Air purifiers are devices designed to remove contaminants from the air in a room. They can be an effective way to improve indoor air quality by trapping particles such as dust, pollen, pet dander, and mold spores. To get the most out of an air purifier, it is important to choose the right size and type for the space you are trying to clean. Look for a purifier with a HEPA filter, which is capable of capturing 99.97% of particles as small as 0.3 microns.