Why is the ozone layer primarily located in the stratosphere?

The ozone layer is primarily located in the stratosphere because this is where ozone is naturally formed and destroyed.

The stratosphere, which extends from about 10 to 50 kilometres above the Earth's surface, is the second major layer of Earth's atmosphere. It is in this layer that the majority of atmospheric ozone is found, forming the ozone layer. The location of the ozone layer in the stratosphere is not random, but rather a result of the specific atmospheric conditions and chemical reactions that occur in this layer.

Ozone (O3) is created through a process called photodissociation. This occurs when high-energy ultraviolet (UV) light strikes a molecule of oxygen (O2), splitting it into two individual oxygen atoms. These atoms can then combine with other oxygen molecules to form ozone. This process primarily occurs in the stratosphere because it is the layer of the atmosphere that absorbs the majority of the Sun's harmful UV radiation.

In addition to the creation of ozone, the stratosphere is also where ozone is naturally destroyed, through a process called ozone-oxygen cycle. In this cycle, ozone absorbs UV radiation, causing it to dissociate into a molecule of oxygen and an oxygen atom. The oxygen atom can then combine with an oxygen molecule to reform ozone. This cycle of creation and destruction maintains a relatively stable amount of ozone in the stratosphere.

The stratosphere's relatively stable temperatures and low levels of water vapour also contribute to the location of the ozone layer. Unlike the troposphere below it, the stratosphere does not have weather systems or much water vapour, both of which can interfere with the ozone-oxygen cycle.

In summary, the ozone layer is located in the stratosphere because this is where the conditions are right for the creation and destruction of ozone. The stratosphere's absorption of UV radiation, stable temperatures, and low levels of water vapour all contribute to this.