The outbreak of SARS-CoV-2 has made us all think critically about
hospital indoor air quality and the approaches to remove,
dilute, and disinfect pathogenic organisms from the hospital
environment. While specific aspects of the coronavirus
infectivity, spread, and routes of transmission are still under
rigorous investigation, it seems that a recollection of
knowledge from the literature can provide useful lessons to cope
with this new situation. As a result, a systematic literature
review was conducted on the safety of air filtration and air
recirculation in healthcare premises. This review targeted a
wide range of evidence from codes and regulations, to
peer-reviewed publications, and best practice standards. The
literature search resulted in 394 publications, of which 109
documents were included in the final review. Overall, even
though solid evidence to support current practice is very
scarce, proper filtration remains one important approach to
maintain the cleanliness of indoor air in hospitals. Given the
rather large physical footprint of the filtration system, a
range of short-term and long-term solutions from the literature
are collected. Nonetheless, there is a need for a rigorous and
feasible line of research in the area of air filtration and
recirculation in healthcare facilities. Such efforts can enhance
the performance of healthcare facilities under normal conditions
or during a pandemic. Past innovations can be adopted for the
new outbreak at low-to-minimal cost.
The outbreak of COVID-19, and its current resurgence in the United States has resulted in a shortage of isolation rooms within many U.S. hospitals admitting COVID-19-positive cases. As a result, hospital systems, especially those at an epicenter of this outbreak, have initiated task forces to identify and implement various approaches to increase their isolation capacities. This paper describes an innovative temporary anteroom in addition to a portable air purifier unit to turn a general patient room into an isolation space. Using an aerosolization system with a surrogate oil-based substance, we evaluated the effectiveness of the temporary plastic anteroom and the portable air purifier unit. Moreover, the optimal location of the portable unit, as well as the effect of negative pressurization and door opening on the containment of surrogate aerosols were assessed. Results suggested that the temporary anteroom alone could prevent the migration of nearly 98% of the surrogate aerosols into the adjacent corridor. Also, it was shown that the best location of a single portable air purifier unit is inside the isolation room and near the patient's bed. The outcome of this paper can be widely used by hospital facilities managers when attempting to retrofit a general patient room into an airborne infection isolation room.
Human activity is known to leave significant effects on indoor airflow patterns. These patterns are carefully designed for many facilities such as cleanrooms, pharmaceutical settings, and healthcare environments, where human‐induced wakes contribute to the transport of contaminants. Therefore, the knowledge about these wakes as it relates to indoor air quality is critical. As a result, a series of experiments were conducted in a controlled chamber to study the three‐dimensional effects of true human walking on airflow. Experiments were designed to capture the effect of human walking under three different flow conditions, and for two different walking schemes. The results show that the effect of walking on the airflow is not negligible and can sustain up to 10 seconds after the moving body has passed. Walking on a straight line creates significant change in the velocity normal to the walking path and vertical to the plane of walking movement. These changes were detectable till 1.0 m away from the walking track. Also, the similarity between airflow patterns of walking once and twice illustrated a promising opportunity of predicting the flow patterns of random walk from a set of base cases.
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