Earth’s Atmosphere and Air Pollution

1. Earth’s Atmosphere and Air Pollution Chapters 20 and 21

2. Earth’s Atmosphere

3. Air Pollution

4. Outdoor Air Pollution • Comes from Stationary or Mobile sources • Two Categories: • Primary: those emitted directly • Ex’s: CO, CO2, SO2, NO, NO2 • Secondary: primary pollutants that react to form new pollutants • Ex’s: SO3, HNO3, O3, PANs

6. Brown Air Smog • Los Angeles

7. San Francisco

8. Photochemical Smog (brown) • SUNLIGHT is a catalyst • NOx-based • COMBUSTION: (internal combustion engines – high temps) • NATURAL: N-cycle, volcanoes, fires, lightning

9. VOC’s: VOLATILE ORGANIC COMPOUNDS • evaporate/vaporize under “normal” conditions • approx. 600 in the atmosphere • solvents, fuels, paints, cleaning supplies, adhesives/glue, pesticides • PLANTS: terpenes

10. Reactions • Cars (and CFPP’s) release NO and NO2 (NOx)

11. Gray Air Smog • Satellite images of China

13. Los Angeles

14. Industrial Smog (gray) • Sources: • Mostly coal-fired power plants • Cars • Reactions: • Mostly carbon and sulfur based • Chemistry:

15. What’s so bad about air pollution anyway????

17. Human health • Asthma/bronchitis/emphysema • Eye irritant • Nose and throat irritants • Cancers • “According to the World Health Organization, at least 3 million people die prematurely each year from the effects of air pollution”.

18. Not to mention… • Climate change

19. Stratospheric Ozone Depletion

20. Factors That Influence Smog • Reduce: • Rain and snow: cleanse the air • Salty sea spray: washes the air • Winds: sweep pollution away

21. Increase • Urban buildings: block wind flow • Hills/mountains: block wind flow • Temperature: higher temps promote reactions • Grasshopper Effect: wind currents carry tainted air to the poles • Temperature inversions: layer of warm air lies on top of cool air – acts as a lid

22. Temperature inversion

24. Mountains/hills exacerbate inversions

25. Grasshopper effect

27. NEWSPAPER HEADLINES: • “Arctic Indigenous Peoples Being Poisoned by Industry Thousands of Miles Away”

28. If you think the pollution in New York, Los Angeles or Detroit is scary, consider this: Arctic indigenous peoples often have levels of persistent organic pollutants (POPs[3]) in their blood and breast milk that are 10 times higher than the residents of major American cities. • Individuals living near industrial hubs expect to bioaccumulate a certain amount of toxic chemicals, but for aboriginal peoples living near the Arctic Circle, thousands of miles from the sources of these chemicals, the levels are both astonishing and disturbing. • The pollution is the result of what scientists call the “grasshopper effect[4]”, in which transboundary pollution[5], dispersing at the point of origin and driven by wind, re-volatilizes (or comes down to earth and oceans) thousands of miles away in the Arctic.

29. Pesticide DDT shows up in Antarctic penguins

30. Acid Deposition

31. Water, soil, vegetation greatly affected:

32. Effects such as chemical weathering: CaCO3 (s) + H2SO4 (aq) → CaSO4 (aq) + CO2 (g) + H2O (l)

33. “Clean” Coal Technology… Solution? • Coal that contains 2% - 4% sulfur is considered HIGH sulfur coal. • Coal that contains less than 2% sulfur is considered LOW sulfur coal. Either way, when we burn coal to produce electricity, sulfur is released into the atmosphere!!

34. Removing the sulfur: • PRE-combustion: • Coal washing: removes unwanted minerals such as sulfur by mixing pulverized coal with a liquid and allowing the impurities to separate.

35. POST-combustion: (Figure 20-18) • Electrostatic Precipitator: removes particulates (that cause things such as asthma) by charging particles with an electrical field and capturing them on collection plates. • Baghouse Filter: removes many of the more hazardous fine particulates.

36. Cyclone Separator: particles that can not follow the cyclone stream of air, strike the wall of the separator, and fall to the bottom. (least expensive) • Wet Scrubber: removes 98% SO2 and particulates; spray or immerse gas with limestone and water – the mixture reacts to form gypsum, a component of drywall. (expensive to install and maintain)

37. Cars have Catalytic ConvertersSolution?? • Converts toxic exhaust from an internal combustion engine into less noxious by-products • Convert CO (Carbon Monoxide) and VOC’s (Volatile Organic Compounds or unburned hydrocarbons) into CO2 • Convert NOx gases into Nitrogen gas and Oxygen gas

38. Preventing/Reducing Air Pollution • Clean Air Acts – (1970, 1977, 1990) • EPA established NAAQS – National Ambient Air Quality Standards for 6 outdoor pollutants (set maximum permissible levels) • 1 • 2 • 3 • 4 • 5 • 6

39. Primary Standard = protect human health • Secondary Standard = prevent environmental and/or property damage

40. EPA established emission standards for HAP’s – Hazardous Air PollutantsStandards set for 188 HAP’s, (most are VOC’s, hydrocarbons, and toxic metals) • TRI – Toxic Release Inventory = source for info about HAP’s in your area

41. Emissions Trading Policy (Cap’n Trade)= (CAA of 1990) • Help to reduce ________emissions

42. A limit (cap) is set on the total amount of a pollutant that can be emitted (SO2), the limit is allocated/sold to groups (power plants, factories, environmental groups) in the form of emissions credits

43. The TOTAL number of credits can not exceed the TOTAL cap, groups that need more credits because they pollute more must BUY them; those that pollute less can SELL them

44. POLLUTERS PAY! (But it the cap is set too high… nobody pays) • Companies have certain numbers of pollution credits • Emit less = keep what’s left for future or emissions at other plants or sell

45. Ozone Depletion • Chemistry:

50. Indoor Air Polltion • asbestos