Portable HEPA Purifiers to Eliminate Airborne SARS‐CoV‐2: A Systematic Review

Abstract

Objective Current epidemiologic predictions of COVID-19 suggest that SARS-CoV-2 mitigation strategies must be implemented long-term. In-office aerosol-generating procedures pose a risk to staff and patients while necessitating examination room shutdown to allow aerosol decontamination by indwelling ventilation. This review summarizes the current state of knowledge on portable high-efficiency particulate air (HEPA) purifiers’ effectiveness in eliminating airborne SARS-CoV-2 from indoor environments. Data Sources Medline, Embase, Cochrane Databases, and the World Health Organization’s COVID-19 Global Literature on Coronavirus Disease. Review Methods Data sources were systematically searched for original English-language published studies indexed up to January 14, 2021 per the following search strategy: (“HEPA” OR “High-efficiency” OR “High-efficiency particulate air” OR “Efficiency particulate” OR “Purifier” OR “Filter” OR “Cleaner” OR “Filtration”) AND (“COVID” OR “COVID-19” OR “SARS-CoV-2” OR “Coronavirus”). Additional relevant studies were identified by searching the reference lists of included articles. Results Eleven published studies have evaluated the effectiveness of portable HEPA purifiers in eliminating airborne SARS-CoV-2 with relevantly sized surrogate particles. Ten studies evaluated aerosols and submicron particles similar in size to SARS-CoV-2 virions. In all studies, portable HEPA purifiers were able to significantly reduce airborne SARS-CoV-2-surrogate particles. The addition of portable HEPA purifiers augmented other decontamination strategies such as ventilation. Conclusion Experimental studies provide evidence for portable HEPA purifiers’ potential to eliminate airborne SARS-CoV-2 and augment primary decontamination strategies such as ventilation. Based on filtration rates, additional air exchanges provided by portable HEPA purifiers may be calculated and room shutdown times potentially reduced after aerosol-generating procedures.

Effectiveness of air purifiers in intensive care units: an intervention study

“…The literature also reports that HVAC-integrated air filtration systems (indoor air purifiers) may decrease aerosolised viral loads [1,3,4]. Air filtration studies also suggest HEPA can be very useful for reducing airborne levels of Covid 19 SARS Cov 2 [9]. Therefore, by protecting and reinforcing existing ventilation systems by means of J o u r n a l P r e -p r o o f 5 hospital environmental and administrative controls, we can minimise the rates of hospitalacquired infections associated with airborne infectious pathogens [8][9][10].…”

“…Air filtration studies also suggest HEPA can be very useful for reducing airborne levels of Covid 19 SARS Cov 2 [9]. Therefore, by protecting and reinforcing existing ventilation systems by means of J o u r n a l P r e -p r o o f 5 hospital environmental and administrative controls, we can minimise the rates of hospitalacquired infections associated with airborne infectious pathogens [8][9][10]. In the first half of 2019, the rate of hospital-acquired infections in the ICUs at our hospital was 1.47%.…”

Indoor Air Quality Evaluation Using Mechanical Ventilation and Portable Air Purifiers in an Academic Dentistry Clinic during the COVID-19 Pandemic in Greece

“…However, the occupancy, as well as the efficiency of the ventilation system used, affects the final measured concentration [22]. Avoiding the recycling of unfiltered air is very important mainly in healthcare-related installations as the airborne transmission of the virus is possible, as mentioned above [14,15,23,24]. In a recent study, it was shown that the combination of the intraoral and extraoral mechanical suction of the produced aerosol had better results in reducing the microbial load in the air than the use of intraoral alone [25].…”

“…In the context of the ongoing COVID-19 pandemic, studies were recently conducted to investigate the efficiency of portable air purifiers in homes and various workplaces [13][14][15]. However, to the best of our knowledge, there is no published study investigating the efficiency of portable air purifiers in academic dental clinics.…”

Characterizing the performance of a DIY air filter

“…Various studies support the benefits of portable HEPA filtration for reducing aerosol concentrations from many sources, including reducing risks of COVID-19 transmission. For example, Liu et al (2021) reviewed portable HEPA air cleaners and concluded that such air cleaners have "potential to eliminate airborne SARS-CoV-2 and augment primary decontamination strategies such as ventilation. " Curtius, Granzin and Schrod (2021) reached similar conclusions based on measurements of aerosol concentration reductions in a classroom.…”