Where and when is ozone depletion most severe?
Depletion varies with latitude. It is lowest over the equator and increases toward the poles. Over the tropics (20N-20S), measurements have shown no significant trend in the total amount of ozone. For the six months after the eruption of Mount Pinatubo, total ozone fell by 3-4 per cent. Over the Arctic, cumulative ozone depletion of up to 20 per cent is thought to have occurred in some altitudes, while ozone loss over the Antarctic has been even greater.
