Stratospheric Ozone


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 The Earth's atmosphere is a very thin layer of gas which surrounds the Earth. It is densest at the sea level, and gets progressively thinner as one moves upwards.

There is no definite boundary between the atmosphere and space - the atmosphere just gets so thin that its effects are negligible.

Scientists have divided the atmosphere into zones or layers based on how the temperature of the atmosphere changes as you move upwards. A zone where the temperature begins to rise from chilly -50oC (about 15 km up) to a relatively balmy 0oC (about 40 km up) is called the stratosphere.

The stratosphere contains most of the atmosphere's ozone. The ozone is in a wide layer whose maximum density is at an altitude of about 30km.


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PROTECTION FROM SOLAR RADIATION

Ozone absorbs ultraviolet radiation from the Sun. This ozone protects living organisms from radiation damage which would otherwise occur if the ozone layer were removed or destroyed.

On Earth we depend on a huge variety of small micro-organisms to break-down and recycle many of the materials essential for such things as plant growth. If ultraviolet radiation were to kill these micro-organisms, successful agriculture and other related industries would be endangered.

OZONE PROTECTS THE EARTH

POLAR OZONE HOLES


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 Ozone is very simple molecule. It is simply made of three oxygen molecules...so you can write O3 instead of the word ozone.

The trouble is that O3 is also a relatively fragile molecule and it can be destroyed by chemical reactions with other atoms, especially chlorine (Cl).

For at least the past one hundred years we have been releasing chlorine compounds into the atmosphere, and now they are affecting the Earth's ozone layer.

Sunlight helps to produce ozone and chlorine tends to destroy ozone. This means that during the dark polar winters ozone gets destroyed and none gets formed. The result is that in the early sunlight days of spring there is much less ozone over the pole. This is known as an ozone hole .

The discovery of an ozone hole forming over the Antarctic (discovered by Canadian Dr. Wayne Evans) came as an alarming surprise to atmospheric scientists around the world. ...the Earth's ozone layer was being depleted at an astonishing rate.

The questions are..."are the ozone holes growing larger and if so, what can be done to remedy the problem?"

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