Preliminary optoacoustic measurements of air pollution generated during laser cleaning of artworks

摘要

In the presented preliminary experiments, a simple glass cup enables to isolate the cleaned surface and to introduce a laser beam and a measuring probe. A sensitive opto-acoustic measurement system was able to detect the time averaged changes of concentrations of benzene, carbon monoxide, carbon dioxide, methane, sulphur dioxide and water vapours at the level of ppm. Final concentrations of carbon monoxide and sulphur dioxide (well known as main pollutants of the atmosphere) can significantly increase during laser cleaning in closed areas. Moreover, concentrations of measured atmosphere contaminants can be considerably different in the case of ablation of encrustation on different substrates (wood, stone, plaster, parchment etc.). The measured values of gas concentrations emitted during laser cleaning showed large changes from point to point, depending on local properties of soiling, its quantity and type.