OZONE Examples of headlines The Ozone Hole! The Ozone

							                    OZONE
Examples of headlines:
The Ozone Hole! The Ozone Hoax! Pollution!
Skin Cancer!

The topic of ozone makes headlines on a regular
basis, but why does a single molecule merit such
media coverage?
A.) Scientists are very concerned about:
    1.) its increase in troposphere
    2.) its disappearance in the stratosphere
B.) What is ozone?
    •Ozone is made of three oxygen atoms (O3).
    •Oxygen we find in our atmosphere is made up
     of two oxygen atoms (O2) which is very stable.
    •Single atom of oxygen (O) is unstable.
     (it wants to combine with something else)
    •O3 is less stable than O2.
    •O3 wants to return to the diatomic state (O2)
     by giving up an oxygen atom.
    •Where we find O3 in our atmosphere
     determines whether we consider it to be Dr.
     Jekyll or Mr. Hyde.
                                               page 1
C.) Ozone:
    1.)in the troposphere (ground-level) = "bad"
        • air pollutant that damages human health
        • damages vegetation
        • damages many common materials
        • is a key ingredient of urban smog.
    2.) in the stratosphere = "good"
        • protects life on earth from the harmful
          effects of the sun's ultraviolet rays.




         **Good up High, Bad Near By***




                                               page 2
D.) Electromagnetic Spectrum
             and
            Ozone




1.) It is the energy emitted from the sun.
2.) Scientists have identified:
    gamma rays, x-rays, ultraviolet radiation,
    visible light, infrared radiation (heat),
    microwaves, and radio waves.
3.) Short wavelengths have more energy than
    long wavelengths.
4.) Ultraviolet radiation(UV) causes skin cancer
5.) Ozone (O3) absorbs the UV radiation
                                             page 3
UV radiation
absorbed by                          One oxygen
ozone (O3)                           separates
                                       leaving an
                                        O + O2.
                                     The single
Therefore,                           oxygen
most of the                          combines
dangerous UV                         with the O2
does not get
to Earth.                            and ozone
                                     is reformed.
  6.) The ozone molecules are continuously
      broken up by UV and reformed.
  7.) Oxygen and ozone together absorb 95 to
      99.9% of the sun's ultraviolet radiation
  8.) The overall amount of ozone is constant-
      that is, it would if humans did not contribute
      to the chemical processes.
  9.) Ozone forms a kind of layer in the
      stratosphere, where it is more concentrated
      than anywhere else.
  10.) However, its concentrations is only 1 to 10
        parts of ozone per 1 million parts of air.
  11.) O2 is about 210,000 parts of oxygen per 1
        million parts of air.                   page 4
E.) Depletion of ozone layer
    1.) Biggest culprit in depleting the ozone in
        the stratosphere are chlorofluorocarbons,
        or CFCs.
    2.) CFCs were introduced in the 1950s in
        aerosols and coolants. Ended in the 1970s
    3.) CFCs are very stable molecules in the
        troposphere (they do not react)
    4.) However, in the stratosphere, they are
        broken down by UV radiation releasing
        chlorine atoms.
            UV                        Cl
                 Cl
             Cl C      F       Cl C        F

                 Cl               Cl

     One chlorine atom can remove 100,000
     ozone molecules               Cl
                      O2 & O    O combines with
                                Chlorine.
                                 Cl C F

       O3                              Cl