Final answer:
Gas vans were mobile killing units used by the Nazis to asphyxiate victims with carbon monoxide, aiding in the mass murder of Jews as part of the Final Solution. Introduced in 1941, they complemented the mass shootings by Einsatzgruppen and preceded the establishment of extermination camps that used stationary gas chambers.
Step-by-step explanation:
The gas vans were primarily used by the Nazis as a means of conducting mass murder as part of the Final Solution. Initially introduced in the autumn of 1941, these vans were equipped with engine exhaust systems reconfigured to pump lethal carbon monoxide gas into the sealed cargo compartment containing the victims, often Jews already persecuted through a variety of discriminatory measures. The creation of gas vans came after Nazi Germany invaded the Soviet Union and was a response to the psychological toll experienced by the soldiers of the Einsatzgruppen who were conducting mass shootings of Jewish communities.
The introduction of gas vans was part of a broader shift by the Nazi regime towards more efficient and less psychologically burdensome methods of genocide. The Nazis built extermination camps with stationary gas chambers using Zyklon B and other poisons, which were deemed more efficient for mass murder. Nevertheless, nearly 2.7 million Jews were murdered via gas or shootings at these killing centers, with gas vans playing a critical early role in the logistics of genocide before the establishment of more permanent extermination facilities.