The Efficacy of Plant-Based Ionizers in Removing Aerosol for COVID-19 Mitigation

Abstract

Small-sized droplets/aerosol transmission is one of the factors responsible for the spread of COVID-19, 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), aerosol presents a different challenge due to their ability to remain airborne for a long time. This calls for mitigation solutions that can rapidly eliminate the airborne aerosol. Pre-COVID-19, air ionizers have been touted as effective tools to eliminate small particulates. In this work, we sought to evaluate the efficacy of a novel plant-based ionizer in eliminating aerosol. It was found that factors such as the ion concentration, humidity, and ventilation can drastically affect the efficacy of aerosol removal. The aerosol removal rate was quantified in terms of ACH (air changes per hour) and CADR- (clean air delivery rate-) equivalent unit, with ACH as high as 12 and CADR as high as 141 ft3/minute being achieved by a plant-based ionizer in a small isolated room. This work provides an important and timely guidance on the effective deployment of ionizers in minimizing the risk of COVID-19 spread via airborne aerosol, especially in a poorly-ventilated environment.

A review of methods to reduce the probability of the airborne spread of COVID-19 in ventilation systems and enclosed spaces

“… Air Ionization ( What is a MERV rating? 2021 ; Nembhard et al, 2020 ; Uk Lee et al, 2004 ; Hyun et al, 2017 ; Sawant et al, 2012 ; Pekárek, 2003 ; Yehia et al, 2000 ; Sung et al, 2019 ; Suwardi et al, 2021 ; Agranovski et al, 2006 ) Causes a significant increase in airborne particle deposition rates. Commercially available technology.…”

“…Furthermore, it is worth noting that electrostatic precipitators induce a local deposition of particles onto the collection plate, whereas a simple air ion emitter will likely cause an increased particle deposition to all surfaces within an enclosed space. Plant-based ionizers also exist and are commercially available ( Suwardi et al, 2021 ), and offer another seemingly viable and effective alternative to generate air ions without also generating ozone. The cited study reported a CADR equal to approximately 4 m 3 /min.…”

The Role of Indoor Plants in air Purification and Human Health in the Context of COVID-19 Pandemic: A Proposal for a Novel Line of Inquiry

“…There results showed that the ionizer device prevented the infection spread with high efficacy in pigs ( Hagbom et al, 2015 ). Also, Suwardi and colleges demonstrated that plant-based ionizers can aid in reduction of erosol-containing virions indoors ( Suwardi et al, 2021 ). However, the wide use and potency of these air ionizing techniques are still not fully investigated.…”

Risk assessment of airborne COVID-19 exposure in social settings

“…More details on the experimental setup can be found in our earlier work along with a more comprehensive review by Su et al on various technologies for studying air quality. 58,59 To quantify the cumulative concentration of aerosol emitted from the fog generator, a reference sensor is always placed right in front of the opening of the fog generator. The remaining sensors are placed at various distances and directions, depending on the test scenario of interest.…”