The 16th September is the International Day for the Preservation of the Ozone Layer!
This 16th September is meant to commemorate the 1987 Montreal protocol banning human made ozone depleting gases, like chlorofluorocarbons. Read here a longer explanation of the chemical reactions which reflects the traditional view.
This NASA graph shows that a few years after Montreal, the yearly minimum of ozone layer thickness at the South Pole stabilized (but did not markedly recover!). The scientific reasons for the ban, which seemed complete and rock-solid at that time, are becoming gradually more uncertain, as more natural sources of ozone destroying gases were found (e.g. bromides emitted by plankton) and a new mecanism in the South Seas has been detected. Also unexpectedly new gases have been found recently that seem to destroy ozone.
Caring for the ozone layer is noble, but as often in environmental problems much hype and hysteria muddled the problem; above all, the science really is not settled!
MeteoLCD measures the thickness of the ozone layer above Luxembourg since 1998, and the linear trend does not show an ongoing thinning; neither are the UVB irradation levels increasing (look at the trends page). Look also here for the results of the Uccle station, which is one of the longest acting measuring stations in the world.
1. data show no continuing further thinning of the ozone layer.
2. the natural occuring ozone hole above Antarctica has stabilized.
3. in our regions, the trend is more on an increase of the layer. The UVB irradiation at ground level is not increasing.
4. In our region the thickness of the ozone layer often varies tremendously on extremely short periods. To expect a constant thickness of the ozone layer is foolish.
PS1: you may read Matt Ridley’s comment in The Times :The Ozone Hole Isn’t Fixed. But That’s No Worry (go to chapter 6 here)
PS2: here is the report of the EEA on the European emissions of ozone depleting substances