Morten Ryhl-Svendsen

Ammonia chemistry within Danish churches.

The increase of agricultural intensity over the last century in rural Denmark has meant that ammonia has been regarded as a significant environmental problem. The deterioration of murals in rural churches is also a matter of concern and focused attention on the potential for ammonia to accelerate damage. Ammonia concentrations measured over 12 months inside and outside nine churches often show a spring maximum outdoors, hinting at the importance of farming activities. The ammonia concentrations are on average some three times greater indoors than outdoors and mass balance calculations suggest that this arises from the decomposition of ammonium nitrate aerosols. The emissions may result from reactions of aerosols deposited at the alkaline walls, which also leads to calcium nitrate becoming the major soluble salt at the very surface layer. The quantities remain small enough, that they probably do not participate in salt damage to the murals.

The Effect of Ventilation, Filtration and Passive Sorption on Indoor Air Quality in Museum Storage Rooms

Abstract A study was conducted in five storage rooms at the National Museum of Denmark, in which the effect on indoor air quality of mechanical ventilation, filtration and passive sorption was investigated. Mechanical ventilation and recirculation/filtration was initiated by introducing new ventilation and filtration units. Passive sorption was initiated by hanging sheets of sorptive materials on walls. The control strategies were evaluated in terms of their ability to lower the concentration of internally generated pollutants, and the indoor-to-outdoor concentration ratio of outdoor pollutants. The overall environmental impact for each method was evaluated by the use of material dosimeters. It was found that passive sorption performed better in a small room compared to a large room. Mechanical ventilation and filtration with activated charcoal gave a high protection against ozone, but were less effective in reducing nitrogen dioxide. Increased ventilation rates were expected to dilute internally generated pollutants, but ambiguous results imply that the emission rate of organic acids may also vary. Recirculation/filtration was generally the most efficient method. A cautious conclusion is that a combination of a low air exchange rate and internal recirculation with filtration will be most beneficial to the indoor air quality for such low-activity storage buildings.

Monitoring the accumulated water soluble airborne compounds deposited on surfaces of showcases and walls in museums, archives and historical buildings

BackgroundCultural heritage objects are subject to the deposition of a multitude of airborne pollutants even when kept inside museums, archives, historical buildings or showcases. Some of the pollutants are quickly deposited onto any available surface, including the interior walls and CH objects themselves. This might make the compounds seem absent from analyses of indoor air samples.Context and purpose of the studyA new method of detecting water soluble pollutants without taking samples from the interior walls or from the CH objects themselves has been developed. The method involves sampling the pollutants accumulated on a surface near the CH object, e.g. a nearby wall or an interior glass surface of a showcase. The samples were obtained by gently flushing the surface with deionised water to collect the ions readily removed from the surface. The method was tested on a variety of surfaces.Results and main findingsThe flushed water were analysed with IC (Ion Chromatography) and ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and included ions of Al, As, Ba, Ca, CH3COOH, Cl, Co, (COOH)2, Cr, Cu, F, Fe, K, Mg, Mn, Na, NH4, Ni, Pb, S, Sb, Si, Sn, Sr, Ti and Zn, and the ions NO3−, PO43−, and SO42−. The resulting concentrations were converted to µEq, providing the ionic balance and the relative amounts of the ions and elements present. Ionic balance was observed on smooth and inert surfaces, but in some cases the chemistry of the wall contributed to the flush water. Solid samples of some of the surfaces have been analysed by XRF to clarify these more complex situations.ConclusionsClear results appear from smooth or well defined surfaces, whereas more complex situations arise when the underlying surface itself contributes to the flush water. The method is working very well and is easy and cheap to implement by curators and conservators, who can the send the flush water to specialized laboratories.Brief summaryA new methodology capable of monitoring the accumulated airborne deposits on surfaces in showcases and historic buildings is presented and tested. The method is cheap and is easy to implement by curators and conservators and allows the assessment of threats to the CH objects which are not always observed by analyses of the indoor air. Graphical abstractA novel method is presented detecting water soluble airborne pollutants without taking samples of the cultural heritage objects themselves. Left: schematic diagram depicting the sampling method. a Handheld squeeze bottle; b funnel made from aluminum foil to collect the flushed water; c plastic bottle collecting the flushed water; right: applying the flush water on the interior glass wall of a show case (Photo: Kaare Lund Rasmussen)

Levels of Preservation for Cultural Heritage within an Open-air Museum

Levels of Preservation for Cultural Heritage within an Open-air Museum Andrea Bernath, Iulia Teodorescu, Morten Ryhl-Svendsen, Elena Badea, Lucreţia Miu and Márta Guttmann ASTRA National Museum Complex, Sibiu, Romania; Royal Danish Academy of Fine Arts, Copenhagen, Denmark; National Research & Development Institute for Textile and Leather, Bucharest, Romania; National History Museum of Transylvania, Cluj, Romania; “Lucian Blaga” University of Sibiu, Sibiu, Romania

A Review of the Physics and the Building Science which Underpins Methods of Low Energy Storage of Museum and Archive Collections

ABSTRACT The need to keep things cool for durability should be the single most powerful influence on storage design. The simplest temperature control is to moderate the outside temperature by a combination of thermal insulation and heat capacity. The low energy storage building is a lightweight, thermally insulated, airtight building put on top of an uninsulated floor slab laid directly on the ground. The thermal insulation is calculated to even out the daily temperature cycle but to allow an annual temperature cycle which is about half the amplitude, but much smoother, than the annual temperature cycle outside. The winter temperature inside will nearly always be above ambient and so will maintain a moderate RH without need for either humidification or dehumidification. The temperature inside in summer will be below ambient and thus will force dehumidification of the infiltrating air. However, the airtightness of the building allows intermittent dehumidification with low energy consumption, less than one kWh/m3 per year. There now exist enough buildings designed on this principle to reassure curators that highly valued collections can be stored in a space with a gentle temperature cycle and with an RH stability as good as air-conditioning usually achieves.

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.