What is atmospheric air?
Atmospheric air is a mixture of gases. The air’s composition by volume is: nitrogen 78.16%; oxygen 20.9%; inert gases (argon, helium, krypton, neon, and radon) 0.94%.
Air’s composition by mass is: nitrogen 75.5%; oxygen 23.2%; inert gases 1.3%.
In addition to oxygen, nitrogen, and inert gases, which make up the bulk of air, it also contains small amounts of carbon dioxide (CO2), water vapor, and dust. Carbon dioxide enters the atmosphere from factories, plants, power plants, and other facilities that burn large amounts of fuel, and is also released into the air due to volcanic activity.
Despite the continuous release of carbon dioxide into the atmosphere, its content in the air is relatively constant. It averages approximately 0.03% (by volume) because carbon dioxide is absorbed by plants and is highly soluble in water.