Lesson 17: Importance of Atmospheric Gases | Variable & Non-Variable Gases | Ozone Layer| eLecturepk

Atmosphere is divided into two regions due to its composition as follows:

1. Homosphere
2. Heterosphere

• Homosphere: Homosphere expands from the surface of earth to 100Kms in atmosphere. Gases are nearly uniform in this layer.
  
• Heterosphere: It expands from 100Kms to final boundary of atmosphere. The chemical composition of air is not uniform in this sphere. From both spheres homosphere is most important for us so we will study it in detail.

The gases in this sphere can be divided into three categories as follows:

1. Non-Variable Gases, Constant or Permanent Gases
2. Variable Gases
3. Other Impurities

Non-Variable Gases, Constant or Permanent Gases
Nitrogen and Oxygen are non-variable gases and makes up 99% of atmosphere.

Nitrogen 78%

It is important part of many cells and processes such as a amino acid that make up protein and in our DNA. It is also needed to make chlorophyll in plants. It is important for growth and reproduction in both plants and animals. It turns into nitrate which are essential for plants nutrients.

Oxygen 21%

It is important for plants and animals respiratory process. It is important part of blood. The burning process of earth is possible due to oxygen.

Organ It 1894 scientists experimentally found another Inactive Gas that doesn't resembles with others and its ratio is only 1%.

Variable Gases:

It includes carbon dioxide, water vapors, ozone and some minor gases. Other Impurities: Atmospheric particulates and aerosols are very small particles of solid or liquid suspended in the air. They have no important function in atmosphere.