Current Exposure Guidelines for Particulates Not Otherwise Classified or Regulated: History and Rationale

Details

• Personal Author:
  Hearl, Frank J.
• Description:
  Exposure limits and guidelines for particles not otherwise classified or regulated (PNOC/R) evolved from several important studies of pneumoconiosis performed early in the 20th century. These studies indicated that exposure to dust concentrations of less than 50 million particles per cubic foot (mppcf) and with low crystalline silica concentrations did not appear to lead to the development of disabling lung disease. Consequently, dusts containing less than 5 percent crystalline silica were termed "nuisance dusts," and an exposure limit of 50 mppcf was recommended. With the advent of mass sampling technology and the ability to sample directly for respirable dust, exposure limits migrated to total and respirable nuisance dust exposure limits of 15 and 5 mg/rn3, respectively, for dusts containing less than 1 percent crystalline silica. Regulatory exposure limits were established by incorporating these exposure guidelines that were in existence when the enabling legislation was enacted. Changes to regulatory limits have lagged behind threshold limit values adopted by the American Conference of Governmental Industrial Hygienists (ACGIH), which have been updated based on current research. Current ACGIH recommendations for inhalable and respirable dusts are 10 and 3 mg/m3, respectively. Recent studies of ultrafine particulate and toxicological investigation of the pulmonary overload phenomena from exposure to PNOC/R indicate that exposure to these materials at sufficiently high concentrations can cause irreversible changes to the airways. The term "nuisance dust" was inaccurate, so the terminology of PNOC/R was substituted as a better descriptor for dusts without component-specific exposure limits. Further reductions in exposure limits and guidelines have been proposed for control of occupational exposure to PNOC/R. These proposals are motivated by increasing recognition that clinically significant chronic air-ways obstruction is caused by occupational dust exposure. [Description provided by NIOSH]
• Subjects:
  Aerosols Dust Environmental Monitoring Inhalation Exposure Occupational Health Particulate Matter Respiratory System Safety
• Keywords:
  Dust-counting Dust-exposure Exposure-assessment Exposure-levels Exposure-limits Exposure-methods Inhalants Inhalation-studies Nanotechnology Particulate-dust Particulates Threshold-limit-values

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• ISSN:
  1047-322X
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DRDS - Division of Respiratory Disease Studies
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  13
• Issue:
  8
• NIOSHTIC Number:
  nn:20025809
• Citation:
  Appl Occup Environ Hyg 1998 Aug; 13(8):608-612
• Contact Point Address:
  Frank J. Hearl, Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, U.S. Public Health Service, 1095 Willowdale Road, Morgantown, WV 26505-2888
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  1998
• Peer Reviewed:
  True
• Source Full Name:
  Applied Occupational and Environmental Hygiene
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:492ee2e226a2990f16cbde9550b86714e916c8938f2d04a16007448f9c58d593326146a93a4df5a5e03eebea51e110a9bbcfd8475e7241897cd301ecb26156bd
• Download URL:
  https://stacks.cdc.gov/view/cdc/197026/cdc_197026_DS1.pdf
• File Type:
  [PDF - 716.97 KB ]