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How did the rise of oxygen lead to the formation of the ozone layer?

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abundance of oxygen — evolution of the atmosphere A “best guess” reconstruction of the abundance of O₂ in Earth's atmosphere as a function of time. The O₂ abundance axis is logarithmic.

The formation of the ozone layer was a critical development in Earth's history, directly enabled by the rise of atmospheric oxygen. As oxygen-producing organisms, such as cyanobacteria, became widespread, the concentration of molecular oxygen ( $O_{2}$ ) in the atmosphere increased significantly.12

In the stratosphere, this rising oxygen was subjected to high-energy solar ultraviolet radiation. Through a process called photodissociation, these high-energy photons broke the chemical bonds of $O_{2}$ molecules, releasing single oxygen atoms. These highly reactive atoms then collided and bonded with intact $O_{2}$ molecules to form ozone ( $O_{3}$ ).3

As these ozone molecules accumulated, they formed a protective layer that effectively screened out lethal levels of ultraviolet radiation. This transition was essential for the evolution of life, as it shielded the planet's surface from harmful rays and facilitated the migration of life-forms from the oceans to land.134