The Convention on Long-Range Transboundary Air Pollution

The Geneva Convention on Long-range Transboundary Air Pollution (CLRTAP) of the United Nations Economic Commission for Europe (UNECE) has existed for more than 40 years. Since 1979, it has served as a bridge between divergent political systems and a source of stability in times of political change. The Convention was among   the first international multilateral environmental agreements and is so far the only international, legally binding instrument for air pollution control. It has been ratified by 51 Parties including the European Union (EU). It is not just a political agreement for international cooperation to combat transboundary air pollution, but also provides a platform for close cooperation between scientists, researchers and policymakers.

The history of the CLRTAP can be traced back to the 1960s, when scientists were first able to prove that sulphur dioxide emissions in Central Europe were causing acidification in Scandinavian lakes. Studies in the years that followed confirmed that pollutants cause damage even at a great distance from the place of emission. This makes cooperation at international level necessary to mitigate the impacts of air pollution on the environment and human health.

Eight protocols (seven protocols addressing air pollution control and one financing protocol) have been developed on the basis of the Convention.

For example, the 1983 EMEP Protocol regulates the central analysis of air pollution measurement data of all Contracting Parties, the collection and analysis of emissions data and the model calculations to determine the transboundary air pollutant loads and their financing.

• The 1998 Aarhus Protocol on Heavy Metals, which was amended in 2012, committed the Parties to drastically reducing air pollution caused by heavy metals. The protocol regulates emissions of mercury, lead and cadmium. At global level, the Minamata Convention covers mercury emissions, including those relevant to air pollution control.
• In another protocol, the Protocol on POPs, also from 1998, many UNECE countries agreed on measures to lower emissions of persistent organic pollutants (POPs). This protocol was amended in 2009. Since the Stockholm Convention entered into force, regulating most of the POPs addressed by the protocol at global level, the UNECE Convention has mainly dealt with taking inventory of POP emissions and measures to reduce the unintentional release of specific POPs (for example, polycyclic aromatic hydrocarbons from burning wood) that are not covered by the Stockholm Convention.
• The most important protocol under the Convention is the Gothenburg Protocol. It focusses on abating the combined impact of several pollutants contributing to acidification, eutrophication and ozone and particulate matter emission loads. This protocol (from 1999, revised in 2012) contains numerous provisions on emission reduction, monitoring, reporting, etc. as well as national emission ceilings (NECs) and national emission reduction commitments (NERCs) for sulphur dioxide, nitrogen oxides, ammonia, non-methane volatile organic compounds (NMVOCs) and fine particulate matter. The national emission reduction commitments, which were binding as of 2020, were incorporated into the EU National Emissions Ceilings Directive (2016/2284). In addition, numerous provisions on the preparation and reporting of emission   inventories and projections, impact monitoring, reduction measures in agriculture, etc. were integrated into EU legislation or are applicable in the EU.

The review of the Gothenburg Protocol completed in 2022 revealed that the provisions of the 2012 version of the protocol are not sufficient or effective enough to reach its objectives. A comprehensive revision process began in December 2023 based on an analysis of policy options.