Scanning electron microscopy with energy dispersive X-ray spectroscopy: an analytical technique to examine the distribution of dust in books

Abstract

Micro-samples of loose dust, paper and paper from areas of pages with accumulated dust were obtained from a collection that was on open display in an historic library with significant levels of particulate pollution. The present study examines the origin of these dust particles and their ingress into the library books. The samples were analysed using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). Qualitative point SEM-EDS was used to identify the characteristics and origins of individual particles, while bulk analysis was achieved by rastering the electron beam over whole samples. The inorganic fraction of the dust comprised 30–40% calcium sulfate, 10–20% sodium chloride and around 50% silicon dioxide, aluminosilicates, iron oxides/hydroxides and calcium carbonate. The ratios of these components were variously maintained as the dust penetrated between the pages of the book, suggesting that in some books sodium chloride moved as a solid, and not in a solution. This preliminary study suggests that SEM-EDS is a useful tool, not only in the determination of the identities of dust particles and their origin, but also in estimating the relative amounts of dust species and the extent to which they have moved into the book.