I'd like to know where you heard or read that. It's not consistent with the information at this Web site:
Particularly this section:
The Discovery of the Ozone Hole
"Dramatic loss of ozone in the lower stratosphere over Antarctica was first noticed in the 1970s by a research group from the British Antarctic Survey (BAS) who were monitoring the atmosphere above Antarctica from a research station much like the picture to the right."
There was no apparent seasonal thinning before about 1965-1966.
My citation for this fact is not currently available via the internet, as far as I'm aware, but can likely still be accessed from the stacks of major university libraries. I was fortunate enough to inherit this volume from my father and mentor.
The citation is Smithsonian Physical Tables, First Reprint of Eighth Revised Edition, volume 88, printed 1934, Table 704, Atmospheric Ozone, dated 1926 and 1929, by Dr. Gordon Dobson. The table and accompanying text shows large variations by season and latitude. The farther north (or south), the greater the seasonal variation. Doctor Dobson specifically states in the table text that "large variations occur(up to 0.1 cm)" that he ascribed to seasonal "meteorological conditions".
Since CFC's were not introduced to the public until 1930, Dr. Dobson's 1929 observations of a large seasonal variation in atmospheric ozone, that occurs in the extreme latitudes, predates that introduction.
Compare the magnitude of the effect Dr. Dobson observed in 1929 to the graph you posted in #78 and you'll see that Dopson's 0.1 cm change is a far greater change than what your source described as "a dramatic loss of ozone".
If one can measure a natural seasonal and latitudinal variation in atmospheric ozone, why then should we be surprised that there might also be a natural periodic (over decades and centuries) variation in that same ozone?
I believe that Dr. Dobson's initial appraisal that the observed effect was due to "meteorological conditions", was essentially correct, but would add that our better understanding of the high energy flux of charged particles from the sun that enter the atmosphere in the vicinity of the poles can also help explain the ozone thinning over the poles.
Keep in mind that the O3 bond is a particularly weak bond (hence its natural scarcity) and one subject to disruption from a multitude of extraneous sources, not the least of which would be from conditions originating outside our own planet, like the aforementioned high energy solar particle flux.
--Boot Hill