The ozone layer helps to sustain terrestrial life by;
Absorbing incoming UV radiation
Keeping levels of ozone in the troposphere low
And, maintaining the Earth's temperature structure
The absorption of ultraviolet light by ozone creates a heat source that forms the stratosphere (a region where temperature increases with altitude).
It plays a decisive role in the structure of the Earth's atmosphere temperature. It is characterized by a concentration of ozone, proportionally greater than in the other layers of the atmosphere, of the order of ten parts per million.