Ozone Depletion - Download as PowerPoint by kqt20646

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									Ozone Depletion

  AP ES 2/2008
Ultraviolet light hits a chlorofluorocarbon
(CFC) molecule, such as CFCl3, breaking
off a chlorine atom and leaving
CFCl2.
                                   Figure 21-21
                                       Sun
           Cl       Cl

             F
                C
                      Cl            Page 485        Once free, the chlorine atom is off
                                                    to attack another ozone molecule
                            UV radiation            and begin the cycle again.


                                                                  Cl
                 Cl

                                                                  O
                                                              O


  The chlorine atom attacks                    A free oxygen atom pulls
  an ozone (O3) molecule,         Cl           the oxygen atom off
  pulling an oxygen atom                       the chlorine monoxide    Cl
  off it and leaving                           molecule to form O2.        O
                          O
  an oxygen            O    O
  molecule (O2).
                                                                                    O
                                       The chlorine     Cl
                                       atom and the        O
Summary of Reactions
                                       oxygen atom join
CCl3F + UV Cl + CCl2F
                                       to form a chlorine    O
Cl + O3 ClO + O2    Repeated
                                       monoxide molecule O
Cl + O Cl + O2      many times
                                       (ClO).
                             400
                                                    Figure 21-22
                                        October monthly means
Total ozone (Dobson units)



                             350
                                                     Page 485
                             300


                             250


                             200


                             150


                             100
                               1955   1960   1965   1970   1975   1980   1985   1990   1995   2000   2005

                                                                  Year
                        35


                        30              Figure 21-2311, 2003
                                                August 6, 2003
                                                October


                        25
                                         Page 486
Altitude (kilometers)




                        20


                        15


                        10


                         5



                             0      5              10             15
                                 Ozone partial pressure (milipascals)
                            Natural Capital Degradation
                             Effects of Ozone Depletion

Human Health
• Worse sunburn
• More eye cataracts
• More skin cancers
• Immune system suppression
Food and Forests
• Reduced yields for some crops
• Reduced seafood supplies from reduced phytoplankton
• Decreased forest productivity for UV-sensitive tree species
Wildlife
• Increased eye cataracts in some species
• Decreased population of aquatic species sensitive to UV radiation
• Reduced population of surface phytoplankton
• Disrupted aquatic food webs from reduced phytoplankton
Air Pollution and Materials
• Increased acid deposition
• Increased photochemical smog
• Degradation of outdoor paints and plastics
Global Warming
• Accelerated warming because of decreased ocean uptake of CO2
 from atmosphere by phytoplankton and CFCs acting as greenhouse
 gases                                                                Figur
                Ultraviolet A   Ultraviolet B




Thin layer of
                                Figure 21-25
dead cells
                                 Page 487                     Hair
                                                                                Epidermis
Squamous
cells

Basal
layer                                                                                Sweat
                                                                                     gland
Melanocyte
cells                                                                               Dermis

Basal
cell
Blood
vessels




 Squamous Cell Carcinoma               Basal Cell Carcinoma          Melanoma
                               DO NOT POST TO INTERNET
                                                           Melanoma

                           Figure 21-25bcd
                              Page 487

Squamous Cell Carcinoma




                                                                                DO NOT POST TO INTERNET
 DO NOT POST TO INTERNET




                                                         Basal Cell Carcinoma
                  What Can You Do?

        Reducing Exposure to UV-Radiation


• Stay out of the sun, especially between 10 A.M. and 3
  P.M.

• Do not use tanning parlors or sunlamps.

• When in the sun, wear protective clothing and sun–
  glasses that protect against UV-A and UV-B radiation.

• Be aware that overcast skies do not protect you.

• Do not expose yourself to the sun if you are taking
  antibiotics or birth control pills.

• Use a sunscreen with a protection factor of 15 or 25 if
  you have light skin.

• Examine your skin and scalp at least once a month
  for moles or warts that change in size, shape, or color
  or sores that keep oozing, bleeding, and crusting
  over. If you observe any of these signs, consult a
  doctor immediately.
                                                            Figur
                                 15,000
                                                           21-27
                                                   Figure protocol
Abundance (parts per trillion)


                                                        No
                                 12,000             Page 489
                                                            1987
                                  9,000                     Montreal
                                                            Protocol
                                  6,000
                                                                          1992
                                                                          Copenhagen
                                  3,000                                   Protocol


                                     0
                                     1950   1975     2000      2025    2050   2075     2100
                                                               Year
   Animation




CFCs destroying ozone animation.



         Click to view
          animation.

								
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