where does this sickness mostly arise from?
DCS most commonly refers to problems arising from underwater diving decompression, but may be experienced in other depressurisation events such as emerging from a caisson, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft.
Decompression sickness
DCS most commonly refers to problems arising from underwater diving decompression (i.e., during ascent), but may be experienced in other depressurisation events such as emerging from a caisson, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. 
two scuba divers are 50 m below the surface of the water UNANSWERABLE what is this sickness about? It is a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation what are some of the causes this sickness? Reduction in ambient pressure and when leaving a high-pressure environment, ascending from depth, or ascending to altitude. how does this pressure react to the atmosphere? Within the atmosphere, the ambient pressure decreases as height increases. how can one calculate this pressure? In fields such as meteorology and underwater diving, it is common to see ambient pressure expressed in bar or millibar. One bar is 100 kPa or approximately ambient pressure at sea level what are some of the signs of the sickness? Joint pain accounts for about 60% to 70% of all altitude DCS cases, with the shoulder being the most common site for altitude and bounce diving, and the knees and hip joints for saturation and compressed air work. how often do people suffer from it? UNANSWERABLE
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Decompression sickness [SEP] Introduction
Decompression sickness (DCS; also known as divers' disease, the bends, aerobullosis, or caisson disease) describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation. DCS most commonly refers to problems arising from underwater diving decompression (i.e., during ascent), but may be experienced in other depressurisation events such as emerging from a caisson, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness. Since bubbles can form in or migrate to any part of the body, DCS can produce many symptoms, and its effects may vary from joint pain and rashes to paralysis and death.