Many different potential causes of indoor air pollution can have similar health effects to those of air pollution on the outside. Indoor air pollution is often reported to be up to five times worse than outside levels. Here are some common air pollutants controlled by an air purifier or through lifestyle changes: Household Cleaners and Chemicals, Mold and Mildew, Pet Dander and Dust Mites, and Tobacco Smoke. Medify Air is one of the best places on the internet to purchase high-quality and the best room air purifier.