Air pollution burden still too high, despite improvements

To adequately protect health and the environment, air pollutant emissions need to be further reduced, according to a new study by the European Environment Agency.

Emission cuts under the National Emission Ceilings (NEC) directive have resulted in environmental improvements and the EU appears to broadly have met its interim environmental objectives to reduce the impacts of air pollution, according to the original scientific understanding used to set the objectives.

But when currently available improved scientific understanding of air pollution is used to evaluate progress, it becomes clear that emissions need to be reduced even further to protect health and the environment, according to the European Environment Agency (EEA).

Originally proposed in 1999 and adopted in 2001, the NEC directive sets national emission ceilings for 2010 for four air pollutants: sulphur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs) and ammonia (NH3). The ceilings proposed by the Commission were designed to ensure the attainment of first step interim environmental and health objectives, and to ensure that this would be done in a cost-effective manner.

However, when the directive was being negotiated in the Council, most member states adjusted their emission ceilings upwards. So the end result was a directive in which the national emission ceilings combined for EU15 were between 6 and 17 per cent higher than in the Commission’s original proposal. But the interim environmental objectives, that were also to be achieved by 2010, remained the same.

It should also be noted that since the directive was adopted in 2001, more countries have joined the EU and emission ceilings for the twelve new member states have been added to the directive.

According to the EEA emission statistics, between 1990 and 2010 air pollutant emissions in the EU27 have come down significantly: SO2 by 82 per cent, VOCs by 56 per cent, NOx by 47 per cent and NH3 by 28 per cent. Nevertheless, preliminary emissions data for 2010, as documented in the EEA’s “NEC directive status report 2011” published earlier this year, show that twelve member states exceeded at least one of the ceilings agreed for these air pollutants. The pollutant with most exceedances was NOx.

In a new report, the EEA investigates whether the EU has actually achieved the interim environmental objectives set out for 2010 in the NEC directive. Such objectives were set to reduce the damaging effects of acidification, health-related ozone, vegetation-related ozone, and eutrophication.

Assessing whether environmental targets have been met can be done in different ways. In order to ensure that results are objective, EEA have used two different approaches. The first approach is based on “past knowledge” that applies the same tools and approaches that were used at the time the objectives were defined more than a decade ago. The second approach is based on “present knowledge” and applies a state-of-the-art assessment which uses, as far as feasible, the latest scientific understanding, including a more advanced methodology and air quality modelling with a higher resolution.

New knowledge and methods include an updated emissions inventory for the base year 1990; an improved air quality dispersion model that now accounts for ecosystem-specific depositions and has a higher level of resolution (from 150 x 150 km grid size to 50 x 50 km); and improved critical loads data and maps.

Using both these approaches showed that the impacts of air pollutants covered by the NEC directive are more serious than would have been evident from using solely past knowledge.

The NEC directive’s 2010 target was to reduce the area of sensitive ecosystems where critical loads for acidification are exceeded by at least 50 per cent in each grid cell between 1990 and 2010. Sulphur dioxide, nitrogen oxides and ammonia emitted into the air contribute to acidification of fresh water and soils.

Based on “past knowledge” assumptions, this target has been largely met across the EU. Similarly, when “present knowledge” is used, the exceedance of critical loads appears to be markedly reduced, but there are still many areas where the acidification target is not yet met. A main reason for this is that the more advanced methodology takes into account the specific effects on different ecosystems, for example the higher rate of acid deposition in forests.

High emissions of nitrogen oxides and ammonia result in excessive depositions of nutrient nitrogen in sensitive ecosystems, such as grasslands, heaths and nutrient-poor lakes. While the directive’s target to reduce areas where the critical loads for eutrophication by 30 per cent was met according to the original assumptions, new methods indicate a smaller reduction of only around 23 per cent. Eutrophication caused by atmospheric deposition is still a major environmental problem, especially regarding its widespread impact on biodiversity.

Ozone – health
Breathing elevated levels of ozone can cause respiratory problems and contribute to premature death. The directive’s target to reduce by two-thirds the human exposure to ozone levels higher than 120 micrograms per cubic metre (µg/m3) has been largely met, according to both methodologies, with the exception of some parts of southern Europe, particularly northern Italy. In this context it should be noted that the World Health Organization (WHO) in 2006 updated its air quality guideline for ozone, lowering the eight-hour mean concentration limit from 120 to 100 µg/m3.

Ozone – vegetation
Ozone also damages vegetation, such as crops and forests. According to the modelling results the directive’s target to reduce by one-third the area where the critical level for protecting crops were exceeded, was mostly met, even when using the new methodology, with the exception of Spain and Portugal. However, the target to protect forests from ozone damage was clearly not achieved in most of the EU, with the exception of the Nordic countries and the United Kingdom.

While this EEA report primarily looks at the adverse effects of air pollutants on the environment, another recent EEA report (Air quality in Europe – 2012 report, published in September) has assessed the state of air quality in Europe. It found that more than 90 per cent of European city dwellers are exposed to levels of PM and ozone pollutants in excess of the WHO air quality guidelines to protect health.

The European Commission is currently reviewing the European Union’s air pollution policy (see AN 3/12). Amongst other initiatives, the Commission is expected to propose a revised NEC directive by 2013 at the latest, which is likely to set new environmental and health objectives for 2020 and beyond as well as accompanying stricter emission ceilings for relevant air pollutants. In the meantime, the NEC directive remains in force and requires EU member states to keep emissions below their 2010 national ceilings.

Christer Ågren

Source: Evaluation of progress under the EU National Emission Ceilings (NEC) Directive, EEA Technical Report No 14/2012. Published 18 October, 2012. Available at:


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