●  Release of bromine and chlorine hydrocarbons (CFC's) injects active bromine and chlorine components in the stratosphere, that destroy ozone.

●  These destruction reactions become faster as the local temperature falls, among others by the formation of polar stratospheric clouds that create reactive halogen compounds.

●  The nitric acid in the polar stratospheric clouds reacts with CFCs to form chlorine, which catalyzes the photochemical distribution of ozone.

●  The phenomenon of the ozone hole is reinforced by the presence of the so-called polar vortex, a special circulation pattern in the stratosphere above the South Pole in local winter that isolates this area from its environment: the local stratosphere should be considered as a well closed reaction chamber in which the ozone destruction gets extremely efficient.