In the early 1970s, it was not known that pollutants could be transported over great distances with air currents and deposited elsewhere with precipitation.
Air pollution was seen as a domestic rather than an international issue. The notion that industrial emissions in one country could contaminate another country was contentious. Researchers who made such claims had to prove them.
Research breakthrough
The breakthrough was the research report “Long-Range Transport of Air Pollutants. Measurements and Findings” which NILU compiled for the Organisation for Economic Co-operation and Development (OECD) in 1977. This research report was crucial for the understanding of how far air pollution could spread.
The report clearly showed that pollution could be transported over large distances and that individual countries could do very little to reduce acid rainfall solely through national measures.
The Convention on Long-Range Transboundary Air Pollution
In 1979, the Convention on Long-Range Transboundary Air Pollution (LRTAP) was established. Its aim was to create an understanding that air pollution can spread across borders – that is, pollution in one country can lead to negative effects in another.
The convention includes eight protocols that identify specific measures that the member states are obliged to implement to cut their own emissions.
The initial LRTAP work was led by NILU, and the institute has since played active roles in international climate cooperation.
What is long-range transboundary air pollution?
Long-range transboundary air pollution includes acidifying gases such as sulphur oxides (SOx) and nitrogen oxides (NOx), ground-level ozone, particulate matter (dust) and environmental pollutants such as heavy metals and persistent organic pollutants (POPs).
Acid rain and eutrophication
Questions related to the acidification and eutrophication of rivers, water and soil have been a central research area for NILU for several decades.
In the 1960s, scientists discovered the relationship between sulphur oxide emissions from Europe and the acidification of waterways in Scandinavia. Mortality among fish populations in southern Norway was eventually linked to long-range transboundary air pollution in the form of sulphur oxides and nitrogen oxides from the continent.
It was also found that ammonia emissions from agriculture and other sources could lead to eutrophication of waterways, which in turn promoted algal growth and oxygen depletion.