Atmospheric processors, atmosphere processors, or simply air filters were devices used to modify the atmosphere of an environment. Some types were used in terraforming to make the atmosphere of a planet more suitable for life. Others may be used to remove pollutants from the atmosphere of an inhabited planet. (VOY: "Friendship One")
The AP 350 was a type of atmospheric processor, invented in 2234 and first deployed following the Crestbrock mining collapse on Titan. In 2259 an AP 350 was transported to Finibus III to prevent its atmosphere from becoming unbreathable, but this mission was cancelled or postponed following the massacre of the colony by the Gorn. (SNW: "Memento Mori")
Starships incorporate atmospheric processors such as the oxygen recycler to maintain habitability on the ship. (ENT: "Exile")