[codemac]

> which is our indication that it pulled more particles out of the air

This is not a good indication.

The larger black particles are not nearly as harmful to you, and generally just fall to the ground. BlueAir and other vertical filters attempt to make sure they don't waste your filter on these large objects, and pull the smaller particles out of the air. Box fans pull a lot off the floor, which isn't super helpful.

The CADR takes into account the differences you speak of, because it measures the amount of clean air. You may enjoy the fans more, but the filter material being the same doesn't mean a box fan cleans air any better.