Which gas has the highest percentage in our atmosphere?

Nitrogen is the gas with the highest percentage in our atmosphere, accounting for approximately 78% of the Earth's air. This is significant because nitrogen is a relatively inert gas, meaning it does not readily react with other chemicals under standard atmospheric conditions. Its abundance provides stability to the atmosphere and is crucial for life, as it acts as a reservoir for other nitrogen compounds that are used by living organisms, such as in the formation of amino acids.

The predominant presence of nitrogen in the atmosphere helps dilute oxygen and other gases, which can be reactive. While oxygen is vital for respiration in most living organisms, it constitutes about 21% of the atmosphere. Carbon dioxide and argon make up much smaller fractions, with carbon dioxide being essential for photosynthesis and argon being a noble gas with little chemical reactivity. Understanding the composition of the atmosphere, particularly the dominance of nitrogen, is fundamental in aeromedical studies as it informs about the environmental conditions encountered during flight.