Ozone (O₃) is a triatomic molecule, consisting of three oxygen atoms. It is a highly reactive gas and a form of oxygen that is much less stable than the diatomic oxygen (O₂) that we breathe. Ozone naturally occurs in the Earth's stratosphere and is essential for protecting life from the sun's ultraviolet rays. However, at ground level, it is a major component of air pollution and poses significant health risks.