A paradigm shift to combat indoor respiratory infection

Morawska, Lidia; Allen, Joseph G.; Bahnfleth, William P.; Bluyssen, Philomena M.; Boerstra, Atze; Buonanno, Giorgio; Cao, Junji; Dancer, Stephanie J.; Floto, Andres; Franchimon, F Francesco; Greenhalgh, Trisha; Haworth, Charles; Hogeling, Jaap; Isaxon, Christina; Jimenez, José L.; Kurnitski, Jarek; Li, Yuguo; Loomans, Mglc Marcel; Marks, Guy B.; Marr, Linsey C.; Mazzarella, Livio; Melikov, Arsen Krikor; Miller, Shawn W.; Milton, Donald K.; Nazaroff, William W.; Nielsen, Peter; Noakes, Catherine; Peccia, Jordan; Prather, Kim; Querol, Xavier; Sekhar, Chandra; Seppänen, Olli; Tanabe, Shin Ichi; Tang, Julian W.; Tellier, Raymond; Tham, Kwok Wai; Wargocki, Paweł; Wierzbicka, Aneta; Yao, Maosheng

doi:10.1126/science.abg2025

Cited by 246 publications

(195 citation statements)

References 12 publications

Supporting

Mentioning

192

Contrasting

Order By: Relevance

“…By removing airborne particles from a room, ventilation systems can reduce exposures that occur by inhalation of infectious aerosols, deposition on susceptible mucous membranes, or conveyance to mucous membranes by contaminated hands. However, in most nonclinical settings, ventilation systems are designed only with sufficient airflow to provide fresh air while maintaining comfortable temperature and humidity levels; these systems typically are not designed to have the much higher airflow rates that are needed to reduce disease transmission ( 8 ). During the ongoing pandemic, public health and professional organizations have provided guidance for increasing ventilation and air filtration to decrease the spread of SARS-CoV-2 ( 2 , 9 , 10 ).…”

Section: Discussionmentioning

confidence: 99%

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

Lindsley¹,

Derk²,

Coyle³

et al. 2021

MMWR Morb. Mortal. Wkly. Rep.

105

View full text Add to dashboard Cite

Release on the MMWR website (https://www.cdc.gov/mmwr).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.A breathing aerosol source simulator was used to mimic a meeting participant exhaling infectious particles (source), and three breathing simulators were used to mimic a speaker and two participants exposed to these aerosol particles (receivers) (Figure 1). The methods used were similar to those used in previous studies of aerosol dispersion and transport in indoor spaces (3,4,6). The simulators were placed in a 584-ft 2 (54-m 2 ) * HEPA air cleaners consist of a filter capable of removing ≥99.97% of particles from the air and a fan or blower to draw air through the filter. HEPA air cleaners are commercially available, relatively inexpensive, and easy to use.

show abstract

Section: Discussionmentioning

confidence: 99%

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

Lindsley¹,

Derk²,

Coyle³

et al. 2021

MMWR Morb. Mortal. Wkly. Rep.

105

View full text Add to dashboard Cite

show abstract

“…Just as there is ever-increasing pressure to act on climate change and urban air pollution, there are already strong calls for a fresh start in the way we think about indoor air, ventilation, and minimising the spread of infectious diseases (e.g. Morawska et al, 2021 ; WHO 2021a). Enhanced societal awareness of airborne particle issues has been aroused as never before by our chastening “anthropause for thought” experience of COVID-19, and is being aided by a better appreciation of modern bioaerosol science won from a spirited burst of open access publications (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Initial emphasis by influential health organisations on the role of fomite and near-range droplet transmission of SARS-CoV-2 has triggered a robust counter-response from the aerosol scientist community (e.g. Fenelly, 2020; Jimenez, 2020 , Morawska and Cao, 2020 , Morawska and Milton, 2020 , Prather et al, 2020 , Tang et al, 2020 , Tang et al, 2021a ,b; Bourouiba, 2021 , Greenhalgh et al, 2021 , Morawska et al, 2021 ; Randall et al, 2021). This response has increasingly insisted that many COVID-19 infections are caused by the inhalation of airborne virus-bearing particles rather than via fomite or gravity-driven droplet contact, and that future health and urban planning policies need seriously to concentrate on indoor air quality issues.…”

Section: Introductionmentioning

confidence: 99%

Aerosol transmission of human pathogens: From miasmata to modern viral pandemics and their preservation potential in the Anthropocene record

Moreno

Gibbons²

2022

Geoscience Frontiers

View full text Add to dashboard Cite

show abstract

“…The transmission of some diseases (such as tuberculosis, measles, and chickenpox) via airborne routes has long been recognized [ 1 ]. For some respiratory viruses, such as SARS-CoV (Severe Acute Respiratory Syndrome CoronaVirus), MERS-CoV (Middle-East Respiratory Syndrome CoronaVirus) and influenza virus, their likelihood of airborne transmission is based on various indirect evidence or spreading events [ [2] , [3] , [4] ]. Correspondingly, for the continued resurgence of coronavirus disease 2019 (COVID-19), the prospects of airborne transmission have again come under intense spotlight [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Aerosols from speaking can linger in the air for up to nine hours

Ding

Teo

Wan

et al. 2021

Building and Environment

View full text Add to dashboard Cite

Airborne transmission of respiratory diseases has been under intense spotlight in the context of coronavirus disease 2019 (COVID-19) where continued resurgence is linked to the relaxation of social interaction measures. To understand the role of speech aerosols in the spread of COVID-19 globally, the lifetime and size distribution of the aerosols are studied through a combination of light scattering observation and aerosol sampling. It was found that aerosols from speaking suspended in stagnant air for up to 9 h with a half-life of 87.2 min. The half-life of the aerosols declined with the increase in air change per hour from 28 to 40 min (1 h −1 ), 10–14 min (4 h −1 ), to 4–6 min (9 h −1 ). The speech aerosols in the size range of about 0.3–2 μm (after dehydration) witnessed the longest lifetime compared to larger aerosols (2–10 μm). These results suggest that speech aerosols have the potential to transmit respiratory viruses across long duration (hours), and long-distance (over social distance) through the airborne route. These findings are important for researchers and engineers to simulate the airborne dispersion of viruses in indoor environments and to design new ventilation systems in the future.

show abstract

A paradigm shift to combat indoor respiratory infection

Abstract: Building ventilation systems must get much better

Cited by 246 publications

References 12 publications

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

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

Aerosol transmission of human pathogens: From miasmata to modern viral pandemics and their preservation potential in the Anthropocene record

Aerosols from speaking can linger in the air for up to nine hours

Contact Info

Product

Resources

About