Characterization of a Nano-Aerosol Using a Portable Scanning Mobility Particle Sizer and Electron Microscopy

Details

• Personal Author:
  Hammad Y ; Marty A
• Description:
  Objective: Portable scanning mobility particle sizers (SMPS) offer convenient means to collect information about nano-sized aerosols because they provide real-time distributions. Electron microscopy applied to a filter sample has been considered the traditional method for the sizing and counting of small particles. However, the later method is time consuming. The objectives of this research are to generate a stable and reproducible sodium chloride aerosol and to compare the size distributions obtained from SMPS and electron microscopy. Methods: A dilute solution of sodium chloride in water was nebulized, dried, and passed through a charge neutralizer before entering the sampling chamber. The size of the generated particles ranged from 20 to 250 nm. The aerosol was mixed with HEPA filtered and humidity-controlled air. The consistency of the aerosol concentration was monitored using a CPC. A portable SMPS was used to determine the size distributions of the generated aerosols. Polycarbonate membrane filters were used to collect the aerosols for subsequent electron microscopy analysis. The particle size distributions were determined from photographs of the membrane filters. SMPS and membrane samples were collected simultaneously. Results: Background counts, as indicated by CPC before data collection, were less than 0.3 particles/cc. Conditions during data collection showed that target particle size, particle concentration, and relative humidity were well controlled. SMPS data yielded log-normal size distributions with a median diameter between 80 to 100 nm. Electron microscopy analysis of the particles collected also yielded log-normal size distributions with median diameters that were about 20 to 30 nm larger than those obtained by SMPS. Conclusions: A well characterized aerosol could be generated and reproduced. Physical counting methods using electron microscopy were cumbersome and slightly different than those obtained from SPMS. The differences in the results could be attributed to the sensitivities of the methods used in this study. [Description provided by NIOSH]
• Subjects:
  Aerosols Occupational Health Particulate Matter Safety
• Keywords:
  Electron Microscopy Filters HEPA Filters High-efficiency Particulate Air Filters Monitoring Systems Monitors Nanotechnology Particle Sizers Particulates Sampling Scanning Electron Microscopy

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• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  Florida ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  131-132
• NIOSHTIC Number:
  nn:20063355
• Citation:
  AIHce 2013: American Industrial Hygiene Conference and Exposition, May 18-23, 2013, Montreal, Quebec. Falls Church, VA: American Industrial Hygiene Association, 2013 May; :131-132
• CAS Registry Number:
  Polycarbonates (CAS RN 25766-59-0) ; Sodium chloride (CAS RN 7647-14-5)
• Federal Fiscal Year:
  2013
• Performing Organization:
  Sunshine Education and Research Center, University of South Florida
• Peer Reviewed:
  False
• Start Date:
  20050701
• Source Full Name:
  AIHce 2013: American Industrial Hygiene Conference and Exposition, May 18-23, 2013, Montreal, Quebec
• End Date:
  20290630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0b7e76f55cc6962767c1883a7afb58f97597552d8a417b9f01d583be114b8999ece33ec76548f9736bc8588f52f2395a192d78ac31987bfc6fcfb9afe9243bb6
• Download URL:
  https://stacks.cdc.gov/view/cdc/226433/cdc_226433_DS1.pdf
• File Type:
  [PDF - 1017.27 KB ]