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Discovered
Christian Schöenbein identifies ozone in the laboratory -
What is ozone
Ozone is a colorless gas. Chemically, ozone is very active; it reacts readily with a great many other substances. Near the Earth’s surface, those reactions cause rubber to crack, hurt plant life, and damage people’s lung tissues. Ozone also absorbs harmful components of sunlight .Ozone in the upper atmosphere filters potentially damaging ultraviolet light from reaching the Earth's surface. -
Ozone reform.
ozone can reform through the following reactions resulting in no net loss of ozone:(Chaplans theory) O3 + hv -> O2 + O
O + O2 -> O3 -
Destroy ozone reaction
Ozone is also destroyed by the following reaction:(Chaplans theory) O + O3 -> O2 + O2 -
Created
Ozone is created when ultraviolet radiation (sunlight) strikes the stratosphere, dissociating (or "splitting") oxygen molecules (O2) to atomic oxygen (O). The atomic oxygen quickly combines with further oxygen molecules to form ozone:(Chaplans theory) O2 + hv -> O + O (1)
O + O2 -> O3 (2) -
Missing reactants
But there was a problem with the Chapman theory. In the 1960s it was realised that the loss of ozone given by reaction (O + O3 -> O2 + O2 )was too slow. It could not remove enough ozone to give the values seen in the real atmosphere. There had to be other reactions, faster reactions that were controlling the ozone concentations in the stratosphere. -
What is Ozone made of ?
Ozone is 3 oxygen atoms. (O3). -
Thick or thin
Charles Fabry makes first spectrometric measurements of "thickness" of ozone layer -
Chlorofluorocarbons
Were created as a nontoxic, nonflamable refrigant. Chloroflaurcarbons werenproduced in the 1930's. This is made of 1 carbon 2 chlorines and 2 fluorines. The first made was CFC-12 -
Altitude
Umkehr method for Dobson instrument establishes that ozone maximum is below 15 miles altitude -
Cfc Growth
CFC market expands rapidly. -
Loss of ozone in Antartica
Dramatic loss of ozone in the lower stratosphere over Antarctica was first noticed in the 1970s by a research group from the British Antarctic Survey (BAS) -
J. Molina and F.S Rowland
J. Molina and F.S Rowland demonstrated how CFCs breakdown the ozone layer. Also high frequencys of UV light will too. -
Depleting the ozone
J. Molina and F.S. Rowland predicted that in 60 years cfs's would depleted the ozone by 7%. Some nations agreed to ban cgs in aerosol xans but faught the banning in many other objects. -
can we make more ozone ?
The difficulty with simply manufacturing ozone is that the sun provides huge amounts of energy for the ozone production process. In fact, to produce the amount of ozone normally in the ozone layer, you'd have to use about double the total annual U.S. electricity production. There's simply no way we could create ozone fast enough, in large enough quantities, to replace the natural ozone production process. -
Depletings problem.
The issue with ozone-depleting substances is that they add chlorine and bromine to the ozone layer, which effectively widens the hole. -
Period: to
A video showing how the Earths Ozone Hole has changed
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Faulty equipment?
When the first measurements were taken in 1985, the drop in ozone levels in the stratosphere was so dramatic that at first the scientists thought their instruments were faulty. Replacement instruments were built and flown out, and it wasn't until they confirmed the earlier measurements, several months later, that the ozone depletion observed was accepted as genuine. -
Ozone depeletion
Ten years of satellite data begin to show measurable ozone depletion globally -
NO CFC!
CFC production ends in US and Europe -
Cfc Reached
Maximum CFC concentrations in stratosphere are reached -
Solve depleting
Since we can't make more ozone, the solution is to reduce the hole in the bucket back to its natural size. The only way to do that is to remove the excess chlorine and bromine from the stratosphere. And the only way to do that is to stop making CFCs and several other chemicals. Although several other measures have been proposed to accelerate the removal of chlorine and bromine from the stratosphere, none has proven to be practical.
