Diffusion Charger-Based Aerosol Surface Area Monitor Response to Silver Agglomerates with 2-D Fractal Dimensions Ranging from 1.58 to 1.94

Details

• Personal Author:
  Ku-BK ; Maynard A
• Description:
  The effect of particle morphology on a diffusion charger-based aerosol surface area monitor has been comprehensively investigated using the LQ1-DC diffusion charger (Matter Engineering, Switzerland). Silver particles sintered at various temperatures ranging from 20 degrees C (no sintering) to 700 degrees C were used to provide different particle shapes. With the exception of the 20 nm particles measured with the diffusion charger, the data response is fitted well with a power model of the form y=axb (where x is mobility diameter, y is normalized surface area and x is in the range from 20 to 100 nm), giving power b equal to almost 2. The deviation at 20 nm may be partly accounted for by the detection limit of the diffusion charger. For the diffusion charger response vs. particle sizes extended up to 200 nm, the power b decreases to 1.62 when instrument response to particles larger than 100 nm is included. The change in response appears to start at mobility diameter 80 to approximately 90 nm. Fitting data above and below 80 nm indicates two distinct response regions, with data above 80 nm being described by a power law with an exponent of 1.5. Diffusion charger response to the agglomerates at temperatures not larger than 300 degrees C (complex shape) is slightly higher than those at temperatures above 500 degrees C (spherical), indicating that the attachment rate of charged ions in the diffusion charger to particles appears to depend slightly on particle morphology. It is hypothesized that complex shaped agglomerates entering the diffusion charger will have a lower charge-to-surface ratio than equivalent spherical particles, thus leading to a greater probability of multiple charging. [Description provided by NIOSH]
• Subjects:
  Aerosols Occupational Health Particulate Matter Safety Silver Temperature
• Keywords:
  Aerosol-particles Models Morphology Particulates Silver-compounds Surface-properties Temperature-effects
• Publisher:
  American Association for Aerosol Research
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Georgia ; Ohio ; OSHA Region 4 ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20029090
• Citation:
  Proceedings of the AAAR 23rd Annual Conference, October 4-8, 2004, Atlanta, Georgia. Mount Laurel, NJ: American Association for Aerosol Research, 2004 Oct; :221
• Contact Point Address:
  National Institute for Occupational Safety and Health (NIOSH), 4676 Columbia Parkway, MS R-3, Cincinnati, OH 45226
• CAS Registry Number:
  Silver (CAS RN 7440-22-4)
• Federal Fiscal Year:
  2005
• Peer Reviewed:
  False
• Source Full Name:
  Proceedings of the AAAR 23rd Annual Conference, October 4-8, 2004, Atlanta, Georgia
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6ba63557d4c8464b06ba448b1c8bb68b9d34640136e7a3cf6236d191a2f5c5f121e843e820ca2fe8cdb9f5da2f73ee64753a10ad50f6d086e475c2c60abcea2b
• Download URL:
  https://stacks.cdc.gov/view/cdc/190154/cdc_190154_DS1.pdf
• File Type:
  [PDF - 68.31 KB ]