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ICP Modeling and Mapping

International Cooperative Programme on Modelling and Mapping of
Critical Levels and Loads and Air Pollution Effects, Risks and Trends

Chair: Ms. Anne-Christine LE GALL

Head of Coordination Centre for Effects: Mr. J.-P. Hettelingh

Interest in the critical loads and levels approach for pollution control has gathered momentum over the past decade, and has been successfully applied to strategies for emission reductions under the 1994 Protocol on Further Reduction of Sulphur Emissions and the 1999 Protocol to Abate Acidification, Eutrophication and Ground-level Ozone.

The objectives of the ICP Modelling and Mapping are to:

  1. assess damage to forests, crops, natural vegetation, soils, surface and groundwaters, and materials by determining critical levels and loads for the response of these systems, with particular attention to the direct effects of air concentrations of sulphur dioxides (SO2), nitrogen dioxides (NO2) and ozone (O3), and the indirect effects of (long-term) deposition of sulphur and nitrogen compounds;

  2.  map geographical areas to determine the scope and extent of pollutant depositions and concentrations which exceed critical loads and levels;

  3.  establish appropriate methods as a basis for assessing potential damage.

A programme Task Force led by Germany is responsible for the detailed planning and coordination of the Programme, in collaboration with the Coordination Centre for Effects (CCE) at the Netherlands Environmental Assessment Agency (MNP). CCE supports the programme by providing scientific and technical assistance for the Task Force and the Working Group on Effects. It also provides assistance to national focal centres (NFC) in participating countries, helping them to develop methods and data for calculating and mapping critical loads, critical levels and exceedances as a basis for developing potential abatement strategies for sulphur, nitrogen and other relevant pollutants.

While CCE is charged with compiling European critical loads/levels maps and databases, NFCs are responsible for producing the national data on critical loads/levels and maps for inclusion in the European maps. At present 25 countries have contributed national data. CCE uses various European databases on soil, land, climatic and other variables to calculate critical loads for countries that are unable to provide national data. It maintains a database of critical loads data, which is used for integrated assessment modelling by the Task Force on Integrated Assessment Modelling and its Centre [for Integrated Assessment Modelling] .

A revised Modelling and mapping manual ("Manual on methodologies and criteria for modelling and mapping critical loads and levels and air pollution effects, risks and trends") -- downloadable from www.icpmapping.org → "Mapping Manual "-- , incorporating the results of years of methodological development and refinement, was published in 2004. The Modelling and mapping manual details the methods for calculating and mapping critical levels and loads that have been agreed at workshops organized under the auspices of the Executive Body for the Convention and Task Force meetings. The Modelling and mapping manual covers the following main items:

  1. guidance for the generation of maps of deposition loads and exposure levels;

  2. recommendations for mapping critical levels for direct effects of air pollutants on forests, crops and natural vegetation;

  3. examples of methods for calculating and mapping critical loads of acidity for terrestrial ecosystems, surface and groundwaters;

  4. procedures for mapping "acceptable exposure values" of pollutants for buildings and materials;

  5. evaluation of the present state of knowledge on the determination and mapping of critical loads for nutrient nitrogen.

Further information is available from the Task Force lead country and from the Coordination Centre for Effects.