Aircuity is unique because of a dual channel particle counter that measures down to .3 microns. This is important because 1) most particles are .3-.5um 2) they stay airborne for a long time and 3) filters are not effective at removing them. A MERV 13 filter is only 40% efficient with a .3 micron particle where it’s about 100% efficient with a 2.5 micron particle.