Terje Grøntoft

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.

Climate change impact on building surfaces and façades

Purpose – The purpose of this paper is to compare indicative expected changes in maintenance costs due to changes in corrosion of building facades caused by climate change or by possible reduction of air pollution, in Norway and Europe.Design/methodology/approach – Available climate and pollution dose‐corrosion response functions from the literature were used to calculate corrosion costs for buildings facades and construction surfaces. Metals and stone were used as indicator materials.Findings – An annual average temperature increase of 2°C and increase in precipitation of 20 per cent in the city of Bergen in western Norway in the twenty‐first century is likely to increase maintenance costs of building facades as much or more than a 50 per cent reduction in the concentrations of single air pollutants, and similarly to between 20 per cent and 50 per cent reduction in all the air pollutants, minus chloride, that have been found to corrode the materials. An increase in costs up to about 1 Euro/m2 10 years ca...

ICP Materials trends in corrosion, soiling and air pollution (1987–2014)

Results from the international cooperative programme on effects on materials including historic and cultural monuments are presented from the period 1987–2014 and include pollution data (SO2, NO2, O3, HNO3 and PM10), corrosion data (carbon steel, weathering steel, zinc, copper, aluminium and limestone) and data on the soiling of modern glass for nineteen industrial, urban and rural test sites in Europe. Both one-year and four-year corrosion data are presented. Corrosion and pollution have decreased significantly and a shift in the magnitude is generally observed around 1997: from a sharp decrease to a more modest decrease or to a constant level without any decrease. SO2 levels, carbon steel and copper corrosion have decreased even after 1997, which is more pronounced in urban areas, while corrosion of the other materials shows no decrease after 1997, when looking at one-year values. When looking at four-year values, however, there is a significant decrease after 1997 for zinc, which is not evident when looking at the one-year values. This paper also presents results on corrosion kinetics by comparison of one- and four-year values. For carbon steel and copper, kinetics is relatively independent of sites while other materials, especially zinc, show substantial variation in kinetics for the first four years, which needs to be considered when producing new and possibly improved models for corrosion.

Assessment of indoor air quality and the risk of damage to cultural heritage objects using MEMORI® dosimetry

Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air pollutants is less often measured or included in risk assessment. The MEMORI® technology presented in this paper was developed as a tool for easy measurement and assessment of the general risk of degradation of heritage objects situated indoors due to indoor exposure to air pollutants. MEMORI dosimetry was performed in locations belonging to English Heritage and Tate (both located in London) and the National Archives of Norway in Oslo, to assess air quality. The related damage risk for collection objects and the protection offered by display and storage designs was assessed. A high level of acidic effect was observed inside a number of showcases, and a high level of oxidizing effect was observed in some room locations. Relatively simple mitigation measures, such as constructing tightly sealed showcases using low emitting materials, installing active carbon absorbing media inside a ‘microclimate’ frame, and using cardboard storage boxes for paper, significantly improved air quality. Overall, implementation of such measures is likely to improve the preservation of objects and reduce conservation costs.

Memori Project: Evaluation of Damage to Exposed Organic-Based Heritage Materials and Nanoforart: Evaluation of Nanoparticle-based Conservation Treatment

This paper presents preliminary studies and work in progress in the framework of two FP7 projects: MEMORI (Measurement, Effect Assessment and Mitigation of Pollutant Impact on Movable Cultural Assets ‐ Innovative Research for Market Transfer) and NANOFORART (Nano-materials for the conservation and preservation of movable and immovable artworks). One of the aims of the MEMORI project is the determination of threshold levels of damage to exposed organic-based heritage objects as little is known about the impact of organic compounds, especially volatile organic acids, on organic-based cultural objects. In the previous PROPAINT project (Protection of Paintings during Exhibition, Storage Transit) it was recently demonstrated that levels of volatile organic compounds (VOCs) were often much higher in the micro-climate frames used to protect paintings than recommended levels. In this paper, examples will be given of changes observed in varnished strips exposed at selected sites. Studies on the effect on collagen-based materials will also be presented. Techniques used in both projects include Dynamic Mechanical Analysis (DMA), micro-thermal analysis ( -TA), and atomic force microscopy (AFM). The NANOFORART project explores the effects of using nanoparticle-based conservation treatment on cellulosic and collagen-based cultural materials. It builds on previous work performed on deacidification of canvas paintings using conventional materials. For collagen-based materials, no previous conservation treatment using nanoparticles has been performed on historical parchment or leather objects. Preliminary work is directed at understanding the type of nanoparticles to use to improve the physicochemical state of collagen-based objects.

A Portable Tool for the Evaluation of Microclimate Conditions within Museum Enclosures, Transit Frames, and Transport Cases

There has been an increase in interest in the quality of environments generated within protective enclosures used for art objects. Evidence of this is in the activities of recent projects that have...

IMPACT LOADS OF AIR POLLUTANTS ON PAINTINGS: PERFORMANCE EVALUATION BY MODELING FOR MICROCLIMATE FRAMES

Abstract Modeling of the transport (fluxes) of gaseous air pollutants to the surfaces of paintings installed inside six different microclimate frames (mc-frames) was performed. Mc-frames are used to protect paintings against the external environment and to provide climate buffering. However, some can trap potentially harmful gases, especially acetic acid, which may be emitted inside the frames. A steady-state mass balance model was used to evaluate how changes in three factors (the ventilation rate, the volume of the mc-frame, and the inclusion of a pollutant absorber) would affect the concentrations of gaseous air pollutants transported to the paintings in the frames. The modeled impact to the paintings was determined to be higher inside than outside for two of six mc-frames when exposed to a 50/50 mixture of acidic (acetic plus formic acid at 100 μg/ m 3 ) and oxidative gases (nitrogen dioxide plus ozone at 2 μg/m 3 ). The concentrations of the pollutants were selected to provide clear degradative effects on the paintings. The modeling indicated the most effective way to reduce the potential pollutant impact on paintings in mc-frames is to reduce both ventilation and volume, and to also install a pollution absorber.