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Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings 17 Atmospheric Science and Air Pollution Part A PowerPoint ® Slides prepared.

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Presentation on theme: "Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings 17 Atmospheric Science and Air Pollution Part A PowerPoint ® Slides prepared."— Presentation transcript:

1 Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings 17 Atmospheric Science and Air Pollution Part A PowerPoint ® Slides prepared by Jay Withgott and Kristy Manning Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

2 Atmospheric composition 78% nitrogen 21% oxygen 1% argon traces of other permanent gases and variable small amounts of: water vapor carbon dioxide methane pollutants etc.

3 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings AIR POLLUTION

4 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Outdoor air pollution Air pollution = material added to the atmosphere that can affect climate and harm organisms, including humans Air pollution can come from human-made chemicals and causes, but the majority is from natural sources. Government policy and improved technologies have helped diminish outdoor or ambient air pollution substantially in developed but not developing countries.

5 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Natural sources of air pollution dust storms fires volcanoes

6 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Artificial sources of air pollution Human-caused air pollution includes: Point sources = specific spots where large amounts of pollution are discharged (factory smokestacks) Non-point sources = diffuse, often made up of many small sources (charcoal fires from thousands of homes)

7 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Artificial sources of air pollution Human-caused air pollution includes: Primary pollutants = emitted into troposphere in a directly harmful form (soot, carbon monoxide) Secondary pollutants = produced via reaction of substances added to the atmosphere with chemicals already present in the atmosphere (ozone in troposphere)

8 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Aggravated air pollution - industry

9 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Clean Air Act legislation Major air pollution legislation: Clean Air Act of 1970: Set stricter standards than previous laws Imposed emissions limits Provided research funds Enabled citizens to sue violating parties Clean Air Act of 1990: Strengthened previous regulations Introduced emissions trading for sulfur dioxide

10 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Six “criteria pollutants” The EPA closely tracks six major types of pollutants according to national ambient air quality standards: Carbon monoxide (CO) Sulfur dioxide (SO 2 ) Nitrogen dioxide (NO 2 ) Tropospheric ozone (O 3 ) Particulate matter Lead

11 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

12 CO / SO 2 / NO 2 Carbon monoxide (CO) = colorless, odorless gas from vehicle exhaust and other sources; dangerous—prevents oxygen uptake Sulfur dioxide (SO 2 ) = colorless gas from coal burning for electricity and industry; contributes to acid precipitation Nitrogen dioxide (NO 2 ) = foul-smelling red gas from vehicle exhaust, industry, and electricity generation; contributes to smog and acid precipitation

13 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings O 3 / Pb / particulate matter Tropospheric ozone (O 3 ) = colorless gas; secondary pollutant from sunlight, heat, nitrogen oxides (NO x ), and C-containing chemicals; contributes to smog; harmful to living tissues Lead (Pb) = metal in atmosphere as particulate; from gasoline additive, phased out in 1980s; diverse health impacts, all bad Particulate matter = any solid (or liquid) particles small enough to be carried aloft in air; dust, soot, sulfates, nitrates; causes respiratory damage Burning fuel wood inside homes for cooking is a major source of indoor pollution in developing countries.

14 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Particulate Material Thousands of different solid or liquid particles suspended in air -Includes: soil particles, soot, lead, asbestos, sea salt, and sulfuric acid droplets Dangerous for 2 reasons -May contain materials with toxic or carcinogenic effects -Extremely small particles can become lodged in lungs

15 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Six “criteria pollutants” Emissions of all of these, especially lead and carbon monoxide, have substantially declined since 1970.

16 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Volatile organic compounds “VOCs” are regulated by many governments. Large group of potentially harmful carbon- containing chemicals used in industrial processes. Hydrocarbons are one example. About half are human-made, half natural. VOCs contribute to smog, produce secondary pollutants.

17 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Toxic air pollutants Toxic air pollutants = chemicals known to cause serious health or environmental problems Include substances known to cause cancer and reproductive defects, and substantial ecological harm Most produced by human activities 188 toxic air pollutants are regulated under the 1990 Clean Air Act.

18 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Industrial smog Smog from industrial pollution, fossil-fuel combustion The kind that blanketed London in 1952 “Gray air smog” Contains soot, sulfur, CO, CO 2 …

19 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Industrial smog The U.S. had its own “killer smog” from industrial pollution. Shown is Donora, Pennsylvania, in 1948, at mid-day. Subsequent demand for legislation against pollution made U.S. air much cleaner.

20 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Photochemical smog Smog from reaction of sunlight with pollutants The kind that blankets so many American cities today “Brown air smog” Contains tropospheric ozone, NO 2, VOCs, 100 more… Hot sunny days in urban areas create perfect conditions.

21 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Photochemical smog Mexico City and many of the world’s cities suffer from the brownish haze of photochemical smog. Inversion layers and mountains can trap smog over certain cities.

