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Ozone loss was first detected in the stratosphere over the Antarctic
Dramatic loss of ozone in the lower stratosphere over Antarctica was first noticed in the 1970s by a research group from the British Antarctic Survey (BAS) who were monitoring the atmosphere above Antarctica from a research station much like the picture to the right. -
Note the sudden change in the curve after about 1975.
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first ozone hole
The British Antarctic Survey's first documentation of the Antarctic ozone hole in 1985 -
decreased ozone levels
In the northern polar regions, ozone levels in the early 1990s measured ten percent lower than those estimated in the late 1970s -
the ozone layer was cut in half
By 1994, the total ozone in October was less than half its value during the 1970s, 20 years previous. -
largest hole in ozone history
The largest ozone hole: 24 September 2006