Halons stratospheric chemistry

This relies on the hypothesis that the hole in the ozone layer is due to reactions induced by the nitrogen oxides, the CFCs and the halons of anthropogenic origin. For this interpretation the Nobel Prize for Chemistry was awarded to ROWLAND, MOLINA and CRUTZEN in 1995 who had established that these compounds contributed to the destruction of the stratospheric ozone in the 1970s. 

Ozone, in turn, can be destroyed by interaction with another photon that breaks it into an oxygen molecule (O2) and an oxygen atom (O). Stratospheric ozone also can be destroyed by reaction with other species, such as nitric oxide (NO), as shown in Eq. (4.42), and halogen atoms, such as chlorine and bromine. Chlorine and bromine atoms are released into the stratosphere from the photodegradation of haloalkanes, often called halons. Classes of haloalkanes that impact ozone chemistry include CFCs and hydrochlorofluorocarbons (HCFCs). The net concentration of ozone in the stratosphere is established by the rates of both the production and the destruction reactions. 

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