The troposphere is made up largely of nitrogen and oxygen with trace amounts of argon, carbon dioxide and hydrogen ozone. The troposphere also contains the majority of the water vapor in the atmosphere.
Up to 75 percent of the weight of the atmosphere is found in the troposphere, weighing more than 14 pounds per square inch. The majority of this mass is gases. Seventy-eight percent of the air in the troposphere is made up of nitrogen. Twenty-one percent is made up of oxygen. One percent is argon, while there are small amounts of other gases such as hydrogen ozone and carbon dioxide.
The troposphere is the lowest layer of the Earth's atmosphere, containing most of the breathable gas as well as water vapor. Because 99 percent of the water vapor in the atmosphere is found in the troposphere, all weather occurs in it. The water vapor forms clouds, providing the world with precipitation in the form of rain or snow, which in turn depends on the temperature of the air. The heat from sunlight is absorbed by the Earth and radiated into the atmosphere. The molecules of water vapor and other gases present in the troposphere absorb and reflect this heat back to the ground, allowing the global temperature to remain fairly stable.