The best car air purifiers Many people put air purifiers in their homes but don’t ever consider that their car may need one, too. Whether you drive with the windows up or down, pollutants like pollen, smog and road dust can enter the vehicle easily. When you think about how much time you probably spend running errands and sitting in traffic in your car, the damage adds up, and the need for an air filter becomes apparent. In this guide, we cover everything you need to know about car air purifiers to make an informed purchase, including our favorite model, the IQAir Atem.