most abundant gases on earth
Answer: The answer depends on the region of the atmosphere and other factors, since the chemical composition of the Earth's atmosphere depends on temperature, altitude, and proximity to water. Usually, the 4 most abundant gases are: 1  nitrogen (N 2) - 78.084%. 2  oxygen (O 2) - 20.9476%. 3  argon (Ar) - 0.934%.
However, water vapor can also be one of the most abundant gases! The maximum amount of water vapor air can hold is 4%, so water vapor could be number 3 or 4 on this list. On average, the amount of water vapor is 0.25% of the atmosphere, by mass (4th most abundant gas). Warm air holds more water than cool air.