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SESK: Stuff Everyone Should Know · sesk.info/aero-earth-air-nitrogen

Which gas makes up most of Earth's atmosphere?

Nitrogen, at about 78 percent.

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  1. Nitrogen ✔
  2. Oxygen
  3. Carbon dioxide

Why: Dry air near Earth's surface is mostly nitrogen. Oxygen makes up about 21 percent, while all other gases share the small remainder.

Huh, didn't know that: Earth's atmosphere also shields the surface from much harmful solar radiation.

The dad joke
Nitrogen took up most of the room because it needed some air space.
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References

Answer: Nitrogen. Dry air near Earth's surface is mostly nitrogen. Oxygen makes up about 21 percent, while all other gases share the small remainder.

  1. Facts About Earth science.nasa.gov/earth/facts
    Earth has an atmosphere that consists of 78% nitrogen, 21% oxygen, and 1% other gases
    Checked 2026-10-10.

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