New type of air filters can kill disease-causing pathogens
Air filters containing a potent biocide has been developed thanks to a joint research project between the University of Birmingham, UK, and private manufacturing firms. The new air filters are coated in a chemical called chlorhexidine digluconate (CHDG) which has proven effective in removing airborne pathogens, including bacteria, fungi, and the infamous coronavirus.
The filters were tested in both laboratory and real-life conditions to determine their efficacy. In the lab, the filters were covered with viral particles of the Wuhan strain of SARS-CoV-2, alongside control filters. They were then checked periodically: while much of the initial quantity of viral particles remained on the surface of the control filters for the experiment’s length, all SARS-CoV-2 cells were destroyed within 60 seconds on the surface of the treated filters.
Similar results applied in experiments involving infectious bacteria such as E. coli and S. aureus.
Treated filters were also installed in the heating, ventilation, and air conditioning systems on train carriages in the UK and left to operate for three months, alongside control filters in matched pairs on the same train line. Analysis later revealed no bacteria colonies survived on the treated filters.
This step demonstrated that the treatment was durable enough to withstand three months of real-world use while maintaining their structure, filtration functions, and anti-pathogen abilities.
“The COVID-19 pandemic has brought to the forefront of public consciousness the real need for new ways to control the spread of airborne respiratory pathogens. 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,” said Dr. Felicity de Cogan, Royal Academy of Engineering Industry Fellow at the University of Birmingham.
Existing ventilation systems which are not designed to prevent the spread of pathogens can instead act as a potential reservoir for harmful pathogens.
“We are excited that we have been able to develop a filter treatment which can kill bacteria, fungi, and viruses—including SARS-CoV-2—in seconds. […] The technology we have developed can be applied to existing filters and can be used in existing heating, ventilation, and air conditioning systems with no need for the cost or hassle of any modifications,” Dr. de Cogan explained. “This level of compatibility with existing systems removes many of the barriers encountered when new technologies are brought onto the market.”
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