1. © 2012 W. H. Freeman & Co.

2. Skin cancer

4. © 2012 W. H. Freeman & Co.

5. Ozone production Ozone destruction

6. Ozone production Ozone destruction

7. 14a–7

8. Ozone production Ozone destruction

9. Ozone production h h Ozone destruction

10. O 2 + h  O + O 498 kJ/mol O 3 + h  O + O 2 383 kJ/mol)

11. O 2 + h  O + O 498 kJ/mol  <242.4 nm O 3 + h  O + O 2 383 kJ/mol  <280 nm

12. Chapman Mechanism (~1930, Sidney Chapman) O 2 + h  O + O 498 kJ/mol  <242.4 nm slow O + O 2 + M  O 3 + M (-106 kJ/mol fast) O 3 + h  O + O 2 383 kJ/mol  <280 nm (fast) O + O 3  2O 2 291 kJ/mol slow O + O + M  O 2 + M

13. Ozone production λ ≤ 240 nm λ ≤ 280 nm h h Ozone destruction

14. © 2012 W. H. Freeman & Co.

15. Intensity

16. Transmittance Absorbance

17. Transmittance Absorbance Beer’s Law

18. dP(x)/dx = -κ P(x)  P(x) = exp(-κ x)

19. λ ≥ 280 nm

20. © 2012 W. H. Freeman & Co.

23. Mean vertical distribution of the ozone concentration according to observations at different latitudes. Note the variations in total column abundance.

30. 1 Dobson unit (DU) is: 0.01 mm of pure O 3 at 1 atm. and 0 o C NB: what does 300 DU expand to at 10 -6 atm?

32. Ozone production λ ≤ 240 nm λ ≤ 280 nm h h WRONG EQUILIBRIUM: Predicts TOO MUCH OZONE

33. X = HO x (  H,  OH, HOO  ) NO x (NO ,  NO 2 ) ClO x (  Cl, ClO  )

34. Catalytic destruction of ozone © 2012 W. H. Freeman & Co.

35. Chlorine reservoirs © 2012 W. H. Freeman & Co.

36. Chlorine reservoirs © 2012 W. H. Freeman & Co.

37. Atomic Cl and Br as X: Cl  can destroy tens of thousands of O 3 molecules each, but is mainly in inactive forms (HCl, ClONO 2 ) in stratosphere. RESERVOIRS: ClO  + NO 2   ClONO 2 Cl  + CH 4  HCl + CH 3  CH 3  does not operate as an X catalyst, since it combines with O 2 to give CO 2.

40. Recipe for ozone loss: 1.POLAR WINTER  Polar vortex  Isolates air 2.LOW TEMPERATURE  PSC (=Polar Stratospheric Clouds) (=Nitric acid – HNO 3 ) 3.SURFACE CHEMISTRY  Cl 2 (+denoxification) 4.LIGHT RETUNS  Cl*  Catalytic destruction of O 3

45. CHAPTER 02: Figure 2.1 © 2012 W. H. Freeman & Co.

48. CHAPTER 02: Figure 2.2 © 2012 W. H. Freeman & Co.

49. NASA projections of stratospheric ozone concentrations if chlorofluorocarbons had not been banned.

51. Mount manitoba, June 1991

54. CHAPTER 02: Figure 2.10 © 2012 W. H. Freeman & Co.

55. PrefixMeaningAtoms in the Molecule CFCchlorofluorocarbonCl, F, C HCFChydrochlorofluorocarbonH, Cl, F, C HBFChydrobromofluorocarbonH, Br, F, C HFChydrofluorocarbonH, F, C HChydrocarbonH, C PFCperfluorocarbonF, C HalonN/A Br, Cl (in some but not all), F, H (in some but not all), C

59. © 2012 W. H. Freeman & Co.