University-developed air purifiers that kill bacteria and viruses may protect elderly and infirm

(From left) Dr Antony Leung, Medical Superintendent of Haven of Hope Holistic Care Centre; Prof Joseph Kwan, Director of HKUST Health, Safety and Environment Office; Prof Yeung King-lun, Associate Dean of Research and Graduate Studies from HKUST School of Engineering and Prof Yang Zifeng, Associate Professor of Guangzhou Institute of Respiratory Disease, Guangzhou Medical University. Photo credit:

A University of Science and Technology-developed air purifier that removes up to 99.99 per cent of airborne bacteria and viruses is now available on the retail market. Costing up to $3000, the devices were first tested in laboratories where they were found to kill influenza and Middle East respirator syndrome viruses.

Most air filters merely trap bacteria. Professor Yeung king-lun, UST research team leader, said the new technology not only kills bacteria, it also destroys pathogens and mould. The elderly and chronically ill are most at risk from airborne disease. Haven of Hope hospice tested the devices for 18 months with good results, Dr Antony Leung, medical superintendent, said. Now the purifiers are being studied in the Kowloon Hospital to see how they improve the air in medical wards.


Middle East respiratory syndrome coronavirus

According to a UST press release, Guangzhou Institute of Respiratory Disease experiments showed the air purifiers eliminated nearly 99 per cent of the Middle East respiratory syndrome virus, 99.999 per cent of H1N1 and 99 per cent of EV71, a cause of hand-foot-and-mouth disease.

antimicrobial coated air filter.PNG
Anti-microbial coated air filters are installed in new devices made by Chiap Hua.

The air purifiers have multi-level anti-microbial filters with biocide and slowly release disinfectants into the air to help sterilise bacteria.  The UST said their lab tests showed the devices eliminated a wide range of bacteria, including legionella pneumophillia, klebsillia pneumonia, serratia marcesens — a cause of urinary and respiratory infections — and pseudomonas putida — a cause of pneumonia.

Environment bacteria sample of HKUST’s antimicrobial coated air filter (left) as compared to sample using normal air filter (right).

Yuki Chung, a UST spokesperson, said the devices can be found at, which turns out to be a brand of Chiap Hua International Ltd, maker of household appliances.

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