Real-World Evidence on the Effectiveness of Plexiglass Barriers in Reducing Aerosol Exposure

Abstract

Reprinted with permission, Cleveland Clinic Foundation ©2022. All Rights Reserved Background: Barriers are commonly installed in workplace situations where physical distancing cannot be maintained to reduce the risk for transmission of respiratory viruses. Although some types of barriers have been shown to reduce exposure to aerosols in laboratory-based testing, limited information is available on the efficacy of barriers in real-world settings. Methods: In an acute care hospital, we tested the effectiveness of in-use plexiglass barriers in reducing exposure of staff to aerosolized particles. A nebulizer was used to release 5% NaCl aerosol 1 meter from staff members with and without the barrier positioned between the point of aerosol release and the hospital staff. Particle counts on the staff side of the barrier were measured using a 6-channel particle counter. A condensed moisture (fog) generating device was used to visualize the airflow patterns. Results: Of 13 in-use barriers tested, 6 (46%) significantly reduced aerosol particle counts detected behind the barrier, 6 (46%) reduced particle counts to a modest, non-significant degree, and 1 (8%) significantly increased particle counts behind the barrier. Condensed moisture fog accumulated in the area where staff were seated behind the barrier that increased particle exposure, but not behind the other barriers. After repositioning the ineffective barrier, the condensed moisture fog no longer accumulated behind the barrier and aerosol exposure was reduced. Conclusion: In real-world settings, plexiglass barriers vary widely in effectiveness in reducing staff exposure to aerosols, and some barriers may increase risk for exposure if not positioned correctly. Devices that visualize airflow patterns may be useful as simple tools to assess barriers.

School health systems under strain: an example of COVID-19 experiences & burnout among school health staff in Pima County, Arizona

“…However, it should be noted that plexiglass effectiveness is variable and highly dependent upon its placing relative to airflow [ 23 , 24 ], while masks, depending up on the filtering material and fit when worn, are a reliable way to reduce exposure [ 23 , 25 ].…”

Experimental studies on airborne transmission in hospitals: A systematic review

“…72,92,111,119 Many studies reviewed in this systematic review had limited experimental scenarios due to high implementation costs. Typically, the number of case scenarios reported in the studies ranged from two to seven, with a few exceptions, such as Cadnum et al 14 with 13 cases and Rogak et al 100 with 41 cases. The relatively simple experimental set-up in the latter two studies facilitated more experimental scenarios.…”

“…108 Other studies in this category evaluated the combined effects of ventilation configurations, layouts, locations of the infected patient and the susceptible, source patient’s postures, exhalation modes and source of bioaerosols on the aerodynamics and the dispersion pattern of bioaerosols. 14,109–117…”

“…108 Other studies in this category evaluated the combined effects of ventilation configurations, layouts, locations of the infected patient and the susceptible, source patient's postures, exhalation modes and source of bioaerosols on the aerodynamics and the dispersion pattern of bioaerosols. 14,[109][110][111][112][113][114][115][116][117] Effects of human movement. A handful of studies investigated human movement's effects on airflow and aerosols' dispersion.…”

“…Notably, environmental factors such as room layouts, bed arrangements and indoor environmental quality (IEQ) factors, including temperature and humidity, as well as human factors such as the movement of people, door opening motions and infected patients' exhalation modes, can significantly influence the aerosol transmission of infectious agents. 14 These factors should be considered when evaluating the risk of airborne transmission in indoor environments and developing effective control strategies to mitigate the spread of airborne pathogens. Preventing nosocomial airborne transmission through engineering controls and management practice, especially in general hospital patient areas, could be the cornerstone to avoiding the next pandemic.…”