What is the main component of the Earth's atmosphere?

The primary component of the Earth's atmosphere is nitrogen, which accounts for about 78% of the total volume. This inert gas plays a critical role in the atmosphere by diluting oxygen and preventing rapid combustion. The presence of nitrogen is essential for maintaining the stability of the atmosphere, as well as supporting life by providing an essential buffer for other gases.

While oxygen is vital for respiration in many life forms and makes up about 21% of the atmosphere, it does not surpass nitrogen in volume. Carbon dioxide, despite being important for processes like photosynthesis and the greenhouse effect, constitutes a very small percentage (about 0.04%) of the atmosphere. Argon is even less prevalent, making up about 0.93% of the atmosphere. Therefore, nitrogen is clearly the dominant component, emphasizing its significance in Earth's atmospheric composition.