What Gases Make up the Earth’s Atmosphere?

The Earth’s atmosphere is primarily made up of nitrogen, oxygen and argon, but it includes trace gases in smaller amounts such as neon, helium, carbon dioxide, methane, nitrous oxide and ozone. The most abundant gases in the atmosphere are nitrogen at 78 percent and oxygen at 21 percent, while the trace gases methane, neon and helium make up around one-tenth of 1 percent of the atmosphere.

Oxygen, nitrogen and argon are classified as permanent gases because their percentages always remain the same. Greenhouse or trace gases, such as carbon dioxide, methane and helium, do not always possess the same percentages and vary in their amounts, depending on the time of day, season and other environmental interactions.