Experimental and Theoretical Study of Early Detection and Isolation of Influenza

Details

• Personal Author:
  Celik I ; Fisher MA ; Khakoo R
• Description:
  The overall goal of this study was to characterize aerosol droplets produced by human subjects while coughing, and then use this information to better understand the mechanisms of influenza transmission and make recommendations for reducing the extent of influenza transmission. A more specific goal was to quantify the extent of viral-laden aerosols in health care settings by using experimental and theoretical techniques. Aerosols produced by 16 adults coughing were measured using a real-time droplet nuclei measurement system. The results of these experiments were compared with a fluid dynamics model developed for simulating the air flow and particle dynamics in the larynx, and to predict the number and size distribution of the aerosols generated during coughing. The droplet size distribution obtained by this model was consistent with the measurements. Furthermore, a saline solution containing the FluMist influenza vaccine was aerosolized by an apparatus capable of reproducing the flow rate and particle size distribution of a human cough into a simulated medical examination room. These flu-laden particles were collected using NIOSH two-stage cyclone bio-aerosol samplers, while particle concentrations were monitored using an optical particle counter. Airborne influenza and RSV viral particles were collected in a hospital emergency department and in an urgent care medical clinic using mobile and stationary samplers during the winter months. Further tests indicated occurrence of viruses within the particles collected. In another study, a breathing manikin representing a healthcare worker was used to test the ability of masks and respirators to block infectious aerosols. Small aerosols were effectively blocked by N95 respirators but not so well by surgical masks. Additionally, the transport and dispersion of cough generated aerosols in the NIOSH simulated medical room, the WVU Ruby Memorial Hospital children's waiting room, and the WVU urgent care waiting and examination rooms were numerically simulated using a commercially available CFD software called Ansys-Fluent. These simulations showed the importance of ventilation on reducing the concentration of airborne particles. A numerical model was also developed in Matlab to investigate the evaporation rate, velocity, temperature and position of a sputum droplet introduced into a turbulent jet representing a human cough issued into a stagnant air room. The evaporation of water, saline solutions, and saliva was also investigated experimentally and successfully compared to theoretical and numerical models. Another semi-empirical model was developed to predict the variation of airborne virus viability with relative humidity and time. Weather measurements in different US cities and the number of influenza like illness cases reported in those cities are used to correlate the indoor relative humidity and the ILI cases in temperate regions. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Movements Communicable Diseases Health Personnel Influenza, Human Occupational Health Personal Protective Equipment Respiratory Protective Devices Safety Ventilation Viral Diseases

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• Keywords:
  Aerosol Particles Air Flow Face Masks Health Care Workers Infectious Diseases Influenza Models N95 Filtering Facepiece Respirators Particle Aerodynamics Respirators Viral Diseases

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• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  OSHA Region 3 ; West Virginia
• 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:
  1-47
• NIOSHTIC Number:
  nn:20060582
• NTIS Accession Number:
  PB2021-100198
• 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, R01-OH-009037, 2010 Aug; :1-47
• Contact Point Address:
  Dr. Ismail Celik, P.I., West Virginia University, College of Engineering and Mineral Resources, Department of Mechanical and Aerospace Engineering, Engineering Sciences Building, Room 307, Morgantown, WV 26506-6106
• Email:
  Ismail.Celik@mail.wvu.edu
• Federal Fiscal Year:
  2010
• Performing Organization:
  West Virginia University
• Peer Reviewed:
  False
• Start Date:
  20060801
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20100831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4efbea31eca08fc91d6d07b1d65159278ca107fd9db3b256f76d7a8b508aeb99bdf64f8fa42d66a24b6e34a858dd7462a3c63e14ae60bdf5a135653780158e20
• Download URL:
  https://stacks.cdc.gov/view/cdc/219003/cdc_219003_DS1.pdf
• File Type:
  [PDF - 1.23 MB ]