what is ozone gas
What is ozone? Ozone, or O3, is a gas containing three oxygen atoms. Ozone is an unstable chemical that is highly reactive with other gases in the air. Ozone at ground level is unhealthy and is a component of smog. Ozone found high up in the atmosphere, called stratospheric ozone, protects us by shielding us from harmful ultraviolet (UV) light.