Air pollution abatement - success and failures

The convention on long range air pollution has helped to clear the skies over Europe and North America over the last three decades - but a few countries are still notorious in failing to fulfil their committments.

Initiated at a time when the detrimental impact of acid rain was gaining increasing public attention in Europe and North America, the Convention on Long-range Transboundary Air Pollution (CLRTAP) was signed in 1979 and entered into force in 1983. As the first regional environmental treaty, the convention has been instrumental in the reduction of harmful air pollutants in Europe and North America.

With 51 parties, the convention covers most of the region of the United Nation’s Economic Commission for Europe (UNECE). Over the years, the convention has been extended by eight protocols, focused upon reducing air pollutant emissions for the protection of human health and the environment. Each of these protocols targets pollutants such as sulphur dioxide (SO2), nitrogen oxides (NOx), persistent organic pollutants (POPs), volatile organic compounds (VOCs), ammonia (NH3), and toxic heavy metals.

The most recent one – the 1999 Gothenburg Protocol to Abate Acidification, Eutrophication and Ground-level Ozone – came into force in 2003, and aims at reducing air pollution damage by setting binding national emission ceilings for SO2, NOx, VOCs and NH3, to be achieved by 2010. The emission ceilings are complemented by technical annexes establishing mandatory emission standards for both stationary and mobile emission sources.

compound US 1990 US 2006 Trend % EU27 1990 EU27 2006 Trend %
Sulphur dioxide, SO2 23,077 14,714 -36 27,323 8,284 -70
Nitrogen oxides, NOx 25,527 17,694 -23 17,136 11,294 -34
Ammonia, NH3 4,320 4,135 -4 5,120 4,094 -20

Table: Emissions of sulphur dioxide, nitrogen oxides and ammonia 1990-2006 in the United States and EU27 (kilotonnes/year). Data from USEPA and EEA.

Figure: Emissions of sulphur dioxide in Europe over the period 1880-2005. Source: Vestreng et al, Atmospheric Chemistry and Physics, 2007.

Negotiations to revise and strengthen the Gothenburg Protocol, including a widening to cover fine particulate matter (PM2.5) as well, will start this year, and the aim is to adopt a revised protocol in December 2011. This should set new, stricter national emission ceilings for 2020.

Renegotiation of the 1998 Heavy Metals Protocol is ongoing, and amendments to the 1998 POPs Protocol were recently adopted (see box).

Encompassing the European continent and North America, the convention is also well known for having successfully linked science and policy. The European Monitoring and Evaluation Programme (EMEP) and the Working Group on Effects, with its International Cooperative Programmes, are effective networks of scientists and research centres, responsible among other things for mapping critical loads/levels, computer modelling for integrated assessment and researching the levels and impacts of air pollutants.

Although much has been accomplished in the past 30 years, air pollution levels are still too high and scientific research continues to identify new risks. One example of such a risk is reactive nitrogen, which has more than doubled during the last century, resulting in a range of negative environmental impacts, including damage to ecosystem biodiversity.

Climate change is a major environmental challenge, and both greenhouse gases and air pollutants originate largely from the same emission sources and their effects can be closely linked.

Consequently, it is a challenge for the convention to exploit the benefits to be gained from policies that simultaneously address climate change and damage from air pollution. One step in this direction was taken at the meeting of the convention’s executive body in December 2009, when it was agreed that the revision of the Gothenburg Protocol should include an evaluation of so-called short-lived climate forcers, primarily black carbon and tropospheric ozone as well as their precursor pollutants (e.g. NOx, VOCs, carbon monoxide and methane).

Over the years, the convention has gradually shifted from a single-pollutant policy (i.e. looking at one pollutant such as SO2, and one effect, such as acidification), to a multiple-pollutants and multiple-effects policy framework, based on the critical load approach. To be able to better account for the links between air pollution and other high-profile issues such as climate change and biodiversity loss, the convention’s approach may need to be widened another step to encompass multiple-issues and multiple-effects. Clearly, as CLRTAP moves forward, the science-policy interface will continue to be crucial.

