Which gas comprises the highest percentage of the Earth's atmosphere?

The gas that comprises the highest percentage of the Earth's atmosphere is nitrogen. Nitrogen makes up about 78% of the atmosphere, which significantly exceeds the amounts of other gases present.

Oxygen, which is essential for life, constitutes around 21% of the atmosphere, while carbon dioxide is present in trace amounts, roughly 0.04%. Argon, another component of the atmosphere, makes up about 0.93%. These smaller percentages highlight nitrogen’s dominance in the atmospheric composition. Understanding these proportions is crucial for comprehending various atmospheric processes, including respiration, combustion, and the greenhouse effect, as well as for fields such as environmental science, meteorology, and climate studies.