Rumor has it that when the first measurements were taken in 1985, the drop in ozone levels in the stratosphere were so dramatic that at first the scientists thought their instruments were defective. Replacement instruments were built and flown out. It wasn't until they confirmed the earlier measurements, several months later, that the ozone depletion observed was accepted as genuine.

Evidence that human activities affect the ozone layer has been building up over the last 20 years, ever since scientists first suggested that the release of chlorofluorocarbons (CFCs) into the atmosphere could reduce the amount of ozone over our heads.

The breakdown products (chlorine compounds) of these gases were detected in the stratosphere. When the ozone hole was detected, it was soon linked to this increase in these chlorine compounds. The loss of ozone was not limited to the Antarctic. Around the same time th

e first firm evidence was produced that there had been an ozone decrease over the heavily populated northern mid-latitudes (30-60N). However, unlike the sudden and near total loss of ozone over Antarctica at certain altitudes, the loss of ozone in mid-latitudes is much less and much slower. Only a few percentage per year.

of instability of the atmosphere, and the amount of ozone loss is still

Ozone (O3 : 3 oxygen atoms) occurs naturally in the atmosphere. The earth's atmosphere is composed of several layers. We live in the "Troposphere" where most of the weather occurs; such as rain, snow and clouds. Above the troposphere is the "Stratosphere"; an important region in which effects such as the Ozone Hole and Global Warming originate. Supersonic jet airliners such as Concorde fly in the lower stratosphere whereas subsonic commercial airliners are usually in the troposphere. The narrow region between these two parts of the atmosphere is called the "Tropopause".

Some common words found in the essay are:
Global Warming, Antarctic Rumor, Ozone Hole, NOx CFC's, Ozone O3, Layer Dramatic, CFC's ChloroFluoroCarbons, Survey BAS, ozone hole, Station BAS, loss ozone, amount ozone, global warming, research station, nitrogen oxides, oxygen molecules, chlorine compounds, atomic oxygen, ozone layer, Hole Ozone, level ozone health, hazard major constituent, major constituent photo, health hazard major, ozone health hazard,
Approximate Word count = 1362
Approximate Pages = 5 (250 words per page double spaced)