Occupational exposure assessment in carbon nanotube and nanofiber primary and secondary manufacturers: mobile direct-reading sampling

Details

• Personal Author:
  Birch, M. Eileen ; Dahm, Matthew M. ; Deddens JA ; Evans DE ; Schubauer-Berigan, Mary K.
• Description:
  RESEARCH SIGNIFICANCE: Toxicological evidence suggests the potential for a wide range of health effects from exposure to carbon nanotubes (CNTs) and carbon nanofibers (CNFs). To date, there has been much focus on the use of direct-reading instruments (DRIs) to assess multiple airborne exposure metrics for potential exposures to CNTs and CNFs due to their ease of use and ability to provide instantaneous results. Still, uncertainty exists in the usefulness and interpretation of the data. To address this gap, air-monitoring was conducted at six sites identified as CNT and CNF manufacturers or users and results were compared with filter-based metrics. METHODS: Particle number, respirable mass, and active surface area concentrations were monitored with a condensation particle counter, a photometer, and a diffusion charger, respectively. The instruments were placed on a mobile cart and used as area monitors in parallel with filter-based elemental carbon (EC) and electron microscopy samples. Repeat samples were collected on consecutive days, when possible, during the same processes. All instruments in this study are portable and routinely used for industrial hygiene sampling. RESULTS: Differences were not observed among the various sampled processes compared with concurrent indoor or outdoor background samples while examining the different DRI exposure metrics. Such data were also inconsistent with results for filter-based samples collected concurrently at the same sites [Dahm MM, Evans DE, Schubauer-Berigan MK et al. (2012) Occupational exposure assessment in CNT and nanofiber primary and secondary manufacturers. Ann Occup Hyg; 56: 542-56]. Significant variability was seen between these processes as well as the indoor and outdoor backgrounds. However, no clear pattern emerged linking the DRI results to the EC or the microscopy data (CNT and CNF structure counts). CONCLUSIONS: Overall, no consistent trends were seen among similar processes at the various sites. The DRI instruments employed were limited in their usefulness in assessing and quantifying potential exposures at the sampled sites but were helpful for hypothesis generation, control technology evaluations, and other air quality issues. The DRIs employed are nonspecific, aerosol monitors, and, therefore, subject to interferences. As such, it is necessary to collect samples for analysis by more selective, time-integrated, laboratory-based methods to confirm and quantify exposures. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Dust Environmental Monitoring Manufacturing And Industrial Facilities Microbiology Occupational Health Particulate Matter Safety
• Keywords:
  Air-monitoring Airborne-dusts Airborne-fibers Airborne-particles Analytical-instruments Author Keywords: Carbon Nanofibers Carbon Nanotubes Diffusion-analysis Dusts Exposure-assessment Exposure Assessment Filters Industrial-environment Microscopic-analysis Monitors Nanomaterials Nanoparticles Nanotechnology Particle-counters Particulate-sampling-methods Photometry Respirable-dust Sampling Sampling-equipment Sampling-methods

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• ISSN:
  0003-4878
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DSHEFS - Division of Surveillance, Hazard Evaluations, and Field Studies ; DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  328-344
• Volume:
  57
• Issue:
  3
• NIOSHTIC Number:
  nn:20041746
• Citation:
  Ann Occup Hyg 2013 Apr; 57(3):328-344
• Contact Point Address:
  Matthew M. Dahm, Industrywide Studies Branch, Division of Surveillance, Hazard Evaluations, and Field Studies, 4676 Columbia Parkway, MS-R14, Cincinnati, OH 45226, USA
• Email:
  mdahm@cdc.gov
• CAS Registry Number:
  Carbon (CAS RN 7440-44-0)
• Federal Fiscal Year:
  2013
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  True
• Source Full Name:
  Annals of Occupational Hygiene
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:d45e8deaa407f3d4e2813951118b3e5c49f8ddf1e447595e92ae3a069cae3b0ca636180e56d0849d420248b11c27a434cfa8a222ff1b5ce0f7dee19e95a5a3cd
• Download URL:
  https://stacks.cdc.gov/view/cdc/194224/cdc_194224_DS1.pdf
• File Type:
  [PDF - 3.61 MB ]