Engineers at the University of Birmingham in the U.K. have developed a coating for heating, ventilation and air conditioning (HVAC) air filters that can kill bacteria, fungi and viruses in mere seconds.

Developed in conjunction with U.K. firms NitroPep Ltd and Pullman AC, the coating — a chemical biocide called chlorhexidine digluconate (CHDG) — was applied to air filters used in HVAC units to prevent the spread of airborne infections.

Source: University of Birmingham

To test the coating, the team applied cells of SARS-CoV-2, the virus that causes COVID-19, to HVAC air filters, both treated with the coating and untreated. The air filters treated with the coating killed the SARS-CoV-2 cells within seconds, while the cells persisted on the untreated filters.

Similar results were achieved when the researchers tested the treated and untreated filters on E. coli, S. aureus, and C. albicans.

Additionally, the filters were installed in HVAC systems on trains traveling throughout the U.K. for three months, after which the filters were removed and subsequently tested. Following testing, the researchers revealed that pathogens did not survive on the treated air filters.

Because the coating can be applied to existing filters and HVAC systems without modification, the researchers are attempting to bring the coating to market, pending further development.

The results of the study are detailed in the article, Efficacy of antimicrobial and anti-viral coated air filters to prevent the spread of airborne pathogens, which appears in the journal Scientific Reports.