Which gas has the highest percentage in atmospheric air?

Nitrogen is the gas with the highest percentage in atmospheric air, making up about 78% of the Earth's atmosphere. This is a fundamental aspect of atmospheric science and respiratory physiology.

Nitrogen serves as an inert filler in the atmosphere, providing a stable environment for biological and chemical processes. Its abundance plays a crucial role in various ecological and environmental functions, such as diluting oxygen, which is present at around 21%. The presence of nitrogen also supports combustion and various life processes without being reactive itself.

While oxygen is vital for respiration in most aerobic organisms, it constitutes a significantly smaller fraction of the atmosphere. Carbon dioxide and water vapor are present in even smaller amounts, with carbon dioxide typically around 0.04% and water vapor varying based on weather and environmental conditions, but generally averaging around 1% to 2% in the atmosphere.

Understanding the composition of atmospheric gases is important for professionals in various fields including perfusion, as it relates to oxygen transport and delivery in physiological systems.