Vladimir Kucera

Effects of air pollution on materials and cultural heritage: ICP materials celebrates 25 years of research

An overview is given of all results from the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments (ICP Materials), which was launched in 1985. Since then, about twenty different materials have been exposed repeatedly in a network of test sites consisting of more than twenty sites with an extensive environmental characterisation and more than sixty official reports have been issued. Recent results on trends in corrosion, soiling, and pollution show that corrosion of carbon steel, zinc, and limestone is today substantially lower than 25 years ago, but while corrosion of carbon steel has decreased until today, corrosion of zinc and limestone has remained more or less constant since the turn of the century. Unique data are given on measured HNO3 concentrations from 2002-2003, 2005-2006, and 2008-2009, and the relative average decrease was about the same from 2002-2003 to 2005-2006 as it was from 2005-2006 to 2008-2009.

UN ECE ICP Materials: Dose-Response Functions on Dry and Wet Acid Deposition Effects After 8 Years of Exposure

The main results of the International Co-operative Programme on Effects on Materials, including Historic and Cultural Monuments (ICP Materials) within the United Nations Economic Commission for Europe (UN ECE) are summarised. The 8-year field exposure programme involves 39 test sites in 12 European countries and in the United States and Canada. Dose-response functions (DRF) expressing the effect of dry and wet deposition as individual terms have been obtained for a wide range of materials including bronze, copper, weathering steel, zinc, aluminium, nickel, tin, stone materials, paint coatings and glass materials. The DRFs includes parameters that are easily available on different geographical scales and can be used for mapping areas of increased corrosion rates and for calculation of costs.

Atmospheric Corrosion Effects of HNO3 A Comparison of Laboratory and Field Exposed Copper, Zinc, and Carbon Steel

The role of nitric acid (HNO3) on the atmospheric corrosion of metals has so far received little or no attention. However, the last decades of decreasing sulphur dioxide (SO2) levels and unchanged HNO3 levels in many industrialized countries have resulted in an increased interest in possible HNO3-induced atmospheric corrosion effects. In this study a new method was developed for studying the corrosion effects of HNO3 on metals at well-defined laboratory exposure conditions. The method has enabled studies to be performed on the influence of individual exposure parameters, namely HNO3-concentration, air velocity, temperature and relative humidity, as well as comparisons with newly generated field exposure data.The corrosion rate and deposition rate of HNO3 on copper was shown to follow a linear increase with HNO3 concentration. The deposition velocity (Vd) of HNO3 increased up to an air velocity of 11.8 cm s-1. Only at a higher air velocity (35.4 cm s-1) the Vd on copper was lower than the Vd on an ideal absorbent, implying the Vd of HNO3 at lower air velocities to be mass-transport limited.Within the investigated temperature range of 15 to 35 oC only a minor decrease in the HNO3-induced copper corrosion rate could be observed. The effect of relative humidity (RH) was more evident. Already at 20 % RH a significant corrosion rate could be measured and at 65 % RH the Vd of HNO3 on copper, zinc and carbon steel reached maximum and nearly ideal absorption conditions.During identical exposure conditions in HNO3-containing atmosphere, the corrosion rate of carbon steel was nearly three times higher than that of copper and zinc. The HNO3-induced corrosion effect of copper, zinc and steel turned out to be significantly higher than that induced by SO2 alone or in combination with either NO2 or O3. This is mainly attributed to the much higher water solubility and reactivity of HNO3 compared to SO2, NO2 and O3. Relative to SO2, zinc exhibits the highest sensitivity to HNO3, followed by copper, and carbon steel with the lowest sensitivity.Extrapolation of laboratory data to an assumed average outdoor wind velocity of 3.6 m s-1 enabled a good comparison with field data. Despite the fact that ambient SO2 levels are still much higher than HNO3 levels, the results show that HNO3 plays a significant role for the atmospheric corrosion of copper and zinc, but not for carbon steel. The results generated within this doctoral study emphasize the importance of further research on the influence of HNO3 on degradation of other materials, e.g. stone and glass, as well as of other metals.

Acid Deposition Effects on Materials: Evaluation of Electric Contact Materials after 4 Years of Exposure

In 1987 a co-operative field exposure program within the UN Economic Commission for Europe was initiated. The aim of the program is to evaluate the effect of sulfur pollutants in combination with NO x and other pollutantson the atmospheric corrosion of important materials. This work presents results from the evaluation of the electric contact materials nickel, copper, silver and tin after 4 years of exposure. Dry deposition of SO 2 dominates the corrosion of nickel, which forms amorphous and crystalline basic nickel sulfate, whereas both O 3 and NO 2 accelerate the dry deposition of SO 2 on copper. Silver forms Ag 2 S as the dominating corrosion product. Since H 2 S is not measured within the program it has not been possible to estimate its contribution. The formation of oxides with different stoichiometries dominates the corrosion of tin and no equation has been found that relates the weight increase of tin to environmental data. Particulate ammonium sulfate contributes to the weight increase of all metals.

Mapping of Acid Deposition Effects and Calculation of Corrosion Costs on Zinc in China

Corrosion damage to materials including objects of cultural heritage due to acid deposition has been shown to cause large costs in several studies in Europe and in the United States. So far no similar extensive studies have been performed in developing countries. The World Bank has therefore initiated and financed a study of the corrosion costs in China based on available data in the literature and obtained through contacts and visits to several institutes and organisations in China. An initial assessment of the corrosion costs in China due to acidifying pollutants has been performed using a model originally developed and applied in Europe, which has been adapted to conditions in China. Here, the model is described using zinc as an example. In the calculation of corrosion costs it is assumed that the stock of materials at risk can be allocated to census data, which enables a separate calculation of the cost for each province in China. The significant differences in corrosion attack is illustrated for zinc with a corrosion map of China based on environmental data and a dose-response function adapted for Chinese conditions including the dry and wet acid deposition effects as separate terms.

Air quality policy

There are two main ways to protect cultural heritage objects from air pollution damage. First, by reducing ambient levels of air pollution and second, by instigating local management strategies tha ...

Acid Deposition Effects on Materials: Evaluation of Nickel After Four Years of Exposure

The atmospheric corrosion of nickel after 4 years of exposure inside a sheltered box has been investigated. Quantitative evaluation of corrosion attack resulted in a linear relation between the weight increase of nickel and the sulfur dioxide concentration. Analysis of corrosion products by X-ray photoelectron spectroscopy combined with diffuse reflectance infrared Fourier transform spectroscopy and X-ray powder diffraction agreed with previous conclusions and suggested the initial formation of an amorphous basic nickel sulfate with less protective ability and subsequent formation of a crystalline basic nickel sulfate with higher protective ability. A carbonate was also detected, more abundant at lower weight increases. Conductivity of precipitation correlated with the weight increase of nickel but not so much as SO[sub 2]. High levels of this parameter are related to high concentrations of the different ions in precipitation. A complementary exposure program was performed to compare actual exposure conditions inside and outside the sample box. It was concluded that the SO[sub 2] deposition outside and inside the sample box differ approximately by a factor of 10. This difference could be separated into air flow conditions (a factor of 2) and concentrations (a factor of 5).

Air Quality Policy Air Quality Policy

There are two main ways to protect cultural heritage objects from air pollution damage. First, by reducing ambient levels of air pollution and second, by instigating local management strategies tha ...

Air Quality PolicyAir Quality Policy

There are two main ways to protect cultural heritage objects from air pollution damage. First, by reducing ambient levels of air pollution and second, by instigating local management strategies tha ...