What is the most abundant gas in Earth’s atmosphere?

Nitrogen is the most abundant gas in Earth’s atmosphere, making up approximately 78% of the air we breathe. This gas plays a crucial role in the atmosphere by contributing to the stability and composition of the air. Nitrogen is mostly inert, meaning it does not readily react with other substances, which helps to maintain a relatively constant composition of the atmosphere over time.

In addition to its abundance, nitrogen is essential for life because it is a key component of amino acids, proteins, and nucleic acids. Although other gases such as oxygen and carbon dioxide are vital for different biological processes, they are present in smaller amounts compared to nitrogen. Oxygen, for example, constitutes about 21% of the atmosphere, and carbon dioxide is only around 0.04%. Hydrogen is present in trace amounts, making its concentration in the atmosphere negligible compared to nitrogen. Understanding the composition of the atmosphere is essential for studies in environmental science, biology, and chemistry, as it affects climate and life on Earth.