1. Chapter 9: Air Quality

2. The Atmosphere and Climate

3. The atmosphere has four distinct zones of contrasting temperature.

4. Energy and the "Greenhouse Effect"

5. Greenhouse Gases Carbon Dioxide - Fossil-fuel burning. Accounts for majority of global warming Methane - Ruminants, Coal-mines Absorbs more infrared than CO 2. Chlorofluorocarbons (CFC’s) - Refrigerants Declined in recent years Nitrous Oxide - Burning organic material Sulfur Hexafluoride - Electrical insulation

6. Climate and Air Pollution Over the past 20 years, developed countries have made progress in improving air quality. Unfortunately, air quality in the developing world has been getting worse.

7. © 2013 Pearson Education, Inc. 9.1 Air Quality and Air Pollution Air quality –Gases and small particles in atmosphere that influence ecosystems or human well-being Air pollution –Gases or particles that are high enough concentrations to harm humans, organisms, or structures

8. © 2013 Pearson Education, Inc. 9.1 Air Quality and Air Pollution Gases of atmosphere –Nitrogen (N 2 ), oxygen (O 2 ), argon (Ar) over 99% of atmosphere Trace gases –Present in concentrations of parts per million Some stable Others vary widely in place and time

9. © 2013 Pearson Education, Inc. 9.1 Air Quality and Air Pollution Volatile organic compounds (VOCs) –Chemicals that vaporize into air –Wide range of chemicals –Natural or anthropogenic Aerosols –Tiny solid and liquid particles suspended in air –Clouds and fog –Size of particle determines residence time

10. © 2013 Pearson Education, Inc. Natural Sources of Air Pollution Natural fires – Smoke Volcanoes – Ash, Acid, Hydrogen Sulfide Sea Spray – Sulfur Vegetation – Volatile Organic Compounds Organic Material in Air (Dust, Pollen, Viruses, Bacteria, etc) – Allergies and Infections Bacterial Metabolism - Methane

11. © 2013 Pearson Education, Inc. Major Air Pollutants: Problems Sulfur dioxide - acid rain, health damage, visibility reduction Nitrogen oxides - acid rain, eutrophication, growth of weedy species Carbon monoxide - inhibited respiration Lead and mercury - neurological damage Chlorofluorocarbons - ozone depletion Particulate matter - lung damage, cancer Volatile organic compounds - CO, CO 2 production in the atmosphere

12. © 2013 Pearson Education, Inc. Conventional Pollutants U.S. Clean Air Act designated seven major (conventional or criteria) pollutants for which maximum ambient air levels are mandated. –Sulfur Dioxide –Carbon Monoxide –Particulates –Hydrocarbons –Nitrogen Oxides –Photochemical Oxidants –Lead

13. © 2013 Pearson Education, Inc. Other Major Pollutants Unconventional Pollutants –Compounds produced in less volume than conventional pollutants, but are especially toxic or hazardous. Aesthetic Degradation –Reduce quality of life.

14. © 2013 Pearson Education, Inc. 9.1 Air Quality and Air Pollution Primary air pollutants –Chemicals or particles directly released in air Secondary air pollutants –Chemicals and particles that are formed by reaction of other chemicals or aerosols in the atmosphere Ozone (O 3 ) –Photochemicals Secondary pollutants facilitated by sunlight

15. © 2013 Pearson Education, Inc. 9.1 Air Quality and Air Pollution Dispersion and deposition –Distance and direction pollution travels determined by three factors Airflow patterns –Temperature inversion Warm air forms above cold air, trapping pollutants near ground Height of emission Time in atmosphere –Dry deposition, wet deposition

16. © 2013 Pearson Education, Inc. 9.2 Pollution in the Troposphere Pollution in troposphere –Three types with greatest impact on humans/ecosystems Acid deposition –Acid rain/snow/fog Heavy metal pollution –Mercury/lead from fossil fuels Smog –Industrial/ photochemical

17. © 2013 Pearson Education, Inc. 9.3 Pollution in the Stratosphere Pollution in stratosphere –No direct effect for human health –Can influence climate Aerosols can cool Earth's surface –Alter sunlight reaching Earth's surface Destruction of ozone layer –Increased UV radiation –Chlorofluorocarbons (CFCs)

18. © 2013 Pearson Education, Inc. Indoor Air Pollution Smoking - diseases related to smoking responsible for 20% of deaths in the U.S. In less-developed countries, poorly ventilated heating and cooking fires represent the greatest source of indoor air pollution.

