The Efficacy of Plant-ionizers in Removing Aerosols for COVID-19 Mitigation

Abstract

Small size droplets/aerosols are believed to be potentially responsible for COVID-19 transmission in addition to large droplets and surface contamination (fomites). While large droplets and surface contamination can be relatively easier to deal with (i.e. using mask and proper hygiene measures), aerosols present a different challenge due to their ability to remain airborne for a long time. This calls for mitigation measures that can rapidly eliminate the airborne aerosols. Pre-COVID-19, an air ionizer has been touted as an effective tool to eliminate small particulates such as these. In this work, we sought to evaluate the efficacy of a novel plant-based air ionizers in eliminating aerosols. It was found that factors such as the ion concentration, humidity, and ventilation can drastically affect the aerosols removal efficacy. Furthermore, the aerosols removal rate was quantified in terms of ACH (air changes per hour)-equivalent unit, with ACH as high as 12 being achieved by using deploying a plant-based air ionizer in a small isolated office room. Lastly, this work provides an important and timely guidance on the effective deployment of plant ionizers in minimizing the risk of COVID-19 spread via airborne aerosols, especially in poorly-ventilated environment.