filter

This is a tough question. We think 90% is easily obtainable with high quality air purifiers, air cleaners, filters, and good practice. This may not be enough and you may want to push the limit. Average counts in the 10 to 20 range on the DC1100 are possible. The air quality throughout the home will vary significantly, but we believe average readings in the 10 to 20 range are possible which, if the outdoor ambient is 500, results in a 96 to 98% reduction in particles within the detection range.

Natural Air is an air regenerator, not a filter. There's no filter to change or replace. Natural Air does have screens which are designed to simply stop large particulates (hair, dust-bunnies, etc) from clogging the works. These filters need to be cleaned only when they become visibly "clogged." Simply brush off the accumulated matter.