It is now clear that air pollution is not limited to the regional scale, but that it is a global – or at least a northern hemispheric – problem. Some air pollutants, such as ozone and fine particles (and their precursors), can be transported thousands of kilometres. This means that pollutant emissions in one continent can cause damage in another continent, and that emissions in Europe, North America or Asia may end up in the sensitive ecosystems of the Arctic.

Scientific matters linked to the trans-continental movements of air pollutants have for the past five years or so been handled by a designated task force under the convention, but the policy implications still remain to be sorted out. To this effect, CLRTAP has initiated various “outreach” activities across the world, and this work may become more important in the coming years.

Implementation of the existing protocol is a matter of high priority, and was discussed by the executive body in December. The convention’s implementation committee reported that a few countries are still failing to comply with the emission reduction demands of the protocols, and several countries are failing to comply with the obligation to report.

Despite repeated sharp reprimands over several years, Greece and Spain have still not reduced their emissions as required by the protocols. Greece expressed expectations to achieve compliance with its obligations under the 1988 NOx Protocol by 2013, which is nearly 20 years too late, but the committee was not convinced that this would actually happen, and also concluded that the country’s responses remained insufficient.

Spain has now been in non-compliance with the NOx Protocol for 15 years, i.e. every year since 1994. Spain currently expects to achieve compliance by 2010, but this was called into question by the committee due to the fact that in 2007 Spanish emissions were still 36 per cent above the target. Spain has also failed to comply with the 1991 VOC Protocol – it is still a long way from achieving the required 30-per-cent reduction. Spain has stated that it still does not expect to achieve compliance before 2020.

The executive body expressed increasing disappointment at the continuing failure of Spain and Greece to fulfil their obligations to take effective measures to attain compliance, and strongly urged both countries to implement the measures necessary to achieve compliance as soon as possible.

In addition, increased use of biomass for domestic heating has meant that emissions in Denmark of polycyclic aromatic hydrocarbons (PAH) continue to increase, which is not compliant with the emission reduction obligation in the Persistent Organic Pollutant (POP) Protocol.

The executive body was disappointed that Denmark has once again indicated it will not achieve compliance for many years, and urged Denmark to speed up abatement measures to shorten the period of expected non-compliance.

As to the requirements to report on emission data and on strategies and policies for abating air pollution generally, the committee noted that despite a general improvement, several parties were still found to be failing to comply with their reporting obligations.

Christer Ågren


Seven harmful chemicals addedParties to the convention’s Protocol on Persistent Organic Pollutants (POPs) agreed in December 2009 to add seven new substances to the protocol, namely: hexachlorobutadiene, octabromodiphenyl ether, pentachlorobenzene, pentabromodiphenyl ether, perfluorooctane sulphonates, polychlorinated naphthalenes, short-chain chlorinated paraffins. This brings the number of POPs regulated under the protocol to 23.

The POPs Protocol, which was signed in 1998 and entered into force in 2003, constituted the first international action to control POPs, and so far it has been ratified by 29 countries. The original protocol regulates 16 substances, banning the production and use of some, while scheduling others for elimination at a later stage or severely restricting their emissions. It also contains obligations for the use of best available techniques to control emissions and for the environmentally sound disposal of waste containing POPs, as well as specific emission limit values for the incineration of waste.

Parties to the convention must now ratify the revised protocol before the new restrictions enter into force.

Note: Persistent organic pollutants (POPs) are particularly harmful chemical substances (pesticides, industrial chemicals and by-products or contaminants) which pose a serious threat to the environment and to human health. POPs are not just toxic – unlike other pollutants, they resist degradation, remaining in the environment for generations and accumulating in the bodies of humans and animals. They are transported over long distances, including to the Arctic. Health hazards from POPs include endocrine disruption, reproductive and immune dysfunction, neurobehavioural and developmental disorders, and cancer.


In this issue