Antimicrobial air filters could drastically reduce the spread of Covid on trains

A new antimicrobial technology for air filters that could help combat the spread of Covid and other microorganisms on trains has been developed by researchers at the University of Birmingham.

The technology can kill an array of bacteria, fungi and viruses in seconds, including providing a potential solution to preventing the spread of airborne infections.

The air filters, which are coated with a chemical biocide called chlorhexidine digluconate (CHDG), have been rigorously tested and compared to standard “control” filters commonly used in laboratories, industrial air condensing units and during a test on board trains running on the British railways.

In the laboratory, Covid-19 cells were added to the surface of the treated and control filters and measured at intervals over a period of over an hour.

The results showed that while much of the virus remained on the surface of the control filter for one hour, all Covid cells were killed within 60 seconds on the treated filter.

Similar results have been seen in experiments testing bacteria and fungi that commonly cause disease in humans, including E. coli, S. aureus, and C. albicans.

In order to determine the effectiveness of the filters in a real environment, the control and treated filters were installed in the heating, ventilation and air conditioning systems of train cars.

The filters were installed for three months in matched pairs on carriages on the same train line, before being removed and shipped for analysis, with the researchers counting the colonies of bacteria remaining on them. The test revealed that no pathogens survived on the treated filter, even after three months on board the train.

Further tests have also revealed that the treated filters are durable and able to maintain their structure and filtration function for the duration of their use.

Dr Felicity de Cogan, a researcher at the University of Birmingham, said: “In crowded spaces, from offices to large indoor venues, shopping malls and on public transport, there is an incredibly high potential for transmission of Covid- 19 and other viruses like the flu.

“Most ventilation systems recycle air through the system, and the filters currently used in these systems are not normally designed to prevent the spread of pathogens, but only to block air particles.

“This means that filters can actually act as a potential reservoir of harmful pathogens. We are delighted to have been able to develop a filter treatment that can kill bacteria, fungi and viruses – including SARS-CoV-2 – in seconds. This fills a global unmet need and could help purify the air in enclosed spaces, helping to prevent the spread of respiratory illnesses.

While other filters have been developed in the past, researchers believe theirs has improved energy efficiency and works much faster.

“In comparison, the technology we have developed can be applied to existing filters and can be used in existing HVAC systems without requiring the cost or hassle of any modifications,” Dr. de Cogan added. . “This level of compatibility with existing systems removes many of the hurdles encountered when bringing new technology to market.”

Partner company NitroPep is currently developing the filters for commercialization as a product.

Sign up for the E&T News email to get great stories like this delivered to your inbox every day.