Ozone is formed through a chemical process that involves the reaction between oxygen molecules and ultraviolet rays.
When oxygen molecules are exposed to ultraviolet rays, they split into individual atoms.
The newly formed single atoms then combine with molecular oxygen to form triatomic oxygen molecules.
The reaction can occur in the upper layers of the atmosphere or close to the ground. However, ground-level ozone can be harmful to our health.
Ground-level ozone forms when volatile organic compounds react with nitrogen oxide gases in the troposphere. Thankfully, most of the ozone on earth is formed in the stratospheric layer of our atmosphere.
When was the ozone layer formed?
Scientists believe that the earth developed enough ozone to protect all biological processes on its surface about 600 million years ago.
This was made possible with the help of aquatic organisms that caused the formation of oxygen molecules*.
Which layer of the atmosphere contains the ozone layer?
The earth’s atmosphere is made of multiple layers. Each layer has a special role that it plays in ensuring the planet remains conducive for all organisms.
Ozone molecules can be found in several zones of the atmosphere. However, most of it is found in the stratosphere.
The stratosphere is the second layer making up the earth’s atmosphere. It contains about 90% of the ozone on our planet.
The lowest region of the stratosphere is about 6 miles from the surface of the earth, while the highest point is at 31 miles.
Ozone molecules can be formed in this region naturally, provided that all conditions are met. There must be oxygen molecules and ultraviolet rays.
Importance of the ozone layer
Both plants and animals need the ozone layer to survive. The earth is habitable because the ozone layer shields it from lethal radiation.
How does the ozone layer protect us?
- The ozone molecules in the atmosphere absorb harmful ultraviolet rays such as UVB. These types of rays can damage our skin and may also cause cancer.
- With the ozone layer in place, the sun’s rays can be filtered before they reach the surface of the earth.
- The ozone layer creates the perfect conditions for plants and animals to thrive.
- Since the ozone levels in the earth’s atmosphere vary from time to time, harmful rays can still reach the planet’s surface. As such, always use sunscreen to protect yourself.
- Without the ozone layer, organisms will find it difficult to survive on earth. Humans and animals will be exposed to life-threatening conditions that will lead to their demise.
- Besides, UV radiation can damage plant and animal DNA, so we need the ozone layer to stay alive.
Can the ozone layer be destroyed?
The ozone layer is made of volatile molecules that can easily be destroyed by certain compounds. It takes a long time to form the ozone layer but destroying it is very easy.
What destroys the ozone layer?
The ozone layer is continuously being destroyed through a process called ozone depletion. There are ozone-depleting substances that are reducing the ozone levels in the atmosphere.
Ozone depletion is mainly caused by chlorofluorocarbons (CFCs), a group of chemical compounds containing chlorine, fluorine, and carbon atoms.
These chemical compounds can break down ozone molecules. Thereby, creating passageways through the ozone shield.
Most of the compounds were formerly found in refrigerants and aerosol spray cans.
Hydrochlorofluorocarbons (HCFCs) can also cause gradual degradation of the ozone layer. HCFCs contain atoms of hydrogen, fluorine, carbon, and chlorine.
A single atom of chlorine can destroy up to 100,000 molecules of ozone, resulting in serious ozone depletion.
HCFCs are not as destructive compared to CFCs because they don’t release a lot of chlorine to the atmosphere compared to the latter.
Halons also release bromine into the atmosphere. Bromine has the same effect on ozone molecules as chlorine and can also lead to ozone depletion*.
NASA for Educators: Ozone
Over the years, the ozone layer has been gradually depleting. This poses a threat to all life forms on earth.
Ozone depletion mainly occurs at the poles of the earth. The destruction is greatest at the southernmost, also known as the South Pole.
What caused the hole in the ozone layer?
When ozone molecules are severely depleted in a certain area, it results in the formation of the ozone hole.
The zone does not have an actual hole, but it acts as a weak point through which ultraviolet rays can pass.
The ozone hole is continually expanding, thus threatening the existence of life at the South Pole and the earth as a whole.
In the past few years, it has become wider and deeper, making it a cause for concern.
The ozone hole is expanding due to human activities that lead to the emission of harmful substances into the atmosphere.
How to protect the ozone layer?
Caring for the ozone layer is very easy. We only have to stop using certain chemical compounds.
Avoid Products with CFCs
CFCs contain large amounts of chlorine, and chlorine has a longer atmospheric lifetime compared to most ozone-depleting substances.
If released into the atmosphere, it can catalyze the depletion process, causing further damage to the ozone layer.
The same applies to HCFCs, so such products should be avoided.
The use of cars and other types of machinery is the leading cause of emissions on our planet. You can protect the ozone layer by resorting to other means of transport such as the use of bicycles*.