For two decades, an ominous hole in the ozone
layer has ballooned over Antarctica, alarming scientists.
This also means that the seasonal holes in the ozone
layer over the Arctic and Antarctic would represent nothing more than normal fluctuations in the ozone
The ring design of the annulus test piece (inside diameter exactly 1/2 the outside diameter) allows a continuous range of strain observations (0 to 100%) when the test piece is mounted in the ozone
test chamber apparatus.
Ozone holes - regional thinnings in the ozone
layer - have developed over the Antarctic continent each September since the late 1970s.
That weakening in the ozone
layer would let some 6 to 12 percent more ultraviolet light reach Earth's surface, raising the risk of skin cancer, cataracts and damage to animals and plants.
Most chlorine in the ozone
layer comes from chlorofluorocarbons and other forms of pollution.
The hole is a reduction in the ozone
layer that normally shields Earth's surface from much of the sun's ultraviolet rays.
Schoeberl, an atmospheric scientist with NASA, also notes that chlorine monoxide (ClO)--a principal chemical active in the ozone
destruction--was not always present at altitudes that would account for the low ozone levels.