Nitrogen makes up approximately 78% of the Earth's atmosphere by volume, making it the most abundant gas in the air

. Specifically, dry air contains about 78.08% nitrogen, with the remaining major components being oxygen (~21%) and argon (~0.93%)

. By mass, nitrogen constitutes about 75.5% of the atmosphere

. This high proportion of nitrogen is consistent across various scientific sources and is a fundamental characteristic of Earth's atmospheric composition.