Silver nanoparticles in the EcoSilver pre-filter prevent the growth of microorganisms on the filter, including bacteria and viruses. EPA EST. 93163-CHN-1 Coconut carbon in the pre-filter neutralizes harmful VOCs (volatile organic compounds) and household odors from cooking, cleaning, smoking, and pets. 3 fan speeds so you get the cleaning power you want when you want it. Sleep mode with whisper-quiet operation for uninterrupted sleep. Filter replacement indicator to remind you when it's time to change the filters.