Pie chart showing the gases that make up the atmosphere: Nitrogen (78%), Oxygen (21%), Inert Gases- mostly Argon (.96%), and Carbon Dioxide (0.04%).

Credit:UCAR

The dry composition of the atmosphere is mostly nitrogen and oxygen. It also contains small amounts of argon and carbon dioxide and trace amounts of other gases, such as helium, neon, methane, krypton, and hydrogen.