Atmospheric Pollution and Acid Rain

Options Magazine, September 1989

It was Professor Sten Nilsson of IIASA’s Forest Study who first drew attention to the impact of pollution on Europe's forest resources, advocating the formulation of a convention on forest decline in Europe. 

iStockphoto © Marek Mnich iStockphoto © Marek Mnich

iStockphoto © Marek Mnich

His recommendation came in response to growing concern about damage to European forests attributed to air pollution and as a result of intensive collaboration between IIASA’s Transboundary Air Pollution Project and the Forest Study in efforts to quantify the problem.

Combining its unique database on forest resources in Europe with projections on forest soil acidification obtained using IIASA's RAINS (Regional Acidification Information and Simulation) model), IIASA’s Forest Study was able to quantify the impact of air pollution on Europe’s forest resources.

The work revealed that 35% of Europe’s coniferous forest and 9% of its deciduous forest areas were affected by nitrogen deposition levels (caused by nitrogen oxide emissions) in excess of those established by the Economic Commission for Europe  (ECE). In addition, 79%   of Europe’s coniferous forest areas and 39% of its deciduous forest areas were currently affected by levels of sulfur deposition in excess of the targets set by the Beijer Institute of Ecological Economics. 

Excess deposition of acids and exposure to atmospheric pollutants will damage trees of different types and ages, resulting in leaf and needle loss. Because the health of a tree 
affects its growth rate, and both this and life expectancy affect the value and timing of 
harvests, these calculations were important for forest industries, as well as from an ecological perspective.

Despite the current agreements on reducing emissions levels, the area of forest likely 
to be affected by excess sulfur deposition in the future was unlikely to change, according to IIASA scientists, unless planned expenditures on emission control were increased or reallocated. Moreover, the work revealed that many of the areas likely to suffer from excess sulfur deposition would also experience excess nitrogen deposition and troubling levels of atmospheric ozone. This implied that many trees would suffer the effects of multiple pollutants.

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Last edited: 11 June 2014

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