Yes, CFCs (chlorofluorocarbons) destroy ozone. This was a groundbreaking discovery made by F. Sherwood Rowland and Mario J. Molina at the University of California, Irvine. [^1, ^3] Their research showed that these chemicals, once released into the atmosphere, rise into the stratosphere. ^2 There, strong ultraviolet radiation breaks them down, releasing chlorine atoms. [^2, ^9] These chlorine atoms act as catalysts, initiating a chain reaction that destroys ozone molecules (O3) much faster than they are naturally created. [^4, ^6, ^7] The depletion of the ozone layer allows increased harmful UV-B radiation to reach the Earth's surface. ^6 This led to the international Montreal Protocol, banning the production of CFCs and other ozone-depleting substances. ^8
How CFCs Deplete Ozone: A Step-by-Step Explanation
- Release: CFCs are released into the atmosphere from various sources, including refrigerants, aerosols, and foam-blowing agents.
- Ascent: CFCs are very stable and slowly rise into the stratosphere.
- UV Radiation: In the stratosphere, strong ultraviolet (UV) radiation breaks down CFC molecules.
- Chlorine Release: This breakdown releases chlorine atoms (Cl).
- Catalytic Destruction: The chlorine atom reacts with an ozone molecule (O3), converting it into oxygen molecules (O2) and a chlorine monoxide molecule (ClO).
- Chain Reaction: The ClO molecule then reacts with an oxygen atom (O), releasing the chlorine atom to repeat the process, resulting in a catalytic chain reaction that destroys many ozone molecules.
The Significance of this Discovery
The discovery of CFCs' ozone-depleting potential was crucial in understanding and addressing the problem of ozone layer depletion. It led to global cooperation and regulations aimed at phasing out these harmful chemicals.
[^1]: At the University of California, Irvine, F. Sherwood Rowland and Mario J. Molina discovered that chlorofluorocarbons (CFCs) could deplete Earth's atmospheric ozone layer, which blocks the sun's damaging ultraviolet rays.18-Apr-2017
