1. Ozone in the stratosphere

1. 1. Ozone in the stratosphere • Is a harmful air pollutant • Helps protect the Earth by blocking harmful UV radiation • Neither A nor B

2. 2. The formula for ozone is • NO • O2 • O3 • CFC

3. 3. Which type of UV radiation is most easily blocked and why is it most easily blocked? • UV-A, because it has the longest wavelength • UV-A, because it has the shortest wavelength • UV-C, because it has the longest wavelength • UV-C, because it has the shortest wavelength

4. UV-C has the shortest wavelength and is therefore most easily deflected in the outer atmosphere.

5. 4. Which type of UV radiation has the most energy and is potentially the most harmful (if we are exposed to it)? • UV-A • UV- B • UV-C

6. Higher frequency wavelengths have the most energy and are the most potentially damaging. (UV-C is used in germicidal lights) However, UV-A penetrates the furthest into skin tissue and can also be harmful.

8. 5. The ozone layer can be depleted by • CFC’s • Methyl bromide • Supersonic jets • A and B • A, B and C

9. Ozone depleting chemicals include CFC’s and other halogen compounds (F, Cl, Br and I) Supersonic jet travel in the stratosphere can release NO2, which when in the ozone layer can break apart O3 molecules.

10. 6. Chlorofluorocarbons (CFC’s) were used in • Refrigerator coolants • Styrofoam containers • Aerosols • A and B • A, B and C

12. 7. The international treaty in 1989 that phased out CFC’s was the • Kyoto Protocol • Montreal Protocol • Copenhagen Accord • Rio Accord

13. 8. The region that has the greatest seasonal depletion of the ozone layer is • The Artic (Northern Pole) • Tropic of Cancer (around 23.5 N) • The Equator • Tropic of Capricorn (around 23.5 S) • The Antarctic (Southern Pole)

14. 9. The South Pole has a greater degree of ozone depletion due to • greater emissions of CFC’s • greater emissions of SO2 • a greater degree of wind mixing with lower latitudes • a lesser degree of wind mixing with lower latitudes

15. The Southern Hemisphere has much less land mass and much lower population. There is NOT a greater amount of CFC or other ozone depleting chemicals released The Southern Hemisphere has a greater degree of ozone depletion because of the formation of a polar vortex in the winter. This occurs due to the fact that the South Pole is encircled by water which heats and cools more consistently. There isn’t as much regional variation in air pressure (and therefore winds) due to differential heating as in the Northern Hemisphere. Southern Hemisphere Northern Hemisphere

16. 10. When traveling to Australia, Argentina or other places near the South Pole, it is most important to slather on a thick layer of sunscreen due to ozone depletion during which months? • July and August (their Winter) • September and October (their Spring) • December and January (their Summer) • April and May (their Fall)

17. While CFC’s accumulate in the polar clouds in winter, the reaction that breaks apart O3 requires sunlight. When the sun returns to the South Pole in spring (September) there is the maximum thinning of the ozone. Later in the year, as the polar vortex is broken up, the ozone is redistributed in the atmosphere.

18. 11. Which of the statement regarding CFC’s is correct? • Are very persistent in the atmosphere, lasting more than 100 years on average. • Each chlorine atom from CFC molecule can catalyze the breakdown of many O3 molecules. • Both A and B • Neither A nor B

20. B • C • D • C • E • E • B • E • D • B