Remember Ozone Day? It has been held on September 16 every year since 1998. Perhaps its full name will help jog your memory: The International Day for the Preservation of the Ozone Layer or, unofficially, TIDPOL.

The ozone layer, or rather the lack of one, is such an important issue it has its very own day on the calendar. However, if you go out on the street in 72 hours’ time and ask 20 people if they know what the day is, they’re likely to grumble something about it being the start of a new working week. Perhaps sending an Ozone Day e-card to a friend or downloading a poster to stick on your wall (www.unep.orgozoneozone_day2002) will help raise awareness.

It’s easy to see why TIDPOL can be forgotten, what with the multitude of International Days we now have, it seems everyone is a bit over Ozone Day. Besides, didn’t we solve that problem in the 1990s?

The fact is that ozone depletion is getting worse, despite many harmful chemicals being phased out of use across the globe. While we may have stopped using certain agents for making foam or deodorant, the chemicals are still up there.

Chlorofluorocarbons, for example, can last in the atmosphere for between 50 and 1,700 years. Halon-1301, which is used in fire extinguishers and was phased out in 1994, hangs around for 65 years. Even hydrofluorocarbon - the replacement chemical for most CFCs - is still harmful to ozone levels, albeit on a much smaller scale. HFCs remain in the atmosphere for up to 19 years and, as greenhouse gases, contribute to global warming. With this long-life chemical soup floating above us, ozone levels are expected to hit an all time low in the next few years.

What would we do without ozone in our atmosphere? Put simply - nothing. We would not exist. Ozone absorbs most of the ultra violet light-B radiation and all of the lethal ultra violet light-C radiation being belched forth from the sun. It is essential for life. A continuing fall in ozone levels will mean more skin cancer and cataracts, as well as weakened immune systems, reduced plant yields, and reduced fishing yields.

After the hole in the ozone layer was discovered over Antarctica in 1985, the world became serious about protecting it. Protocols were introduced, the most notable of which was the Montreal Protocol of 1987. It was signed by 180 countries and involved a structured phasing out of CFCs and halon. If it were not for those countries agreeing to the protocol, by 2050 ozone depletion would have reached 50 per cent in the northern hemisphere and 70 per cent in the southern hemisphere - 10 times worse than current levels. There would be 19 million more cases of non-melanoma cancer; 1.5 million more cases of melanoma cancer, and 130 million more cases of cataracts.

However, the protocol in itself is not enough and is being continually amended as science and technology develop. The amendments are not legally binding until a country ratifies the amendment. So, although the Montreal Protocol got global support, the Montreal Amendment of 1997, which finalised the schedule for phasing out methyl bromide (a fumigant for crops), has been ratified by only 63 countries. The Beijing Amendment of 1999, which required the immediate phase out of bromochloromethane (mainly used in fire extinguishers), has been ratified by only 11 countries.

If the Montreal Protocol and its amendments are adopted in full by 180 countries, scientists predict the ozone layer will return to normal by 2050. It’s just a matter of making the ozone layer an issue that’s exciting enough to get it back on the agenda of governments, the public and the media. So getting out in the sunshine on Monday and spreading the word that it’s TIDPOL is the very least we can do.

For further information visit:The Centre for Atmospheric

Science www.atm.ch.cam.ac.uktour The United States Environmental Protection

Agencywww.epa.govdocsozoneHow Stuff

Workswww.howstuffworks.comozone-pollution.htm