Illustrated Glossary of Organic Chemistry

Ozone hole: A region in the ozone layer with low ozone concentration. Ozone holes occur naturally late each year over the Earth's Antarctic and Arctic regions, but their size may be amplified by radical chain ozone depletion by atmospheric organohalides of natural origin (such as methyl bromide) and of man-made origin (such as chlorofluorocarbons).

A false color image of the Antarctic ozone hole, as measured on September 24, 2006. Bluer color = less ozone; redder color = more ozone. At 11.4 million square miles, this was the largest ozone hole measured to date.