1. 1. Importance of ozone 2. Interaction of ozone with halogenated organic gases 3. Effects of UV rays 4. Reduction of ozone depleting substances 5. Evaluation of reduction strategies * 5.6 Depletion of STRATOPHERIC ozone

2. * Starter * Watch and take note ‘Ozzy Ozone’Ozzy Ozone

3. * 5.6.1 Where and what is ozone? * Ozone is O 3 * It is found as a concentrated layer in the STRATOSPHERE * Task: use page 69 to sketch the layers of the atmosphere marking on the ‘ozone layer’

4. * 5.6.2 What does ozone do? * Ultra violet (UV) radiation is high energy * UVc is highest and most dangerous to UVa which is least * Ozone filters 99% of UVc and 50% UVb * If it didn’t * Life wouldn’t exist on our planet 1. Importance of ozone 2. Interaction of ozone with halogenated organic gases 3. Effects of UV rays 4. Reduction of ozone depleting substances 5. Evaluation of reduction strategies

5. * 5.6.3 Halogenated organic gases? Whaaaaaaaaaat? * The halogens: fluorine, chlorine, bromine, iodine and astatine (At). * An example of their reaction with ozone: 1. Importance of ozone 2. Interaction of ozone with halogenated organic gases 3. Effects of UV rays 4. Reduction of ozone depleting substances 5. Evaluation of reduction strategies

6. * 5.6.4 so what? * If more UV radiation gets through to the Earth’s surface: * Damage to photosynthetic organisms (esp phytoplankton) * Damage to consumers of photosynthetic organism (esp zooplankton) * Genetic mutations (esp DNA- cancers, cataracts…) Task: Answer questions 1-4 on the questions sheet using pp289- 1. Importance of ozone 2. Interaction of ozone with halogenated organic gases 3. Effects of UV rays 4. Reduction of ozone depleting substances 5. Evaluation of reduction strategies

7. * 5.6.5 Three ways to reduce * Replace * Regulate * Restore Task: Explain the three pollution management ‘groupings’ and give examples of strategies using page 291 (fig 15.6) 1. Importance of ozone 2. Interaction of ozone with halogenated organic gases 3. Effects of UV rays 4. Reduction of ozone depleting substances 5. Evaluation of reduction strategies

8. * 5.6.6 * Task: use pp291- to answer the question 5-10 on the question sheet question 1. Importance of ozone 2. Interaction of ozone with halogenated organic gases 3. Effects of UV rays 4. Reduction of ozone depleting substances 5. Evaluation of reduction strategies

9. * Plenary * Importance? * Halogenated gases? * UV effects? * Reduction...? * Evaluation of strategies? 1. Importance of ozone 2. Interaction of ozone with halogenated organic gases 3. Effects of UV rays 4. Reduction of ozone depleting substances 5. Evaluation of reduction strategies

10. * HW * Research what steps national governments are taking to comply with the agreements made towards reducing ODS. China and India might be good examples.