The impact of air change rate on the air quality of surgical microenvironment in an operating room with mixing ventilation

Zhang, Yixian; Cao, Guangyu; Guo, Feng; Xue, Kai; Pedersen, Christoffer; Mathisen, Hans Martin; Stenstad, Liv-Inger; Skogås, Jan Gunnar

doi:10.1016/j.jobe.2020.101770

Cited by 17 publications

(14 citation statements)

References 18 publications

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“…Small droplet (10 μm) floated farther with airflow, and the settlement effect of large droplet (100 μm) was more obvious. Zhang et al [ 84 ] studied the relationship between ACH and pollutant concentration in the operating room, and found that higher ACH significantly reduced pollutant concentration and wound exposure risk. A higher ventilation rate could better dilute the concentration of pathogens and reduce the risk of airborne transmission [ 85 ].…”

Section: Impacts On Thermal Comfort Air Quality and Virus Spread Controlmentioning

confidence: 99%

A review of different ventilation modes on thermal comfort, air quality and virus spread control

Fan

Wang

et al. 2022

Building and Environment

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In the era of Corona Virus Disease 2019 (COVID-19), inappropriate indoor ventilation may turn out to be the culprit of microbial contamination in enclosed spaces and deteriorate the environment. To collaboratively improve the thermal comfort, air quality and virus spread control effect, it was essential to have an overall understanding of different ventilation modes. Hence, this study reviewed the latest scientific literature on indoor ventilation modes and manuals of various countries, identified characteristics of different ventilation modes and evaluated effects in different application occasions, wherefore to further propose their main limitations and solutions in the epidemic era. For thermal comfort, various non-uniform ventilation modes could decrease the floor-to-ceiling temperature difference, draft rate or PPD by 60%, 80% or 33% respectively, or increase the PMV by 45%. Unsteady ventilation modes (including intermittent ventilation and pulsating ventilation) could lower PPD values by 12%–37.8%. While for air quality and virus spread control, non-uniform ventilation modes could lower the mean age of air or contaminants concentration by 28.3%–47% or 15%–47% respectively, increase the air change efficiency, contaminant removal effectiveness or protection efficiency by 6.6%–10.4%, 22.6% or 14%–50% respectively. Unsteady ventilation mode (pulsating ventilation) could reduce the peak pollutant concentration and exposure time to undesirable concentrations by 31% and 48% respectively. Non-uniform modes and unsteady modes presented better performance in thermal comfort, air quality and virus spread control, whereas relevant performance evaluation indexes were still imperfect and the application scenarios were also limited.

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Section: Impacts On Thermal Comfort Air Quality and Virus Spread Controlmentioning

confidence: 99%

A review of different ventilation modes on thermal comfort, air quality and virus spread control

Fan

Wang

et al. 2022

Building and Environment

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“…On the contrary, recommended air change rate from standards or guidelines were frequently applied in risk assessment, which cannot represent the real condition. In reality, ventilation rates are influenced by multiple factors, including the ventilation modes, location and size of the openings, heat source within the building, system operation & management and so on [ 32 , 33 ]. When evaluating infection risks of COVID-19, it is important to acquire the actual ventilation rate.…”

Section: Introductionmentioning

confidence: 99%

Study on ventilation rates and assessment of infection risks of COVID-19 in an outpatient building

Tang

2021

Journal of Building Engineering

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A modified Wells-Riley model combining the airborne route and close contact route was proposed to predict the infection risks of coronavirus disease 2019 (COVID-19) in main functional spaces of an outpatient building in Shenzhen, China. The personnel densities and ventilation rates in the 20 waiting rooms, outpatient hall and hospital street were on-site measured. The average fresh air volume per person and occupant area per person in the 20 waiting rooms were 77.6 m 3 /h and 6.47 m 2 /per, satisfied with the Chinese standard. The average waiting time of the occupants was 0.69 h. Thus, assuming the proportion of infected people in the outpatient building was 2%, the daily average infection probabilities of COVID-19 in the 20 waiting rooms were 0.19–1.88% with a reasonable setting of the quanta produced by an infector ( q = 45 quanta/h) and the effective exposure dose of pathogen per unit close contact time ( β = 0.05 h −1 ). The design of the semi-closed hospital street with a height of 24 m improved its natural ventilation with a fresh air volume per person of 70–185 m 3 /h and further dilute the viral aerosol and decreased the infection risk to a negligible level (i.e., below 0.04% with an infector proportion of 2%). The assessment method provides real-time prediction of indoor infection risk and good assist in spread control of COVID-19.

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“…Although determination of the infection risk represented by aerosolized material is challenging, dental aerosols in everyday clinical practice should be controlled to the maximum extent. Common practices for reducing the health‐related hazard associated with (bio)aerosol emissions, apart from the use of personal protective equipment, include the pre‐procedural antiseptic mouth rinsing, the minimization of biofilm formation in dental unit water lines and improvement of the indoor air quality by efficient air exchange rates and ventilation of the operation rooms 29–33 …”

Section: Introductionmentioning

confidence: 99%

“…Common practices for reducing the health-related hazard associated with (bio)aerosol emissions, apart from the use of personal protective equipment, include the pre-procedural antiseptic mouth rinsing, the minimization of biofilm formation in dental unit water lines and improvement of the indoor air quality by efficient air exchange rates and ventilation of the operation rooms. [29][30][31][32][33] To our knowledge, there is no previous detailed measurement of particulate matter coupled with in-depth analysis of airborne bacterial diversity in a dental clinic. The primary objective of the present work was to conduct comprehensive measurements of the particle number size distribution (10 nm-10 μm) accompanied with bioaerosol sampling during real working conditions with subsequent evaluation of the impact of dental procedures to both quantities in terms of indoor air quality for the dental clinic and inhalation levels for the personnel.…”

mentioning

confidence: 99%

Airborne particles and microorganisms in a dental clinic: Variability of indoor concentrations, impact of dental procedures, and personal exposure during everyday practice

et al. 2021

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Studying air quality in healthcare facilities comprises of identification of the contaminant sources, their dispersion, and impact on indoor air. 1,2 Considering as ultimate purpose pathogen mitigation, minimization of the acquired infections both for the patients and the personnel is a challenging issue, 3,4 not only because of the direct contact with the contaminant sources but also due to their great variability in their characteristics and properties.Airborne particulate contaminants consist mainly of aerosols and/or particles of biological matter, that is, bioaerosols. Airborne aerosol properties vary considerably depending on their size and chemical/biological composition. 5 In turn, their size and composition are governed by their origin (natural environment, anthropogenic

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The impact of air change rate on the air quality of surgical microenvironment in an operating room with mixing ventilation

Cited by 17 publications

References 18 publications

A review of different ventilation modes on thermal comfort, air quality and virus spread control

A review of different ventilation modes on thermal comfort, air quality and virus spread control

Study on ventilation rates and assessment of infection risks of COVID-19 in an outpatient building

Airborne particles and microorganisms in a dental clinic: Variability of indoor concentrations, impact of dental procedures, and personal exposure during everyday practice

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