Atmosphere

Ozone

Ozone and the ozone layer

What is Ozone?

Ozone is a naturally occurring molecule containing three atoms of oxygen. Ozone molecules form a gaseous layer mostly in the upper atmosphere (the stratosphere) 15-30 km above the surface of the earth, and protects life on earth by absorbing ultra-violet (UV) radiation from the sun.

The Ozone layer

Download Twenty Questions and Answers about the ozone layer  - from the World Meteorological Organisation web site.

Concerns about the depletion of the ozone layer  exist because the ozone layer reduces the amount of harmful ultraviolet radiation that reaches the earth's surface. The ozone layer is also an important part of the global atmosphere-climate system in which present day living organisms, including humans, have evolved. Any significant change to this layer can have far-reaching consequences for human health.

CFCs, halons, methyl chloroform, carbon tetrachloride, HCFCs, hydrobromofluorocarbons and methyl bromide are directly implicated in the depletion of the ozone layer. These and other ozone depleting substances also contribute to varying extents to the enhanced greenhouse effect.

In 2003, the size of the ozone hole peaked at around 28 million square kilometers, making it the second largest on record.

See also:

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Ozone molecule, from the publication: Twenty Questions and Answers About the Ozone Layer by DW Fahey (available from the World Meteorological Organisation web site)