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The term inert gas is context-dependent because several of the inert gases, including nitrogen and carbon dioxide, can be made to react under certain conditions. [1] [2] Purified argon gas is the most commonly used inert gas due to its high natural abundance (78.3% N 2, 1% Ar in air) [3] and low relative cost.
Hazards with inert gases and the risks of asphyxiation are well-established. [4] An occasional cause of accidental death in humans, inert gas asphyxia has been used as a suicide method. Inert gas asphyxia has been advocated by proponents of euthanasia, using a gas-retaining plastic hood device colloquially referred to as a suicide bag.
Many gases have toxic properties, which are often assessed using the LC 50 (median lethal concentration) measure. In the United States, many of these gases have been assigned an NFPA 704 health rating of 4 (may be fatal) or 3 (may cause serious or permanent injury), and/or exposure limits (TLV, TWA/PEL, STEL, or REL) determined by the ACGIH professional association.
Because asphyxiant gases are relatively inert and odorless, their presence in high concentration may not be noticed, except in the case of carbon dioxide (hypercapnia). Toxic gases, by contrast, cause death by other mechanisms, such as competing with oxygen on the cellular level (e.g. carbon monoxide ) or directly damaging the respiratory ...
The noble gases have also been referred to as inert gases, but this label is deprecated as many noble gas compounds are now known. [6] Rare gases is another term that was used, [7] but this is also inaccurate because argon forms a fairly considerable part (0.94% by volume, 1.3% by mass) of the Earth's atmosphere due to decay of radioactive ...
The noble gases helium, neon, argon, krypton, xenon are nonreactive and have no known direct biological role — albeit xenon nevertheless very surprisingly exhibits both anesthetic and neuroprotective side-effects despite usually being considered "chemically inert," and can activate at least one human transcription factor. (Radon is ...
Decompression sickness can occur after an exposure to increased pressure while breathing a gas with a metabolically inert component, then decompressing too fast for it to be harmlessly eliminated through respiration, or by decompression by an upward excursion from a condition of saturation by the inert breathing gas components, or by a ...
Inert gas continues to be taken up until the gas dissolved in the tissues is in a state of equilibrium with the gas in the lungs (see: "Saturation diving"), or the ambient pressure is reduced until the inert gases dissolved in the tissues are at a higher concentration than the equilibrium state, and start diffusing out again. [2]