Abstract: The invention provides a wearable air purification device which actively generates a propelled stream of purified air for direct delivery to a region proximal to a user's mouth or nose for their immediate inhalation. An air chamber comprises a flexible diaphragm adapted to fluctuate between two extreme positions, thereby altering the volume within the chamber and alternately sucking and blowing air into and out of the chamber. Filtration elements are arranged in said air chamber. The filtration elements are arranged so as to make fluid communication with air displaced into the air chamber and, to make fluid communication with air displaced out of said chamber so that air is cleaned as it passes both into, and out of, the air chamber. The filtration elements actively remove particulate or gaseous pollutants. Embodiments of the invention may comprise a plurality of such air chamber assemblies, arranged so as to collectively deliver a continuous flow of air to a breathing zone of the user.