Thornton Gail M, Fleck Brian A, Kroeker Emily, Dandnayak Dhyey, Fleck Natalie, Zhong Lexuan, Hartling Lisa
Faculty of Engineering, Department of Mechanical Engineering, University of Alberta, Edmonton, Canada.
Faculty of Medicine & Dentistry, Department of Pediatrics, University of Alberta, Edmonton, Canada.
PLOS Glob Public Health. 2022 Jul 5;2(7):e0000552. doi: 10.1371/journal.pgph.0000552. eCollection 2022.
Aerosol transmission has been a pathway for the spread of many viruses. Similarly, emerging evidence has determined aerosol transmission for Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) and the resulting COVID-19 pandemic to be significant. As such, data regarding the effect of Heating, Ventilation, and Air Conditioning (HVAC) features to control and mitigate virus transmission is essential. A systematic review was conducted to identify and comprehensively synthesize research examining the effectiveness of ventilation for mitigating transmission of coronaviruses. A comprehensive search was conducted in Ovid MEDLINE, Compendex, Web of Science Core to January 2021. Study selection, data extraction, and risk of bias assessments were performed by two authors. Evidence tables were developed and results were described narratively. Results from 32 relevant studies showed that: increased ventilation rate was associated with decreased transmission, transmission probability/risk, infection probability/risk, droplet persistence, virus concentration, and increased virus removal and virus particle removal efficiency; increased ventilation rate decreased risk at longer exposure times; some ventilation was better than no ventilation; airflow patterns affected transmission; ventilation feature (e.g., supply/exhaust, fans) placement influenced particle distribution. Few studies provided specific quantitative ventilation parameters suggesting a significant gap in current research. Adapting HVAC ventilation systems to mitigate virus transmission is not a one-solution-fits-all approach. Changing ventilation rate or using mixing ventilation is not always the only way to mitigate and control viruses. Practitioners need to consider occupancy, ventilation feature (supply/exhaust and fans) placement, and exposure time in conjunction with both ventilation rates and airflow patterns. Some recommendations based on quantitative data were made for specific scenarios (e.g., using air change rate of 9 h-1 for a hospital ward). Other recommendations included using or increasing ventilation, introducing fresh air, using maximum supply rates, avoiding poorly ventilated spaces, assessing fan placement and potentially increasing ventilation locations, and employing ventilation testing and air balancing checks. Trial registration: PROSPERO 2020 CRD42020193968.
气溶胶传播一直是许多病毒传播的一种途径。同样,新出现的证据表明,严重急性呼吸综合征冠状病毒2(SARS-CoV-2)和气溶胶传播导致的新型冠状病毒肺炎大流行具有重要意义。因此,关于供暖、通风和空调(HVAC)功能对控制和减轻病毒传播影响的数据至关重要。进行了一项系统综述,以识别和全面综合研究通风对减轻冠状病毒传播有效性的研究。截至2021年1月,在Ovid MEDLINE、Compendex、科学网核心数据库中进行了全面检索。由两位作者进行研究选择、数据提取和偏倚风险评估。编制了证据表,并对结果进行了叙述性描述。32项相关研究的结果表明:通风率增加与传播减少、传播概率/风险、感染概率/风险、飞沫持久性、病毒浓度降低以及病毒清除和病毒颗粒清除效率提高相关;通风率增加在较长暴露时间下降低了风险;有通风总比没有通风好;气流模式影响传播;通风功能(如送风/排风、风扇)的位置影响颗粒分布。很少有研究提供具体的定量通风参数,表明当前研究存在重大差距。调整HVAC通风系统以减轻病毒传播不是一种适用于所有情况的方法。改变通风率或使用混合通风并不总是减轻和控制病毒的唯一方法。从业者需要结合通风率和气流模式,考虑占用情况、通风功能(送风/排风及风扇)的位置以及暴露时间。针对特定场景(如医院病房使用9次/小时的换气次数),根据定量数据提出了一些建议。其他建议包括使用或增加通风、引入新鲜空气、使用最大送风速率、避免通风不良的空间、评估风扇位置并可能增加通风位置,以及进行通风测试和空气平衡检查。试验注册:PROSPERO 2020 CRD42020193968。