The Ozone Layer

Ozone (O3) is present in trace amounts throughout most of the atmosphere, but is most abundant in the stratosphere, which extends from about 12 to 50 km above the Earth’s surface. The stratosphere contains nearly 90 percent of total atmospheric ozone, which plays an important role in filtering harmful solar rays and in regulating temperatures. This should not be confused with ground-level ozone which is the primary component in urban smog.