On 16^th September, the International Day for the Preservation of the Ozone Layer is celebrated all around the world in order to remind us how important the ozone layer is for our life and, in the same time, how vulnerable it is on our influence. The decision to celebrate this day was made in 1994, by the United Nations General Assembly[i]. The date 16th September is not a circumstance- it is the anniversary of the signature of the Montreal Protocol in 1987[ii]. The document was aimed to regulate the production of substances, CFCs, which contribute to the depletion of the ozone layer.   

 

Why ozone layer is important?

The ozone particles absorb UV radiation coming from the Sun, and therefore protect us, living under their layer. Why this radiation is dangerous? It actually causes skin cancer, and genetic damage[iii]. Although the prolonged exposition to UVB light is said to have negative effects the direct evidence on the influence of the ozone depletion on the health has not been showed[iv],. It is probably because the ozone depletion across the globe is only by few percent – its significant degradation can be, however, observed over the Antarctic. It is called the ozone hole.

In addition, the depletion of the ozone layer and the intensity of the UV light might affect the phytoplankton living the world?s ocean, which may significantly reduce their number. Consequently, it may well decrease the concentration of the oxygen in the atmosphere, because It is estimated that about 50% - 85% of the atmospheric oxygen has been produced

By these organisms living on the surface of the ocean[v]. So small, but so important of our survival.

 

How It is destroyed and are the consequences?

The depletion of the ozone layer is caused by the chemicals released to the atmosphere, like chlorofluorocarbons (CFCs). Chlorofluorocarbons, which used to be applied in cooling systems in refrigerators, and aerosols contain chlorine atoms, which when released under the exposition on the UV radiation, they attack the ozone atoms and contribute to the ozone layer depletion. Although these chemicals were banned in 1987 by the Montreal Protocol, the effect of their past use can be experienced even today due to their long lifetime.

 

Why the ozone hole is over the Antarctic?

That is the question which always sparked my interest- why is it there but not, let?s say, over the Arctic? The substances which deplete the layer are present all around the world, but the hole appears only there! I did some research and here is what I found?

The Antarctic is known for its really low winter temperatures, and they are partially responsible for the phenomenon. They cause the formation of so-called polar stratospheric clouds (PSCs)[vi]. They are made of small parts of ice, which are formed inside the Antarctic polar vortex, which is the ring of the moving air. In this moving air, there are particles, to which chlorine is attached. Such configuration prevents them from reacting with ozone and depleting the ozone layer. However, when the ice particles in the PSC are formed, the chlorine binds to these structures and Cl₂ particles are let free. During the winter months when the PSC are formed, more Cl₂ molecules occur[vii].

When the summer starts over the Antarctic, the Sun begins to shine. The emitted UV radiation cause the formation of chlorine free radicals from produced chlorine particles in the vortex, which attack the ozone particles and cause their depletion[viii].

 

Montreal Protocol - and International Project to Stop the Ozone Depletion

 

Montreal Protocol is an example of the international project which aim was to save the Ozone Layer. The aim of the treaty was to withdraw the use of substances which contribute to the depletion of the ozone layer[ix]. It is very interesting that that the treaty was introduced before the scientists reached their conclusion about the factors causing the ozone depletion. The first misgivings were raised when the ideas of the introduction of supersonic planes were being put into practice. NO molecules, already known to be able to deplete ozone to oxygen, would be released in high levels of the atmosphere and causing the destruction of the priceless layer[x]. Afterwards, it has been discovered chlorofluorocarbons, used for air-condition and freezers, may produce chlorine radicals, depleting the ozone in the atmosphere[xi]. The introduction of the protocol was followed by different amendments, which included different other substances, accelerating the depletion of the ozone layer, to be phased out from the use. This treaty is a great example of the common effort which results in the great improvement of the Earth?s environment. The ozone hole is healing and is predicted to close between 2050-2070[xii]. 

 

How can you help? How have we already helped?

It turns out that the concerted effort may have far-reaching results. The measurements in September 2016 showed that the hole above the Antarctic is by 4 million square kilometres smaller than it was in 2000[xiii]. In January 2018, ozone hole was announced to be the smallest since 1988[xiv].That is a great achievement of the worldwide society hat through the cooperation, we managed to overcome this threat. However, due to the really long lifetime CFC, chemical responsible for the ozone layer depletion, their effect can be still observed and we still need to engage in the ozone layer protection. NASA scientists estimate the ozone layer might be gone between 2060 and 2080[xv].

Modern refrigerators and air-conditioning do not contain the CFCs, so their use is safe. The ozone layer need to take its time to heal. What we can do is protecting ourselves and inhibiting the global warming. Use the sun cream and the hat when the sun shines to protect your skin from the UV radiation. Give cycling and walking a go. Look for more sustainable transportation alternatives, like electric vehicles or low fuel consumption petrol driven cars. Such actions will decrease the emissions of greenhouse gases – the substances which contribute to the rise of global temperatures.

 

How International Day for the Preservation of the Ozone Layer Day is celebrated?

 

In many different countries, this day is celebrated in different ways. Sometimes awards ceremonies of different environmental competitions are organized, children at schools organize events to raise awareness of the importance of the ozone layer[xvi]. I think this day is important to remind us that, whenever we can, we should take action. It shows that with the effective cooperation, we can change a lot. This day can not only be used to raise awareness about the importance of the ozone layer, but also about the role of cooperation in making things better. This celebration may encourage us to introduce such cooperative approach in ongoing worldwide challenges.