Air pollution travels over long distances and over national boundaries. In order to limit air pollution responsible for acidification, eutrophication and ground-level ozone pollution the European Community has policies in place limiting individual sources but also national totals of atmospheric emissions of four pollutants.
Directive 2001/81/EC of the European Parliament and the Council on National Emission Ceilings for certain pollutants (NEC Directive) sets upper limits for each Member State for the total emissions in 2010 of the four pollutants responsible for acidification, eutrophication and ground-level ozone pollution (sulphur dioxide, nitrogen oxides, volatile organic compounds and ammonia), but leaves it largely to the Member States to decide which measures – on top of Community legislation for specific source categories - to take in order to comply.
The NEC Directive has been amended as part of the accession of new Member States. A consolidated NEC Directive for the EU 27 includes the entire Community including the 2009 amendment of committee decisions. The implementation of the directive requires that Member States develops national programmes in 2002 and, where needed, revise those plans in 2006 that aim at meeting fixed ceilings of national emissions by 2010 and therafter. Further Member States have to report their emission inventories to the EEA and the European Commission in order to monitor progress and verify compliance.
The Thematic Strategy on Air Pollution in 2005 identified a number of key measures to be taken to help meeting the 2020 interim objectives for human health and the environment. The revision of the NEC Directive was identified as one of the key measures.
Parallel to the development of the EU NEC Directive, the EU Member States together with Central and Eastern European countries, the United States and Canada have negotiated the "multi-pollutant" protocol under the Convention on Long-Range Transboundary Air Pollution (the so-called Gothenburg protocol, agreed in November 1999). The emission ceilings in the protocol are equal or less ambitious than those in the NEC Directive.
The Gothenburg protocol is presently under revision and negotiations are ongoing with the aim to agree on an amended or new protocol by the end of 2011. The revision considers also new components like emissions of particulate matter, Black Carbon and intercontinetal transport of air pollution. In order to obtain a better understanding of the role of intercontinental transport of air pollution and a Task Force on Hemispheric Transport of Air Pollution (HTAP), jointly lead by the US and the EU, explores the importance of such long-range pollution. The work of the Task Force can be followed on the website www.htap.org, including the HTAP 2010 assessment detailing findings for ozone, particulate matter, mercury and persistent organic polutants.