Prabin Kalikote

The lower region of the thermosphere contains ions ofnitrogen, oxygen, etc. Thegaseousmolecules like nitrogen,oxygen, etc. undergo ionization and gives ions due tothe effect of UV radiationof sun. Therefore, thermosphereis also called ionosphere.

Theuppermost layer of stratosphere contains the ozonelayer. This thick layer of air absorbs much of the solarradiation and shields the earth from the harmfulultraviolet radiation. It prevents us from dangerousdiseases. Therefore, the stratosphere is called aprotectiveumbrella.

The uppermost part/layer of the stratosphere containsthe ozone layer. This thick layer of air absorbsmuch of the solar radiation. Due to absorption of thesolar radiation, the temp. of the stratosphereincreasesas the heightincreases.

Troposphere is called the variable sphere because itstemperature varies accordingto its height. It decreasesas the height increases.

Various toxic gaseslike CO₂, SO₂, SO₃, NO, NO₂, N₂Os, etc.which are released by industries are called industrialgases.
Their adverseeffects are:
-It results in ozone layer depletion.
-It hinder human muscular and mental functioning.
-It causes various diseaseslike pneumonia, eye diseases, bronchitis, etc.
-It resultsin the pollution of atmosphere.

The steps to prevent ozone layer depletion are:
-Alternative chemicals should be used instead of CFCs.
-The production and use of chlorofluorocarbonsand oxides of nitrogen should be banned.
-Public awareness should be generated about ozonelayer depletion and its protection.
-Afforestationprogramsshould be encouraged.
-Production of greenhouse gases should be stopped.
-Use of chemical fertilizersshould be banned.

- Mechanism of ozone layer formation:
O₂ -----------> [O] + [O] (Nascent Oxygen)
O₂ + O -----------> O₃ (Ozone)

- Mechanism of ozone layer depletion:
CFCl₃ ----------> CFCl₂ + Cl
Cl + O₃ -----------> O₂ + ClO
2ClO ------------> 2Cl + O₂