ATMOS

ATMOS devices were used in the plans of the Sontarans to invade Earth in 2009. ATMOS devices were fitted to automobiles to reduce carbon dioxide emmissions. Their ulterior usage was that they were to be used as weapons by the Sontarans, as it gave them control over the cars and released poisonous fumes. The ATMOS devices were sold to Humans by the company owned by Luke Rattigan, supposed to be his own invention. (DW: The Sontaran Stratagem / The Poison Sky)

Behind The Scenes
ATMOS is a major plot element of The Sontaran Stratagem / The Poison Sky. However, the word "ATMOS" first appeared on a taxi in Partners in Crime.