19. © 2013 Pearson Education, Inc. 9.4 Indoor Air Pollution Indoor air pollution –Generally more polluted than outside air –Combustion by-products Carbon monoxide, nitrogen and sulfur oxides, VOCs, particulate matter –Indoor burning –Secondhand smoke

20. © 2013 Pearson Education, Inc. 9.4 Indoor Air Pollution Construction materials Emit many volatile organic compounds (VOCs) –Paints, adhesives, synthetic fabrics, wood preservatives Asbestos –Fibrous material for heat/fire proofing Breathing fibers leads to lung disease/cancer Banned in 1973

21. © 2013 Pearson Education, Inc. 9.4 Indoor Air Pollution Radon –Nontoxic gas produced from decay of radium- 226 ( 226 Ra) –Radon decays to radioactive isotopes Polonium ( 218 Po) and lead ( 214 Pb) –Bind to particulate matter –When inhaled, cause cancer Not significant outdoors Indoor concentration may be 1,000X concentration

22. © 2013 Pearson Education, Inc. 9.4 Indoor Air Pollution Pesticides –Wide range of toxic chemicals –Many pesticides of the past now banned –Many stored in fatty tissues in body DDT, chlordane, pentachlorophenol May lead to nervous and digestive system issues

23. © 2013 Pearson Education, Inc. Long-range transport Stratospheric ozone depletion Montreal Protocol - 1987 Temperature inversions Heat islands, dust domes Interactions Between Climate Processes and Air Pollution

24. © 2013 Pearson Education, Inc. Long-Range Transport Fine aerosols can be carried great distances by the wind. –Sensitive monitoring equipment increasingly reveals industrial contaminants in places usually considered the cleanest in the world. Contaminants trapped by winds at the North Pole, concentrate and eventually precipitate out, entering the food chain.

25. © 2013 Pearson Education, Inc. Long-Range Transport

26. © 2013 Pearson Education, Inc. Stratospheric Ozone Discovered 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.

27. © 2013 Pearson Education, Inc. CFC Production

28. © 2013 Pearson Education, Inc.  28 Urban Climates Temperature Inversions –Cool, dense air trapped below a warmer, lighter air mass. Pollutants cannot disperse and thus increase in concentration. Heat Islands –Temperature in cites warmer than surrounding areas. Dust Domes –Tall buildings create updrafts.

29. © 2013 Pearson Education, Inc. Effects of Air Pollution Human health Plant pathology Visibility reduction Acid deposition

30. © 2013 Pearson Education, Inc. Ecosystem damage caused by sulfur dioxide emissions and acid rain.

31. © 2013 Pearson Education, Inc. EFFECTS OF AIR POLLUTION Human Health –EPA estimates each year 50,000 people 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.

32. © 2013 Pearson Education, Inc. Human Health Irritate and damage tissues in eyes and respiratory passages Inflammation impairs lung function, and triggers cardiovascular problems CO binds to hemoglobin and decreases ability of RBC to carry oxygen –Asphyxiation

33. © 2013 Pearson Education, Inc. More Human Health Chronic Health Effects: –Bronchitis Persistent inflammation of airways in the lung that causes mucus build-up and muscle spasms constricting airways –Emphysema Irreversible obstructive lung disease in which airways become permanently constricted and alveoli are damages or destroyed

34. © 2013 Pearson Education, Inc.  34 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.

35. © 2013 Pearson Education, Inc.  35 Acid Deposition Acid Precipitation - Deposition of wet, acidic solutions or dry, acidic particles from the air. –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.

36. © 2013 Pearson Education, Inc. Acid Precipitation, 2000

37. © 2013 Pearson Education, Inc.  37 Acid Deposition Cont’d 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.

38. © 2013 Pearson Education, Inc.

39. Air Pollution Control Early approach: "Dilution is the solution to pollution" Particulate removal - air filters Sulfur removal - scrubbers Nitrogen oxide reduction - catalytic converters Hydrocarbon controls - afterburners

40. © 2013 Pearson Education, Inc. Clean Air Legislation Clean Air Act (1963) - First national air pollution control. Clean Air Act (1970) rewrote original Act. –Identified critical pollutants. –Established ambient air quality standards. Primary Standards - Human health Secondary Standards - Materials, environment, aesthetic and comfort.

41. © 2013 Pearson Education, Inc. Clean Air Act Revision (1990) - Included provision for: –Acid Rain –Urban Smog –Toxic Air Pollutants –Ozone Protection –Marketing Pollution Rights –Fugitive emissions of volatile organics –Ambient ozone, soot, and dust –NO x emissions

42. © 2013 Pearson Education, Inc. 9.5 Air Pollution Policy and Law Biological contaminants Buildup of virus, bacteria, fungi –Legionnaires' disease Bacterium that build up in air-conditioning system Transmitted in aerosols to hotel lobby Many similar diseases occur

43. © 2013 Pearson Education, Inc. 9.5 Air Pollution Policy and Law Policies to control air pollution changed substantially over past 60 years –Public outcry after tragedies –Air pollution Act–1955 Standards set by states –1963–1990 responsibility shifted to federal government Clean Air Act–1963 –Regulated emissions from stationary sources –Factories, power plants

44. © 2013 Pearson Education, Inc. 9.5 Air Pollution Policy and Law International Air Pollution Policy –Agreements to limit air pollution among countries –Driven by shared sense of need and cost sharing Geneva Convention on long-range transboundary air pollution–1983 –Led to protocols for reducing air pollution internationally

45. © 2013 Pearson Education, Inc. 9.5 Air Pollution Policy and Law International Air Pollution Policy 1999 Protocol –Addressed acidification, eutrophication, and ground-level ozone Montreal Protocol on Ozone –Aimed to reduce ozone destruction –Established timeline and protocols for phasing out CFCs and ozone-destroying substances