3.4 Transboundary air pollution

In the 1980s and 1990s, the achievements in abating emissions from stationary sources was almost counterbalanced by increased emissions due to more mobility, despite improvements in motor vehicle technology. Energy consumption, particularly by transport in 2010 will mean, for the EU, a 17% increase from stationary sources and a 37% rise from mobile sources. In the agricultural sector, activity levels (livestock, nitrogen fertiliser use) are likely to fall, resulting in lower emissions from agricultural sources.

Integrated abatement strategies are needed – not least to address the important interaction with other major environmental problems, such as climate change. In densely populated areas in Northwest Europe, smog formation is most strongly affected by volatile organic compounds (VOC) emissions. In less populated areas it is more dependent on nitrogen oxides (NO x ) emissions. All EU tropospheric ozone threshold values set under the current EU Ozone Directive have been exceeded since 1994, when the Directive came into force. During short periods of two to four days, high levels of ozone above the threshold values set for protecting people’s health occur regularly over large parts of Europe. During the summer, there is a general blanket of medium to high ozone levels over Europe at least twice as high as during the 1850s. Proposals are being formulated for a new Ozone Directive, setting out target values for 2010. However, even the most realistic options for abating emissions will not bring ozone levels down enough to prevent adverse effects on human health and ecosystems by that time.

Ozone concentrations vary considerably from year to year. Model calculations indicate that the increases in tropospheric background concentrations will continue, due to growth in background levels of nitrogen oxides, carbon monoxide, and methane. The cumulative EU population exposure is expected to decrease, but large exceedance will continue to appear in 2010. Similarly, the vegetation exposure should decrease by a quarter.

The observed decrease in emissions of acidifying substances should result in significantly lower deposition levels in the period 1990 to 2010. For EU15 the emissions reduction between 1990 and 2010 of sulphur dioxide (SO 2 ) is estimated at 70%, 45% for nitrogen dioxide (NO 2 ) and around 18% for ammonia (NH 3 ). The corresponding reductions for the Accession Countries are: almost 60%, around 27%, and only 1%. EU agreed emission targets for NO x are 30 per cent reductions between 1990-2000, and for SO 2 a 40 per cent reduction between 1990 and 2000. The 2000 target for SO 2 will probably be achieved, while the one for NO x is not expected to be met. Lower emission and deposition levels should mean significant improvements for ecosystems. In the EU, ecosystems with acid deposition above their critical loads will fall from 25% in 1990 to 7% in 2010; with ecosystems in several countries virtually no longer exposed to exeedances. The corresponding figures for ecosystems with nitrogen deposition above their critical loads are 55% in 1990 and 39% in 2010. A substantial improvement in the area of ecosystems affected by acidification is forecast for Accession Countries; from 44% in 1990 to 6% in 2010. With eutrophication, a more modest gain in protected ecosystems is forecast: from 84% in 1990 to 72% in 2010.

The EU Acidification Strategy is targeting full protection of all ecosystems in the long term. Current interim emission targets for 2010 require reductions of 83% for SO 2, 55% for NOx, and 29% for NH 3 compared to 1990 levels. These will not be achieved with existing and proposed policies.

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