A new study by NitroPep, Pullman AC and the University of Birmingham has looked at the efficacy of NitroPep’s antimicrobial and antiviral air filters to prevent the spread of pathogens in public spaces – particularly transport.
NitroPep antimicrobial technology and antiviral air filters
Developed and patented by research teams at the University of Birmingham, NitroPep antimicrobial coating uses patented technology to permanently bind the chemical biocide chlorhexidine digluconate (CHDG) to surfaces.
When applied to metal and plastic, the coating prevents surface colonisation and biofilm formation by killing pathogens on contact, ensuring surface ‘recontamination’ and onward transmission is prevented.
Crucially, NitroPep’s antimicrobial coating can be easily applied to existing air filtration systems, rendering them biocidal. The new research<link> looked at the efficacy of these antiviral air filters.
Protection from Covid-19 in less than one minute
In the laboratory study, NitroPep’s antimicrobial coating was applied to a modified MK3 air filter. Cells of SARS-CoV-2 – the virus that causes Covid-19 – were added to the surface of this treated filter and to a second, untreated control filter.
The filters were measured at intervals over a period of more than an hour. While much of the virus remained on the surface of the control filter for an hour, when applied to the NitroPep-treated filter, all SARS-CoV-2 cells were killed within 60 seconds.
There were similar results when bacterial and fungal pathogens were tested, the treated filter killing MRSA, E. coli and Candida albicans in less than 15 minutes.
Long-term protection from pathogens
To test whether the antiviral air filters maintained their efficacy over the long term, they were then tested in field trials. Control and treated filters were installed in heating, ventilation and air conditioning systems onboard UK train carriages.
After three months, the filters were removed and researchers counted how many colonies of bacteria remained on them. It was found that no pathogens survived on the treated filter.
What’s more, further tests found that the treated filters were extremely durable, and were able to maintain their structure and filtration function over the operational lifetime of the product.

Antiviral air filters on public transport
As we cautiously return to our pre-pandemic lives, we are more aware than ever of the risk posed by the airborne transmission of pathogens. This is particularly the case on public transport, where former studies have shown higher rates of flu-like illnesses in people travelling on London’s underground, as well as a 6-fold increase in respiratory infection in people using a tram or bus.
Earlier attempts at introducing antiviral air filters to improve air quality have been unsuccessful. Novel filters installed in heating, ventilation and air conditioning (HVAC) systems have proved to be energy inefficient, with slow effectiveness or requiring significant infrastructure upgrades to use.
As a result, there has never been a greater need for antimicrobial technology that maintains its efficacy without incurring prohibitive costs.
Long-term, cost-effective protection from disease
The study demonstrates that NitroPep’s antimicrobial and antiviral air filters offer an efficacious and cost-effective method of improving air quality and ventilation, while reducing the risk of disease transmission.
To discuss how our antiviral air filters could be installed in your filtration or air flow control system, get in touch today.