1. a form of oxygen with three atoms per molecule that exists naturally in the upper atmosphere and protects Earth from harmful ultraviolet radiation
Usage: chemistry; environmental science
2. a bluish gas with a sharp smell that is produced by electrical equipment and can be harmful to breathe
Usage: chemistry

Examples

• The ozone layer shields us from dangerous UV rays.
• Scientists are concerned about ozone depletion over Antarctica.
• Chlorofluorocarbons can destroy ozone in the atmosphere.
• The air purifier produces ozone to kill bacteria.
• High levels of ground-level ozone can cause breathing problems.
• You can smell ozone in the air after lightning strikes.
• The ozone hole has been slowly recovering since the 1990s.