he AC-9966 features 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 and kill bacteria, virus, volatile organic compounds (VOCs), odors and harmful particles, for rooms up to 465 sq.. Both HEPA and VOC filters are designed to operate continuously for up to 2,000 hours. Pp mesh Pre-Filter: traps larger air pollutants such as dust and dander. Plasma technology (tungsten filament + grounding net): tungsten (ionization) filaments are the components to generate plasma through constant positive Corona discharge. The grounding net carries negative high voltage and serves as a guidance of the electrons movement and helps enlarge the electric field. Effectively kills airborne bacteria and virus. (formaldehyde) filter: formaldehyde and other VOCs can be found in building materials, foam insulation, household products and fuel-burning appliances. They can prompt headaches, vomiting, rashes, asthma attacks and some are suspected to cause cancer. Ac-2102 VOC honeycomb filter has 8.5oz of modified activated carbon impregnated with 8.5oz of zeolite particles. Effectively removes formaldehyde, toluene and VOC. Factory tested: VOC removal efficiency reaches 95percent , under the following conditions: 1M3 test room; initial concentration: 1.9-2Mg/M3; 4Hrs testing. Heap filter: a high-efficiency air filter that captures 99.5percent of airborne pollutant particles as small as 0.3 microns, including spores, pollen, mold, pet dander and dust.