This article is part of the Journal of Raman Spectroscopy special issue entitled “Raman spectroscopy in art and archaeology” edited by Juan Manuel Madariaga and Danilo Bersani.
Degradation potential of airborne particulate matter at the Alhambra monument: a Raman spectroscopic and electron probe X-ray microanalysis study†
Article first published online: 4 JUL 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Raman Spectroscopy
Special Issue: Raman spectroscopy in art and archaeology
Volume 43, Issue 11, pages 1570–1577, November 2012
How to Cite
Potgieter-Vermaak, S., Horemans, B., Anaf, W., Cardell, C. and Grieken, R. V. (2012), Degradation potential of airborne particulate matter at the Alhambra monument: a Raman spectroscopic and electron probe X-ray microanalysis study. J. Raman Spectrosc., 43: 1570–1577. doi: 10.1002/jrs.4052
- Issue published online: 21 NOV 2012
- Article first published online: 4 JUL 2012
- Manuscript Accepted: 16 JAN 2012
- Manuscript Revised: 10 JAN 2012
- Manuscript Received: 21 NOV 2011
- airborne particulate matter;
- micro-Raman spectroscopy;
- degradation potential;
It is well known that airborne particulate matter (APM) has an impact on our cultural heritage. A limited number of articles have been published on the sequential application of elemental and molecular techniques to estimate the degradation potential of APM in environments of cultural heritage importance, and most of these were concerned with indoor environments. The Alhambra monument (Granada, Spain) represents one of the grandest and finest examples of Islamic art and architecture from the Middle Ages. As part of an air quality investigation, two sets of APM were collected at the Hall of the Ambassadors and characterised to determine its potential degradation profile. These were analysed by means of micro-Raman spectroscopy (MRS) and electron probe microanalysis with X-ray detection (EPXMA). The Raman data indicated the presence of various mixed salts of acidic and/or hygroscopic nature, such as sodium and ammonium nitrates and sulfates, especially in the finer fraction. Automated EPXMA estimated this fraction to be as high as 50%. Apart from the potential chemical attack, the soiling due to carbonaceous matter deposition is a real concern. Soot was identified by MRS and EPXMA in all size fractions, reaching values of up to 55%, and was often intertwined with soluble inorganic salts. Ongoing degradation of the pigments is implicated by the presence of brightly coloured particles. MRS and molar abundance ternary diagrams elicited the chemical structure of individual APM so that the degradation potential could be established. Copyright © 2012 John Wiley & Sons, Ltd.