The importance of the ozone layer and its structure
The ozone layer
The ozone layer is located at the height from 20 to 40 km above the sea level , And it is located in the lower part of the stratosphere layer , As it is the first layer of the atmospheric envelope which contains a suitable amount of oxygen gas , and it also faces the ultraviolet radiations that emitted from the Sun .
The structure of the ozone layer
The ozone layer is composed of the ozone gas which consists of three oxygen atoms .
The formation of the ozone gas
|Each oxygen atom combines with an oxygen forming the ozone molecule .|
The oxygen molecule absorbs the ultraviolet radiation ( UV ) , Which causes the break down of the bond between the two oxygen atoms giving two free oxygen atoms , And each oxygen atom combines with an oxygen molecule forming the ozone molecule which is composed of three oxygen atoms .
The thickness of the ozone layer
The value of the atmospheric pressure in the stratosphere layer is 0.001 of the normal atmospheric pressure at the sea level , And the temperature is less than that at the sea level . So , In these conditions , The zone gas forms a layer of a thickness 20 km .
The English scientist ” Dobson ” postulated that the thickness of the ozone layer is compressed into 3 mm . Only if it is under the normal atmospheric pressure , and at the zero temperature ( STP ) .
STP means standard temperature , and normal atmospheric pressure .
So , The scientists took ” Dobson ” as a measuring unit of the degree for the ozone layer . The natural degree of the ozone is 300 Dobson units ( 100 Dobson unit ( DU ) is defined as 1mm thickness ) .