A Review of Antimicrobial Air Filters over Normal Air Filters: Unique Insights on SARS-CoV-2 Virus Deactivation

In this study, we discuss the benefits of “antimicrobial air filters” over “normal air filters” for protection against airborne pathogens and air pollutants developed in the laboratory of IISc Bangalore and IIT Kanpur. While normal air filters work on a capture mechanism to become a breeding ground for captured germs, antimicrobial air filters are coated with bio-polymers and polycationic polymers that can deactivate the germs. The formation of ROS (reactive oxygen species) i.e. H2O2 leads to the deactivation of germs. Polymers being used, in this study are a safe and sustainable alternative to heavy metal (Ag/Cu) doped coating that has proven toxic to humans. The antimicrobial filters are tested to deactivate micro-organisms, such as Escherichia Coli, Staphylococcus Aureus, Influenza, MS2 Bacteriophage, Aspergillus brasiliensis, and SARS-CoV-2 (delta variant). It was also proven that normal filters have a negative reduction which implies the growth of microorganisms. Structural and filtration integrity of anti-microbial air filters were upheld without affecting the filter's porosity and initial pressure drop. There was no statistically significant difference in pressure drop and filtration efficiency observed between coated and uncoated filters. Furthermore, the coated air filters maintained antimicrobial activity throughout the operational lifetime with regenerative ROS formation. Antimicrobial air filters pave the way for better protection against infection spread and air pollutants. It prevents the air filter to become a breeding ground for germs using bio-polymers that are biodegradable and non-toxic.