International Day for the Preservation of the Ozone Layer – celebrating 35 years of ozone layer protection

International Day for the Preservation of the Ozone Layer falls on 16th September each year. It may not be the catchiest title for an awareness day, but it’s really important. It’s also a good news story, which we love! World Ozone Day celebrates the world’s governments adopting the Vienna Convention for the Protection of the Ozone Layer. In 2020, World Ozone Day marks 35 years of ozone protection.

But what is the ozone layer and what can we do as individuals to help preserve it?

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8 minutes to read

What is ozone and where is the ozone layer?

Ozone is a gas that is made up of 3 oxygen atoms (O3) and occurs naturally in the Earth’s atmosphere. It is also created via chemical reactions due to human activity. But did you know that there is both good and bad ozone? So what’s the difference?

Good ozone

Surrounding the Earth, there are 5 atmospheric layers. These are the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere. The stratosphere is the second-closest part of the atmosphere to the Earth’s surface. It starts around 12 kilometres from the Earth’s surface, and ends around 50 kilometres high. Most of the atmosphere’s naturally-occurring ozone is found in this area. This area is therefore known as the ozone layer.

innternational day for the preservation of the ozone layer - layers of the atmosphere

At this level, ozone absorbs the majority of the Sun’s harmful UV rays to protect life on Earth. Without the ozone layer, the Sun’s rays would be able to hit the Earth’s surface at full strength. As a result, nothing would be able to survive. So the ozone layer has a pretty essential job!

Bad ozone

Ozone is also found in the troposphere. This is the layer of atmosphere closest to the Earth’s surface. It is sometimes known as ground-level ozone, and is a pollutant that damages crops and is harmful to breathe. Ground-level ozone is a “secondary” pollutant because it’s formed when two primary pollutants react with stagnant air and sunlight. These primary pollutants are usually nitrogen oxides (NOx) and volatile organic compounds (VOCs).

How did International Day for the Preservation of the Ozone Layer come about?

In the 1970s, scientists discovered that human activities were affecting the levels of “good” ozone in the atmosphere. As a result of this research, they found that CFCs and other harmful gases were destroying the ozone layer.
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Discovery of ozone depletion

Over the following years, more research was done into the harmful effects CFCs have on the ozone layer.  Because of this research, scientists began monitoring and measuring the global thickness of ozone. In the early 1980s, low ozone levels in various locations were reported. In 1984, scientists discovered a hole in the ozone layer over Antarctica that reappeared every spring.

The Vienna Convention for the Protection of the Ozone Layer

Governments from across the world recognised that collective action was required to help reduce damage to the ozone layer. Subsequently, in March 1985 the Vienna Convention for the Protection of the Ozone Layer was adopted by 28 countries. Since then, it has been seen as one of the most successful treaties of all time. In 2009 it became the first treaty in the history of the UN to be universally ratified.  It’s therefore the main factor for setting the world on its course to ozone healing.
This then led to governments adopting the Montreal Protocol on Substances that Deplete the Ozone Layer. World leaders, scientists and businesses worked together to begin to cut out over 100 substances that deplete ozone levels. CFCs are the most well-known of these chemicals, but halons and other substances also form part of the agreement.

What are CFCs and halons and where are they used?

CFCs (chlorofluorocarbons) are gaseous compounds made up of carbon, chlorine and fluorine atoms. They sometimes also include hydrogen, which makes them into HCFCs. Before they were developed in the early 1900s, more dangerous products such as ammonia were used. At this time, CFCs were preferable because they are non-toxic and non-flammable.

Before the Montreal Protocol, the majority of CFCs were used in a variety of common applications. These included refrigeration, air conditioning, insulation, packing materials, solvents and aerosol can propellants. It was therefore difficult to eradicate CFC use quickly. However, since 1987 the use of CFCs has been gradually phased out. CFC production ended worldwide in 2010 but some older appliances are still in operation. This means that CFCs from those appliances and items will continue to be released unless they are safely disposed of. It’s also been reported that some illegal CFC manufacture is still happening, but this has not been confirmed.

an empty aerosol can

Halons are liquefied, compressed gases, that are known for their fire extinguishing properties. The manufacture of halon extinguishers is no longer allowed and halon extinguishers have been banned in the UK since 2003.

The ozone hole

The ozone hole is an annual thin spot that forms in the ozone layer over Antarctica in mid-September and October. This thinning occurs due to chemical reactions between man-made and naturally-occurring chemicals within polar vortexes. These reactions turn otherwise harmless chemicals, bromine and chlorine, into chemicals that destroy ozone.

The buildup of chemicals in the atmosphere has occurred over many years. This means it will take many more years to help repair the hole in the ozone layer.  This is why the world’s governments continue to honour the agreement that was made back in 1985.

International Day for the Preservation of the Ozone Layer introduced

In 1994, 16th September was named as International Day for the Preservation of the Ozone Layer. 2020’s theme is “35 years of ozone protection” because 1985 was seen to be the turning point towards ozone healing.

Why is International Day for the Preservation of the Ozone Layer so important?

Even though we started to take action to protect the ozone layer back in 1985, it wasn’t until 2000 that the highest concentrations of CFCs in the stratosphere were recorded. So, despite 15 years of actively working towards removing CFCs from production, levels were still rising.
International Day for the Preservation of the Ozone Layer is a reminder to governments, industry and the general population that we should be mindful of our actions. The UN and its partners campaign each year to raise awareness of the importance of the ozone layer and its protection.

What can we do as individuals this International Day for the Preservation of the Ozone Layer?

Even though governments and industry have worked hard to protect the ozone layer, there are still actions we can take this World Ozone Day.


Check aerosol cans

Even though CFC-containing aerosols have been banned for some time, there are still some out there. So check any cans, particularly older ones, and take any that contain CFCs to a waste centre for safe disposal. You should be able to find details on your local authority’s website.

Dispose of old appliances correctly

If you have an old fridge, freezer or air conditioner that you’re looking to replace, make sure you dispose of them correctly. As above, your local authority should be the first port of call.

fridge open in the dark

Check fire extinguishers

Halon-containing fire extinguishers are now illegal in the UK. The only exceptions are on aircraft, in the Channel Tunnel and for military use.

Even so, there could be an old extinguisher lurking. The good news is, they’re easy to spot, as they’re usually green. If you find one, let your company health and safety representative know if you’re at work. Or if it’s your company, make sure you dispose of it safely as soon as possible.

Again, your local authority is the best place to find information on safe disposal.

How healthy is the ozone layer today?

This is where the good news comes in. The Antarctic ozone hole is heading towards recovery! In 2019, the hole was the smallest on record. This is a huge step in the right direction, but it’s still predicted that the hole won’t close until 2050.

Is the ozone hole related to global warming?

The short answer to this is no. The issues caused by the damage to the ozone layer are unrelated to global warming. In fact, the hole in the ozone layer actually has a slight cooling effect on the planet. This is because the hole allows heat to escape at a faster rate than if it wasn’t there.

beautiful landscape sunset scene with trees and mountains

However, some important lessons can be learned from the action that’s been taken to heal the ozone layer. The world’s most powerful leaders have worked together to make a huge difference to ozone health. This means we could make a similar impact on the climate crisis to further protect our amazing planet.

Remember, there are always actions we can take as individuals to help the planet. So whether it’s safely disposing of your old fridge or trying some of our tips for living more sustainably at home, every effort helps.

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