Largest hole in the ozone layer

The largest hole in the ozone layer was observed on 9 September 2000 above Antarctica and measured 29.9 million km² (11.54 million square miles). This is area is about three times the area of the USA.

Ozone (O3) is a gas present in the atmosphere, at an altitude between 10 and 50 km from the ground; this layer of ozone is essential for our lives/health, as it blocks some ultraviolet radiations from the Sun, so they do reach the Earth. The hole in the ozone layer is caused by the emission in the atmosphere of gases such as chlorofluorocarbons (CFCs), used as refrigerants, because these gases react with the ozone. With a larger hole in the ozone layer, more ultraviolet radiations will reach the Earth, with negative consequences for our health.

Although still there, the ozone layer today is getting smaller, as CFCs have been banned and replaced by other gases. In the year 2016, for instance, the maximum size of the hole was 23.0 million km² (8.88 million square miles), about 23% less than the maximum value of 2000.