ABSTRACT
Human activities that have led to the emission of
chloroflourocarbons (CFCs), in particular, have reduced
the concentration of stratospheric O
. The most dramatic
loss of O
has been observed over Antarctica during the
austral spring where a 50% reduction in O
the widely
discussed “ozone hole”—has been documented. The ozone
has been depleted by a catalytic cycle involving Cl and
ClO
ClCO
/ClOCO
ClOCO
/ClCO
net OCO
/2O
where Cl and ClO are the eventual breakdown products of
the CFCs after they have reached the region of strong
ultraviolet radiation in the middle and upper atmosphere.
Many predict further reductions in average global strato-
spheric O
