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In this test chamber, air pressure drops suddenly to that of the atmosphere at 60,000 ft (18,000 m). Air humidity immediately condenses into fog, which within seconds evaporates back into gas. The term uncontrolled decompression here refers to the unplanned depressurisation of vessels that are occupied by people; for example, a pressurised ...
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. [1] [2] Fog can be considered a type of low-lying cloud usually resembling stratus and is heavily influenced by nearby bodies of water, topography, and wind conditions.
Sudden drop in ambient pressure during an ascent to the surface from a 6 m final stop on oxygen. A shift from breathing oxygen at the final 6 m decompression stop at a partial pressure of 1.6 bar to breathing air at the surface with a partial pressure of 0.2 bar, could have vasodilatory effects during the period directly after surfacing.
At very high altitude, from 3,500 to 5,500 metres (11,500 to 18,000 ft) arterial oxygen saturation falls below 90% and arterial P O 2 is reduced to the extent that extreme hypoxemia may occur during exercise and sleep, and if high altitude pulmonary edema occurs. In this range severe altitude illness is common. [2]
Hypoxia (hypo: "below", oxia: "oxygenated") refers to low oxygen conditions. Hypoxia is problematic for air-breathing organisms, yet it is essential for many anaerobic organisms. Hypoxia applies to many situations, but usually refers to the atmosphere and natural waters.
Humid air is less dense than dry air because a molecule of water (m ≈ 18 Da) is less massive than either a molecule of nitrogen (m ≈ 28) or a molecule of oxygen (m ≈ 32). About 78% of the molecules in dry air are nitrogen (N 2). Another 21% of the molecules in dry air are oxygen (O 2). The final 1% of dry air is a mixture of other gases.
An oxygen molecule is split by higher frequency UV light (top end of UV-B, UV-C and above) into two oxygen atoms (see figure): 1. oxygen photodissociation: O 2 + ℎν (<242 nm) → 2 O. Each oxygen atom may then combine with an oxygen molecule to form an ozone molecule: 2. ozone creation: O + O 2 + A → O 3 + A
About 90% of total ozone in the atmosphere is in the stratosphere, and 10% is in the troposphere. [5] Although ground-level ozone is less concentrated than stratospheric ozone, it is of concern because of its health effects. [6] Ozone in the troposphere is considered a greenhouse gas, and as such contribute to global warming.