Slow progress on ozone concerns
When it comes to ozone, there is good news and there is bad news this week.
But environmentalists will not be celebrating just yet, as the holes are closing very slowly and will not be back to pre-1970s 'safe' levels for several decades to come and ground level ozone is still regularly exceeding healthy levels right across the European Union.
Ozone in the stratosphere protects the earth's surface from harmful ultra-violet radiation which can cause skin cancer and eye disease in humans.
The British Institute of Physics reports that global efforts to reduce the use of ozone-depleting chemicals such as CFCs appear to be having the desired effect, though more must still be done.
The report published by the Institute of Physics, The Rise of Ozone Research by Dr Peter Hodgson says that despite legislation, it will be decades before the ozone layer is restored.
The ozone holes over the polar regions are currently as deep and persistent as ever observed, leading to elevated levels of damaging ultra-violet radiation at the Earth's surface.
Dr Hodgson, a specialist working with independent consultants Sci-Fact, warns that the ozone layer is still under threat from many ozone-depleting substances, especially rising levels of CFC replacement compounds, which could undermine the progress made in controlling damaging emissions through legislation.
He warns against complacency and calls for further international efforts to strengthen and extend the Montreal Protocol, drawn up in 1987, which sought to restrict the production and use of ozone-depleting chemicals.
He also says that scientists have a crucial role to play in driving political change in this area.
Hodgson said: "The Montreal Protocol is doing a pretty good job but I think that an element of complacency has crept in.
"Although 180 countries have signed up, only a couple of dozen have actually ratified it and the amendments which came along a few years later.
"The pressure needs to be kept up on the other countries to ratify it and other substances need to be brought under the Montreal umbrella."
Evidence suggests that while the level of ozone-depleting chlorine is at or near its peak, levels of other ozone-depleting substances, such as bromine, is continuing to rise, the report says.
The ozone layer is now repairing itself and gradually sealing the hole but it is a slow process and scientists at the institute believe it will be many, many years before it has fully mended itself.
Meanwhile the European Environment Agency (EEA) has published its analysis of ground-level ozone monitored throughout the continent last summer.
While the figures look much better than those for the previous summer, the EEA has warned there is nothing to suggest three will be continued improvement as 2003 was an exceptional year and the most recent results are roughly in line with others recorded over the past decade.
Ozone is a strong photochemical oxidant and when found in relatively high concentrations at ground level it has serious implications for human health.
It can cause heart and respiratory disease as well as harming eco-systems, crops and industrial materials.
Most emissions come from road transport, heat and power generation, industry and the transport and storage of petrol.
The EC has set a threshold of 180 µg/m3 and believes exceeding this level is harmful to humans. There is a long term target to keep the level below and average of 120µg/m3 for any eight hour period. According to the EEA report: "Exceedances on the long-term objective for the protection of human health were observed in almost every country, every month at most of the stations." Out of all the EU states, only Latvia did not exceed safe levels last summer. Worst affected areas were Southern France, Northern Italy, Spain, Portugal and Greece, where levels frequently reached alarming levels.
By Sam Bond