A Direct-Reading Inhalable Particle Sizer with Elemental Composition Analyzer

Details

• Personal Author:
  Volckens J ; Yalin A
• Description:
  Exposure to inhalable aerosols contributes significantly to the burden of occupational morbidity and mortality. While respirable, and to a lesser extent, thoracic aerosols have received attention from instrument developers in recent years, no direct-reading instruments currently exist to determine the size and chemistry of large, inhalable particles, i.e., those greater than 20 µm. Current methods for inhalable aerosols call for the collection of filter-based samples over an 8-hr work shift, after which the sample is shipped to a lab for gravimetric and/or chemical post facto analysis. These filter-based methods lack temporal and spatial information and provide no information on the size distribution or chemical composition of the aerosols. Knowledge of particle size and chemistry are critical to the evaluation, recognition, and control of aerosol hazards, as these properties are key drivers of adverse health outcomes. While particles smaller than 20 µm penetrate into (and tend to deposit in) the lower respiratory system, particles larger than 20 µm target the throat and head airways. Thus, large inhalable aerosols are suspected of driving health effects like sinusitis, rhinitis, nasal cancers, and gastrointestinal disorders (due to particles eventually swallowed). Particle chemistry also drives health risks: A 30 µm particle made from beryllium likely has a different risk profile than one made from copper or elemental carbon. Despite the recognition that size and composition are important in determining and preventing health effects, few instruments exist capable of characterizing both, particularly in real time. We have previously developed a virtual, portable inhalable particle separator (termed DRIPS) capable of characterizing the size distribution of particles in the range of approx. 10-100 µm. Research under the present grant has advanced the underlying methods needed to expand the capabilities of the DRIPS instrument to characterize the size-dependent chemical composition of inhalable aerosol particles in situ and in real time. We have developed and characterized an optical counting method, based on Mie scattering, to detect and count particles in the aforementioned 10-100 µm size range. The method uses a pair of laser beams to determine particle (aerodynamic) diameter based on time-of-flight of measurements of falling particles. We have also developed and integrated a laser induced breakdown spectroscopy (LIBS) diagnostic capability to the earlier DRIPS instrument. With appropriate triggering, the LIBS diagnostic uses a pulsed laser beam to form microplasmas by illuminating the falling particles, the spectra of which allow composition measurements of constituent atoms within the particles based on known emission wavelengths. We have developed and optimized methods to determine composition of particles with low rates of false-positives and demonstrated the methods for four particle compositions. Overall, our research has made significant progress towards the development of a portable, direct-reading instrument that can characterize both the size and chemical composition of inhalable aerosol hazards (approx. 10-100 µm diameter particles) in the workplace. [Description provided by NIOSH]
• Subjects:
  Aerosols Occupational Exposure Occupational Health Safety
• Keywords:
  Aerosol Sampling Direct-reading Methods Exposure Assessment Mobile Equipment Occupational Exposure Particle Counters Particle Size Analysis Sampling Equipment Spectroscopes
• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  Colorado ; OSHA Region 8
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-11
• NIOSHTIC Number:
  nn:20065536
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R21-OH-011287, 2021 Dec; :1-11
• Contact Point Address:
  Azer Yalin, PhD, Colorado State University-Fort Collins 2002 Campus Delivery, Fort Collins, CO 80523-2002
• Email:
  azer.yalin@colostate.edu
• Federal Fiscal Year:
  2022
• NORA Priority Area:
  Manufacturing
• Performing Organization:
  Colorado State University
• Peer Reviewed:
  False
• Start Date:
  20180901
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20200831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1915fe9324d1a25d5dd06be206b40659c8ecdebb01fada59a3a0d2078be4c48c876d7064a14f8ad66d66156cef717d81db786ad0c9c9f1964ca7122da3612fa2
• Download URL:
  https://stacks.cdc.gov/view/cdc/219114/cdc_219114_DS1.pdf
• File Type:
  [PDF - 547.72 KB ]