There is not much ozone in the atmosphere, all molecules at eye level would build a layer of a few millimeters. There is also not much usable atmosphere around our planet, oxygen is down to half at 5km and beyond 30km you’ll see stars on pure black above a blue planet.
Technically the atmosphere ends with exosphere phasing out at 100km. SpaceShipOne pilot Brian Binnie returned in good shape from 112km, but consult your doc before planning an altitude of 6,000m without life support.
Most triatomic oxygen exists in the stratosphere between 15 and 25 kilometers and filters out DNA damaging solar UV-B radiation. It is estimated that 1% less ozone increases some forms of non-melanoma skin cancer by 3%.
The first ozone hole detected above Antarctic in 1985 was a surprise and let scientists double-check their instruments, the Arctic twin was not. Earlier this year time a persisting polar vortex isolated cold gases long enough to reduce ozone concentration below the threshold of 220 Dobson units defining a ozone hole in late March 2011.
Greenhouse gases trap outgoing infrared radiation below the stratosphere and thus support colder conditions at the ozone layer. Also less ozone absorbs less energy and leads to further stratospheric cooling. This positive feedback may produce more Arctic ozone holes.
The scientific evidence pointing at man-made CFCs and related halocarbons was strong and 1995 the Nobel Prize in Chemistry was awarded jointly to Paul J. Crutzen, Mario J. Molina and F. Sherwood Rowland "for their work in atmospheric chemistry, particularly concerning the formation and decomposition of ozone".
Facing skin cancer and other medical conditions not consumable from tabloids the UN installed a strong environmental force: 67% percent of all members decide the list of 100% forbidden chemicals - binding to all parties without the possibility of objection.
Four amendments progressively restricted emissions of ozone depleting substances down to zero in 2010. Chlorine compounds persist for decades in the upper atmosphere, starting with first scientific reports it will take a up to a century to fully restore the ozone layer.
The industry opposed with well-known subterfuge and obfuscation. However, in a remarkable move global market leader DuPont committed 1988 to unilateral phaseout CFCs through orderly transition to alternatives. Cynthia Pollock Shea wrote same year on April 10 in the New York Times:
Despite great uncertainty surrounding the chemistry of ozone depletion and the commercial viability of C.F.C. substitutes, Du Pont has reacted to the new scientific data as a responsible and ethical corporate citizen. Its action sets a compelling precedent for those skeptical of the urgent need to develop alternatives.
Such an approach to corporate responsibility is unfortunately rare. But if other companies were to follow Du Pont's lead and act quickly to allay the impending threats to the global environment, all the earth's citizens would benefit, including the corporate citizens who could plan their futures in the board room instead of the courtroom.
[Why Du Pont Gave Up $600 Million]
The Montreal Protocol saves every year millions from skin cancer and eye cataracts and avoids effects on crops as rice and wheat. 196 nations ratified the treaty and established what Kofi Annan called "perhaps the single most successful international agreement to date”.
Nevertheless until the ozone layer recovered high and low latitudes may experience dangerous low concentrations and following the local UV-index is strongly advised. This is the price of releasing gases into the atmosphere which can not be removed neither easily nor timely.
If you can’t fix it, don’t break it!
Nature.com: Unprecedented Arctic ozone loss in 2011
UNEP Ozone Secretariat
Nature.com: Canadian ozone network faces axe
WHO: Stratospheric ozone depletion, UV radiation and health
Temis.nl: Near-real time global ozone field