The harmful Ozone hole in the Southern hemisphere and not in the North.

I asked a scientist friend of mine who works on the UN agreement to limit the use of CFC’s gasses, which are used in refrigerators and cause the hole in the ozone layer.   ‘Why is it that the industrial Northern hemisphere countries emit the CFC’s and we, in the Southern Ocean have the hole in the ozone layer and its lack of protection exposes us to cancer from sunburn’.
This is a very shortened version of her explanation.

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CFC gas is released in the Northern hemisphere and because the gas is light it rises into the upper atmosphere with warm air and, in the strong circulating upper atmosphere winds, it is carried down to the equator where it crosses to the Southern hemisphere. 

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The CFC’s have a chemical reaction that kills ozone when exposed to extreme cold and UV light. Antarctica is different to the North Pole because it is very high and as a result it is very cold. In the spring when the sun returns to the South Pole, with the combination of the UV light and extreme cold the CFC’s react with the Ozone and destroy it. 

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​The circular motion of the Southern Ocean winds holds the ozone depleted hole in the atmosphere in position and stops it being repaired by fresh ozone, which means that there is a single large region that has no ozone in the upper atmosphere.

​The North pole does have depleted ozone regions but they are smaller and split into two or three patches.

The very fact that the countries of the world came together to reach an agreement to stop using CFC's and use a less harmful gas was incredible. Then, when they realised that the CFC replacement was also a harmful greenhouse gas, they came to a new agreement and adopted a gas that had almost zero greenhouse gas emissions.
There is some hope that we can collectivly get CO2, methane and other greenhouse gasses under control and avoid the very worse of climate change.