Otsonikerrokselle

Otsonikerrokselle refers to the ozone layer. The ozone layer is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It is primarily located in the lower portion of the stratosphere, from approximately 15 to 35 kilometers (9 to 22 miles) above Earth, although its thickness varies seasonally and geographically. The ozone layer is crucial for life on Earth because UV radiation, especially UV-B and UV-C, can be harmful to living organisms, causing skin cancer, cataracts, and damaging DNA. It also plays a role in regulating Earth's temperature.

Ozone (O3) is a molecule consisting of three oxygen atoms. It is continuously created and destroyed in the stratosphere. The primary process of ozone formation involves UV radiation from the Sun splitting oxygen molecules (O2) into individual oxygen atoms. These highly reactive atoms then combine with other oxygen molecules to form ozone. Ozone is also destroyed when it absorbs UV radiation, breaking back down into an oxygen molecule and an oxygen atom. This dynamic cycle maintains the ozone layer's presence.

In the late 20th century, scientific research revealed that certain human-produced chemicals, particularly chlorofluorocarbons (CFCs) and halons, were depleting the ozone layer. These substances release chlorine and bromine atoms in the stratosphere, which catalytically destroy ozone molecules. This led to the formation of the "ozone hole," a significant thinning of the ozone layer, most prominently observed over Antarctica. International efforts, such as the Montreal Protocol on Substances that Deplete the Ozone Layer, have been successful in phasing out the production and consumption of these ozone-depleting substances, leading to a gradual recovery of the ozone layer.