IAQ 2003, Presentation 2:
Air Pollution Effects on the Paintings kept within MMCA Depots in Rijeka, Croatia
Ana Alebic-Juretic1 & Duska Sekulic2
The most important parameters determining the microclimate within museums and exhibition areas are: temperature, relative humidity and indoor air pollution, often related to outdoors (1). To assess the possible impact of air pollution on artworks kept in the Museum's depots, soiling material (dirt) removed during process of restauration was analised for its ionic content, lead, soot and polynuclear aromatic hydrocarbons (PAHs). The samples of dirt were taken from 4 paintings: two of them kept in the central depot within the Museum building since mid-seventies or eighties (with unknown prior history of storage), while the other two were kept in the temporary depot in the wider city centre since the mid-nineties. The description of the paintings taken into analyses are given in Table 1.
Table 1: Description of the paintings taken into analyses
The common characteristics for all the paintings analysed is the dominance of sulphate and calcium in the water
The individual PAH profile also indicate the possible air pollution impact. The complete profile# is found in paintings kept in the auxiliary depot (No 3 and 4), i.e. in the vicinity of the busy street - the source of PAHs. Lack of some individual PAHs in paintings from the central depot (No1 and 2) suggest their earlier exposure to exhaust gases containing PAHs and their subsequent degradation. Unexpectedly low lead content in water extract from the painting No4 was found. The possible reasons for are: either the low possibility of sticking the mineral particles onto nonpolar wax surface, or the mineral particles were embedded into the wax layers that prevent their efficient extraction.
The highest amount of total "dirt", soot, lead and total PAHs are obtained from painting No 1 (Butozan). Since this is the second oldest painting in this study, the unknown previous history of storage, as well as the nature of thick oily paint might be responsible for this result. In the oldest painting No 2 (Seferov) lower values of total "dirt", soot and particularly lead and total PAHs are found, thus indicating better storage conditions, e.g. more distant from traffic source emissions, prior to arrival in the Museum's depot. The lowest amount of total "dirt" and total PAHs are found in painting No 3 (Lusic). This might be the result of the very smooth acrylic coated surface with high static electricity that prevents deposition of airborne aerosols and gases. The (nonpolar) wax coated surface of painting No 4 (Grozdanic) collected more total "dirt", soot and total PAHs than painting No 3, that was contemporary kept in the auxiliary depot. In conclusion, the analysis of dirt removed from the paintings stored in the Museums depots indicate the impact of outdoor air pollution on soiling processes. The nature of pigments, furnish and paints is also crucial for the aerosol deposition and/or surface gas reactions on artworks. Therefore it is hard to quantify their deposition/reaction rates.
(1) Camuffo D., Van Grieken R., Busse H-J, Sturaro G., Valentino A., Bernardi A., Blades N., Shooter D., Gysels K., Deutsch F., Wieser M., Kim O. And Ulrych U.: Environmental monitoring in four European Museums, Atmos Environ, 35, Suppl. 1 (2001) S127-140.
(2) Matkovic N. and Alebic-Juretic A.: Emissions and Ambient Levels of Sulphur Dioxide in the Rijeka Bay Area, Arh hig rada toksikol, 49 (1998) 155-163.
# The complete PAH profile: anthracene, phenanthrene, fluoranthene, pyrene, benzo(a)anthracene+chrysene, benzo(b)fluoranthene+benzo(k)fluoranthene, benzo(a)pyrene and indeno(1,2,3-c,d)pyrene
* Author to whom correspondence may be addressed:
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