The stratosphere is the second layer of Earth's atmosphere, just above the troposphere. It extends from about 10 to 50 kilometers (6 to 31 miles) above the surface of the Earth. The stratosphere is characterized by relatively stable temperatures, with a slight increase in temperature with increasing altitude.

The composition of the stratosphere is also relatively constant, with nitrogen making up about 78% of the total volume, oxygen making up about 21%, and argon making up about 0.9%. The remaining 0.1% is composed of trace gases, including water vapor, carbon dioxide, ozone, and nitrous oxide.

The ozone layer is a region of the stratosphere that contains a high concentration of ozone (O3) molecules. Ozone is a powerful absorber of ultraviolet (UV) radiation, and the ozone layer helps to protect the Earth's surface from harmful UV rays. The ozone layer is located at an altitude of about 25 kilometers (16 miles) above the Earth's surface.