Percentage of oxygen in air | oxygen at high altitudes | Oxygen vs Ozone


The percentage of oxygen in air is 20.95%. Nitrogen is the most prevalent gas and forms 78.08% of the atmosphere. Rest is other gases mainly Argon (0.9340%) and Carbon dioxide (0.0410%).

Percentage of oxygen in air

Oxygen at high altitudes

As we gain elevation, the percentage of oxygen in the air does not decrease. Rather the atmospheric pressure decreases, meaning there is less air per unit volume for us to breathe at higher elevations.

Acute mountain sickness commonly known as AMS is a common sickness experienced by people who are not able to acclimatize to lower atmospheric pressure at higher elevation. Symptoms include headache, vomiting, dizziness, etc. If you are travelling to higher elevation it is advised that you gain elevation at a slow rate.

Oxygen vs Ozone

  • Oxygen molecules (O2) are made up of two atoms of Oxygen element while ozone molecules (O3) are made up of three atoms of oxygen.
  • Diatomic oxygen is more stable than Ozone.
  • Ozone is bluish in color while oxygen is colourless.

The ozone layer present in the stratosphere protect the Earth from the harmful ultraviolet radiations of the Sun.


Quick question

Which is the most prevalent gas on Venus?


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Answer to quick question

Carbon dioxide is the most prevalent gas on Venus and forms more than 96 % of Venus’s dense atmosphere.


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