se7enW
Back to What
📖 what

What Is the Ozone Layer?

EnvironmentAtmosphere

Quick Answer

The ozone layer is a region of the stratosphere, 15 to 35 km above Earth, where concentrated ozone (O₃) absorbs most of the Sun harmful UV-B and UV-C radiation.

The Full Story

Ozone (O₃) is a molecule made of three oxygen atoms. In the stratosphere, it forms naturally when UV-C radiation splits O₂ molecules, and the freed oxygen atoms recombine with other O₂ to make O₃. This layer absorbs 97-99% of the Sun medium-frequency ultraviolet light, protecting life on Earth from DNA damage, skin cancer, and cataracts. In the 1980s, scientists discovered that man-made chlorofluorocarbons (CFCs) were depleting the ozone layer, particularly over Antarctica. The 1987 Montreal Protocol phased out CFCs, and the ozone layer is now slowly recovering.

Key Facts

1.If all the ozone in the atmosphere were compressed to sea-level pressure, it would form a layer only about 3 mm thick.
2.The Antarctic ozone hole reached its largest recorded size in September 2000, covering 29.9 million km².
3.The Montreal Protocol is considered the most successful international environmental agreement in history.

YouTube Angle

Suggested video title for this topic:

"The Ozone Layer — Earth Invisible Shield and Its Near-Destruction"