The AC-9966 features Ionizer and a Four-Stage filter assembly: Pre-Filter (PP Mesh Filter), cutting-edge Plasma Technology (Tungsten Filament + Grounding Net), VOC filter and HEPA filter. Targeted to effectively remove smoke, dust, pollen, PM2.5, bacteria, mold and virus in a 1,000 cu.ft. space. Both HEPA and VOC filters are designed to operate continuously for up to 3,000 hours.The performance is tested by Intertek. 99.9% reduction of Escherichia coli (bacteria), Staphylococcus epidermidis (bacteria), Aspergillus niger (mold) and Phi X174 Bacteriophage (virus) in 30 minutes.The air purifier cannot offer complete protection on its own. Other prevention of airborne transmission of infections includes vaccinations, wearing personalized protective equipment (like masks), and performing basic infection prevention measures (like hand washing). The tests did not measure whether the air purifier was able to prevent transmission of the virus or bacteria from person to person.