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Located in stratosphere (15-30 km above sea level) layer with an increased concentration of ozone, that is protecting us from harmful ultraviolet radiation is showing the first signs of rebuilding itself, after many difficult years. At least, that is what UN (to be more specific – United Nations Environment Programme, UNEP) says in its report. What’s more, the report says it is definitely caused by globally taken efforts – the prohibition of substances depleting the ozonosphere.

Ozone Hole

In the 80s of the last century scientists began to test the thickness of ozone layer regularly. They found out, that this very important for our (and other living organisms) life thin layer of ozone located above the ground is getting thinner, and even completely disappears seasonally in some areas of the Antarctic (where it’s naturally very thin).

It was not long to find the culprits of this state of things – mainly chlorofluorocarbons  (CFC). These gases, used very widely – in fridges (refrigerant) and cosmetics products (lacquers, deodorants), but also in medicine and industry – decompose in atmosphere in a photo-induced scission to carbon, fluoride and chloride. The last one, formed as a radical is very reactive and causes decomposition of ozone.

In response to that, diplomats in Montreal forged a treaty, the Montreal Protocol in 1987. It was signed by almost 200 countries. This international agreement committed the parties to cease production and use of compounds that might be destructive and depleting for the ozone layer.

First effects!

Luckily, tough since early 90s the amount of ozone in the stratosphere was still getting lower and in the next decade remained unchanged, since last year we can talk about first signs of its recovery. The report issued by UN says, that it’s caused by limiting the usage of CFCs. It is estimated, that without Montreal Protocol the level of chlorofluorocarbons would be ten times higher in 2005.

And it still is not everything. We can read in the report, that progressive restoration of the ozone layer will prevent developing about two million cases of skin cancer each year, until 2030. Similarly, increasing the amount of ozone in the stratosphere will help to prevent eye and immune system diseases. Farmers should also feel the positive impact. What’s more, because chemicals associated with the destruction of the ozone layer are also potent greenhouse gases, Montreal Protocol has also contributed to reduce the greenhouse effect.

More information at: http://ozone.unep.org , http://www.unep.org

Samanta Makurat

Chemistry student at the University of Gdańsk, fascinated with molecular modeling. Nature enthusiast.

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