It is used to gather anaesthetic gases, after it is exhaled from the patient or left the area of the patient, and transport it to the atmosphere, skipping the closed environment of the operating room.
In the operating room the anaesthetic gas scavenging system collects and removes waste gases from the patient breathing circuit and the patient ventilation circuit.
In most jurisdictions, there is a legal requirement to scavenge waste gases to maintain the level of waste gases in the operating room below the legally acceptable limit.
For example, in the UK the limits are typically 100ppm for nitrous oxide and 50ppm for halogenated volatile anaesthetic agents (except halothane which is 10ppm).
[citation needed] The basic functional components of an anaesthetic gas scavenging system are as follows: