On the stage of global change, ozone plays the role of both hero and villain. This brief document discusses about the tracking of Tropospheric Ozone, where ozone forms and where it travels have become key concerns for international health and economic policy-making.

Although it represents only a tiny fraction of the atmosphere, ozone is crucial for life on Earth. Depending on where ozone resides, it can protect or harm life on Earth.

In the stratosphere, ozone is created primarily by ultraviolet radiation. When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone. There is so much oxygen in our atmosphere, that these high-energy ultraviolet rays are completely absorbed in the stratosphere.

The term "ozone depletion" means more than just the natural destruction of ozone, it means that ozone loss is exceeding ozone creation.

The amount and distribution of ozone molecules in the stratosphere varies greatly over the globe. Ozone molecules are transported around the stratosphere much as water clouds are transported in the troposphere. Therefore, scientists observing ozone fluctuations over just one spot could not know whether a change in local ozone levels meant an alteration in global ozone levels, or simply a fluctuation in the concentration over that particular spot. Satellites have given scientists the ability to overcome this problem because they provide a picture of what is happening daily over the entire Earth.