Antimicrobial Air Filter as a Sustainable Alternative to Ultraviolet Germicidal Irradiation for Inactivating Airborne Microorganisms in Building Ventilation System

Indoor air quality is critical as people spend most of their time inside. The COVID-19 pandemic intensified concerns over airborne pathogens, leading many buildings to install ultraviolet germicidal irradiation (UVGI) in ventilation systems. However, UVGI is often ineffective due to short pathogen exposure times and energy intensive. This study proposes a sustainable alternative: antimicrobial air filters. These fibrous filters trap microorganisms, prolonging contact with the microbicidal agent to inactivate them. The approach was tested in two Hong Kong office buildings, comparing UVGI with ordinary filters against disabled UVGI with antimicrobial filters. Air sampling upstream and downstream measured viable microorganism levels via culturing and counting. The antimicrobial filters outperformed UVGI, achieving 8.1–93.3% greater microbial reduction. They also eliminated 2,700W and 750W of UVGI power per floor, saving the buildings 574,000 kWh and 344 tonnes of carbon annually. Global adoption could save 2,358.5 million kWh and reduce CO2 by 1.07 million tonnes yearly. This strategy offers superior performance, lower costs, and significant carbon reduction, confirming antimicrobial filters as a viable alternative to in-duct UVGI.