You might not expect it, but the air inside your home could be even more polluted than the air outside. And since there might be little circulation, an air purifier could be an important part of keeping your home clean. An air purifier cleans the air in your home by filtering out allergens and the particles that make up air pollution. Some of these allergens include pet dander, hair, mold spores, and gaseous pollutants that can cause odor and respiratory issues. These indoor allergens and pollutants can hover in the air for long periods of time. Many popular air purifiers use fans to circulate air through their HEPA filters. Inside, the filters remove impurities, releasing clean air back into the room. Some air purifiers include UV-C sanitizing, as well as activated carbon odor filters.