Reductions in Exposures to Simulated Respiratory Aerosols by a Ceiling-Mounted HEPA Air Filtration Unit

Details

• Personal Author:
  Blanchere, Francoise M. ; Boots T ; Coyle JP ; Derk RC ; Lindsley, William G. ; Martin SB Jr. ; Mead, Kenneth R. ; Noti JD
• Description:
  Supplemental air filtration can reduce indoor exposure to hazardous aerosols without requiring modifications to building heating, ventilation, and air conditioning (HVAC) systems. Portable air cleaners were widely used during the COVID-19 pandemic, but they can have drawbacks including noise, space obstruction, and electrical cord safety considerations. Built-in air filtration units are an alternative to provide supplemental air filtration. We conducted a case study of a HEPA air filtration unit installed in the ceiling of a conference room using radial laminar flow or square cone ceiling air supply diffusers. A respiratory aerosol simulator exhaled aerosol particles (0.3 to 10 µm), and the particle concentrations were measured in the personal breathing zones of three breathing simulators representing a speaker and two meeting participants. For the speaker, using one square cone supply diffuser reduced inhalation exposure by 49 % to 81 % while using two square supply diffusers reduced exposure by 68 % to 93 %. For the participants, the exposures were reduced by 23 % to 64 % with one square supply diffuser and 58 % to 86 % with two square supply diffusers. Results when using the radial supply air diffusers were more variable and more dependent on the simulator layouts. Combining the use of cloth face masks on all simulators with the ceiling unit reduced the speaker's exposure by 87 % to 99 % and the participants' exposures by 84 % to 97 %. In most cases the ceiling air filtration unit provided protection against simulated respiratory aerosol particles comparable to that seen previously with portable air cleaners. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollution, Indoor Communicable Diseases Occupational Health Personal Protective Equipment Respiratory Protective Devices Safety Ventilation
• Keywords:
  Aerosol Particles Air Filtration Author Keywords: Aerosol Transmission Disease Transmission Face Masks HEPA Filters High-efficiency Particulate Air Filters Indoor Air Quality Infectious Diseases Infectious Disease Transmission
• ISSN:
  0360-1323
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Chicago Region [OSHA] ; Ohio ; Philadelphia Region [OSHA] ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; DSI - Division of Science Integration ; RHD - Respiratory Health Division ; DFSE - Division of Field Studies and Engineering
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  271
• NIOSHTIC Number:
  nn:20070483
• Citation:
  Build Environ 2025 Mar; 271:112611
• Contact Point Address:
  William G. Lindsley, Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 1000 Frederick Lane, M/S 4020, Morgantown, WV 26508-5402, USA
• Email:
  wlindsley@cdc.gov
• Federal Fiscal Year:
  2025
• Peer Reviewed:
  True
• Source Full Name:
  Building and Environment
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:aa441cf64633d9ce5f6f557e89d8f0d03f59fe9e8ad49814ec6fc654a7d063b923fea4b0c40359662c48e29c89ed3db402c68725c6c17e7b947b97a8019b45b9
• Download URL:
  https://stacks.cdc.gov/view/cdc/208684/cdc_208684_DS1.pdf
• File Type:
  [PDF - 3.24 MB ]