22 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Urban Air Pollution Photochemical Smog (ex: Los Angeles below) -Brownish-orange haze formed by chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons

23 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Case-In-Point Air Pollution in Beijing and Mexico City Beijing (left) Mexico City (above)

24 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Effects of Air Pollution Low level exposure -Irritates eyes -Causes inflammation of respiratory tract Can develop into chronic respiratory diseases

25 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Health Effects of Air Pollution Sulfur Dioxide and Particulate material -Irritate respiratory tract and impair ability of lungs to exchange gases Nitrogen Dioxides -Causes airway restriction Carbon monoxide -Binds with iron in blood hemoglobin -Causes headache, fatigue, drowsiness, death Ozone -Causes burning eyes, coughing, and chest discomfort

26 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Children and Air Pollution Greater health threat to children than adults -Air pollution can restrict lung development -Children breath more often than adults Children who live in high ozone areas are more likely to develop asthma

27 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Asthma Link

28 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

29 Air Pollution Around the World Air quality is deteriorating rapidly in developing countries Shenyang, China -Residents only see sunlight a few weeks each year Developing countries have older cars -Still use leaded gasoline 5 worst cities in world -Beijing, China; Mexico City, Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India

30 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stratospheric ozone depletion Ozone at low altitudes = beneficial layer protecting us from UV radiation Ozone layer— ~ 12 parts per million in lower stratosphere—is enough to absorb UV and protect us. But in the 1960s scientists noticed ozone concentrations were dropping.

31 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stratospheric ozone depletion In 1974, Sherwood Rowland and Mario Molina pegged the blame on chlorofluorocarbons (CFCs). They won the Nobel Prize for this scientific detective work. CFCs = human-made molecules in which hydrogens of hydrocarbons are replaced by chlorine and fluorine atoms Mass-produced by industry, in refrigerants and consumer products like aerosol sprays

32 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stratospheric ozone depletion Scientists worried about the effects of extra cancer-causing UV on people, organisms, ecosystems. The ozone hole (blue) reached its greatest extent in September 2000 (satellite imagery).

33 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stratospheric ozone depletion In 1987, over 180 nations signed the Montreal Protocol, which restricted CFC production globally. Follow-up agreements strengthened the pact. Today CFC levels are down, and stratospheric ozone is starting to recover. The Montreal Protocol is one of the biggest environmental success stories of our time. We have apparently avoided a major environmental problem.

34 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Acid Deposition Sulfur dioxide and nitrogen dioxide emissions react with water vapor in the atmosphere and form acids that return to the surface as either dry or wet deposition pH scale

35 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings How Acid Deposition Develops

36 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Effects of Acid Deposition Declining Aquatic Animal Populations Thin-shelled eggs prevent bird reproduction -Because calcium is unavailable in acidic soil Forest decline -Ex: Black forest in Germany (50% is destroyed)

37 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Acid Deposition and Forest Decline

38 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Acid Rain

39 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Indoor air pollution More disease from indoor (orange) pollution than outdoor (red) In developing nations, indoor cooking fires are common, and a major health risk.

40 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Indoor air pollution In developed nations, the 2 biggest threats seem to be: Cigarette smoke: lung cancer risk for smokers and those inhaling secondhand smoke Radon: naturally occurring colorless, odorless gas; radioactive—seeps up from ground and collects in buildings; lung cancer risk

41 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Radon Radon varies in its occurrence, depending on an area’s underlying geology. It is best to have your home tested for radon.

42 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Indoor air pollution risks in the home

43 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Other indoor air pollution sources Many VOCs pollute indoor air (plastics, oils, cleaning fluids, adhesives, pesticides, building materials). Tiny living organisms (dust mites, animal dander, fungi, mold) can produce indoor air pollution, causing allergies, asthma, etc. When the cause of building-related illness is a mystery, the illness is often called sick-building syndrome.

44 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Reducing indoor air pollution Buy and use low-toxicity products Provide good ventilation Limit exposure to plastics, treated wood, pesticides, cleansing fluids (put in garage, not home) Test home for radon Test drinking water for lead from pipes In developing world, provide ventilation, install clean- burning stoves, shift to gas

45 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Conclusion Indoor air pollution is a potentially serious health threat. Outdoor air pollution has been addressed more effectively by government legislation and regulation. There is much room for improvement in reducing acidic deposition and photochemical smog. This will continue to pose a challenge as less-wealthy nations industrialize.

46 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which atmospheric layer contains the gases we breathe and is responsible for the weather we experience? a.Troposphere b.Thermosphere c.Stratosphere d.Mesosphere e.Tropopause

47 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which pollutant is involved when air pollution over cities interacts with sunlight, heat, oxygen, and other chemicals? a.Nitric oxide b.Nitrogen dioxide c.Tropospheric ozone d.All of the above

48 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which statement about acid precipitation is FALSE? a. It alters soil chemistry. b.It damages buildings and statues. c.It can occur far from the source of its pollutants. d.It can kill trees. e.It did not occur until 1970.

49 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which are thought to be the most severe indoor air pollution threats in developed and developing nations, respectively? a.Indoor cooking fires; radon b.Pesticides; cigarette smoke c.Cigarette smoke; indoor cooking fires d.Industrial smog; carbon monoxide

50 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Weighing the Issues Look around your classroom or lecture hall. What changes might you suggest to improve indoor air quality? a.Open windows or otherwise increase ventilation. b.Remove certain products, materials, or items. c.Get tests run for radon, lead, or asbestos.

51 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Interpreting Graphs and Data Temperatures decrease with increasing altitude in the…? a. Stratosphere and thermosphere b. Troposphere and mesophere c.Stratosphere and tropopause d. Tropopause and ozone layer

52 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Interpreting Graphs and Data a.CFCs are much larger molecules. b.There is such a great abundance of oxygen molecules available. c. Each chlorine atom can split many ozone molecules in succession. d.Chlorine is a carcinogen. From what you can see here, why are CFCs such potent destroyers of ozone molecules?

53 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Viewpoints What is the best way to reduce outdoor air pollution from industry? a.Regulate industry strictly, and punish those businesses and plants that violate laws. b. Invest in developing new technologies to help industry do its work more cleanly. c.Set up market-based emissions-trading programs. d.We should focus on automobile pollution and consumer behavior rather than industry.


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