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Convention on Long-Range Transboundary Air Pollution

Protocol to Abate Acidification, Eutrophication and Ground-level Ozone - A multi-pollutant and multi-effects protocol (Gothenburg Protocol).

Despite improvements, the amounts of air pollutants that sweep across national borders are still far too high. Some of these pollutants, including compounds of nitrogen and sulphur as well as volatile organic compounds, continue to cause serious damage both to health and the environment, natural and man made. The main causes of anxiety are:

Ground-level ozone: Concentrations are now three to four times higher than they were in the pre-industrial period, so that the thresholds that have been set for the protection of human health and of sensitive plants are frequently being overstepped. Damage to sensitive plants, including agricultural crops and forest trees, is occurring at current ambient concentrations.

Acidification: Over large areas that are considered to be sensitive to acidification, the deposition of sulphur and nitrogen continue to exceed the critical loads - the amounts that nature can tolerate. When forest soil becomes acidified, essential nutrients are leached out, reducing its fertility. Acidification also causes the release of potentially harmful metals. Widespread damage to plant and animal life in tens of thousands of lakes and rivers is another serious consequence of acidification.

Eutrophication: Extensive biological effects on terrestrial as well as aquatic ecosystems can be traced to an excess of nitrogen, which greatly change and impoverish the systems by reducing the diversity of their plant species. This is also a problem in marine environments, causing algal blooms and oxygen depletion.

A key pollutant, contributing to all the above effects, is NOx. Volatile organic compounds aid the formation of ground-level ozone too, while ammonia contributes both to acidification and eutrophication. Despite the progress made in controlling SO2 emissions, this pollutant still dominates the acidification of ecosystems. Further measures are needed to reduce the impacts of each of these pollutants.

The new "multi-pollutant, multi-effect" protocol was adopted by the Executive Body at its seventeenth session in Gothenburg (Sweden) on 29 November - 3 December 1999. The protocol is a natural continuation of the earlier protocols under the Convention. As a modern, "second-generation" protocol, it takes full account of the interdependence of various environmental problems and the related pollutants.

Procedure for development of the new protocol

As in the 1994 protocol for sulphur, the critical-loads approach is used. The essence of this concept is that emission reductions are negotiated according to the effects of air pollutants, instead of requiring an equal reduction in per cent from each country. The long-term aim is to reduce the emissions of air pollutants in a cost-effective manner to levels where the critical loads will, ultimately, no longer be exceeded. It is however recognized that economic, technological, and other constraints mean that the reductions may not be attainable everywhere or in one step, and that several steps will therefore be needed.

As part of the stepwise approach, interim targets for environmental quality are investigated. Such targets can take the form, for instance, of the degree to which ecosystems are to be protected from depositions in excess of the critical loads. The analysis is carried out with the use of computer models for integrated assessment. By using models, comparisons can be made of the cost and effectiveness of various strategies for the achievement of specified interim targets for environmental quality. This procedure enables the assessment to take into account a wide variety of factors which are of importance for the outcome of the modelling.

The Protocol sets emission ceilings for 2010 for four pollutants: sulphur, NOx, VOCs and ammonia, which were negotiated on the basis of scientific assessments of pollution effects and abatement options. Parties whose emissions have a more severe environmental or health impact and whose emissions are relatively cheap to reduce will have to make the biggest cuts. A full implementation of the Protocol should cut Europe's sulphur emissions by at least 63%, NOx emissions by 41%, VOC emissions by 40% and ammonia emissions by 17% (compared with 1990).

The protocol also sets ELV's for various industrial sectors and sufficient signatories had been received for it to come into force by May 2005. By Spring 2010 it had become apparent that a significant number of signatories to the protocol would not meet their pollutant ceilings for 2010. The UK and a number of other EU member states expect to fail their NOx ceilings but generally the other pollutant ceilings will be met. The UNECE began to review the protocol in the summer of 2009. It plans to update the national ceilings to 2020 as well as review and probably expand the annexes that set emission standards for various types of processes and operations. It is believed that a ceiling is also being considered for small particulates but no public proposals had been seen for this by Spring 2010.

EU using the same approach

Preparations are being made within the EC for a directive on national ceilings for emissions. While also using the critical-loads approach and data generated within the Convention, the new directive is based primarily on Community strategies for reducing acidification and ground-level ozone.

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