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Using a High-Flow Extractor to Reduce Aerosol Exposure in Medical Environments
BOWEN DU, Tianyuan Li, Clyde Matava, Vincent Collard, Simon Denning, John Fiadjoe, Pierre Fiset, Thomas Engelhardt, Jeffrey Siegel, University of Toronto
Abstract Number: 419
Working Group: Indoor Aerosols
Abstract
The transmission modes of the severe acute respiratory syndrome SARS-CoV-2 include droplets and droplet nuclei (aerosols). Thus, aerosol-generating procedures, in addition to normal breathing, coughing, and sneezing of patients, pose an elevated infection risk to healthcare workers especially in confined spaces such as operating rooms and dental operatories. Some clinicians are using transparent plastic barriers to reduce aerosol spread, but these barriers may limit access to the patient and mobility of the clinician and may offer limited protection depending on room airflow patterns. As an alternative, this work proposed using high-flow extractors which combines local suction and high-efficiency filtration to capture and remove aerosols generated by patients and medical procedures. Using a test dust (1 – 20 μm) in a coughing mannequin and emissions from an essential oil diffuser (0.01 – 1 μm) to simulate abrupt coughing aerosols and continuous breathing aerosol, respectively, we carried out experimental investigation of the particulate matter removal efficiency of a portable high-flow air extractor with an exhaust rate of up to 235 L/s. A wide range of aerosol equipment was used to characterize size distributions and spatial variation in concentrations. We found approximately 76% and 97% reductions in PM1 concentration near the source and at the clinician’s head, respectively, when the extractor was on during the coughing tests. For PM10, we saw similar reduction rates of 80% and 97% at the two locations, respectively. In the continuous emission scenario, the extractor achieved a 99%-100% reduction in PM concentrations near the source, resulting in a complete reduction of detectable concentrations at the clinician’s head. Therefore, the use of high-flow extractors should be considered in medical environments where strong sources of aerosols are present.