The Gothenburg Protocol was signed in Gothenburg, Sweden, on 30 November 1999 and entered into force on 17 May 2005.
The protocol is part of the Convention on Long-Range Transboundary Air Pollution which is itself an international agreement to protect human health and the environment from air pollution by control and reduction of, local and long-range, air pollution. The agreement covers Europe, North America and countries of Eastern Europe, Caucus and Central Asia as it is widely recognised that air pollutants can be carried long distances, and cross-boundaries, by winds.
The protocol is a multi-pollutant protocol designed to reduce acidification, eutrophication and ground-level ozone by setting emissions ceilings for sulphur dioxide, nitrogen oxides, volatile organic compounds and ammonia which were to be met by 2010.
Revisions are now underway to strengthen the Gothenburg Protocol and create new targets for 2020. Negotiating sessions are typically held twice a year at the United Nations office in Geneva.
Further information on the protocol can be found here.
A copy of the protocol is available here.