ICP Materials
International Cooperative Programme on Effects of
Air Pollution on Materials, including
Historic and Cultural Monuments
Co-Chairs:
Mr. J. Tidblad (Sweden) and Mr. S. Doytchinov (Italy)
Head of Programme
Centre: Mr. J. Tidblad
Several studies of materials have
indicated that atmospheric corrosion influenced
by acidifying pollutants is costly. Extensive damage
has also been observed on historical and cultural
structures and monuments calcareous stones, medieval
glass and metals. For these reasons, the Materials
Programme was launched in 1985 to fill some of the
major gaps in our knowledge.
ICP Materials has
two objectives:
- to perform a quantitative evaluation
of the effect of sulphur and nitrogen compounds
and other major pollutants, including the effects
of low concentrations of these pollutants on the
atmospheric corrosion of important materials, and
- to assess the trends of corrosion and pollution.
The quantitative evaluation aims at determining
dose-response relationships as a basis for assessing
acceptable and/or target levels and calculating
costs due to material damage. Structural metals,
stone materials, paint coatings, electric contact
materials, samples of medieval stained-glass windows
and polymer materials are included. The aim of the
trend exposures is to serve as a confirmation of
the environmental effects of previous pollutant
reductions achieved under the Convention, as well
as a method for identifying extraordinary environmental
changes that result in materials damage
The Task Force of the programme
is led by Sweden, which provides the Main Research
Centre at the Corrosion and Metals Research Institute (KIMAB), Stockholm.
Since 2005 Sweden and Italy (ENEA) are co-chairing
the programme. The Czech Republic, Germany, the
United Kingdom, Norway, Austria and Switzerland
are responsible for sub-centres, which prepare and
distribute specimens of particular materials and
evaluate corrosion attack after exposure. In all
countries, national contact persons are responsible
for the exposure and withdrawal of specimens and
for reporting environmental parameters to the environmental
sub-centre in Norway. A network of 30 exposure sites
across 18 ECE countries covers a broad band of geographic
zones in Europe and North America. At these, atmospheric
pollution is characterized by measuring the gases
sulphur dioxide (SO2) and nitrogen dioxide
(NO2) and ozone (O3) concentrations.
During some periods also the nitric acid (HNO3)
concentration and deposition of particulate matter
(PM) are included. Wet deposition of pollutants
is characterized by analysis of rainwater. The first
exposure programme included evaluation of specimens
after 1, 2 and 4 and 8 years (1987-1995). Statistical
analysis has provided dose-response relations for
several materials linking deterioration with environmental
parameters.
The reduction of the sulphur pollution
has created a new multipollutant situation where
SO2 is no longer the dominating corrosive
pollutant. Therefore, a second "multipollutant
programme" was performed in 1997-2001 using
a subset of test sites and materials from the original
programme, along with some new test sites. A new
set of dose-response functions was developed describing
the deterioration of material in the new mixture
of pollutants.
Both long-range
transport and local emissions of pollutants are
important for materials exposed to the atmosphere.
In addition, the concept of a threshold of harmful
pollution, a critical load or level, is not applicable
to materials. Any amount of pollution leads to some
deterioration. Instead an "acceptable"
deterioration rate has been defined as a multiple
(e.g. 1.5) of the background deterioration rate.
Acceptable levels of pollution can be calculated
using dose-response relations for the individual
materials and the acceptable deterioration rate.
This concept is now used for mapping of areas with
exceedances and together with assessments of the
stock of materials, especially cultural heritage
objects, at risk for cost-benefit analyses in different
pollution scenarios.
Further information is available
from the Programme Centre.