The ozone layer acts as a natural sun filter, like a pair of sunglasses blocking out most of the sun's harmful ultraviolet rays. Without the ozone layer, more people would suffer from sunburn, skin cancer and develop eye problems. Plants and animals would also be affected. We can therefore think of the ozone layer as our planet's own protective sunscreen!
Questions and answers
What is ozone?
The air we breathe contains oxygen molecules that are made up of two oxygen atoms combined (O2). Ozone is a molecule made up of three oxygen atoms combined (O3). Ozone is everywhere in our atmosphere – but in different amounts.
What is the ozone layer?
The ozone layer is found high up in the atmosphere – between 10 and 40 kilometres above the ground, which is above where most airplanes fly – and contains most of the ozone. It acts as a “sunscreen,” absorbing ultraviolet (UV) light and protecting life below (animals, plants and humans) from excessive UV exposure, which could be harmful.
What is the ozone hole?
A massive hole in the ozone layer over the Antarctica was first discovered in 1985. In 2009, the hole had expanded to about 25 million square kilometres. WMO and UNEP played a leading role in setting up the 1985 Vienna Convention for the Protection of the Ozone Layer. It was followed by its Montreal Protocol, signed in 1987, to control substances that could damage the ozone layer (for example, cooling chemicals in refrigerators). WMO and the scientific community monitor the development of ozone worldwide by using meteorological data obtained from the ground, balloons, aircraft and satellites.
With the ozone hole, the amount of UV reaching us has slightly increased. This small increase does not mean that we cannot enjoy the outdoors, but we should always protect ourselves against the UV.