Air Purifier vs. Humidifier: Which is Right for You? Claire Gagne Replay Video Air purifier vs. humidifier Do you have a runny nose or a cough? You might be wondering if a humidifier or an air purifier could help your symptoms. But which one do you choose? Humidifiers and air purifiers don't do the same thing. Here's what they do to the air in your home and how to figure out which device is the one you might need. How does an air purifier work? "Air purifiers remove pollutants from the air in your home, such as dander, pollen, mold spores, dust, and bacteria," says Peter Bailey, MD, a family practice physician in Oakland, California.