Notes: The Hole in the Ozone Layer Notes: The Hole in the Ozone Layer If you were gone, use the notes handout and this presentation to get caught up. If you were gone, use the notes handout and this presentation to get caught up.
Troposphere Stratosphere Mesosphere Thermosphere
1. What are the components of solar radiation (sunlight) 1. What are the components of solar radiation (sunlight) 9% UV 9% UV 46 % light 46 % light 45 % infrared: a.k.a. “heat waves” 45 % infrared: a.k.a. “heat waves” EM spectrum
Electromagnetic Spectrum
2. The Hole in the Ozone layer Area over Antarctica where ozone (O 3 ) loss exceeds 50 % Area over Antarctica where ozone (O 3 ) loss exceeds 50 % Happens every Sept., Oct. Nov. since 1980s Happens every Sept., Oct. Nov. since 1980s It cannot be seen It cannot be seen
Ozone Hole Animation
Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. Next: Watch 15 minutes of video “ The Hole Story ”
troposphere stratosphere mesosphere
Troposphere Stratosphere Mesosphere Thermosphere
3. Ingredients for O 3 destruction A. Polar Vortex: isolates the air over Antarctica (polar vortex) A. Polar Vortex: isolates the air over Antarctica (polar vortex)polar vortexpolar vortex B. Clouds of ice crystals in stratosphere over S. Pole B. Clouds of ice crystals in stratosphere over S. PoleClouds of ice crystals Clouds of ice crystals C. Sunlight: Breaks apart the CFC molecules. C. Sunlight: Breaks apart the CFC molecules. D. CFCs: provide the chlorine (“bad guy”) D. CFCs: provide the chlorine (“bad guy”) CFC use began to increase rapidly in the 1960s CFC use began to increase rapidly in the 1960s... continued from yesterday.
4. Some uses of CFCs? Refrigerators, freezers: 15 % (FREON) Refrigerators, freezers: 15 % (FREON) Air conditioners in cars and homes: 20 % Air conditioners in cars and homes: 20 % Aerosols: 15 % Aerosols: 15 % Foams: 24 % Foams: 24 %
the current hole in the ozone layer the current hole in the ozone layer the current hole in the ozone layer the current hole in the ozone layer
The destructive chemistry: CCl 2 F 2 + light ---> Cl + CClF 2 CCl 2 F 2 + light ---> Cl + CClF 2 Cl + O 3 ---> ClO + O 2 Cl + O 3 ---> ClO + O 2 ClO + O ---> Cl + O 2 ClO + O ---> Cl + O 2 Rowland and Molina 1974 paper Nobel Prize 1995
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5. Polar vortex? Polar vortex? June - Nov. June - Nov. Ice crystals? Ice crystals? Sunlight? Sunlight? Sept. - June Sept. - June CFCs? CFCs? Isolates the air over Antarctica Isolates the air over Antarctica Provide a surface for one of the reactions Provide a surface for one of the reactions Breaks CFC apart Breaks CFC apart Provide Chlorine atom (bad guy) Provide Chlorine atom (bad guy) What it does
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6. Risks to humans Sunburn Sunburn Skin cancer: 9,500 deaths per year in USA (How does it kill?) Skin cancer: 9,500 deaths per year in USA (How does it kill?) Decreased immune system Decreased immune system Cataracts Cataracts Caused by UV exposure
Melanoma: Benign? Malignant (5%)? What about tanning beds?
170,000 in Tanzania
In some Tanzania albino people are killed and their body parts are used by witch doctors to make potions - believe skin, bones, blood of albinos bring wealth and luck.
7. Precautions Avoid the midday sun (noon-3p.m.) Avoid the midday sun (noon-3p.m.) No tanning beds! No tanning beds! Sunscreen, lip balm (at least SPF* 15) Sunscreen, lip balm (at least SPF* 15) Hat, long sleeves Hat, long sleeves Sunglasses (UV filtering) Sunglasses (UV filtering) Slip, Slop, Slap!
8. Why is exposure more of a concern in places like Denver, Butte and Helena? Altitude (a.k.a. elevation) Which Helena High sport is most likely to contribute to development of cataracts later in life?
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