Wood's Active ION HEPA Filter for AD20/AD30 The Wood's Active ION HEPA filter is the secret behind the high purification capacity, low energy consumption, and quiet operation of Wood's air purifiers. Premium Filtration! The Wood's Active ION HEPA filter is crafted with a special synthetic media where the fibers are slightly electrically charged, capturing airborne particles very effectively. It removes 99.98% of all harmful particles in your indoor environment. Every day, we inhale large amounts of harmful particles in our homes or workplaces. The Wood's Active ION HEPA filter eliminates pollen, dust, bacteria, radioactive radon daughters, and mold spores from the air, providing an immediate improvement in indoor air quality. The Active ION HEPA filter removes particles as small as 0.0003 mm, which is 50 times smaller than a bacterium. Specifications: - Premium filtration - Low pressure drop - Made in Sweden