ozone layer

An atmospheric region - also known as the ozone layer - that occupies most of the stratosphere, extending from about 12 to 40 kilometers of altitude. Within it, the percentage of ozone is relatively high, reaching its maximum concentration between about 20 and 25 km. The ozone layer became widely known in the 1980s, when a significant loss of that gas (the so-called "ozone hole") was detected over Antarctica during the austral spring, and was unequivocally linked to atmospheric emissions of chlorofluorocarbon (CFC) compounds of anthropogenic origin.