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International Day for the Preservation of the Ozone Layer
16 September

The Ozone Hole and Science

What is ozone?

ozoneOzone is a special form of oxygen with the chemical formula O3. The oxygen we breathe and that is so vital to life on earth is O2.

Ozone constitutes a very small part of our atmosphere, but its presence is nevertheless vital to human well-being. Most ozone resides high up in the atmosphere, between 10 and 40km above Earth's surface. This region is called the stratosphere and it contains about 90% of all the ozone in the atmosphere.

Why do we care about atmospheric ozone?

Ozone in the stratosphere absorbs some of the Sun’s biologically harmful ultraviolet radiation. Because of this beneficial role, stratospheric ozone is considered “good” ozone. In contrast, excess ozone at Earth’s surface that is formed from pollutants is considered “bad” ozone because it can be harmful to humans, plants, and animals. The ozone that occurs naturally near the surface and in the lower atmosphere is also beneficial because ozone helps remove pollutants from the atmosphere.

A video on atmospheric ozone:

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The Ozone hole and science

Following the publication of the findings of a British Antarctic Survey article in May 1985, the phenomenon of ozone depletion over Antarctica was referred to as the "ozone hole", a phrase first attributed to Nobel Prize winner Sherwood Rowland. The satellite image of the Ozone Hole has become a global symbol of this environmental threat that has helped mobilize public support for the Montreal Protocol.

The work of atmospheric scientists and environmental researchers continues to play a paramount role in informing the policymaking under the Montreal Protocol. Images and scientific bulletins about ozone depletion are useful communication tools to the public about progress made and challenges ahead.

Latest ozone measurements

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