Stratospheric ozone formation and destruction

The formation of ozone is a photochemical process that uses the energy involved in light. The shorter the wavelength of light, the larger the amount of energy it 

The UV photon here is symbolized by hv. Once oxygen atoms (O) have been formed, they can react with 02. 

The production of 03 by this photochemical process can be balanced against the reactions that destroy 03. The most important is photolysis  

Similar reactions can be written for nitrogen-containing species, for example nitric oxide (NO), which arises from supersonic aircraft, or nitrous oxide (N20), which crosses the tropopause into the stratosphere  

Reactions involving these species sum in such a way as to destroy 03 and atomic oxygen while restoring the OH or NO molecules. They can thus be regarded as catalysts for 03 destruction. In this case the catalysts are chemical species that facilitate a reaction, but undergo no net consumption or production in the reaction (see also Box 4.4). The important point of these catalytic reaction chains in the chemistry of stratospheric 03 is that a single pollutant molecule can be responsible for the destruction of a large number of 03 molecules. 

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