Dyson Pure Cool vs Rowenta Intense Pure Air XL 

This is missing the conclusion. At first glance, the purifier seems to be belching out smoke while the Dyson looks like it is not exhausting much smoke, but part of it could just have to do with how the two units exhaust air differently. If you look at 0:23, both units look equally cloudy, and at 0:39 the Dyson looks less foggy than the purifier. The implication is that the Dyson has vented more smoke (implying the filters stop less of the smoke from passing through. To be able to make an accurate conclusion, you need to have a measure of the pollution levels inside and outside the box, both at the start and the finish. Also, that is just one type of test to show how much of the air passing through the purifier is actually purified in one pass. It could be that given enough time, both units would purify the air in a space to a comparable level.

On Rowenta the pollution sensor has been deactivated. You can see no Red warning on the purifier.