Odors are the results of gaseous compounds floating around in the air and getting inhaled. There are plenty of causes of offensive household odors and they do not differ all that much. Whether it is pets, cooking, smoke or any other cause, the best air purifiers for odors will have a good amount of high quality activated carbon inside. Additionally, an ionizer or ozone emitter of some sort can help to neutralize many of these gases rendering them harmless.
This unit offers 18 lbs of activated carbon, the most I have seen and plenty to take care of odors and gaseous toxins.
The Austin Air Healthmate offers 15 lbs. of activated carbon and true HEPA filtration for great results against odors.
This unit utilizes several different filtration technologies to combat odor causing compounds and features an odor sensor which allows the purifier to actively and efficiently reduce odors in your home.