A Pilot Study of Nanoparticle Levels and Field Evaluation of N95 Filtering Facepiece Respirators on Construction Sites

Details

• Personal Author:
  Adhikari A ; Mirta A ; Rashidi A
• Description:
  Little attention has been paid to the generated submicron ultrafine and nanoparticles and their exposure levels on construction jobsites. This information is needed because cytotoxicity of nanoparticles is well known now. In addition, the performance of particulate respirators generally used by construction workers has never been evaluated in field conditions against ultrafine and nano-sized particles. We hypothesized that workers on construction jobsites are exposed to high levels of nanoparticles and current NIOSH-recommended N95 respirators may not provide them adequate protection against aerosolized nanoparticles. Our exposure assessments of ultrafine and nanoparticles on several construction sites using SMPS nanoparticle counters showed that particle mass concentrations ranged between 1.41 and 99.96 microg/m3. The real-time filtration efficiency of N95 respirators against nanoparticles greater than 20.5 nm in aerodynamic diameter was often less than 95%. When surface electrostatic charge was removed in N95 respirators by isopropanol treatment, the filtration efficiency of larger nanoparticles dropped compared to smaller nanoparticles of <27.5 nm sizes. Key findings: a. Different construction tasks can release different levels of airborne nanoparticles and ultrafine particles of 11.5 - 365.2 nm sizes ranging from 103 to 105 particles/cm3 (number concentration) and 1.41 to 99.96 mcirog/m3 (mass concentrations). b. The field experiments in this study showed that concrete blasting and grinding activities can release more nanoparticles than wood building framework construction and soil moving activities on construction sites. c. N95 respirators may not provide 95% protection for all categories of nanoparticles and generally 95% protection is achievable for particles of 11.5 to 20.5 nm sizes. d. Foldable N95 respirators were found to be less efficient than pleated N95 respirators in filtering nanoparticles mostly in the soil moving site and the wooden building framework construction site. This trend was, however, not observed on the concrete blasting/grinding site possibly due to different electrostatic and physical properties of nanoparticles generated in this site. e. When electrostatic charges were removed from mask fibers by isopropanol treatment, filtration efficiency dropped, but mostly for larger nanoparticles rather than smaller ones. f. Morphology of nanoparticles differed by task. Porous silicious nanoparticles, however, were not prevalent in the outdoor concrete blasting and grinding site as anticipated. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollutants, Occupational Construction Industry Filtration Occupational Exposure Occupational Health Particulate Matter Personal Protective Equipment Respiratory Protective Devices Safety Workplace

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• Keywords:
  Aerosol Particles Airborne Particles Blasting Concretes Construction Construction-industry Construction-workers Electrical Charge Electrostatic Fields Employee Exposure Equipment Reliability Grinding Equipment N95 Filtering Facepiece Respirators Nanoparticles Nanotechnology Particle Aerodynamics Particle Diameter Particle Size Particulates Performance Capability Personal Protective Equipment PPE Respiratory Protection Ultrafine Particles Work Environment

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• Publisher:
  CPWR-The Center for Construction Research and Training
• Document Type:
  Text
• Funding:
  Cooperative Agreement
• Genre:
  Field Study
• Place as Subject:
  Georgia ; Maryland ; OSHA Region 3 ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-17
• NIOSHTIC Number:
  nn:20052110
• Citation:
  Silver Spring, MD: CPWR-The Center for Construction Research and Trainings, 2018 Apr; :1-17
• Contact Point Address:
  Atin Adhikari, Ph.D., Georgia Southern University, PO Box 8015, Statesboro, GA 30460-8015
• Federal Fiscal Year:
  2018
• NORA Priority Area:
  Construction
• Performing Organization:
  CPWR - Center for Construction Research and Training
• Peer Reviewed:
  False
• Start Date:
  20090901
• Source Full Name:
  A pilot study of nanoparticle levels and field evaluation of N95 filtering facepiece respirators on construction sites
• End Date:
  20240831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:cba7246708fe3796a89c7b735d6a65d3f66503ee3c989894bd8b64cf49459f9f0f119796c2c50a1c3f80b889516f4f1fa3116ec59dd26aaf0984ac4e6fcb465a
• Download URL:
  https://stacks.cdc.gov/view/cdc/211701/cdc_211701_DS1.pdf
• File Type:
  [PDF - 580.16 KB ]