Composition of the atmosphere
- The proportion of gases in the air has not changed much in 200 million years
- The composition of the atmosphere today is:
- About four-fifths (approximately 80%) nitrogen
- about one fifth (approximately 20%) oxygenÂ
- small proportions of other gases including carbon dioxide, water vapour and trace quantities of the noble gases
The composition of the atmosphere
The atmosphere mainly consists of nitrogen and oxygen
Examiner Tip
Although the proportion of carbon dioxide is very small, it plays a substantial role in global warming as a greenhouse gas.
