International Preservation of the Ozone Layer Day

The Ozone Layer. We’ve all heard of it. But do we all know what it is and why it’s important? Well, in honour of“International Preservation of the Ozone Layer”, here’s the basic information you need to know and what you can do to help to preserve it.

Background to the day

In 1987, 24 countries met in Montreal to discuss the ozone layer, and the ever-growing hole that was appearing. On this day, all 24 countries signed the ‘Montreal Protocol on Substances that Deplete the Ozone Layer’, pledging to stop the use of harmful chemicals and gases that had been shown to be destroying the ozone layer, by the year 2000. However, it wasn’t until December 19th, 1994 that the ‘International Preservation of the Ozone Layer’ Day was proclaimed to be held on the 16th of September every year.

So, what exactly is the ozone layer?

The ozone layer is effectively a blanket of gas made up of a special type of oxygen known as ozone – O3 – that sits around 30 miles above the surface of the Earth. This layer acts as the Earth’s suncream, as it is responsible for absorbing around 97 – 99% of the suns UV-B rays that would otherwise penetrate through to the Earth’s atmosphere.

So what? You may be thinking. Who cares if the ozone layer disappears or the hole simply gets bigger? We’ll just wear more of our own suncream!

Well, unfortunately, it’s not quite that simple! Not only can excessive UV cause sunburn, it can also increase the risk of skin cancer, a suppressed immune system and blindness. On top of this, UV-B exposure can be extremely damaging to other life on earth, including single-celled organisms, terrestrial plants and whole aquatic ecosystems.

This is because UV rays can travel through water, killing tiny animals such as plankton, which live in the photic zone. Plankton is the main food source for many animals, accounting for roughly 30% of the world’s animal protein intake. A reduction in plankton would be damaging to the environment in two ways:

  1. There would be a reduction in the amount of food for the fish to eat. This would further reduce the fish populations, which are already at risk from overfishing.
  2. Without the organic matter (plankton) on the surface of the sea, the UV-B rays would be able to penetrate further down into the ocean. This would therefore lead to more damage on larger, more complex animals and plants. For example, UV-B is known to affect the early development of many animals, including; crustaceans; fish and amphibians.

What is the ozone hole?

So, now I’ve got you interested, and maybe even a little bit worried, you might be wondering what the ozone hole is and what we can do to prevent it from getting bigger.

Well, firstly, the ozone hole is essentially areas of the ozone layer where there is a reduction in the concentration of O3 leading to a thinning of the layer. The size and position of the hole is constantly fluctuating – changing daily as the earth spins, seasonally as the earth’s position towards the sun changes, as well as annually due to the orbit of the earth causing the planet to be further away or closer to the sun. Another factor – how much UV is being released from the sun itself – can also have an effect.

So, if the hole is constantly changing from very natural factors that we cannot control, then why should we even be fretting in the first place? Well, before you stop your worrying just yet, the ‘hole’ has been steadily growing in size over the past two decades, but from very unnatural sources. The hole has been growing because of us.

Chlorofluorocarbons (CFC’S), defined as any compound of hydrogen, chlorine, carbon or fluorine, have been steadily released into the atmosphere from our homes. Up until recent years, CFC’s were found refrigerators, fire extinguishers, air conditioning systems and aerosol cans.

Once released into the atmosphere, CFC’s are broken down by light into a colourless gas called ‘Dichlorodifluoromethane’ and a chlorine radical, as shown by the formula below.


CCl3F CCl2F. + Cl.


The chlorine radical is then responsible for the breakdown of ozone into the standard oxygen we need to survive, causing the ‘holes’ to appear.

If you think this is a good thing, because there’s more air for us to breathe, you clearly haven’t been reading this blog properly!

So, instead of it being all doom and gloom, what can we do to prevent the expansion of the ‘ozone hole’?

Well, it’s the bog standard environmentally friendly stuff really!

  • Use public transport, walk or car share to reduce the amount of carbon released into the atmosphere
  • Turn off any lights you may not be using
  • Recycle your waste
  • Educate yourself and your community

But most importantly:

  • Buy ozone friendly products
  • Remove any of your old products that may use CFCs in the correct manner

If you want to find out more about the ozone layer, the hole, and what you can do, please follow these links:


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