write:Examination of raw NASA satellite data (which excluded extreme results in data summaries) revealed that the phenomenon began to occur in the mid-1970s. Satellite data also indicate

it reacts relatively slowly with organic compounds such as CH4. Consequently
Br sink processes are slower. In addition
photolysis of brominated compounds to produce Br is much faster than the corresponding photolysis of chlorinated compounds. 4.6.5 The Antarctic Ozone Hole In 1985
British scientists conducting ground-based measurements of total column O3 above Halley Bay (76°S latitude) observed unusually large declines in O3 levels associated with the beginning of the southern hemispheric spring. Since such declines had not been previously reported (measurements were also being made by satellites)
observed O3 declines were thought to be anomalous. After careful reevaluation of the accuracy and precision of their instruments
British scientists concluded observed O3 declines were real. Examination of raw NASA satellite data (which excluded extreme results in data summaries) revealed that the phenomenon began to occur in the mid-1970s. Satellite data also indicated that the area affected by the Antarctic O3 hole extended over several million square kilometers (~1.5 million mi2). Since its discovery
the geographical area affected by the Antarctic O3 hole has increased from a few million square kilometers in 1979 to >25 million km2 (15 million mi2) in 2000
with lowest column values of <90 dobson units and O3 depletions of nearly 100% (~0 dobson units) at altitudes of 15 to 20 km (~9–12 mi). Its persistence has increased from weeks to months. The Antarctic O3 hole begins to form as the sun comes up over the Antarctic in the beginning of the austral spring. Changes in O3 levels reported as partial pressure Atmospheric effects 127