Ozone, or O3, is a gas composed of three oxygen atoms. It occurs naturally in the Earth's atmosphere, primarily in the stratosphere, where it forms the ozone layer. This layer plays a crucial role in protecting life on Earth by absorbing the majority of the sun's harmful ultraviolet (UV) radiation. While ozone is beneficial in the stratosphere, it can be harmful at ground level. In the troposphere, ozone is a major component of smog and can cause respiratory problems and other health issues. It is formed when pollutants from vehicles and industrial sources react with sunlight, highlighting the importance of air quality management.