Bought on the advice of a friend, I have a lot of allergies. Didn't believe the thing would work. When I cook, he signals it. When I clean my house with a hygienic cloth, he signals it. A friend came over, smoked a cigarette, all the warnings on the device kicked in. Also signals wood basket neighbors. Basically, the device signals everything. And then also cleans the air. Have him for a week and hardly any more problems with lungs, throat, nose. Are there any drawbacks? Yes, two for me. In the automatic mode, it controls everything itself, ventilates loudly with a decent sound. When that airflow passes you you feel it, it's chilly. I set the device so that the airflow does not hit me. But the disadvantages do not outweigh the advantages for me, I absolutely recommend the product.
(And for the folks at Dyson, I would have liked it quite a bit and would have paid more if the top part, the halo, had been lit).