Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.
Air is the most common and only natural breathing gas. Other artificial gases, either pure gases or mixtures of gases, are used in breathing equipment and enclosed habitats such as SCUBA equipment, surface supplied diving equipment, recompression chambers, submarines, space suits, spacecraft, medical life support and first aid equipment, high-altitude mountaineering and anaesthetic machines.
Most breathing gases are a mixture of oxygen and one or more inert gases. Other breathing gases have been developed to improve on the performance of air by reducing the risk of decompression sickness, reducing the duration of decompression stops, reducing nitrogen narcosis or allowing safer deep diving.
A safe breathing gas for hyperbaric use has three essential features:
- it must contain sufficient oxygen to support life, consciousness and work rate of the breather.
- it must not contain harmful gases. Carbon monoxide and carbon dioxide are common poisons in breathing gases. There are many other possibilities.
- it must not become toxic when being breathed at high pressure such as when underwater. Oxygen and nitrogen are examples of gases that become toxic under pressure.
The techniques used to fill diving cylinders with gases other than air are called gas blending.
Read more about Breathing Gas: Common Diving Breathing Gases, Unwelcome Components of Breathing Gases, Moisture Content, Gas Detection and Measurement
Famous quotes containing the words breathing and/or gas:
“Mark the babe
Not long accustomed to this breathing world;
One that hath barely learned to shape a smile,
Though yet irrational of soul, to grasp
With tiny finger—to let fall a tear;
And, as the heavy cloud of sleep dissolves,
To stretch his limbs, bemocking, as might seem,
The outward functions of intelligent man.”
—William Wordsworth (1770–1850)
“A new father quickly learns that his child invariably comes to the bathroom at precisely the times when he’s in there, as if he needed company. The only way for this father to be certain of bathroom privacy is to shave at the gas station.”
—Bill Cosby (20th century)