Stratospheric ozone
Stratospheric ozone is a layer of ozone (O₃) molecules located in the Earth's stratosphere, approximately 10 to 30 miles above the Earth's surface. It plays a critical role in absorbing the majority of the Sun's harmful ultraviolet (UV) radiation.
Ozone-Depleting Substances (ODS):
- Chlorofluorocarbons (CFCs): These man-made chemicals, once commonly used in refrigerants, air conditioners, and aerosol propellants, are major contributors to ozone depletion.
- Halons and Other Chemicals: Other substances, such as bromine compounds (halons), also contribute to ozone layer depletion.
Ozone Depletion:
- The Ozone Hole: Ozone depletion is most prominent in the polar regions, particularly over Antarctica, where the ozone layer has become significantly thinner, leading to the so-called "ozone hole."
- Mechanism: CFCs and other ozone-depleting substances are released into the atmosphere, where they eventually reach the stratosphere. Ultraviolet light breaks down these chemicals, releasing chlorine and bromine atoms, which then destroy ozone molecules in a catalytic process.
Cl + O₃ → ClO + O₂
ClO + O → Cl + O₂
These reactions continue, leading to a significant loss of ozone.
