Editing Altitude sickness (section)

=== Oxygen enrichment ===
In high-altitude conditions, oxygen enrichment can counteract the hypoxia related effects of altitude sickness. A small amount of supplemental oxygen reduces the equivalent altitude in climate-controlled rooms. At {{convert|3400|m}} ({{convert|67|kPa|atm|abbr=on|disp=or}}), raising the oxygen concentration level by 5% via an [[oxygen concentrator]] and an existing ventilation system provides an effective altitude of {{convert|3000|m|-3|abbr=on}} ({{convert|70|kPa|atm|abbr=on|disp=or}}), which is more tolerable for those unaccustomed to high altitudes.<ref name="pmid7777705">{{cite journal |vauthors=West JB |title=Oxygen enrichment of room air to relieve the hypoxia of high altitude |journal=Respiration Physiology |volume=99 |issue=2 |pages=225–32 |date=February 1995 |pmid=7777705 |doi=10.1016/0034-5687(94)00094-G}}</ref>

Oxygen from gas bottles or liquid containers can be applied directly via a nasal cannula or mask. Oxygen concentrators based upon [[pressure swing adsorption]] (PSA), VSA, or vacuum-pressure swing adsorption (VPSA) can be used to generate the oxygen if electricity is available. Stationary oxygen concentrators typically use PSA technology, which has performance degradations at the lower barometric pressures at high altitudes. One way to compensate for the performance degradation is to use a concentrator with more flow capacity. There are also portable oxygen concentrators that can be used on vehicular DC power or on internal batteries, and at least one system commercially available measures and compensates for the altitude effect on its performance up to {{convert|4000|m|abbr=on}}. The application of high-purity oxygen from one of these methods increases the partial pressure of oxygen by raising the [[FIO2|FiO<sub>2</sub>]] (fraction of inspired oxygen).