The ozone layer

The ozone layer is already famous worldwide. We already know it protects us from harmful sun rays, and that we need to protect it. Now it would be great to have the details, don't you think?

For a start, let's understand what the ozone is. The formal definition is that it is "an allotropic form of the molecule of oxygen". In plain English, that means it is a different arrangement of atoms in a molecule of oxygen: not O2, but O3. Ozone is produced naturally by a chemical reaction between some particular form of the sun energy, and molecules of oxygen. It exists all over the planet, but it is particularly concentrated about 20 km above our heads in what we call the ozone layer.

It is said that the ozone layer protects life on the planet. It does indeed. This happens because the ozone layer uses just the most damaging solar energy that comes to the planet to go into a chemical reaction which creates and destroys ozone once and again. The process, in three steps, is like this:

1. Damaging solar rays collide with normal molecules of oxygen, creating two free atoms of oxygen

O2 + sun = O + O
(that was the solar radiation breaking a molecule of oxygen)

2. These free atoms collide with other molecules of oxygen, creating the allotropic form we know as ozone

O + O2 = O3
(that was the free atom of oxygen joining a molecule to form ozone)

3. The damaging solar rays collide with the molecules of ozone once more to separate it into molecules of oxygen and free atoms, which will subsequently restart the process.

O3 + sun = O2 + O
(that is a molecule of oxygen colliding with some other solar radiation to separate the oxygen again)

With this simple yet intense exchange of atoms, most of the dangerous solar energy is left outside of the planet, and there can be life.

The famous problem of the ozone layer

For decades, people all around the world have been referring to a sort of hole in the ozone layer which is letting perilous sun rays get through. The hole is supposed to be in both south (mainly) and north poles (more recently), and it is noticeable every spring of each hemisphere.

Why there, and what is causing the hole in the ozone layer? Both answers have the same reply, fortunately: It is because of pollution, and because winds make pollution concentrate in the poles.

What happens is this: A pollutant concentrated in the south pole, say, chlorine (Cl) meets one of the molecules of ozone. They are compatible by nature, so, with solar energy (that's why the hole in the ozone layer is noticeable mainly in spring), a reaction will occur:

Cl2 + O3 = ClO + O2

As you see, the reaction produced chlorine oxide, and a normal molecule of oxygen as a result. The ozone available was reduced after the reaction, and there is one atom of oxygen less to create new ozone. Now, repeat this a dozen million times for every ozone molecule a free molecule of chlorine can find, and you will easily understand the point. If we don't stop the pollution, there will be less and less ozone available in the future. There is no need to alarm the whole world again, though. We just need to become aware of our doings.

A reversible problem

For those who wonder whether something can be done to stop and reverse the ozone problem, the answer is yes: the ozone layer problem is reversible. We need just two things: more oxygen and less pollution. Oxygen is provided by plants, and for free, so one part of the solution is as easy as recovering vegetation around the world. As for the need of less pollution, on the other hand, things are not as positive. This idea of polluting less is somewhat "conflictive" for many in charge of large industries. After all, they make a lot of money with the usual procedures. They think they can always change them "later".

That said, the solution of the problem should be more collective. Governments should be strict and just forbid the use of the most destructive pollutants; communities should not but their products. You know? This has been said zillions of times too. While everybody makes up their minds, just think twice before buying something.


Knowledge and information + Nature