Reducing sulphur dioxide emissions

The few rich countries account for the vast majority of sulphur dioxide (SO2) emissions. SO2 emissions cause acid rain and oxidant smog. As the poorer countries industrialize these problems may increase significantly. Reducing its emission requires cross-sectoral action, as well as improving and making available environmentally friendly technologies.

The ECE Convention on Long-range Transboundary Air Pollution came into force in 1983, and states that governments should commit themselves to at least a 90% reduction of SO2 (based on 1980 levels) by the year 2000. The Protocol on the Reduction of Sulphur Emissions or their Transboundary Fluxes by at least 30%, was adopted in 1985. The Protocol on Further Reduction of Sulphur Emissions was adopted in 1994 and came into force in August 1998. It adopts a novel approach in that it sets individual emission ceilings and reduction targets for each party. These ceilings and targets are based on the environment's vulnerability, which differs from country to country.

In 1994, the Regional Clean Air Incentive Market (RECLAIM) will operate in four counties in the Los Angeles area, affecting 390 companies that emit in excess of 3.6 tonnes of nitrogen oxides (NOx) or sulphur dioxide (SO2) annually. RECLAIM is based on an emission trading system. It provides firms economic incentives to reduce pollution by enabling them to sell pollution credits if they beat set emission reduction targets, whilst credits will be marketable to companies that do not meet the target. It is considered that this flexibility will enable pollution to be cut in the most economically efficient way. Cumulatively, these firms will be obliged to reduce their emissions by 5 to 8% a year for ten years, so that their emissions of SO2 are cut 60% by 2003.

The Helsinki Protocol on the Reduction of Sulphur Emissions or their Transboundary Fluxes (1987), has been ratified by 21 Parties. Taken as a whole, the 21 Parties to the Helsinki Protocol (1985) reduced 1980 sulphur emissions by 52% by 1993. Individual country reductions ranged from 30% to more than 85%. Nineteen Parties have achieved reduction of more than 50% by 1995. The whole of Europe, including non-Parties to the Protocol, that sum of emissions is below 30000 kt which corresponds to a reduction of more than 48% compared to 1980. Also five non-Parties have achieved sulphur emission reduction of 30% or more. By 1995 (emission data) most Parties have either maintained or further reduced their sulphur emissions. Given that the target year for the Helsinki Protocol was 1993, it can be concluded that all Parties have reached the target of reducing emissions by at least 30%.

UK sulphur dioxide emissions fell to 2.0 million tonnes in 1996 from 2.4 million tonnes in 1995, a decrease of 14 per cent. Total emissions were 4.9 million tonnes in 1980 and 6.4 million tonnes in 1970. Power stations accounted for 65 per cent of emissions in 1996, compared with 61 per cent in 1980 and 46 per cent in 1970. Emissions by fuel type show coal accounting for 67 per cent of emissions in 1996, compared with 64 per cent in 1980 and 57 per cent in 1970. Exceedences of the UK standard for sulphur dioxide of 100 ppb measured as a 15 minute mean were recorded at 31 sites out of 42 sites on at least one occasion in 1996.