Before the pandemic, few of us would have given thought to whether the air in a grocery store or our offices was safe. But now that we have to be concerned about the airborne transmission of COVID-19, air quality can sometimes be all we think about.
Air purifiers, such as ionizers, can help allay some of our concerns about air quality. Ionizers emit static electricity that helps draw floating particles towards surfaces where they will not be inhaled. Unfortunately, many ionizers emit harmful ozone gas as they operate.
Taking a leaf from nature, a team of scientists from A*STAR’s Institute of Materials Research and Engineering (IMRE) and Institute of High Performance Computing (IHPC) investigated whether plant-based ionizers could play a role in the fight against COVID-19. Plant-based ionizers are small devices attached to living plants that use the plant’s leaves to create an ionizing effect. Unlike normal ionizers made from mechanical parts, plant-based ionizers do not emit ozone.
Surprisingly, the team led by IMRE group leaders Ady Suwardi and Dan Daniel found that plant-based ionizers were even more effective than traditional ones. They found that it took 24 minutes for 95 percent of the aerosols in a room to dissipate with no ionizers running, a figure that dropped to 15 minutes with a traditional ionizer. However, it took just six minutes for a plant-based ionizer to achieve the same effect.
“In a windowless room, it may take up to 30 minutes for human-generated aerosol to clear,” said Daniel. “With proper usage of plant-based ionizers, the time it takes to clear the aerosol can be easily reduced to as low as six minutes.”
The team also used sophisticated simulations to show how efficient different types of plant-based ionizers would be in different spaces. The models showed that a large plant-based ionizer could provide enough clear air for a room as large as 40 square meters.
Currently, the researchers are working on other techniques for reducing the spread of COVID-19 indoors, like adding surfaces to a room so that aerosols will be more likely to settle on them.
“We are also actively involved in testing the efficacy of various mitigation measures on venues such as churches, restaurants and meeting rooms,” said Suwardi. “We work hand in hand with our sister institute, IHPC, which uses computational fluid dynamics to simulate the aerosol and airflow patterns in various settings.”
The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering (IMRE) and the Institute of High Performance Computing (IHPC).