OZONE & CFCs O024
Before we begin I must explain a couple of terms I will be using in the following paragraphs:
- An atom – The smallest particle of an element that can enter into a chemical combination.
- A molecule – The smallest particle of an element or compound that can exist separately without loss of any original chemical properties.
- Atmosphere – The whole gaseous envelope surrounding our planet
- Stratosphere – A layer of the atmosphere about seven miles (eleven kilometers) above the earth, within which the temperature remains approximately constant.
- Ultra violet light – Very short light rays that are beyond the “violet” in the visible light spectrum.
It is the ozone in the stratosphere that protects humans by reflecting potentially dangerous UV radiation away from our atmosphere.
Ozone is produced any time a free oxygen atom (O) combines with a pure oxygen molecule (O2) to form ozone (O3). It is a collision process and atoms and molecules collide easier if they are moving fast. Any high-energy source like lightning, electric sparks or UV radiation will produce the heat or energy needed to get the particles moving rapidly.
Step outside after an electrical storm and you can smell ozone in the air. The sparks from electric motors and circuit breakers also produce ozone in the work place. There is no problem producing ozone in the earth’s atmosphere, but that is not where we need it. We need it in the stratosphere and no one has figured out how to push what we produce up there.
The culprit is CFCs (Chloroflurocarbons). They destroy the ozone layer in the stratosphere allowing the potentially harmful UV radiation to penetrate to the earth. We find these CFCs every where. Here is the break down:
|Vehicle air conditioning||16.2%|
|Refrigeration and air conditioning||15.6%|
|Halons (mainly in fire extinguishers)||12.0%|
Here is how the process works:
Two oxygen atoms make a molecule, and three oxygen atoms make a molecule of ozone (O3). The ozone layer is made up of a combination of oxygen atoms (O), oxygen molecules (O2) and ozone (O3)
|Ultra violet radiation is another high-energy source. It will split the oxygen molecule into two free atoms. Like all atoms, these oxygen atoms are very unstable and continually combine with other atoms and molecules|
|If there are other oxygen molecules in the area, the oxygen atoms will combine with them to form new ozone (O3) molecules|
|Ultra violet (UV) radiation is not at all selective. It will use its high energy to convert ozone (O3) back to oxygen molecules (O2) and oxygen atoms (O). this process is normal and goes on continually in the stratosphere. All of this means that there are plenty of oxygen atoms and molecules available.|
|Chlorflurocarbons (CFCs) mess up the system because the UV radiation will also “break off” a chlorine atom (Cl) from the CFC.|
|This free chlorine atom is also very unstable and will react with any other atom or molecule in the area. If it collides with an ozone molecule it will “strip off an oxygen atom.|
|The chlorine atom then combines with the oxygen atom it stripped off, to form a chlorine monoxide molecule (ClO). The remaining two oxygen atoms (O) combine to form a pure oxygen molecule (O2)|
|When the newly formed chlorine monoxide molecule encounters another free oxygen molecule that was produced during the normal formation of oxygen and ozone, the oxygen atom breaks up the chloride monoxide molecule and binds the oxygen atom to its self, leaving the chlorine atom free to make some more pure oxygen out of ozone.|
The newly formed free chlorine atom will continue this process forever and the more of them you have, the bigger the problem. Oxygen atoms and oxygen molecules continue to break apart and form ozone, but the chlorine monoxide slows down the process and that is the problem. Oxygen, unlike ozone, will not reflect UV radiation.
And what does all of this mean to you? No question about it, you are going to have to use dual seals and a leakage recovery system on all of your CFC applications.