how a furnace filter works, trapping dust and dirt in the fibers of the carpet. Over time, as more air circulates and deposits more particles, the stains become darker and more pronounced. This is particularly common in homes with forced air heating or cooling systems, which can increase the movement of air—and therefore particles—throughout the home.
3. Common Household Sources of the Fine Particles Causing the Stains
The fine particles that contribute to filtration soiling can come from a variety of sources within the home. Common culprits include dust, pet
