When scientists in the 1960s investigated the causes of the “acid rain” that was destroying forests, causing fish loss in lakes and putting entire ecosystems at risks in the Northern Hemisphere, they found that air pollutants, a significant part of which were emitted thousands of kilometres away, were the culprit.
In order to solve this problem, 32 countries in the pan-European region decided to cooperate to reduce air pollution. In 1979, they signed the UNECE Convention on Long-range Transboundary Air Pollution, creating the first international treaty to deal with air pollution on a broad regional basis. The Convention entered into force in 1983, laying down the general principles of international cooperation for air pollution abatement and setting up an institutional framework which has since brought together research and policy. Over the years, the number of substances covered by the Convention and its protocols has been gradually extended, notably to ground-level ozone, persistent organic pollutants, heavy metals and particulate matter.
The Convention has substantially contributed to the development of international environmental law and has created the essential framework for controlling and reducing the damage to human health and the environment caused by transboundary air pollution. It is a successful example of what can be achieved through intergovernmental cooperation.