Efficacy of Portable Air Cleaners and Masking for Reducing Indoor Exposure to Simulated Exhaled SARS-CoV-2 Aerosols — United States, 2021

Details

• Journal Article:
  Morbidity and Mortality Weekly Report (MMWR)
• Personal Author:
  Beezhold, Donald H. ; Blachere, Francoise M. ; Boots, Theresa ; Brooks, John T. ; Coyle, Jayme P. ; Derk, Raymond C. ; Lindsley, William G. ; Martin, Stephen B. Jr. ; Mead, Kenneth R. ; Noti, John D.
• Corporate Authors:
  National Institute for Occupational Safety and Health. Health Effects Laboratory Division ; National Institute for Occupational Safety and Health. Respiratory Health Division ; National Institute for Occupational Safety and Health. Division of Field Studies and Engineering ; CDC COVID-19 Response Team
• Description:
  What is already known about this topic? Ventilation systems can be supplemented with portable high efficiency particulate air (HEPA) cleaners to reduce the number of airborne infectious particles.
  
  What is added by this report? A simulated infected meeting participant who was exhaling aerosols was placed in a room with two simulated uninfected participants and a simulated uninfected speaker. Using two HEPA air cleaners close to the aerosol source reduced the aerosol exposure of the uninfected participants and speaker by up to 65%. A combination of HEPA air cleaners and universal masking reduced exposure by up to 90%.
  
  What are the implications for public health practice? Portable HEPA air cleaners can reduce exposure to simulated SARS-CoV-2 aerosols in indoor environments, especially when combined with universal masking.
  
  SARS-CoV-2, the Virus that causes COVID-19, can be spread by exposure to droplets and aerosols of respiratory fluids that are released by infected persons when they cough, sing, talk, or exhale. To reduce indoor Transmission of SARS-CoV-2 between persons, CDC recommends measures including physical distancing, universal masking (the use of face masks in public places by everyone who is not fully vaccinated), and increased room ventilation (1). Ventilation systems can be supplemented with portable high efficiency particulate air (HEPA) cleaners* to reduce the number of infectious particles in the air and provide enhanced protection from Transmission between persons (2); two recent reports found that HEPA air cleaners in classrooms could reduce overall aerosol particle concentrations by ≥80% within 30 minutes (3,4). To investigate the effectiveness of portable HEPA air cleaners and universal masking at reducing exposure to exhaled aerosol particles, the investigation team used respiratory simulators to mimic a person with COVID-19 and other, uninfected persons in a conference room. The addition of two HEPA air cleaners that met the Environmental Protection Agency (EPA)–recommended clean air delivery rate (CADR) (5) reduced overall exposure to simulated exhaled aerosol particles by up to 65% without universal masking. Without the HEPA air cleaners, universal masking reduced the combined mean aerosol concentration by 72%. The combination of the two HEPA air cleaners and universal masking reduced overall exposure by up to 90%. The HEPA air cleaners were most effective when they were close to the aerosol source. These findings suggest that portable HEPA air cleaners can reduce exposure to SARS-CoV-2 aerosols in indoor environments, with greater reductions in exposure occurring when used in combination with universal masking.
  
  Suggested citation for this article: Lindsley WG, Derk RC, Coyle JP, et al. Efficacy of Portable Air Cleaners and Masking for Reducing Indoor Exposure to Simulated Exhaled SARS-CoV-2 Aerosols — United States, 2021. MMWR Morb Mortal Wkly Rep. ePub: 2 July 2021.
  
  mm7027e1.htm?s_cid=mm7027e1_w
  
  mm7027e1-H.pdf
  
  
• Subjects:
  Air Conditioning Air Pollution, Indoor Coronavirus COVID-19 Disease Transmission, Infectious/Prevention & Control Particulate Matter Personal Protective Equipment Respiratory Protective Devices Ventilation
• Source:
  MMWR: Morbidity Mortal Weekly Rep. 2021; v. 70 Early Release
• Series:
  Weekly Report: Morbidity and Mortality Weekly Report (MMWR)
• ISSN:
  0149-2195 (print) ; 1545-861X (digital)
• Publisher:
  Centers for Disease Control and Prevention (CDC) (U.S.)
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  United States
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; RHD - Respiratory Health Division ; DFSE - Division of Field Studies and Engineering
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  5 pdf pages
• Volume:
  70
• NIOSHTIC Number:
  nn:20063015
• Collection(s):
  National Institute for Occupational Safety and Health Morbidity and Mortality Weekly Report (MMWR)
• Main Document Checksum:
  urn:sha-512:b7e66612eed6cf3bd7f45b918e2f4bdb5573a9904e58dde006cb997c1011e373fa8cb698c31e0b41541dcfa45861213819e21ff11f3b29deed30c4d6c9400a18
• Download URL:
  https://stacks.cdc.gov/view/cdc/107669/cdc_107669_DS1.pdf
• File Type:
  [PDF - 477.29 KB ]