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7 Cards in this Set
- Front
- Back
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7-1 The Oxygen-Ozone Screen |
UV radiation energy can break down O2 and O3 O2 bonds are stronger than O3 bonds UV radiation has three categories: UV-A, UV-B, UV-C UV-C is the strongest and it can be absorbed by oxygen while UV-B is absorbed by O3 |
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7-2 Where is the Ozone? |
Ozone exists in Stratosphere Chapman Cycle Less than 240 nanometers wavelength hits molecular oxygen (O2) It splits into two separate Oxygen (O and O) One of the O joins a O2 to make O3 The other O joins the O3 to make 2 molecular Oxygen 2 O2 |
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7-3 The Ozone Layer is Disappearing |
Dobson Unit(DU) = 1 ppb Avg. of 250 DU at Equator and 320 DU in N. Hemisphere Prevalent mostly during September to November |
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7-4 Why CFCs and Why at the Poles? |
CFCs exist in stratosphere Really good solvent properties for grease and oils CFCl3 reacts with UV CFCl2 is created while one Cl is separated The Cl forms a bond with Oxygen Molecular Oxygen(O2) takes Oxygen from Cl Cl repeats process 100,000 times until it becomes unstable |
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7-5 What are the Implications of Increases in the Size of the Ozone Hole? |
Lower ozone conentrations lead to higher chance of skin cancer 1% decrease in O3 = 2% increase in skin cancer Using tanning devices causes 1.5 to 2.5x more times of skin cancer |
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7-6 Can we do anything about the Ozone Hole? |
Production of CFCs stopped in Dec. 31, 1995 by U.S. and 100 countries Stockpiles of CFCs can still be sold and used Smuggling CFCs = more profit than smuggling cocaine |
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7-7 What will replace CFCs? |
HCFCs and HFCs replaced Cl and Br with H Global Warming Potential of CFC, HCFC, and CFC equal to 7.5 billion metric tons of CO2 HCFC and HFC can still cause ozone depletion |
