Plant ionisers, air filters can curb droplet transmission: Study

Study also finds air filters are effective at lowering aerosol concentrations

Researchers looking at ways to reduce the risk of Covid-19 transmission have found that plant and natural fibre ionisers and air filters are effective in reducing aerosol concentrations in the air, and can take safe management to the next level.

The Agency for Science, Technology and Research (A*Star) and Temasek Foundation, working with research agencies here, have come up with a handbook of measures that individuals, families and companies can take, as the nation opens up further.

These solutions are now being offered to businesses and organisations, as well as families and individuals, to explore what best fits their needs and circumstances, the agencies said in a release yesterday.

Aside from air filters in homes and offices to reduce the spread of small respiratory droplets, or aerosols, researchers have looked at other solutions, including table-top dividers in foodcourt settings.

"Temasek Foundation, A*Star and other research partners such as ITE College East and Temasek Life Sciences Laboratory have done extensive scientific studies in collaboration with public agencies, and gleaned insights which could be useful in further reducing the risk of Covid-19 transmission," said the foundation.

Tests were conducted at various venues such as concert theatres, offices, eateries and on public transportation.

Dr Ady Suwardi, deputy head of soft materials at A*Star's Institute of Materials Research and Engineering (IMRE), said researchers found that plant and natural fibre ionisers were the most useful in reducing the concentration of aerosol particles in poorly ventilated indoor spaces.

Professor Loh Xian Jun, executive director of IMRE, said: "Plants are naturally able to generate ions, so when it is fitted with an electrical ioniser device, the plant is stimulated such that it is able to emit up to a million times more ions compared with a normal plant."

They also found that air filters can effectively capture microbes such as bacteria and viruses found in aerosols. When used on fans and air conditioners, the filters can help purify indoor air and reduce the spread of aerosols.

The researchers also looked at other solutions such as disinfecting surfaces with ultraviolet light and found that it can help inactivate different types of bacteria and viruses.

However, the researchers stressed that these solutions are "additional levels of defence" to reduce transmission risks through surfaces, droplets and aerosol routes.

Safe management measures including mask wearing, maintaining 1m safe distancing and keeping good personal hygiene remain the first line of defence in curbing the spread of Covid-19.