Quantitative analysis of unique deposition pattern of submicron Fe3O4 particles using computer-controlled scanning electron microscopy

Details

• Personal Author:
  Gao, Peng-Fei ; Hopke PK ; Jaques PA
• Description:
  This study was designed to optimize particle counting of a unique deposition pattern of iron oxide (Fe3O4) particles that were collected by a multidomain magnetic passive aerosol sampler (MPAS). Fe3O4 is paramagnetic with a high magnetic susceptibility, rendering high collection efficiencies. The MPAS was designed exclusively for measuring particle penetration through protective clothing. To quantify particle deposition by size, two counting methods were employed with a computer-controlled scanning electron microscope (CCSEM). Based on a sequential set of measurements at known coordinates, particles were quantified across particle clusters collected by individual magnets. Because all magnets were of equal dimensions and strength, the particle concentration per cluster across the entire MPAS substrate was expected to be relatively uniform. However, since individual CCSEM fields are extremely small compared with the full sample, a randomized counting approach was used to determine how many fields were needed to obtain a representative subsample. Results by the sequential method show that particle numbers were higher toward the edge of the cluster, dominated by smaller particles; moderate at the center, dominated by larger particles; and null at the corners. The results additionally show that counting by the random method was comparable with the sequential method and repeatable for particle counts ranging from 3 to 383 particles per field, or 409,565-52,287,826 particles per substrate, taking between 25 and 53 min, respectively. The results suggest that with the random method, the CCSEM provided a powerful tool for quantitative analyses of particle numbers with unique deposition patterns. [Description provided by NIOSH]
• Subjects:
  Aerosols Occupational Health Particulate Matter Safety
• Keywords:
  Aerosol-particles Aerosol-sampling Iron-oxides Magnetic-properties Measurement-equipment Nanotechnology Particulate-dust Particulates Quantitative-analysis
• ISSN:
  0278-6826
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  New York ; OSHA Region 2 ; OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  NPPTL - National Personal Protective Technology Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  46
• Issue:
  8
• NIOSHTIC Number:
  nn:20040714
• Citation:
  Aerosol Sci Technol 2012 Aug; 46(8):905-912
• Contact Point Address:
  Pengfei Gao, National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, 626 Cochrans Mill Road, Pittsburgh, PA 15236
• Email:
  PGao@cdc.gov
• CAS Registry Number:
  Ferrous oxide (CAS RN 1345-25-1)
• Federal Fiscal Year:
  2012
• NORA Priority Area:
  Manufacturing ; Public Safety
• Peer Reviewed:
  True
• Source Full Name:
  Aerosol Science and Technology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:06fc7a5a442f5fe876b925265dd02680324f788cc4d923129c92493eacfc4fed787a3139cc621dca71cc91bb3d295e6f7b3124b1f845e6fc5fdb7c7a7940a53d
• Download URL:
  https://stacks.cdc.gov/view/cdc/193482/cdc_193482_DS1.pdf
• File Type:
  [PDF - 563.84 KB ]