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  2. Effects of high altitude on humans - Wikipedia

    en.wikipedia.org/wiki/Effects_of_high_altitude...

    Room air at altitude can be enriched with oxygen without introducing an unacceptable fire hazard. At an altitude of 8000 m the equivalent altitude in terms of oxygen partial pressure can be reduced to below 4000 m without increasing the fire hazard beyond that of normal sea level atmospheric air.

  3. Armstrong limit - Wikipedia

    en.wikipedia.org/wiki/Armstrong_limit

    At 11,900 m (39,000 ft), breathing pure oxygen through an unsealed face mask, one is breathing the same partial pressure of oxygen as one would experience with regular air at around 3,600 m (11,800 ft) above sea level [citation needed]. At higher altitudes, oxygen must be delivered through a sealed mask with increased pressure, to maintain a ...

  4. Alveolar–arterial gradient - Wikipedia

    en.wikipedia.org/wiki/Alveolar–arterial_gradient

    For example, in high altitude, the arterial oxygen PaO 2 is low but only because the alveolar oxygen (PAO 2) is also low. However, in states of ventilation perfusion mismatch, such as pulmonary embolism or right-to-left shunt, oxygen is not effectively transferred from the alveoli to the blood which results in an elevated A-a gradient.

  5. Cabin pressurization - Wikipedia

    en.wikipedia.org/wiki/Cabin_pressurization

    At this altitude, there is about 25% less oxygen than there is at sea level. [5] Hypoxia may be addressed by the administration of supplemental oxygen, either through an oxygen mask or through a nasal cannula. Without pressurization, sufficient oxygen can be delivered up to an altitude of about 40,000 ft (12,192 m).

  6. Useful conversions and formulas for air dispersion modeling

    en.wikipedia.org/wiki/Useful_conversions_and...

    As an example, given a concentration of 260 mg/m 3 at sea level, calculate the equivalent concentration at an altitude of 1,800 meters: C a = 260 × 0.9877 18 = 208 mg/m 3 at 1,800 meters altitude Standard conditions for gas volumes

  7. High altitude breathing apparatus - Wikipedia

    en.wikipedia.org/wiki/High_altitude_breathing...

    An oxygen partial pressure equivalent to sea level can be maintained at an altitude of 10,000 metres (34,000 ft) with 100% oxygen. Above 12,000 metres (40,000 ft), positive pressure breathing with 100% oxygen is essential, as without positive pressure even very short exposures to altitudes above 13,000 metres (43,000 ft) lead to loss of ...

  8. Altitude sickness - Wikipedia

    en.wikipedia.org/wiki/Altitude_sickness

    Altitude acclimatization is the process of adjusting to decreasing oxygen levels at higher elevations, in order to avoid altitude sickness. [17] Once above approximately 3,000 metres (10,000 ft) – a pressure of 70 kilopascals (0.69 atm) – most climbers and high-altitude trekkers take the "climb-high, sleep-low" approach.

  9. Density altitude - Wikipedia

    en.wikipedia.org/wiki/Density_altitude

    The density altitude is the altitude relative to standard atmospheric conditions at which the air density would be equal to the indicated air density at the place of observation. In other words, the density altitude is the air density given as a height above mean sea level .