Integrating IAQ control strategies to reduce the risk of asymptomatic SARS CoV-2 infections in classrooms and open plan offices

Zhang, Jensen

doi:10.1080/23744731.2020.1794499

Cited by 57 publications

(59 citation statements)

References 17 publications

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“…Social distancing (91) and well-fitting masks (121) help to reduce aerosol transmission as well as large droplet transmission, but other precautions specific to aerosols are also needed. These could include operational changes to ventilation systems in public buildings and public transport (98)(99)(100)(101), UV lamps in some indoor locations (112,116,117), and attention to wind (61) and sunlight (7) in outdoor settings.…”

Section: Discussionmentioning

confidence: 99%

“…To minimize infection, heating and ventilation in public buildings and in transportation may need to be modified or operated in different ways from those intended at installation (87). This provides opportunities for rapid, simple interventions (17,(99)(100)(101)(102). These were noted by the building services industry at an early stage of the pandemic, and detailed practical guidance is available for an American context (101,102) and from trade associations in Europe (103,104) and the UK (105).…”

Section: Implications For Ventilationmentioning

confidence: 99%

“…This provides opportunities for rapid, simple interventions (17,(99)(100)(101)(102). These were noted by the building services industry at an early stage of the pandemic, and detailed practical guidance is available for an American context (101,102) and from trade associations in Europe (103,104) and the UK (105). Hospital ventilation is not considered here because it is designed to prevent infection (86).…”

Section: Implications For Ventilationmentioning

confidence: 99%

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Aerosol Transmission of SARS-CoV-2: Physical Principles and Implications

Jarvis

2020

Front. Public Health

127

116

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Evidence has emerged that SARS-CoV-2, the coronavirus that causes COVID-19, can be transmitted airborne in aerosol particles as well as in larger droplets or by surface deposits. This minireview outlines the underlying aerosol science, making links to aerosol research in other disciplines. SARS-CoV-2 is emitted in aerosol form during normal breathing by both asymptomatic and symptomatic people, remaining viable with a half-life of up to about an hour during which air movement can carry it considerable distances, although it simultaneously disperses. The proportion of the droplet size distribution within the aerosol range depends on the sites of origin within the respiratory tract and on whether the distribution is presented on a number or volume basis. Evaporation and fragmentation reduce the size of the droplets, whereas coalescence increases the mean droplet size. Aerosol particles containing SARS-CoV-2 can also coalesce with pollution particulates, and infection rates correlate with pollution. The operation of ventilation systems in public buildings and transportation can create infection hazards via aerosols, but provides opportunities for reducing the risk of transmission in ways as simple as switching from recirculated to outside air. There are also opportunities to inactivate SARS-CoV-2 in aerosol form with sunlight or UV lamps. The efficiency of masks for blocking aerosol transmission depends strongly on how well they fit. Research areas that urgently need further experimentation include the basis for variation in droplet size distribution and viral load, including droplets emitted by “superspreader” individuals; the evolution of droplet sizes after emission, their interaction with pollutant aerosols and their dispersal by turbulence, which gives a different basis for social distancing.

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Section: Discussionmentioning

confidence: 99%

Section: Implications For Ventilationmentioning

confidence: 99%

Section: Implications For Ventilationmentioning

confidence: 99%

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Aerosol Transmission of SARS-CoV-2: Physical Principles and Implications

Jarvis

2020

Front. Public Health

127

116

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“…The spread of pathogen-laden aerosols is significantly affected by the complicated and transient interactions among the respiratory flows and thermal plumes of occupants, and ventilation flow, which results in the spatially and temporally non-uniform distribution of pathogen-laden aerosols [ 10 ]. Since occupants generally spend more than 90% time conducting indoor activities, indoor ventilation is one of the most effective engineering solutions for reducing airborne transmission by diluting the pathogen-laden aerosols with pathogen-free air [ 11 , 12 ]. Airflow patterns of advanced ventilation with non-uniform aerosol distribution can more effectively reduce airborne transmission risk.…”

Section: Introductionmentioning

confidence: 99%

Dilution-based evaluation of airborne infection risk - Thorough expansion of Wells-Riley model

Sheng

Lin

2021

Building and Environment

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Evaluation of airborne infection risk with spatial and temporal resolutions is indispensable for the design of proper interventions fighting infectious respiratory diseases ( e.g. , COVID-19), because the distribution of aerosol contagions is both spatially and temporally non-uniform. However, the well-recognized Wells-Riley model and modified Wells-Riley model ( i.e. , the rebreathed-fraction model) are limited to the well-mixed condition and unable to evaluate airborne infection risk spatially and temporally, which could result in overestimation or underestimation of airborne infection risk. This study proposes a dilution-based evaluation method for airborne infection risk. The method proposed is benchmarked by the Wells-Riley model and modified Wells-Riley model, which indicates that the method proposed is a thorough expansion of the Wells-Riley model for evaluation of airborne infection risk with both spatial and temporal resolutions. Experiments in a mock hospital ward also demonstrate that the method proposed effectively evaluates the airborne infection risk both spatially and temporally. The proposed method is convenient to implement for the development of healthy built environments.

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“…We assume that the infector densities are 0.5 people per cell and 0.1 people per cell in the Potential Contaminated Zone and Contaminated Zone, respectively. The q is set as 100 quanta/s ( Zhang, 2020 ), the occupants’ pulmonary ventilation p is set at 0.36 m 3 /h, and the ACH is set as 12.…”

mentioning

confidence: 99%