An air purifier can be useful in certain situations, in my opinion. In households with persons who have allergy symptoms, or even other respiratory problems, and if there are also potential triggers around (like many pets, or if it is that time of year when pollen or mold levels are high), then they can help. In these situations, however, one must make sure that there are enough purifiers to handle the volume of air within the house (they are rated according to the size of space that they can "purify"). One must also make sure that they are actually rated to remove these sorts of particulate.
For most people, however, an air purifier is not known to provide any benefit.
Hope this helps - Dr. Fay
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