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Impacts
able. The CORINAIR database is the body for the EU countries including
more detailed data and more air pollutants. For Denmark the
emission inventories are being carried out as a cooperative effort
between NERI and Research Centre Risoe covering CO 2, SO 2, NH y ,
NO x, CH 4, N 2O, NMVOC and CO.
For scenarios the variables in emissions are due to changes in energy
policy, environmental policy and technology. Changes in energy use
in the different economical sectors such as industry, agriculture,
transport, housing and trade are related to energy efficiency, fuel
type and emission control.
Air pollution is monitored in Denmark in the permanent survey programme
(BOP) and reports to EMEP and other international bodies.
The EMEP grid is presently 50 km x 50 km for description of air pollutants
over Europe. All major air pollutants are measured in field
stations including a number of elements. Two different types of
models for calculating long-range transport of air pollution and
deposition are used. The Danish Eulerian Model (DEM) is calculating
in- and output to fixed grids whereas Atmospheric Chemistry and
Deposition model (ACDEP) follows an air package (a trajectory)
during four days and calculating in- and output from this package.
Both models cover the whole of Europe. Deposition of long-range
transported air pollutants can be calculated with reasonable precision
with these models, but ammonia is locally very heterogeneously distributed
and deposited close to the source.
Impacts of air pollutants can be estimated at three levels: Level 0 being
empirical data judged by national experts; Level 1 being static
modelling of steady-state for an ecosystem using input-output models;
Level 2 being dynamic models with detailed data modelled
stepwise between start and end state.
Critical loads of acidifying and eutrophying substances are judged by
level 0 for heathlands and bogs in Denmark, whereas Level 1 is used
for forests and permanent grasslands. Critical loads for acidification
are a combination of two basic factors: the balance between the acidifying
deposition and the natural acid-neutralising (buffer) capacity of
the soil and vegetation. The critical loads for eutrophication influence
the growth and competition among organisms in the ecosystems and
may alter composition of vegetation and sensitivity of forest trees to
biotic and abiotic stress such as insect attacks, frost etc. The critical
loads of Danish ecosystems and the models used for calculation are
discussed in chapter 5.1. However, eutrophying substances can also
acidify the soil and consequently interrelationships between these
effects are discussed in chapter 5.1. In practice today, the so-called
protection isolines for individual ecosystems within one grid cell are
calculated for the combinations of S and N depositions above which
the critical loads are exceeded.
Critical levels are also mainly calculated at Level 1 and the definition
of the threshold level for damages is being thoroughly discussed in
international fora. The most used method is to make experiments in
Open-Top-Chambers fumigating crops with different concentrations
and exposure length of different gasses. Most effort has been given to
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