title: Morphology, chemical composition and nanostructure of single carbon-rich particles studied by transmission electron microscopy: source apportionment in workroom air of aluminium smelters.
abstract: Sources of C-rich particles at work places in two aluminium smelters in Norway were studied by transmission electron microscopy and energy-dispersive X-ray microanalysis. Based on morphology, nanostructure and chemistry, three different types of C-rich particles are distinguished: (a) chain-like agglomerates (70-100% by number, relative to the sum of C-rich particles) consisting of primary particles with typical onion-shell structure of graphene layers, (b) multi-walled carbon nanotube particles (≈3%) and (c) spheres or agglomerates of amorphous C-rich particles (0-30%). Chain-like agglomerates are interpreted as diesel soot in accordance with literature data on primary particle diameter, chemical composition and nanostructure of primary particles. The source of the observed multi-walled carbon nanotubes is not known. The amorphous C-rich particles most likely consist of organic carbon species which cannot be characterized further by X-ray microanalysis. Unaltered graphitic electrode material was not found among the C-rich particles. The high fraction of diesel soot particles indicates that elemental carbon is generally suited as proxy for diesel soot in aluminium smelters. However, due to the presence of carbon nanotubes and amorphous C-rich particles, detailed characterization of sources of carbon-rich particles by electron microscopy is recommended for accurate assessment of adverse health effects.
authors.affiliation: Institute of Applied Geosciences, Technical University Darmstadt, Schnittspahnstr. 9, 64287, Darmstadt, Germany. weinbruch@geo.tu-darmstadt.de.|National Institute of Occupational Health, Gydas vei 8, PO Box 8149 Dep, 0033, Oslo, Norway. weinbruch@geo.tu-darmstadt.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Weinbruch
authors.affiliation: Institute of Applied Geosciences, Technical University Darmstadt, Schnittspahnstr. 9, 64287, Darmstadt, Germany.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Benker
authors.affiliation: Institute of Applied Geosciences, Technical University Darmstadt, Schnittspahnstr. 9, 64287, Darmstadt, Germany.
authors.forename: Konrad
authors.initials: K
authors.lastname: Kandler
authors.affiliation: Institute of Applied Geosciences, Technical University Darmstadt, Schnittspahnstr. 9, 64287, Darmstadt, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Ebert
authors.affiliation: National Institute of Occupational Health, Gydas vei 8, PO Box 8149 Dep, 0033, Oslo, Norway.
authors.forename: Dag G
authors.initials: DG
authors.lastname: Ellingsen
authors.affiliation: National Institute of Occupational Health, Gydas vei 8, PO Box 8149 Dep, 0033, Oslo, Norway.
authors.forename: Balázs
authors.initials: B
authors.lastname: Berlinger
authors.affiliation: National Institute of Occupational Health, Gydas vei 8, PO Box 8149 Dep, 0033, Oslo, Norway.
authors.forename: Yngvar
authors.initials: Y
authors.lastname: Thomassen
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D000535:Aluminum; D002244:Carbon / Q000032:analysis / Q000737:chemistry; D004577:Electron Probe Microanalysis; D008669:Metallurgy; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D053758:Nanoparticles / Q000032:analysis* / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000032:analysis / Q000737:chemistry*; D009664:Norway; D052638:Particulate Matter / Q000032:analysis / Q000737:chemistry
chemical_list: D037742:Nanotubes, Carbon; D052638:Particulate Matter; D002244:Carbon; D000535:Aluminum
keywords: Carbon nanotubes; Electron microscopy; Elemental carbon; Soot; Source apportionment; Workplace aerosol