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Degradation potential of airborne particulate matter at the Alhambra monument: a Raman spectroscopic and electron probe X‐ray microanalysis study
Author(s) -
PotgieterVermaak Sanja,
Horemans Benjamin,
Anaf Willemien,
Cardell Carolina,
Grieken René Van
Publication year - 2012
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4052
Subject(s) - microanalysis , raman spectroscopy , particulates , chemistry , environmental chemistry , electron probe microanalysis , degradation (telecommunications) , mineralogy , analytical chemistry (journal) , chemical engineering , electron microprobe , organic chemistry , physics , optics , telecommunications , computer science , engineering
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.