A small air purifier in a room will provide protection from air pollutants and dust mites only partially. However, large air purifiers will protect from dust mites 24/7.
Congestion is a common problem in the basement, among many others like bacteria, pollen, and mold spores, and the moment you step into your basement after a long period of time. In most cases, congestion is the result of accumulated dust and smoke. The best air purifier for the basement can clean the air as well can effectively deal with all other issues.
As much as we would like to believe that pet allergy is not a very big deal, this is not true. Pet allergies can be devastating to our respiratory system. If the precautionary measures are not taken, the symptoms of PET allergies can be as obvious as having a high fever, constant sneezing, and runny nose. In extreme pets, allergies can even cause asthma.