What Is the Ozone Layer?

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The ozone layer is a band of gas high up in the stratosphere, roughly 15 to 35 kilometres above the ground, that acts like sunscreen for the whole Earth. It is made of ozone — a special form of oxygen where three oxygen atoms join together (O₃) instead of the usual two (O₂) that we breathe. Although it is invisible and thin, this layer wraps right around the planet.

It matters because it soaks up most of the Sun's harmful ultraviolet (UV) rays before they reach us. Without it, UV light would badly burn skin, damage eyes, and harm plants and animals. In the 1970s and 80s, chemicals called CFCs — once used in old fridges and spray cans — floated up and thinned the layer, creating an 'ozone hole' over Antarctica.

Learners will grasp what ozone is made of, where the layer sits, how it shields living things, why the ozone hole formed, and how the world's countries agreed to stop using CFCs so the layer is slowly healing.

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Frequently asked questions

What is the ozone layer made of?
It is made of ozone, a gas whose molecules contain three oxygen atoms joined together (O₃). This is different from the ordinary oxygen we breathe, which has only two atoms (O₂).
Where is the ozone layer found?
It sits in a part of the atmosphere called the stratosphere, about 15 to 35 kilometres above the Earth's surface — far higher than clouds, planes, or the tallest mountains.
Why is the ozone layer important?
It absorbs most of the Sun's harmful ultraviolet (UV) rays, protecting people, animals, and plants from sunburn, eye damage, and other harm.
What caused the ozone hole?
Man-made chemicals called CFCs, once used in old fridges and aerosol spray cans, drifted up into the stratosphere and broke apart ozone molecules, thinning the layer — especially over Antarctica.
Is the ozone layer getting better?
Yes. After countries agreed to stop using CFCs under an agreement called the Montreal Protocol, the ozone layer began to repair itself and scientists expect it to keep healing over the coming decades.

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