Which component of air is present in the largest percentage?

In the composition of Earth's atmosphere, nitrogen is indeed the most abundant component, making up about 78% of the atmosphere. This is a crucial point to understand, as nitrogen is essential for various biological and chemical processes, although it is not directly used by most living organisms.

Oxygen, while vital for respiration in humans and many other forms of life, constitutes about 21% of the atmosphere. Argon, a noble gas, is present at about 0.93%, and carbon dioxide, although important for processes like photosynthesis and contributing to the greenhouse effect, makes up only about 0.04% of the atmosphere.

Understanding the composition of air is essential for various applications in diving physics and environmental science, as it impacts buoyancy, gas exchange, and life support systems in both terrestrial and underwater environments. Nitrogen's predominance plays a crucial role in discussions of diving and the effects of pressure and gas mixtures at depth.