Ozone Hole — Definition

Definition

The ozone hole is severe seasonal depletion of the stratospheric ozone column, especially over Antarctica. It is not a literal empty opening in the atmosphere. Monitoring commonly delineates the Antarctic hole using the area with total-column ozone below 220 Dobson Units.

Long-lived source gases release reactive chlorine or bromine in the stratosphere, and polar conditions enable rapid catalytic loss when sunlight returns. The issue differs from ground-level ozone pollution and from the main greenhouse-warming mechanism, although atmospheric chemistry, climate and policy connect them.

Measurements and recovery claims must retain their location, baseline and timescale.