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Why does stratospheric ozone help protect living things from harmful ultraviolet radiation?

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ozone depletion — Ozone depletion The Antarctic ozone hole reaches its maximum extent in October of each year. On October 7, 2021, when this image was captured, the Antarctic ozone hole spanned 24.8 million square km (9.6 million square miles).

The ozone layer acts as a vital protective shield for life on Earth by absorbing the most harmful ultraviolet (UV) radiation emitted by the Sun.12

Specifically, ozone molecules ( $O_{3}$ ) in the stratosphere effectively block almost all solar radiation with wavelengths shorter than 290 nanometers. This includes high-energy UV rays that are capable of damaging or killing living organisms by altering DNA and destroying cellular structures. By screening out these lethal levels of radiation, the ozone layer historically facilitated the migration of life from the oceans to land and continues to protect modern ecosystems and human health from the hazardous effects of overexposure, such as skin cancer, immune system damage, and the destruction of essential marine life like plankton.2341