title: Characterization of exposure to carbon nanotubes in an industrial setting.
abstract: While production and use of carbon nanotubes (CNTs) is increasing, workers exposure to CNTs is expected to increase as well, with inhalation being potentially the main pathway for uptake. However, there have been few studies reporting results about workers' personal exposure to CNTs. In this study, worker exposure to single-walled CNTs (SWCNTs) during the production of conductive films in a modern up-scaling factory was assessed. Particulate matter concentrations (2.5-10 μm) and concentrations of CO and CO2 were monitored by using real-time instruments. Workers' exposure levels to SWCNTs were qualitatively estimated by analyzing particle samples by transmission electron microscopy (TEM). TEM samples identified high aspect ratio (length/width > 500) SWCNTs in workplace air. SWCNT concentrations estimated from micrographs varied during normal operation, reactor use without local exhaust ventilation (LEV), and cleaning between 1.7×10(-3), 5.6 and 6.0×10(-3) SWCNT cm(-3), respectively. However, during cleaning it was unclear whether the SWCNTs originated from the cleaning itself or from other reactor openings. We were unable to quantify the SWCNT emissions with online particle instrumentation due to the SWCNT low concentrations compared to background particle concentrations, which were on average 2.6±1.1×10(3)cm(-3). However, CO concentrations were verified as a good indicator of fugitive emissions of SWCNTs. During normal operation, exposure levels were well below proposed limit values (1.0×10(-2) fibers cm(-3) and 1 µg m(-3)) when LEV was used. Based on the results in this study, the analysis of TEM grids seems to be the only direct method to detect SWCNTs in workplace air.
authors.affiliation: 1.Institute of Environmental Assessment and Water Research (IDAEA-CSIC), C/ Jordi Girona 18, 08034 Barcelona, Spain 2.Faculty of Chemistry, Department of Analytical Chemistry, University of Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain ana.godinho@idaea.csic.es.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Fonseca
authors.affiliation: 3.Finnish Institute of Occupational Health, Nanosafety Research Centre, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland.
authors.forename: Anna-Kaisa
authors.initials: AK
authors.lastname: Viitanen
authors.affiliation: 3.Finnish Institute of Occupational Health, Nanosafety Research Centre, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland 4.National Research Centre for the Working Environment, Lersø Parkallé 105, Copenhagen DK-2100, Denmark.
authors.forename: Antti J
authors.initials: AJ
authors.lastname: Koivisto
authors.affiliation: 3.Finnish Institute of Occupational Health, Nanosafety Research Centre, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland.
authors.forename: Annelli
authors.initials: A
authors.lastname: Kangas
authors.affiliation: 3.Finnish Institute of Occupational Health, Nanosafety Research Centre, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland.
authors.forename: Marika
authors.initials: M
authors.lastname: Huhtiniemi
authors.affiliation: 5.Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland 6.Faculty of Science, Department of Physics, University of Jordan, Amman, JO-11942, Jordan.
authors.forename: Tareq
authors.initials: T
authors.lastname: Hussein
authors.affiliation: 3.Finnish Institute of Occupational Health, Nanosafety Research Centre, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland.
authors.forename: Esa
authors.initials: E
authors.lastname: Vanhala
authors.affiliation: 1.Institute of Environmental Assessment and Water Research (IDAEA-CSIC), C/ Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Viana
authors.affiliation: 1.Institute of Environmental Assessment and Water Research (IDAEA-CSIC), C/ Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Querol
authors.affiliation: 5.Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland.
authors.forename: Kaarle
authors.initials: K
authors.lastname: Hämeri
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis; D006801:Humans; D007221:Industry; D019570:Inhalation Exposure / Q000032:analysis; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D037742:Nanotubes, Carbon / Q000032:analysis*; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D010316:Particle Size; D017132:Workplace
chemical_list: D000395:Air Pollutants, Occupational; D037742:Nanotubes, Carbon
keywords: SWCNT; fibers; industry; nanoparticle; nanotube; occupational exposure limits; workplace exposure