The Ozone Layer

What is The Ozone Layer?

Earth's Ozone Layer

Ultra Violet Rays

The ozone layer is a protective layer of naturally occurring ozone gas, found in the Earth’s stratosphere, 15 to 30 kilometres above the Earth’s surface.

Why is The Ozone Layer Important?

The ozone layer protects life on Earth because it acts as an umbrella and shields us from 97 to 99% of the Sun’s dangerous rays. By blocking out these rays, the ozone layer stops them from reaching the Earth’s surface.

Have you ever had sunburn? Sunburn is caused by Ultraviolet (UV) rays.  If too many UV rays reach Earth, they can damage humans, animals and crops.  

UV rays cause skin cancer, cataracts and a weakened immune system in humans, which means we can get sick easily. The rays can also affect algae which will disrupt the whole food chain.

What is the Hole in the Ozone Layer?

In 2000, a hole in the ozone layer, nearly 30 million square kilometres in size, (roughly as large as North America), was discovered.

In Antarctica, 65% of the ozone layer has already been destroyed. The low temperatures of the polar regions speed up the conversion of CFCs to chlorine. The ozone layer is thinnest at the North and South Poles.

There are many smaller holes in the Arctic regions, so now UV rays are reaching the densely populated areas of Europe.

In other parts of the world, the layer has been destroyed by as much as 20%. Nearly 5% of Earth is already not covered by the ozone layer. Also, ozone levels are dropping by 4% a year.

Hole in Ozone Layer (1979 and 2008)
Source: Wikimedia Public Domain, Created by NASA

How is the Ozone Layer Being Destroyed?

In the 1980s, scientists discovered that the ozone layer was getting thinner. Since then, research has found that it is being damaged by chemicals such as chlorine, fluorine and bromine. One of the main ways that these reach the ozone layer is through Chlorofluorocarbons (CFCs).

CFCs are gases that are used to keep things cold, such as refrigerators and air conditioners. These gases are also used to make soap and foam, like fire extinguishers, as well as pesticides, which are sprayed on crops. One of the main culprits of CFCs is spray aerosols, like deodorants.

When used, CFCs are carried by the wind and find their way into the stratosphere. Once there, they are broken down by UV light and then release chlorine, which breaks down the ozone. One atom of chlorine can destroy 100,000 molecules of ozone. In this way, the ozone layer is being destroyed, and dangerous UV rays are now reaching Earth.


CFCs in Fire Extinguisher
CFCs in Aerosol
CFCs in Pesticides

What Can You Do?

Encourage your parents and family to buy CFC-free or ozone-friendly products.

Remember the following if you play outside or play sport in the Sun:

  • Always wear sunscreen with an SPF of at least 30.
  • Cover your body and wear a wide-brimmed hat.
  • Do not play outside in the bright sunshine.

Use Sunscreen
Wear a Hat

What Has Been Done?

  • 1978 – Sweden was the first country to ban aerosol sprays.
  • 1987 – The Montreal Protocol was signed by many countries to stop the production and use of substances that cause ozone depletion.
  • 1996 – The United States and European countries banned the use of CFCs.
  • 2003 – Scientists announced the destruction of the ozone layer is slowing down.

BUT ... Some nations are still using CFCs.

Scientists predicted that ozone depletion peaked around 2010.

CFCs can last for up to 100 years in the atmosphere, so it will take another 50 years for nature to repair the ozone layer and for it to return to the same levels as in the 1980s. Until then, we need to protect ourselves from the danger of UV rays.

The Ozone Layer from Space