Use advanced electronic ionizer breeze technology. Utilize high voltage electrons release principle to create negative ions and active oxygen. Therefore it rapidly kills bacteria, viruses, mites and effectively prevent air transmitted diseases. Clean particles as small as 0.01 micron. Negative ions force particles as small as 0.01 micron from the air. They can also neutralize airborne viruses and microorganism as well. Dust collection plates to absorb airborne contaminant. Static electricity dust collector captures airborne dust, pollen, mould, mites and allergen. Silent, cost efficient & no HEPA filter. HF 100 uses no mechanical parts and save energy. The HF 100 features virtually silent operation. HEPA machine on the other hand cause serious noise pollution and wastes hundreds of dollar in electricity as compared to HF 100 $3 of electricity per year.