbon dioxide in CAA

50. 50 CURRENT CONDITIONS AND FUTURE PROSPECTS In the United States, air quality has improved dramatically in the last decade in terms of major large-volume pollutants.  Cities where pollution is largely from traffic still have serious air quality problems. Major metropolitan areas of many developing countries are growing at explosive rates, and environmental quality is very poor.

51. 51 Air Pollution in Developing Countries Many metropolitan areas of developing countries are growing at explosive rates.  Mexico City - Pollution levels exceed WHO health standards 350 days per year.  China’s 400,000 factories have no air pollution controls.  Bangkok, Thailand reduced their air pollution by combining sensible regulations like tailpipe emissions standards, simple fixes like street washing, and a substantial mass-transit expansion; have air standards similar to European standards

52. 52 Signs of Hope Sweden and West Germany cut their sulfur emission by two-thirds between 1970 and 1985. Australia and Switzerland even regulate motorcycle emissions. South Coast Air Quality Management District in California has adopted rules to clean the air in the Los Angeles Basin.

53. 53 Summary Natural Sources Human-Caused Air Pollution  Conventional Pollutants  Unconventional Pollutants  Indoor Air Pollution Climate and Topography Effects of Air Pollution Air Pollution Control Clean Air Legislation Current Conditions and Future Prospects

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